Hot, dry summer continues in California; severe fire season looms; El Niño update

Filed in Uncategorized by on July 6, 2014 323 Comments

Overview of recent conditions

In many ways, the weather over the past few weeks has been pretty typical of early summer in California.

Subtropical moisture continues to stream into California from the southeast. (NOAA/NWS)

Subtropical moisture continues to stream into California from the southeast. (NOAA/NWS)

It’s been hot in the inland valleys, and not so hot near the coast, with a sharp gradient in between. Conditions have been largely dry, though an increasingly moist monsoonal flow has finally brought respectable thunderstorms to some mountain and high desert regions lately. We’ve seen a modest marine layer along the coast, and periodic heat waves inland that have brought sweltering temperatures to Central Valley and southeastern desert communities. None of these events is particularly noteworthy for late June and early July.

 

Drought update

Despite this semblance of pseudo-normality, though, there are a number of rather stark reminders that conditions are far from what would normally be expected this time of year.

California's record-warmest year continued into June 2014. (NOAA/DRI)

California’s record-warmest year continued into June 2014. (NOAA/DRI)

California continues to endure its warmest year on record to date (as of May 31st; I’ll update this point in a day or so when the official June numbers become available). Huge wildfires are burning with an intensity not normally witnessed until the driest days of September and October, and various metrics suggest that wildfire risk in many regions is at or near record high levels. The Sierra snowpack is long gone–and snowmelt-driven river and streamflows into the state’s reservoirs continue to plummet. An even greater fraction of California is experiencing “exceptional” (i.e. maximum-severity) drought conditions than just a few weeks ago–a region which now includes both the San Francisco Bay Area and the greater Los Angeles Metro area. Given California’s distinct wet winter/dry summer climatology, it’s extremely unlikely that this overall picture will change much between now and the start of the next rainy season.

West-east wind anomalies over the northeastern Pacific Ocean since May 1. (NCEP/ESRL)

West-east wind anomalies over the northeastern Pacific Ocean since May 1. (NCEP/ESRL)

A persistent dipole wind anomaly continues to bring anomalous northerly flow over California. (NCEP/ESRL)

A persistent dipole wind anomaly continues to bring anomalous northerly flow over California. (NCEP/ESRL)

Persistent ridging continued during May and June over the North Pacific. (NCEP/ESRL)

Persistent ridging continued during May and June over the North Pacific. (NCEP/ESRL)

 

 

 

 

 

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Medium-term outlook

Monsoonal moisture continues to stream northwestward over much of California this evening, and will continue to do so periodically over the next week or more. High mountain and some high desert regions have already experienced some locally intense thunderstorm activity in association with this moisture, but precipitation coverage overall has been quite sparse. There is a slight possibility that some of this moisture could spark some mostly dry, high-based convection over the next 72 hours over parts of northern and central California, which would of great concern fire weather-wise. However, at the moment it doesn’t look like we’re headed for a major “lightning bust” in the immediate future.

Hot to very hot conditions will continue over interior California, with widespread 100+ temperatures expected for much of the coming week. While this heat won’t extend all the way to the coast (where a shallow marine layer will keep things seasonably cool), the state overall will remain considerably warmer than average. Some moderation will probably occur late this week as a weak trough develops off the coast of California, but conditions will remain quite warm inland.

There has been some suggestion in recent numerical model forecasts that a more substantial push of southeasterly winds/monsoonal moisture may affect California during the first half of July.  A slow-moving upper-level low may develop off the coast towards the end of the coming week, which may turn flow to the south or southeast over California  by next weekend. If this relatively moist southeasterly flow from the Gulf of California and Desert Southwest can interact with some weak instability generated by the offshore low, there may be the possibility of a more widespread elevated convective event at some point in the 6-10 day period. Recent solutions have become a little less consistent regarding this possible evolution, but this probably bears close watching over the next week or so. I’ll have an update if this starts to appear more likely.

 

El Niño update

After a remarkably rapid warming of Eastern Pacific sea surface temperatures during early June as the powerful Kelvin wave from earlier this year surfaced, SST anomalies have recently begun to decrease. This has occurred because the large subsurface temperature anomalies have largely exhausted themselves and have not recently been reinforced by new warm water from the West Pacific. This evolution is consistent with recent coupled atmosphere-ocean model projections, but is somewhat different than what had been projected a couple of months ago, when more consistent warming was expected.

Animation of 4-month global SST anomalies. Note persistent N. Pacific warm pool and developing equatorial El Nino signature. (NOAA)

Animation of 4-month global SST anomalies. Note persistent N. Pacific warm pool and developing equatorial El Nino signature. (NOAA)

There’s a lot of speculation presently surrounding the “demise of El Niño” on the basis of this recent development, which I’d argue is just as premature as the equally confident headlines which–just a few short months ago–called for a “mega/monster/hyper El Niño” later this year. The reality is: the ocean-atmosphere system is very complex and responds to both foreseeable longer-term forces and unforeseeable random ones. What does this mean in the present context? Well, so-called “westerly wind bursts”–which help to enhance developing El Niño events by disrupting the prevailing equatorial trade winds and allowing warm West Pacific water to “slosh” eastward–typically result from individual low pressure systems (sometimes typhoons) that spin up in the West Pacific.

Large positive SST anomalies exist along the Southern California coast. (NOAA)

Large positive SST anomalies exist along the Southern California coast. (NOAA)

These sorts of events–which fall under the purview of “weather,” since they evolve on timescales of a few days to perhaps a week–are very difficult to predict more than a week in advance, yet they are fundamentally important to ENSO’s evolution. While we did finally witness a new (but fairly weak) westerly wind burst over the past week, the continued evolution toward an El Niño state will require additional and sustained westerly wind bursts later this summer, and we don’t yet know if that’s going to occur. The dynamical models appear to think so–since the ensemble mean remains fairly bullish in predicting a moderate-to-strong event by next winter (and, interestingly, above-normal precipitation in coastal California during the same time frame).

However, as recent events have demonstrated quite clearly, the real world sometimes deviates from even our most reasoned expectations. There are a few things we can say with high confidence about conditions over the next few months, though. Sea surface temperature will likely remain quite elevated in the Eastern Pacific (including along the coast of Southern California, where water temperatures are currently as high as the upper 70s in San Diego Bay, and a very impressive 3-6 F above normal across a wide region).

Recent CFS model projections hint at early signs of a wetter-than-average DJF 2014-2015. (NOAA/NCEP/CPC)

Recent CFS model projections hint at early signs of a wetter-than-average DJF 2014-2015. (NOAA/NCEP/CPC)

This will probably keep near-coastal regions in the southern part of the state warmer than usual for the remainder of summer, and may allow for a higher-than-usual likelihood of tropical cyclone remnant moisture to affect California for the rest of summer and early fall.

Finally, recent trends and current model projections suggest that SST anomalies by the fall and winter months may be quite different across the North Pacific than in recent years–more reminiscent of the positive phase of the Pacific Decadal Oscillation than of the negative phase, which has been the prevalent condition since the last big El Niño ended in 1998. Historically, such SST configurations have favored wetter winters in California, though it’s not at all clear that this will be the case in 2014-2015. For now, it’s probably wisest to prepare for what will nearly certainly be a hot, very dry 3 months to come.

As a quick reminder: for frequent weather/climate micro-updates through the summer, follow Weather West on Twitter and Facebook!

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  • fssbob

    Thanks for your exceptionally clear (especially for a layperson like myself) weather/climate postings.

  • Pingback: California Weather Blog: Hot, dry summer continues in California; severe fire season looms; El Niño update » MAVEN'S NOTEBOOK | MAVEN'S NOTEBOOK

  • Kamau40

    Dan-
    Another great updated post! Thank you.

    • craig matthews

      Ditto on that! I refer so many people to his posts. So good!

      • Kamau40

        Read my latest blog about the current status on El Niño. I’m now starting to have doubts about a strong ENSO event. The sub surface temp in the Tropical Pacific Ocean is cooling based on latest observations(hence, not a good sign for a strong event.) My other concern is that the WWBs are currently weak to produce another strong oceanic Kelvin Wave and the atmosphere is currently not responding to the warmer ocean water like it should at this time. This supports your earlier concerns too about a week ago. At this time though I think it is still premature to say we won’t have a major event, but if we do not get another strong oceanic Kelvin Wave within the next couple of months then we have to reconsider of the possibility we will not have a strong ENSO event.

  • Kamau40

    Lots of alto-cumulus clouds from monsoonal moisture have made it all the way up here in the North Bay counties. Folks, this could be an interesting week weather wise for the state. Stay tuned.

  • Joseph B.

    Great clouds today.

  • Xerophobe

    Radar appears to have lit up entire east side of Diablo range. Eastern Sierra’s and some on the west foothills of Sierra.

    http://radar.weather.gov/radar.php?product=NCR&rid=dax&loop=yes

  • snow755

    https://www.facebook.com/snow755/media_set?set=a.10202449471298089.1073741827.1233349411&type=3&uploaded=3

    this been out two new melons two see what the lake was and wow we are setting at 895! olny 70ft drop more be for we can see the old bridge has there uesd to be a old town wish is now under water if this lake drops even more this will turn back in two the S fork or n fork river not good news but at the same time i find it cool has i was not around at the time when it was a river be for they made the dam that flooded that town

  • Kamau40

    To further add weight to what Dan had posted above regarding the current severe-extreme Ca. drought, below are the actual latest data/facts regarding the state’s precipitation and water levels closing out 2013-14 rainfall year. It was ranked as the 3rd driest in history and indeed one of the driest years in modern history. I’m still very shocked that the state has not yet enforced mandatory water rationing, but I’ll bet that will change within the next 2-3 months when we approach the height of the dry season.
    http://www.wunderground.com/blog/weatherhistorian/comment.html?entrynum=288

  • http://www.weatherwest.com/ Weather West

    New ECMWF runs very aggressive with monsoonal push next week.

  • craig matthews

    18zGFS back on to possible big monsoonal push in a little over a week from now. Is this a similar scenario the ECMWF is showing, that Dan is talking about? Can’t get access to ECMWF now, anyone have a link?

    • so.cal.storm.lover

      Does this monsoonal surge include so cal more specific the valleys in so cal.

      • craig matthews

        Models are flipping around a bit on the idea, but the general theme is a pretty decent monsoon moisture surge from the southeast moving up over the entire state next week.

      • craig matthews

        It looks like a chance of convection for the whole state next week, including the coastal valleys. But we will see if that really happens. Its over 7 days out.

  • Bandini

    Dark clouds and the occasional droplet in Truckee.

  • Jeff

    What, if any, impact could that exceptional typhoon affecting the western pacific have on our current weather pattern or future El Nino-ish indicators?

    Excellent blog!

    • http://www.weatherwest.com/ Weather West

      Little impact on El Nino. Might temporarily enhance atmospheric wave pattern over Pacific ocean next week, which may play into the possible monsoonal surge in 6-7 days.

  • lightning10

    Me and my friend John went out and storm chased. Here is a picture near Newberry Springs, CA. We saw 10 or so CG’s lightning strikes. This was on Saturday.

    I have a question regarding lightning in July. This is just a thought but I have noticed that lightning isn’t as frequent in July storms. Is this because the lack of cold air even at upper levels? I do remember reading that lightning gets going best when the top of the clouds cool around sunset.

  • Guest

    Here is that picture it failed for some reason.

  • Guest

    Lets try this again.

  • lightning10

    Lets try one more time. Most of that lightning was in the rain shaft.

    http://img.photobucket.com/albums/v681/packerfan10/DSC08826_zps08e38cd0.jpg

    • TheNothing

      I clicked on your photobucket picture and you turned into a hot chick in lingerie, good times.

  • Kamau40

    Very interesting information about the current El Nino status. I’m increasingly beginning to think that the upcoming winter precipitation signals are up in the air now even more so now than a month ago. In other words, we just don’t know, which has also been my argument all along. We will have a much better idea I think by Oct. Furthermore, Andrew from weathercentre who once supported the idea of a strong event a few months ago is also starting to having doubts too along with Howard Schectner. Review their blogs below.
    http://theweathercentre.blogspot.com/2014/07/el-nino-in-serious-trouble-upcoming.html
    http://mammothweather.com/

    • http://www.weatherwest.com/ Weather West

      It’s silly to talk about California precipitation signals for a weak El nino event: there are none.

      • Kamau40

        Howard has been doing weather in Ca for over 35yrs in the Mammoth Mountain area. The context of his blog is very clear that he is not making any kind of prediction for precipitation for the state. He’s just simply going by his experience over many years of observation of what could happen to the jet steam and precipitation outcome for the state which is what I have also observed over the years too during weak El Niño patterns. We really won’t have a good idea of what type of weather pattern we could have for the upcoming until about Oct or Nov.

  • Kamau40

    The AMO has trended more strongly positive now at 0.85. Still waiting for June values for the PDO which should be coming out shortly.
    http://www.esrl.noaa.gov/psd/data/correlation/amon.us.data

    • Dan the Weatherman

      We can get a wet winter with a +AMO, +PDO regime in Socal and that happened during the Dust Bowl Era several times (1934-35, 1936-37, and 1937-38) and those were ENSO neutral years as well. What I am worried about for next winter is if El Nino fails miserably and we have another ENSO neutral or weak El Nino bone dry winter with the atmosphere having the memory of last year’s -PDO, +AMO pattern. From looking at past records, it seems that the atmosphere takes about a year to respond to a change in the PDO and/or AMO. If we can get at least a moderate El Nino, then the odds of a wetter winter increase quite a bit even though it is not a guarantee.

      • Kamau40

        Yes, your analysis is correct based on what I have studied and researched. In addition, if El Niño fails miserably and the PDO starts trending backed to negative territory(which is certainly very possible) based from a historical perspective, as much as I hate to think or say it these trends could very well mean the potential for another dry winter ahead for us. I’m still waiting to find out what the actual latest PDO values for June were.

        • Dan the Weatherman

          The last thing I want to see is the PDO to go negative and the AMO to remain positive. Another -PDO, +AMO, ENSO neutral or weak ENSO year would almost certainly spell doom for California! It would aggravate me to no end if we have that combination again.

          • Kamau40

            Dan-
            I totally agree with you on your statement above. I will be praying that we do not have another episode of -PDO, +AMO neutral or weak ENSO. We already know what the end result will be after what has happened over the past 3yrs, especially what we just experienced this past winter. I think by the time we get to Oct or Nov we will have the best assessment and prediction of how the upcoming winter season will play out.
            Right now it is still too early to tell how the new precipitation year will go. This is why we need to continue to watch what happens regarding the strength of the ENSO, the phases of the PDO/AMO.

          • Dan the Weatherman

            After the failed El Nino attempt in late 2012 that went ENSO neutral, 2012-13 turned out to be the 6th driest year on record for Los Angeles and was just as dry in most of Socal.

  • so.cal.storm.lover

    Does anyone know if the new tropical storm off the coast of mexico will affect our weather or help enhance next weeks monsoon surge?

    • http://www.weatherwest.com/ Weather West

      It could, though it might be a little too early. GFS once again trending toward ECMWF in bringing a significant surge of moisture northward days 6-9.

      • so.cal.storm.lover

        Hopefully the models are right we need rain!!

        • http://www.weatherwest.com/ Weather West

          In any case significant rainfall would be very unlikely. These sorts of events are more noted for lightning and scattered light showers, which is typically not good news for fire weather concerns.

          • so.cal.storm.lover

            Unless if the tropical storm was to hit so cal as it least a depression (which is very unlikely).

          • snow755

            did you see my facebook pages of the photos i took ?

            https://www.facebook.com/snow755

  • xeren

    anyone notice that the PDO went negative again? :(

    http://www1.ncdc.noaa.gov/pub/data/cmb/teleconnections/pdo-5-pg.gif

    • Kamau40

      I’m still waiting for what the latest PDO June values were. If it is true the values are going back to the negative phase territory and remains there for the rest of the year, which is certainly possible that would not be a good sign for both the strength of the ENSO and the precipitation signals for Ca for the upcoming winter. It something we have to keep in mind for sure in the coming months.

      • xeren

        Unless I’m counting the bars wrong, I believe it is already showing the June value, which is negative

        • Kamau40

          I’m still waiting for the official values for June which should come out any day now. According to Dan and other sources, the PDO is still in its negative phase. However, I have mentioned in a previous blog awhile back that the PDO can easily trend back to negative later in the year because the positive phase is not a constant. Dan has also mentioned several times before that we don’t know if the current positive phase is temp or long term.

  • Ian Alan

    I’m with Dan – I’d go crazy if we had another dry year. Just couldn’t stand it, I’m already losing too much hair. LoL

  • Bandini

    Couple sprinkles today, blah. The heat seems to really be the story right? My place was roasting last night.

  • Kamau40

    A similar weather pattern, much like what we had in Jan is developing? The other very interesting feature to note is that the ridge of high pressure or “RRR” associated with the very warm waters in the Gulf of Alaska is still present. Something I think should be kept in mind approaching the upcoming winter.
    http://theweathercentre.blogspot.com/2014/07/unseasonable-cold-blast-looming-pattern.html

    • http://www.weatherwest.com/ Weather West

      Yep. Very RRR-like, with a strong North American Dipole. Has different consequences during the summer, though, and it may help to enhance the monsoonal push next week. This time, there is a clearer large-scale forcing: the injection of energy into the Westerlies by the decaying super typhoon near Japan.

  • craig matthews

    I don’t know if the ssta taken July 7 is sending here. Anyway, El Nino or Not, Positive PDO or not, we aren’t going to know probably till September,,,,maybe, what “might” happen. Seams like there is something out there that prevents the atmosphere from fully switching into El Nino mode. Now colder waters re surfacing between pt conception and Hawaii and the North Pacific Warm pool is kind of retrograding and flattening a bit. Which to me kinda looks like might affect the PDO in a negative way. But. Hard to really pin down what is really going on out there. Seams like the whole pattern across the pacific both in the ocean and in the atmosphere wants to make a big shift, but, oh wait, something is not allowing that to fully occur. Wish we could figure out what “it” is.

  • craig matthews

    GFS is being more consistent with potential monsoon moisture surge next week as Dan earlier mentioned a couple days ago. This models shows 500mb heights, wind, and rh early next week. But gives us an idea of what might happen early next week, as the 4 corners ridge expands, or elongates to the west northwest placing eventually almost all of California in a deep southeast flow. These set ups, if all the elements line up right with the weak trough offshore, could produce thunderstorms just about anywhere in California. The action would first start in socal and migrate northwest over the whole state.

    • Kamau40

      Models seem to be very consistent on the poss. of a strong moonsonal surge for Ca. This is the 3rd day in a row the models have been hinting at this idea. So far though, the local weather forecast are not mentioning anything about this yet probably because it is still 5 days out. If the models continues to be consistent over the next 2 days, we should start seeing this come up in the local weather forecasts.

      • craig matthews

        18zGFS even more bullish! And keeps a prolonged southeast flow over California going way out to day 8 or 9. Also, the high latitude blocking pattern that you mentioned earlier seeing in January that is repeating itself now is a good set up for California to see more periodic monsoon surges, as the ridge center is to our north, placing us in more southeast and even easterly flow regimes. This could turn out to be quite an active summer for California. But we shall see.

        • Kamau40

          Yes, projected “dipole” setup pattern for next week is quite interesting because it may continue for the rest of the Summer and may help give us more tropical or moonsonal moisture surges. Something to keep in mind indeed.

        • Dan the Weatherman

          While this pattern may be good for summer monsoonal surges, I hope it doesn’t set up again in the winter months that results in the 3rd ultra dry winter in a row.

          • Kamau40

            Dan
            Exactly correct. This is definitely not a pattern we want setup again for this winter or else we will be in very Big Trouble.

          • Dogwood

            It’s right there- the elephant in the room.
            The warm Gulf of Alaska waters are not changing, moderating, swishing around, cooling.
            Why expect anything different until that pool changes?
            (Again, amature weather observer disclaimer.)

          • Kamau40

            You’re concerns are very legitimate. It has been my concern in recent days too.

        • Kamau40

          Yes, I’m noticing those trends too.

    • Kamau40

      Craig,
      What particular website(s)do you use to load up these types of model forecasts?

      • craig matthews

        I use the NWS San Francisco office site, then click on the icon that says “models” on the left hand side. That will take you to a selection of computer models. If you like GFS, click on GFS, and take it from there. Hope that works. I will try to get a better ip address for you though. Weather west posted one a while back and I will try to find it for you.

  • Kamau40

    Ken Clark, from accuweather.com, also discusses the very bleak precipitation numbers for Ca. He also mentions with great caution about El Nino and for upcoming winter. Rightly so, he urges that we must conserve as much water as possible and cross our fingers and pray that it rains next winter.
    http://www.accuweather.com/en/weather-blogs/clark/20132014-california-rainfall-season-ends-with-bleak-numbers/29644997

    • craig matthews

      It amazes me how many people don’t realize the magnitude of our water defecate as a state. This has never been seen before. Yet, for some odd reason, it seams to not be such a big deal in the media so far. We get bits and pieces of it. The only people that really understand are the ones who solely depend on it like farmers and ranchers and people with property that have wells on them. I have neighbors that have no water for the first time ever on their property. Their old well dried up the other day

      • http://www.gdanmitchell.com/ G Dan Mitchell

        “…the magnitude of our water defecate…” Yikes! Typo alert! ;-)

        • craig matthews

          Hah, yikes is right! Water deficit. So “deficit is incorrect according to my computers spell check. So how do you spell deficit then??? My spell check says its defecate. Sup with that???

          • Dan the Weatherman

            That’s weird that your computer’s spell check would show deficit being incorrect because that is the correct spelling. Even more strange is that it would suggest the word “defecate” instead, which of course means something entirely different!

          • craig matthews

            Exactly, and it made me so frustrated I just gave up and went with what the computer showed. And that word has a totally different meaning.

      • Kamau40

        It is so true. It amazes me too because I see neighbors almost all of the time wasting water like there is no tomorrow. For example, just a couple of weeks ago, a neighbor was just letting gallons of water run down their drive way into the sidewalk. They were not home and their hose was in the backyard. But, because their gate was locked I couldn’t just turn it off for them. People in this state don’t seem to have a clue the seriousness of this current drought. I’m wandering what kind of world do they think they are living in?? Anyway, it looks like the state is finally going to get tough and enforce emergency water restrictions which tells me some people are slowly starting to wake up regarding our extreme water crisis. See article below.
        http://sacramento.cbslocal.com/2014/07/08/california-considers-fines-of-500-a-day-for-overusing-water-during-drought/

        • xeren

          you could always kink the hose and then tie it in a knot next time :)

          • Kamau40

            Thanks, I will do that in the future.

      • Robin White

        Spoke with a produce distributor last week…one of the biggest in the Salinas Valley. How goes the year? I asked.
        Fine, he replied. Everyone’s using wells to make up the difference between what they need for irrigation and the reduced supplies from the usual sources. Only, well levels are dropping he said. They (the growers) are betting on a wet winter to recharge the aquifer. What happens if it’s not a wet winter? I asked.
        No crops next year, no Salinas Valley, no produce to sell, he replied. Other states are gearing up for this possibility by planting new acreage with ready water supplies. The quality won’t be there,the distributor said, but they’ll have a crop. We won’t.
        Robin White

        • http://www.weatherwest.com/ Weather West

          There really are a lot of people banking on a very wet winter that is statistically quite unlikely. I do still think that a repeat of last winter (i.e. record dryness) is also unlikely, but the reality is that the drought is of such severity that even a pretty wet winter wouldn’t dig out of the hole.

  • Bandini

    40% of “Heavy Rain” in Tahoe/Truckee tomorrow. Fingers crossed but I’ll believe it when I see it!

    • rob b

      I got caught in the storms in Reno Tuesday, heavy rain soaking I80. By the time I got back to Truckee, just some clouds and no rain at all.

      • Bandini

        Yeah it seems to be doing that again. I can see rain falling above and east of the carson range, but pretty quiet here in the basin so far besides a few drops. Hope it moves a little west.

  • Kamau40

    Local weather forecast for Nor Cal is now hinting at poss. moisture surge early next week with the GFS models especially more aggressive. Now with the amplified pattern currently developing in the Northern Hemisphere, it is something bears close watching:

    http://www.wunderground.com/DisplayDisc.asp?DiscussionCode=MTR&StateCode=CA&SafeCityName=Napa

  • http://www.weatherwest.com/ Weather West

    Have a feeling there could be some surprises in terms of thunderstorm coverage over the next 48 hours. That offshore upper low is in a very favorable position, even if in-situ moisture is limited Weather West will update on Twitter if anything unexpected pops up…

    • Bartshe

      Please elaborate. We get drunk on hope while we thirst for rain.

      • http://www.weatherwest.com/ Weather West

        Mountains might get some hefty thunderstorms next 48 hours. Parts of Sac Valley might see some activity, and even slight chance there could be something closer to the Bay Area. I still think the surge slated for days 6-8 has better potential, but in my experience it’s the low-key events that slip in under the radar that sometimes result in the most spectacular lightning events.

        • craig matthews

          September 9, 1999 comes to mind. The 14 hour thunderstorm event over Monterey bay and SFO bay that nobody predicted!

          • craig matthews

            That low was further south though, and did have a little tropical tap from that ts off Baja. A slightly different set up, but there was absolutely no forecast for thunderstorms along the central coast and we ended up having the one of the best lightning displays this area has ever seen: Sept. 9, 1999.

          • so.cal.storm.lover

            Looks like so cal was getting so significant southeast flow at that time too! Looks like it was getting pulled from a tropical storm west of cabo san lucas .

          • craig matthews

            Sorry this satellite picture isn’t as close up as it appears on GIBBS satellite archives, and doesn’t quite do the event justice. But the line of convection that developed from san luis obisbo county up into the bay area the evening of sept 9, 1999 produced the most intense lightning storm I have ever seen in big sur. And with the moisture source being from that tropical storm off cabo, it seams like socal would have had some activity as well.

          • so.cal.storm.lover

            It would be epic to see another light show like that but dangerous fire wise. This setup doesn’t look to be as potent as 1999, is it? Considering we have a tropical storm off the coast of mexico too.

          • so.cal.storm.lover

            Hey that was on 9/9/99 maybe all the nines!! Just kidding. Lol

          • Kamau40

            I remember this convective activity event very well. Note, it happened in Sep ’99, which is the most likely time of the year statistically speaking when these events can occur for Ca. That was an awesome event indeed.

        • Bartshe

          thanks… would be nice to have a front-row seat, but local forecast here is calling for prevailing/dry southwest flow by Friday at Mono/Yosemite area-meanwhile lightning strike starts a small fire in the June Lake Loop at Silver Lake

  • Kamau40

    Here is the latest update regarding El Nino development from NOAA. The bottom line, as we have said many times on this blog and so has Dan(Weather West) the atmosphere-warm ocean water has not yet officially coupled. Until that happens, an El Nino event cannot be declared; but according to NOAA, they are still projecting that to happen by Fall.
    http://www.climate.gov/news-features/blogs/enso/en-so

    • Xerophobe

      There is some activity at about 150E, but it just popped up today and seems innocuous. There is a very good possibility of a technical El Nino, albeit weak.

      It’s been interesting for me to look back at the ENSO model plumes. From mid-December 2013 to Mid June 2014 the dynamic average has for the most part been at El Nino threshold, up to a little over 1.0 with mid-June dropping to under 1.0. mid-July plume, who knows, but it wouldn’t surprise me if it between .5 and 1.0.

      http://iri.columbia.edu/our-expertise/climate/forecasts/enso/

      • Kamau40

        We just don’t know how strong this event will be and it is certainly premature to make any estimation at this time. Realistically, we need to wait until about Sep or Oct which at that time will see how much heat content that the newly weak oceanic Kelvin Wave will produce into the E. Pac ocean.

  • TheNothing

    Thunderstorms are really starting to take shape in the Sierras right now, could be juicy.

    • rob b

      A few Twitter postings had S. Lake Tahoe seeing dark clouds after 2pm. Just before 4pm the dark clouds seem to be making their way towards Truckee. Hopefully there’s plenty of water in these storms!

  • http://www.weatherwest.com/ Weather West

    FYI: there’s a fantastic new real-time lightning site out there which aggregates from personal/crowdsourced lightning detectors to give coverage over the contiguous 48 states (you can see strikes less than 10 seconds after they’ve occurred). The interface is really nice, too.

    http://www.blitzortung.org/Webpages/index.php?lang=en&page_0=30

    This is actually a big deal, since lightning data is one of the few privately-owned forms of weather information in the United States. It has been difficult even as an atmospheric scientist to see this sort of real time data, so I’m glad to see that this is now publicly available. This is one of the many new links that will be included in the much-revamped Links page on this site later this summer.

    Note: make sure to select the “live strikes” option on the left menu.

    • Xerophobe

      Kewl! bookmarked.

    • craig matthews

      This is very awesome! My fire weather friend has had access to something like this in his line of work having to direct firefighters to lightning strikes that could potentially be fire starts. But that was never made public. Maybe this is what the fire weather people have, or something similar?? It was NASA related. Anyway, way cool Dan! So glad to see this come available. Just one more weather “thing” that will keep me up late at night doing what I love to do the most… observing weather phenomena.

      • http://www.weatherwest.com/ Weather West

        This site is probably less reliable since it comes from people’s personal sensors (there are very reliable, privately-owned networks that federal scientists have access to, but these data are a distributed on a pay-per-use basis). However, for casual weather-watching, it certainly does the trick. NASA did recently launch a new satellite capable of detecting lightning, and that data will eventually be in the public domain (since we’ve already paid for it as taxpayers!).

        • craig matthews

          Hope so. If I am paying for it, would be nice if I could use it too.

    • Kamau40

      This is a great resource to have for those who love weather. Thanks!

  • craig matthews

    Interesting article: http://www.nbcnews.com/science/environment/cool-weather-experts-say-polar-vortex-making-comeback-n153246 This may pertain more to folks back east, but this, of course affects us as well. Typhoon Neoguri could be causing a chain reaction of weather shifts….which could be in part the reason for the latest highly amplified pattern that was also seen back in January. However the question is; will the pattern become locked in place as it did in January, for an extended period. We are obviously in a different season, in which the same pattern that was observed in January, that caused warm dry offshore flow regimes in California, could just place us in an extended period of being in a moist southeast flow aloft with a more persistent marine layer along the coast. But, the article is worth reading.

    • Kamau40

      Great article to read. The developing weather pattern is definitely similar to Jan, while we had the “dipole” or polar vortex that kept the West Coast high and dry. Now, the article mentions hot record low high temp in the mid and eastern section of the United States and hot weather on the West Coast next week. But, there is no mentioning of the possibility of a strong moonsonal surge developing and now the local weather forecast is not mentioning that possibility either. Why do you think that is the case??

      • craig matthews

        As the 4 corners ridge expands west northwest over northern California/Nevada early next week, that places at least the southern half of the state in a deep southeast to easterly flow regime for a few days. If this draws monsoon moisture over the state from Mexico and the desert southwest, the question is, will there be any lifting mechanism to generate thunderstorms in areas other then the sierra or highest terrain? Some of the models show a disturbance rotating northwest around the periphery of the ridge that could be a lifting mechanism of monsoon moisture in the mid levels. But not all the models agree on this play out. So perhaps the NWS is waiting to see what will happen before making the call to add clouds and a possibility of thunderstorms to the forecast just yet. But, this is all guess work on my part. I don’t fully understand NWS methods when it comes to potential monsoonal moisture surges.

        • Dan the Weatherman

          If that disturbance (easterly wave) materializes as some of the models are showing, that could provide the dynamics (lifting and instability) needed for developing thunderstorm activity west of the mountains and there could be some nocturnal thunderstorms as well if the timing of everything is right. If there is too much cloud cover, then there may not be as much instability from lack of daytime heating and thunderstorm activity could be less than it could potentially be.

          • Ian Alan

            Nws has my area at 40% chance tstorms for Monday and ‘chance’ continuing at least through wed. Unusual for pops to be that high this far out for a summer monsoon event, usually no pops mentioned or left at 20% until the day before.

            Coolest morning in a month at 53F this morning, feels nice.

          • Zepp

            No convective activity here in the Mount Shasta area, but it is overcast with light sprinkles. Even just a tenth of an inch of rain would be a major delight right now, but we’ll need some luck for that.

            Meanwhile, we’re experiencing near-record warm nights, with lows around 60. Our normal low this time of year is 48, with anything above 55 considered unusual.

        • Kamau40

          Looking at the recent satellite imagery here on the West Coast, it looks like there is a wave of energy developing in Mexico along with plenty of area of monsoonal moisture. The Continental High is also starting to expand westward which we have been discussing over the last couple of days. One of the latest local models here in the North Bay is finally hinting at some instability coming in as early as Sunday night into Mon. Is this the beginning of the big monsoonal moisture surge that is beginning to develop that we have talking about?? See below the latest satellite imagery and local forecast statement:
          http://www.ssec.wisc.edu/data/us_comp/us_comp_big.html

  • Kamau40

    Andrew, from Weather Centre, is already predicting a very similar weather pattern for the winter 2014-15 based upon the current setup(which is generally long term) of the SSTA gradient of both the Pacific/Atlantic Oceans. Note though, which has been mine and other bloggers on this forum concern in recent days now is that Andrew discusses that the persistent ridge of high pressure in the Gulf of Alaska along with the mysterious pool of warm water in the N.E Pacific is likely to remain going thru the winter. He also says that the winter in the Midwest and in the Eastern part of the USA will mostly likely to be more harsh this year. This may mean another “Dipole” type winter is likely to setup. The only difference though is that we will have some type of an EL Nino pattern unlike like last year we were in the neutral phase of the ENSO with a -PDO. Also, we have to watch what happens to the phase of the PDO in the coming months as well. The question the BIG remains, how will these different sst gradients in the Pacific/Atlantic will affect the jet streams this upcoming winter? Any thoughts about all of this information. Review blog below:
    http://theweathercentre.blogspot.com/2014/07/upcoming-winter-shaping-up-similar-to.html

    • Dan the Weatherman

      If we have a strong enough El Nino, then we may have an energized southern branch of the jet stream along with the subtropical jet stream that would undercut that ridge in the Gulf of Alaska to help bring rain to CA. I believe that in some El Nino years in the past, the ridge has set up over western Canada with the jet undercutting it into CA.

      1977-78 was another harsh winter in the Midwest and East Coast region, and yet Los Angeles recorded over 33″ of rain that season after CA overall experienced one of its driest years on record in 1976-77.

      • Kamau40

        Great answer. Let’s hope that happens.

      • Kamau40

        Yes, there has indeed been some years which I have seen where the ridge would setup over Western Canada and the jet stream undercutting right into Ca. Perhaps that will happen this winter with that persistent ridge in place with a strong enough ENSO and that the PDO remains in its positive phase.

    • craig matthews

      The same persistent blocking ridge in the north pacific that has been bringing severe drought to California can also bring severe flooding to California. It all depends on strength, size, and positioning of the ridge axis or center, and the strength and placement and extension of the Asian jet as it moves into and across the north pacific basin. If this persistent blocking ridge were to retrograde, allowing both the polar branch from the north out of Canada, and the pacific jet and associated westerlies flowing under the ridge to break through and merge over California, combining continental polar and maritime air, we would be looking at prolonged very wet conditions across the state.

      • Kamau40

        Yep, all of your above statements are correct. I was hoping we would see the correct setup last winter and there were some attempts for that to happen, but failed to materialize. I really do believe that Neutral ENSO, -PDO and +AMO combo is part of the BIG reason we did not see the westerlies break through like we have witnessed in years past. So far though, the setup of the major global tele-connections are quite different than what we have seen in the last few years. It does gives us a glimmer of hope that we will have a different weather pattern setup for Ca. this winter.

    • http://www.weatherwest.com/ Weather West

      I’m not convinced that the RRR has been caused by the North Pacific warm pool. The two certainly appear to be related–and there is probably some degree of positive reinforcement between them–but there is evidence that the ultimate causal mechanism for the ridging is the pre-El Nino conditions in the West Pacific:

      http://www.wunderground.com/blog/JeffMasters/california-droughtpolar-vortex-jet-stream-pattern-linked-to-global-wa

      The Wang et al. paper is the only one currently out on the CA drought, though ours has been accepted for publication in September and I know other groups are working on the same question (and will probably have papers out by the fall). If, indeed, a substantial component of the RRR pattern stems from West Pacific teleconnections, then the coming winter is likely not to be a repeat of the past winter (regardless of how El Nino does/doesn’t evolve over the next few months, we definitely won’t be in a “pre-El Nino” state anymore). That said, the amplified dipole pattern (of which the RRR comprises the western half) does appear to be becoming more common as a result of climate change.

      In any event, I have a strong suspicion that that SST configuration in the Pacific this fall/winter will indeed look quite different from last year’s, and thus an exact replication of atmospheric conditions is unlikely. I’m still planning on having a more in-depth post of the RRR in a broader context sometime during September.

      • Unbiased Observer

        Is the current strong ridging that we have been experiencing so far this summer a continuation of the RRR because we have not transitioned yet to an El Nino state in the atmosphere?

      • Dan the Weatherman

        From looking at the jet stream pattern illustration that is posted in the article linked to above, it looks to me as if a moderate strength or greater El Nino pattern would have enough of a southern jet and/or subtropical jet to undercut that persistent high latitude ridge to bring rain to CA. We had absolutely no southern branch or much of a subtropical jet near our latitude last season probably due to the -PDO, ENSO neutral conditions, and even possibly the +AMO.

      • Kamau40

        But, in reality the jury is still out regarding “man made” climate change over natural variability.

        http://www.theguardian.com/environment/2013/aug/28/cooling-pacific-dampened-global-warming

  • lightning10
    • Dan the Weatherman

      That looks almost exactly like last January’s pattern! The entire west coast was dry in January from border to border.

  • Kamau40

    According to Howard Schectner, it looks like another robust Kelvin Wave is in the making is currently progressing east along the equator around 160E. This should help to re-energize some of the lost warmth in the E.Pac later this Summer into early Fall. Also, there are great website information about the strength of ENSO and its precipitation relationships nationwide in the past from Jan Null(expert on climate/weather) which I and others who have linked up here on this forum before. Also, there is a brief discussion about the “possibility” of the moonsonal moisture surge next week. See discussion below:
    http://mammothweather.com/

    • Unbiased Observer

      Sorry to do this because I hate correcting people…but you keep mispelling Howard’s last name….it’s “Sheckter” not “Shecktner”. Although he probably wouldn’t mind because he is a self-admitted, horrible speller.

  • Kamau40

    Here is the latest update from a local Bay Area news source about El Nino. Strength and impacts as we already know is still unknown at this time. But, a moderate El Nino event would be good to help prevent another record dry winter or perhaps put a dent in the current dry spell. As Dan(Weather West) posted recently even if we do have a very wet winter, the drought is unlikely to end because the deficits are so huge. I still think it will take at least 2 good solid wet winters to get us back to where we need to be.
    http://sanfrancisco.cbslocal.com/2014/07/10/el-nino-likely-to-return-to-drought-stricken-california-this-winter-intensity-unknown-water-rain-flooding-bay-area-climate-prediction-rainy-season/

    • Dan the Weatherman

      You are right in that it will take at least a couple of years to end this drought due to its severity. I also feel that a moderate El Nino will boost our odds substantially toward having a wetter season. It is the weaker El Nino events that seem to be more iffy in terms of precip. Even an El Nino like 1957-58, 1968-69, 1972-73, or 1994-95 would be good. Even a 2010-11 type of pattern (which was a La Nina) would be good since that brought healthy amounts of snow to the Sierras and really helped out our water supply, but the only downside of that year was the rest of the Desert SW remained in drought conditions.

      • Kamau40

        That is exactly correct!!

    • inclinejj

      Folsom rose 31 feet last Feb.

      Folsom Lake filed much faster than first thought during a long period of Pineapple Express storms. I will look for the info this weekend.

      • http://www.weatherwest.com/ Weather West

        That was a matter of human intervention, though (i.e. they literally closed the floodgates). That particular reservoir is not exceptionally large (compared to Shasta/Oroville, for example), and was well-positioned to take advantage of a brief period of regionally intense runoff. This was not the kind of rain event that benefited a very large area or (more importantly) made a meaningful contribution to the groundwater/snowpack situation.

  • so.cal.storm.lover
  • Kamau40

    Here is another great article resource I have regarding the PDO/AMO. There is very strong evidence, which I have always supported, from a historical perspective that the phases of the oceans do play a much bigger role in our overall climate/weather. The author who wrote this article at the end of May ’14 says the switch we seen in the oceans so far this year is short lived(6-9mo) for the PDO to remain in the positive phase before switching back to the negative phase. He also says we have about another 20yrs to go before the PDO goes back to positive as a constant phase and another 6-10yrs before the AMO goes back to its negative phase as a constant. Review article below:
    http://www.weather5280.com/blog/2014/05/28/drought-relief-el-nino-not-only-player-also-pdo-and-amo

    • Dan the Weatherman

      The AMO had been in its positive phase from 1995 until just recently. Looking back at the past, these indices tend to remain in predominantly one mode anywhere between 20-35 years. Another 6-10 years is a possibility for the AMO to remain largely positive before going back to negative, since this phase has been in place for 19 years now. The last -AMO cycle lasted from 1963-1995 (32 yrs) and the last +PDO cycle went from 1976-1998 (22 yrs). The previous -PDO cycle lasted from around 1944-45 to 1976 (~31 years). Some sources say the current -PDO began in 1998, while others say 2007. I tend to side with the 1998 crowd on this one even though there was a period of neutral to positive PDO from mid 2002 until sometime in 2007 before tanking that fall.
      Of course it is also possible that positive and negative cycles of the PDO and AMO can vary more in length than is currently believed due to only knowing a short history of the cycles dating back to the early or mid 20th century. If there is any reconstructed data for earlier time periods, I don’t know how accurate it would be.

      • Kamau40

        Dan-
        Great detailed insight. I’m always learning something new about how all of these rather important global tele-connections work and how they affect our climate/weather. Thanks again.

        • Dan the Weatherman

          Thanks for linking that site! It reinforces what I have been saying all along and it explains it in a very clear manner.

          • Kamau40

            You’re very welcome. This is what you have been explaining all along and that is what has gotten me interested to do more research on these phases and to learn and understand how these oscillations play a significant role in long term weather; because in reality it is all about looking at the BIG picture how these key global tele-connections affect our weather/climate.

      • craig matthews

        To me, and this is just in my observation, which may not be correct, when the PDO is in its negative phase, the flow pattern tends to be more anti-cyclonic in both the ocean and atmosphere off the west coast in the eastern north pacific, which appears to force the pacific jet further north as it travels across the central into the eastern north pacific basin. That is why the “tendencies” are for the pacific northwest to be cooler and wetter, and the pacific southwest to be drier during a -PDO. But it is interesting that in recent years, that la nina has actually brought more precipitation to all of California then what one would think. Examples: 2005-06, and 2010-11. Maybe, during a La Nina, with a -PDO/+AMO, the ridge that can develop in the northeast pacific has more of a tendency to retrograde to the central north pacific as the trades are much stronger to the south, placing the entire west coast in the sweet spot under a longwave trough. But, of course, there is a lot more to it then just that. And this is just observation from a non educated weather freak. But just a thought.

        • Dan the Weatherman

          You may be on to something here with the retrograding ridge because this happened quite a bit during 2007-08. I have been wondering why La Nina years tend to be wetter during -PDO, +AMO episodes than ENSO neutral years. I do want to note that the PDO was positive during 2006, but it was definitely negative in 2010-11 and 2007-08.

          • craig matthews

            And, I haven’t delved much into MJO stats, but perhaps MJO activity may have contributed to the heavy precip in all of California during those La Nina/-PDO/+AMO winters. Maybe you might know more about that. Anyway, Here’s a satellite pic of Jan 22, 2008. I hope it sparks some interest even without animation

          • craig matthews

            Oh yeah, you are right about the PDO being positive in 2006, sorry I had that wrong.

        • Kamau40

          Craig-
          Very interesting observation. I think you could very well be onto something here. For example, during 2005-06 that was a very wet year statewide, but the PDO was in its positive phase and so was the AMO with a neutral ENSO. On the other hand, 2010-11(the last wet year), the PDO was negative and the AMO was positive, but we also had a very strong La Nina pattern and the storms came right over the entire state. This tells us that either of these phases do indeed affect the positioning of the jet stream over the Pacific Ocean during the cold season. So we need to carefully observe what happens for this upcoming winter of what weather pattern we will get with these phases as we continue to research and learn about them. This is exciting stuff. Thanks for your great insights because it is all very educational and helpful for all of us.

          • craig matthews

            Yes, the PDO was positive in 2005-06. Had that backwards, sorry. Have the Nino 3.4 index listed that year as weak la nina but that may have changed. Probably doesn’t matter that much. To sum up all I have tried to understand about “weather patterns”, or weather cycles, I have come to find that in the midst of weather patterns and weather cycles, there is a lot of random-ness. And more often then not, it seams like we get surprised at what happens with what the weather does in this state as time goes on.

          • craig matthews

            For instance, we get a strong El Nino-strongly positive PDO-negative AMO strong pacific jet at a low latitude….and yet California will end up with a dry winter…It has happened before. This is just rhetoric though.

    • http://www.weatherwest.com/ Weather West

      I’m always wary of making strong causal statements on the basis of teleconnection index statistics only. All of these indices are ultimately proxies for real physical linkages in the atmosphere, and effects on California precipitation (for example) ultimately arise because certain phases of these oscillations favor certain SST configurations and atmospheric Rossby wave excitations. This means that the different modes of variability can interact in complex and unpredictable ways, especially given some of the substantial changes that have taken place in both the high latitudes (Arctic) and low latitudes (especially the tropical West Pacific) over the past two decades.

      For California, the Pacific indices are (perhaps unsurprisingly) the most relevant. The PDO and ENSO are arguably the most reliable (especially when taken together), but even here it’s not clear that they are entirely distinct modes of variability unto themselves. The past 3 years have been very strange over the Pacific, and so it’s really not clear what we should expect in the near future given that we have an “El Nino behaving badly” and a PDO that may (or may not) have evolved toward a more favorable state for CA winter precip.

      We shall see.

      • Kamau40

        Absolutely!! The atmosphere is very complex and there are other variables/oscillations involved. It has been very strange over the Pacific in these last few years. We know something definitely is going on out there, but no one has concrete answers. Although, the ideas and thoughts are quite sound and reasonable. Nevertheless, to research, study and learn about all of this is quite fascinating.

        • Dan the Weatherman

          I still wonder if there is a chance all the pollution and industrial emissions in China and other parts of Asia has increased to the point that it has reached a tipping point in which it is altering weather patterns in that part of the world as well as portions of the western north Pacific, which in turn is affecting our weather patterns here downstream. This increase in pollution has been occurring during the last 10-15 years or so since so much manufacturing has been offshored to that region of the world.

          • craig matthews

            I am not a cloud physics person, but it seams to me that when more pollution particles are added to the atmosphere, that more cloud formation occurs, and possibly more storminess in turn. So, if a large quantity of pollution is being added to the atmosphere east and northeast of china over the northwest pacific, this would cause more storminess over that region. The downstream effects of more storminess then usual in the northwest pacific could be more ridging to the east…over the Gulf of Alaska. I wish I could explain it better. Maybe someone will here with an education in atmospheric science and cloud physics will do a better job then me.

  • snow755

    this is the best link on all the major reservioir

    http://cdec.water.ca.gov/cdecapp/resapp/getResGraphsMain.action

    rignt now folsom lake is setting at 45%

    New Melones how ever is setting at 28% and droping

    • http://www.weatherwest.com/ Weather West

      We’re going to see some exceptionally low reservoir levels by September/October.

  • craig matthews

    http://mag.ncep.noaa.gov/model-guidance-model-area-php# . Kamau40. Here is a link to GFS computer model. Anyway, I am still learning how to read these and get a better understanding. But it sure looks like the “monsoon door” will open over the next 48 hours to at least the southern half of California. Some of the models hold a southeast flow over the entire state from early next week all the way out to almost 10 days. That would be quite a long duration of southeast flow. Does anyone see any disturbances or possibly any lifting mechanisms to generate convection in areas other then the high terrain?

    • http://www.weatherwest.com/ Weather West

      Focal points for dynamic lift are not prominent in current model solutions, except perhaps over parts of SoCal. However, mid-upper level moisture is expected to be very high–and column-integrated values are expected to be ~1.5 inches (which is comparable to a moist winter storm!). So, while there are currently no obvious triggers, past experience tells me that it’s likely that something will be able to act on all this moisture at some point in the next 2-7 days. I’ll update as appropriate (but check Twitter, too! Those updates come out faster and are more frequent).

      • craig matthews

        Thanks. With that much moisture into the mid levels, do you think there is a better chance that raindrops will make it to the ground if something develops?

    • craig matthews
    • Kamau40

      Awesome! Thanks for the model links. Yes, some of the models are showing a strong moisture surge coming up extending all the way out to 10 days from now which is what I shared with you yesterday. This could be an interesting week ahead indeed. In fact, if you look at the satellite below you can see the moisture surge over Mexico ready to be drawn up along the western periphery of the Continental High over the four corners.
      http://www.ssec.wisc.edu/data/us_comp/us_comp_big.html

      • Dan the Weatherman

        I hope something happens during the next week with the moisture surge because we are WAY overdue for some excitement in the weather! I will definitely post observations here if I witness something interesting down here in the O.C.

        • Kamau40

          I totally agree. I am so tired of this extremely boring weather for the last 3yrs+. Hopefully, we will get some exciting weather up here in the North Bay too. I think we have a much better chance than last week this time. In fact, the local weather forecast statement is increasing the moisture surge starting as early as tomorrow nite into late Mon evening and they are projecting to add slight chances of thunderstorms already which is a good sign. I will certainly be posting my observations if activity develops.

      • craig matthews

        Yes, there are a couple of circulations evident on the Water Vapor Satellite imagery loop SW of California, and one big cluster of t-storms in central Baja area that appear to be some type of meso-scale, or small low formation in the convergent zone between the sea of cortez and the pacific. At present time, it appears these circulations are almost moving east to west, in which one would think most of the activity might stay south of us. But in Daniel Swains post, it shows that circulation pulling moisture northwest over the state. I cant believe how much moisture is being shown at the 850mb level for Monday-Tuesday. Where did this moisture originate? PW anomaly +2.5 standard deviation!!!! What generated this healthy plume? Seams like if we get any sun breaks, even the coast ranges of the central coast could generate convection.

        • Kamau40

          Yet, some of the local models are suggesting that most of the activity will remain offshore.

  • http://www.weatherwest.com/ Weather West

    Huge precipitable water (vertically integrated moisture) anomalies headed for CA this week. While instability and convective triggers are modest, this is a pretty impressive event by moisture standards. Widespread cloudiness, muggy conditions, and mountain/desert thunderstorms for sure, and a pretty good chance that some valley and coastal areas will get in on the action at some point. Stay tuned…may do an update tomorrow if looks promising.

    • craig matthews

      With that amount of moisture at 850mb, seams like something should pop off the coast ranges of Monterey co and the bay area. Where did this moisture originate?

  • lightning10

    There is one plant that is doing quite well with this current weather. One of the only native cactus in California.

    Ferocactus cylindraceus

  • craig matthews

    Sorry if this doesn’t animate. But it looks like a new “blob” of warmer then average subsurface ocean temps (aka new warm kelvin wave) is developing in the western equatorial pacific as many have recently said. Lets hope its going to be another big one to keep this El Nino alive.

    • craig matthews

      Sorry, didn’t get the animation thing going here. But if one goes to CPC’s ENSO page maybe you can see what I am trying to post here

      • Xerophobe

        Hi Craig..maybe this will help. so.cal.storm.lover posted this a few days ago.This is just the latest from July 7th, It seems to be for sure. It’s pushing the cooler water below it as it moves east as seen in the depth anomalies.

  • Kamau40

    This is still early, but take a look at the strong precipitation signals for the entire state of CA from Jan-Mar 2015 according to the latest CFS long range models. The long range projections keep looking better every time for the upcoming winter season. It will be very interesting to see if these projections continue to consistently hold together in the coming months and hopes that all of this ends up coming to fruition.
    http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/usPrecSeaInd6.gif

    • theboreworms

      There were similar long-term projections for a wet winter last year, and even the shorter-term models throughout the winter frequently predicted large storms in the 10-14 day time period. Nearly all fell prey to the RRR. Here’s hoping this winter will be different.

      • Kamau40

        Of course, there is nothing guaranteed here this far out because the atmosphere is very complex and it will go thru many changes between now and then. This is a weather pattern we can only hope for at this time and pray that it comes true which is what I’ve implied in the blog.

      • Bob G

        I dont recall last fall a projection of a wet winter. I thought the prediction was equal chance for average rainfall.

        • Kamau40

          Bob-
          You are aboalutely correct! In fact last Fall, the CFS models predicted that at least the first part of the winter 2013-14(Dec/Jan)would be very dry and as well all know that indeed unfortunately verified. This time so far the long range models have consistently been projecting a wetter weather pattern for next winter. But, again with great caution it is still to early to say for sure, we can only hope and pray that these trends will come to fruition and it is something we can at least look forward to in the future.

          • Bob G

            If we experience another dry year, it will spell disaster here in the Central Valley. It will look like a dustbowl.

          • Kamau40

            Yes it will.

          • Dan the Weatherman

            I predicted in the late summer or early fall last year that the winter would start off very dry and that it would be wetter during the second half from late January through April, with the total amount of precip still being below average. It actually turned out to be even drier than I thought it would be and I forecast that Los Angeles would finish with 8-12″ of rain instead of 6.08″.

          • Kamau40

            Yes you did. I do remember your predictions and we were hoping too that the second half of the wet season would be wetter too. Let’s hope this upcoming winter will be a complete different story.

  • snow755

    any one no what part one of are rainey season will look like part 1 would run from oct two dec why part 2 of rainey season would run from jan two may so that dos the CFS have for oct two dec wish would be part 1 of are rainey season

  • Kamau40

    Here is something we can also look forward to in the more medium term future. This latest episode of the monsoonal moisture surge will probably not be the last event we will see between now and Oct. What is even more interesting is that the same CFS models in the shorter term is hinting at more monsoonal moisture surges or moisture influx from a decaying E.Pac system(s) sometime during the month of Aug. Notice: The above normal chances for all of So.Cal and making it all the way up to almost near Central Ca. coastal sections. Hence, if we miss out on this one event the chances are much higher that we will have more opportunities down the road. Remember, historically, Aug-Oct are the prime months for us to witness more convective activity for Ca.
    http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/usPrecMonInd1.gif

  • lightning10

    How nice that the radar is going to be down. It will be hard to tell what is coming in from the East if Thunderstorms try to push over the from the desert tomorrow.

    • Dan the Weatherman

      If you are referring to the Santa Ana Mountains radar (KSOX), that was a message issued on July 10 indicating that the radar was going to be down for a period of time on that day only. I didn’t see any indications that any of the local radars were going to be down for maintenance tomorrow.

      • lightning10

        No KEYX

        • Dan the Weatherman

          I was only looking at the radars surrounding the Los Angeles Basin and San Diego and forgot to check the status of the Edwards Air Force Base (KEYX) radar.

  • lightning10

    It wont matter to much the ML kicked up this morning that should prevent enough heating for thunderstorms today for the beaches and valley.

  • Ian Alan

    This mornings 9am San Diego AFD reads like a bad catch22 – hopefully something pops it would be nice to get over an inch total rain for July. Had a TR of rain yesterday evening and the clouds have only gotten thicker and darker since yesterday morning….just looked outside and we’re getting another TR at the moment…

  • so.cal.storm.lover

    Does it look like so cal, inland empire will get anything today?

    • lightning10

      I would say to many clouds today. Its not that warm at all very limited clearing. This is a situation much like last July where it looked like a very good day but morning clouds prevented enough surface heating.

      • so.cal.storm.lover

        What about tomorrow?

        • lightning10

          Again I think it would be little better if clearing but the flow changes quickly and it gets rather dry. :-/ Welcome to the monsoon that fails to do anything in July like it has for the most part since the early 2000’s.

  • lightning10

    I have a riddle. With the flow almost East/West how did the marine layer find a way to kick up today?

  • so.cal.storm.lover

    In case clouds clear out I will say if we got any thunderstorms today.

  • Kamau40

    The latest models continue show that will just middle-level cloudiness, but not enough lift in the atmosphere to trigger convective activity. Although that could change with all of this moisture coming up. Will see what happens within the next 24-36hrs.
    http://www.wunderground.com/DisplayDisc.asp?DiscussionCode=MTR&StateCode=CA&SafeCityName=Napa

    • craig matthews

      NWS San Fran AFD tonight says maybe Wednesday some convective potential for us. We shall see what becomes of that low to our southwest. Best activity may be right along, or just off the coast. In any case, its good to see this large monsoon push early in the summer season. Makes me wonder if this is the beginning of a very active summer. As you pointed out earlier, CFS thinks so.

      • Kamau40

        Craig-
        I think seeing such an unusual large monsoonal push this early in the Summer season could be a good sign of things to come down the road. I really do believe that Aug-Oct will be our greatest potential for seeing more convective activity for Ca. This is based on a historical fact. It will be interesting to find out what statistics reveal, but I’m sure it will reveal a higher probability next to the winter season. Usually during that time of the year, the steering currents are much more favorable for seeing such convective events. Also, when we get cut-off low pressure systems off the So. Ca coast combined with a large continental high pressure system cell established within the four corners area, it creates even greater opportunities for us to seeing major convective events which is what I have witnessed and observed here in years past.

  • lightning10

    In this picture I noted what is good for beach and valley thunderstorms over the years for the summer. When the flow comes from the South to Northwest that is good, North to Southwest is good, and pure East to West bad.

    http://img.photobucket.com/albums/v681/packerfan10/Capture_zps95103f33.jpg

  • so.cal.storm.lover

    In 2012 august 12 I believe, temecula got slammed with a thunderstorm, lightning every 15 seconds, heavy rain, and gusty winds. I believe that was east to west flow, do you remember that event?

  • Ross Mccorkle

    A fair bit of rain an hour ago in Irvine.

    • Dan the Weatherman

      I have had a few sprinkles here in Orange a couple of times today, but not enough to wet the ground. It has been mostly a mid-level cloud deck and that has likely limited daytime heating for convection to form.

      It does appear that some convection is occurring in northern Mexico and San Diego County mountains now that the mid-level cloud deck has cleared that region with more heating. It also appears that the flow is more southerly to southeasterly there as opposed to easterly.

  • Dogwood

    Nice cloud cover in San Jose. Was clear and 93 by 11am until these built in. Feels breezy, warm and tropical.
    I love it, rain or no rain.

  • lightning10

    Showing once again putting a man made lake in an area that should not have one in the first place is not always the best idea.

    http://www.dailymail.co.uk/news/article-2692335/Water-levels-Lake-Mead-time-low-14-year-drought-leaves-marinas-abandoned-tourist-attractions-bone-dry.html

  • craig matthews

    We just had quite a heavy shower come through just south of Big Sur about 9pm. It was quite a nice surprise given the stratiform look to these mid level clouds passing overhead this evening. Enough to make puddles though. Looks like the blackest clouds are remaining over the ocean off big sur though, out over the marine layer, which seams strange given that stable layer of air offshore. Whatever the case, I hope there’s more to come.

    • Xerophobe

      I saw a long radar loop this morning and it appeared you guys had a decent shower.

      • craig matthews

        Yep, .05 inches of rain in my rain bucket. RAWS reports .02 just to my north in Big Sur. It sure smelled nice.

        • Kamau40

          I bet it smelled nice. It would be great to get some of that shower activity up here in the north bay.

  • TheNothing

    Anyone else just see a shooting star to the west? It was so bright I could see it through the clouds.

  • lightning10

    Moderate showers are being reported just south of Whittier. Things might not be over quite yet.

  • http://www.weatherwest.com/ Weather West

    Checking recent hi-res model output + radar+satellite trends, starting to look like a band of convection and possible thunderstorms could develop and rotate over much of NorCal in the early morning hours, perhaps even including the Bay Area. This would mostly be dry lightning, which would be bad news for wildfire concerns. Stay tuned…

    • Xerophobe

      Had some sprinkles in Monterey area. No thunder, though.

  • alanstorm

    104? yesterday on my porch. 107? in Ukiah. Geeez. Big winds every afternoon are NOT welcome..Dry lightning?? Every day without a major wildfire breaking out in Mendocino County is a miracle. Holding my breath……

  • lightning10
    • TheNothing

      A map of California showing where the most and least water conservation is taking place would go a long way in getting the point across.

      • Xerophobe

        I saw on local news this morning that did give a broad breakdown by region. I live in Monterey County so it was included. LA area was up 8% so factor that into the equation may get to that 1% overall, I guess. The Valley was down 13%, MRY County down 10% (voluntary). In my area raising rates by tiers has been most effective in conservation.

  • http://www.weatherwest.com/ Weather West

    18z GFS has convective precip over Bay Area and NorCal tonight. With Bay Area dew points currently in mid-upper 60s, it certainly feels like there’s some potential.

    • Kamau40

      Dan-
      Here in Nor. Cal, I can certainly feel the dew points and humidity along with some alto-cumulus clouds. Would not be surprised to see or hear some activity later tonite into the early morning hrs.

  • TheNothing

    A very impressive thunderstorm in the Stanislaus National Forest, looks like it’s heading down the West slope of the Sierra’s towards my direction in Rocklin.

  • craig matthews

    Here’s another GFS computer model output generated 18z for early-mid next week. Still learning how to fully understand these, but is a 600dm ridge center at 500mb over the 4 corners considered very strong? Seams like I remember hearing that strength mentioned in July 2006, and then we ended up with one impressive heat wave that summer. Next week could be a hot one if I am reading this right.

    • Kamau40

      Yep, a 601dm ridge(very strong) is likely to develop by next Tue according to the latest models. This means very hot conditions are very likely next week for the West. See also weather statement below making the same prediction:
      http://www.wunderground.com/DisplayDisc.asp?DiscussionCode=MTR&StateCode=CA&SafeCityName=Napa

      • xeren

        i still don’t understand how dm (decameters?) works in weather- does 600dm at 500mb mean that a chart showing how high up in the atmosphere 500mb of pressure reaches up has a point on it that gets up to 600dm high?

        • Chowpow
          • xeren

            thank you! this makes a lot more sense now

        • craig matthews

          Chowpow great answer..I myself do not fully understand that either. All I know is that I don’t see that 600dm line appear too often in the US. I see ‘em more commonly over the Sahara. The last time I saw that “circle” of the 600dm line, it was in July 2006, and man that was a hot heat wave. But I think that 600dm ridge was centered more to the west then what that current model shows, so this time the greatest heat anomaly might be more to our east. I hope that is the case, being how much stress has already been placed on the land.

          • TheNothing

            I remember the heat wave in 2006, two weeks straight of 105 plus and the warehouse I worked in had no ac.

          • craig matthews

            40 people died in Fresno during that heat wave, July 2006. I think it was over 100 deaths in the state, atleast. It would be extremely stressful on the land to see that kind of heat re occur this summer given the excessive dryness this state has experiences since 2012. I hope it stays to our east.

    • http://www.weatherwest.com/ Weather West

      Yes, indeed. There are suggestions that we could be headed for a very substantial heat event (even relative to the recent hot weather inland). Stay tuned.

      • alanstorm

        Neat. A relentless summer after a bone dry winter. Not even Aug yet. Water, or lack of, returning to the top of the news again.

  • Bandini

    Just got pounded by a pretty rad storm, southeast Truckee. About 15 minutes of torrential rain with plenty of thunder and lightning.

    • craig matthews

      That is so awesome when those elements line up right over the top of you, and you are in the right place to witness it. I can see them on vis satellite. Looks like you might get more.

      • Bandini

        Definitely fun, pretty legit storm. Smells fresh out now which is always great. Hoping for more, so far most of the action seems to have been staying a little south, in between Mammoth and Bridgeport, but that one snuck further north.

  • Dan the Weatherman

    There was a sudden deepening of the marine layer this afternoon and is completely overcast here in Orange right now. It feels almost like we went back to a June pattern for the time being and it has cooled down into the low 70’s early this evening. There were some cumulus buildups toward the mountains earlier this afternoon but didn’t look as if thunderstorms formed as the clouds didn’t quite build into thunderheads.

    • Kamau40

      Dan-
      It looks like this is the end of this episode of the monsoonal surge. Perhaps, this could be a sign of things to come later down the road. Remember, history reveals that the real opportunities for convective activity along with much better dynamics along with moisture potential for Ca. is Aug-Oct.

      • Dan the Weatherman

        I think we are going to have some good opportunities for monsoonal events later this month on into August and September. If El Nino develops and becomes at least moderate, there may be more storm activity in the fall beginning in October (not huge winter storms, but more like cutoff lows like you mentioned and smaller storm systems).

        • Kamau40

          Yes, I can definitely see that happening. There are even now some early suggestions that another moonsonal moisture surge will make a major comeback by the end of the month.

  • Mike Stephenson

    Maby its just me, but I remember much hotter summers here growing up in the 90’s. It was nice and breezy here in Corona. Seems like more summer toughing now days over all or something?

    • Dan the Weatherman

      There has been more summer troughing in recent years due at least in part to the -PDO, which began after the 1997-98 El Nino. This troughing pattern was really dominant in the summers of 2010 and 2011. The PDO was neutral to positive for a few years from mid 2002 to somewhere in 2007, and has just recently turned positive again earlier this year.

    • xeren

      Just about every year, i forget that summer in socal actually starts in mid to late july, and lasts through the end of October. Summer is a tad late this year- it hasn’t even started.

      After that, fall is a month long, then we have “winter” if you can call it that.

    • http://www.weatherwest.com/ Weather West

      Summers along the immediate coastline of California have generally been somewhat cool over the past decade, while summers inland have been quite hot (this year is no exception). A lot of our recent heat waves have been quite impressive inland but have featured a marine layer than doesn’t want to budge, and so have been much less impressive within 10 miles of the coast or so.

      • Bob G

        The Central Valley to me feels like a typical summer. Mostly mid 90s with a couple of 100 degree days. I cant remember what year it was, but we had something like 15 consecutive days of temps over 100 degrees. That was a hot summer.

  • Xerophobe

    Here’s latest on equatorial temp. anomalies by depth. The WWB seems to have sent a modest and growing Kelvin wave east. No one knows how strong or what kind of El Nino will present itself in boreal winter.

    • Xerophobe

      I can’t seem to post an animated .gif, sorry.

    • craig matthews

      Yes, I see the most updated one, and it does appear new warm kelvin wave is forming for sure in the western equatorial pacific. Being that it has just begun to develop, seams like we should know by August how strong it will become. The last one had a little more organization in the beginnings of its development. This one appears a little disconnected from the surface down to 300meters. But that could change in a week, as we have seen in the past. Regardless, even if it is a weak kelvin wave, it should be enough to sustain at least some of that left over warm water in the eastern equatorial pacific.

      • Xerophobe

        I’d like to see it pop a +3 but I’ve read it’s modest. Still no engagement with atmosphere. It’s kinda late as far as current SOI behavior and boreal winter El Nino’s. Here’s a different animation but it might give you a better idea as to the what was going on as far as intensity earlier in the year.

    • Kamau40

      Howard Schectner posted on his blog yesterday that there are actually several small oceanic kelvin waves currently traveling east near the equator. See brief discussion below:
      ENSO UPDATE:

      Several smaller Kelvin Waves are moving east near the equator. Subsurface warming is taking place again from the eastern portions of the “western pacific” to the central pacific. Eventually, this warm subsurface water will begin to show up in the SSTA’s of the NINO 4 an 3.4 indices later this month with indications of further warming.

      Dr Howard and the Dweebs………………………………………………………:-)
      – See more at: http://mammothweather.com/#sthash.m97vEoSc.dpuf

      • Xerophobe

        Thanks, it’s a good read. I just don’t want to see big WWB’s or Kelvins develop in Western Pacific after August. They take too long to upwell and mess up most chances to possibly influence boreal winter precip in CA. Prime example of a too late bloomer with peak ONI’s out of boreal winter is the 86-87-88 El Nino(s).

        • Kamau40

          Yes. I do remember that El Nino very well, which was a mild one that developed late in1986 and that is what actually started our long 6 and a half year drought period.

          • Dan the Weatherman

            The period from 1986-87 to 1990-91 was quite a dry and warm period here in Socal and was one of our worst droughts in recent years. The March Miracle of 1991 signaled the beginning of the end of that drought as it was much wetter in the 90’s.

  • xeren

    latest daily nino 3.4 value is back up to 0.5 degrees after dipping all the way to 0 degrees a week ago. i can’t take all this volatility!

  • craig matthews

    Ok, not animated. But there must have been a lightning event up in B.C, because it looks more like smoke plumes rather then high clouds that are drifting southeast toward Montana from interior coastal B.C. That is a lot of smoke! If it is smoke.

  • Dogwood

    A conversation below about feeling like a cooler summer led me to look for NUMBERS, Glorious Numbers. The curious might be able navigate the site to find their city, and go month by month back in time to see all the data and make comparisons.
    Fun.
    http://weather-warehouse.com/WeatherHistory/PastWeatherData_SanJose_SanJose_CA_July.html

  • ApocalypseNow

    Anyone have the latest updates on the PDO? It looks like Nino 1+2 is going to be back to neutral by fall which means we could get a Modoki after all or maybe not any El Nino at all. The best hope is for a winter like 2004-2005 that could still be much wetter than normal with only a weak Nino in place. The worst case scenario is that we get another winter like the last one :(.

    • Mike Stephenson

      I hope the new kelvin wave really takes off

    • xeren

      never trust those SST forecasts – they are garbage. but even if you wanted to trust them, they still show Nino1+2 back up to warm temps by winter after dipping in the fall

      there’s nothing to show a modoki. coming in the future- i don’t know why you want one so badly!

  • Kamau40

    The official PDO values as of June is 0.82. It is still in its positive phase, but has dropped substantially compared to May’s values which was at 1.80. Will see where this goes towards the end of the year. I have said before it could easily switch backed to the negative phase.
    http://jisao.washington.edu/pdo/PDO.latest

    • Xerophobe

      I saw that yesterday, too. Wonder why it took so long or maybe it’s just posted mid month? An updated ENSO plume should be out, soon, too. I think a +PDO can help as well as a -NAO. I’m selfish but all I want for Christmas is a lot of precip in western US, especially in CA this coming winter.

      • xeren

        that’s not selfish at all. the PNW gets more than enough water, even on a “dry” year :)

        • Dan the Weatherman

          We really need a wet year in the western and southwestern U.S. this winter due to the bad drought conditions. I am hoping we get out of this late 1950’s to early 1960’s-like weather pattern we have been in for the last three years.

          • Xerophobe

            Yup, that was a time of a couple of ‘feasts’ with mostly ‘famines’. Looking at some other things it’s impossible to say two or three or four things MUST line up for above average rainfall. I can give myself a headache trying to do something the pros haven’t been able to do…ouch! I’m trying to get some knowledge and understanding about MEI now. Anyway case in point regarding PDO and ENSO, just look at 94-95 +ENSO -PDO with the SSTA and rainfall that winter.

          • Kamau40

            What you said is absolutely correct about 1994-95 wet season which was another great year for the state. In fact, we had lots of flooding that winter and very heavy snowfall in the Sierra’s. The PDO was in its negative phase from Aug ’94 thru Jan ’95. It then turned positive from Feb ’95 until later that year with a “weak to moderate” +ENSO event and there were also other years like this in the past. So this tells me that we can still have a wet year even when the PDO is negative with a “weak to moderate” El Nino event. But, notice how most of the warming was confined to the Western to Central-Tropical Pacific that year as opposed to the E.Pac.
            http://jisao.washington.edu/pdo/PDO.latest

  • http://www.weatherwest.com/ Weather West

    Interestingly, both the GFS and ECMWF now suggest convective precip over much of NorCal (inc. Bay Area) this weekend when the weak low offshore finally moves inland. Definitely worth watching. I’m planning to have a substantial update by Sunday regardless.

    • Zepp

      We’ve had brief intermittent sprinkles over the past 30 hours, only a trace, but it did cut into the oppressive heat we’ve been experiencing. Today might break the string of days (8 so far) where it’s been above 97. Our low last night was 63, just one degree above our all-time warmest night.

    • ApocalypseNow

      Hopefully rain with those thunderstorms and not just dry lightning? It seems that the Bay Area has a hard time squeezing out moisture out of those desert monsoons.

  • Bandini

    Getting absolutely bombed in Truckee and North Lake the past hour. Pretty colorful colors on that Doppler. Some of the loudest thunder I’ve heard in a while.

    • rob b

      It looked like some parts of the North side of Tahoe and Truckee were really hammered. Noticed so much hail on the ground along 89 it looked like a snow storm. Also found it interesting East of of Donner Lake had cleared out around the Tahoe Donner Beach Club yet the West End still had people on the water according to the Donner Lake Village Webcam.

      • Dan the Weatherman

        It is good to see the Sierras getting some activity. The hail that fell melted and maybe some of that water actually soaked into the ground as opposed to being runoff.

  • xeren

    okay, heavenly’s observation deck cam is pretty cool. the timelapse option for the day lets you see the clouds move in

    http://www.skiheavenly.com/video-and-interactive/web-cams.aspx

  • Bartshe

    After so many days of big build up we finally got some rain near Mono Lake–.25 inches in Lee Vining to .67 inches and more between Mono City and Conway Summit. Ground strikes, rain, flash floods, and smoke from a regional forest fire near Bridgeport area made for an exciting day. Meanwhile, just saw this in the Las Vegas discussion:

    ANOTHER FEATURE TO KEEP TRACK OF BY MID WEEK WILL BE THE POTENTIAL DEVELOPMENT OF A TROPICAL SYSTEM IN THE EASTERN PACIFIC AS A WAVE MOVES OFF THE CENTRAL MEXICAN COAST. HOW CLOSE A TROPICAL SYSTEM TRAVERSES THE MOUTH OF THE GULF OF CALIFORNIA WILL IMPACT THE POTENTIAL FOR A GULF SURGE. BY THURSDAY THE STRONG RIDGE OF HIGH PRESSURE WILL MOVE SLIGHTLY WEST AND BE CENTERED IN THE VICINITY OF THE FOUR CORNERS. TEMPERATURES WILL TREND UPWARD AND HAVE MADE
    LITTLE CHANGE TO THE TEMPERATURE FORECAST AT THIS POINT. THE EXACT POSITION OF THE RIDGE AND ANY TROPICAL DEVELOPMENT WILL HAVE A SIGNIFICANT IMPACT ON THE TEMPERATURES AND PRECIP FORECAST. &&

    • Dan the Weatherman

      Moisture from that tropical system if it develops could help enhance the monsoonal flow if the pattern sets up just right and bring a good chance of thunderstorms for the SW states. Even areas west of the mountains in Socal could get something in a pattern like this if it manages to develop.

      • Kamau40

        How about Nor.Cal? I have noticed these moisture surges keep getting stronger every time. One of these days we will get it. This last surge, even though it did not bring any convective activity in our area, produced a lot of alto-cumulus clouds which were beautiful to see. The only thing that was missing was the lifting and the dynamics in the atmosphere.

        • Dan the Weatherman

          If the steering currents are favorable and direct moisture into Norcal, you could see some activity there as well.

  • Utrex

    There’s finally actually some Lifted Index (LI) values of -2 over the central valley of NorCal on Monday! I think there may be some dry t-storms if it verifies, or if there is increased moisture later on, there may even be some “regular” t-storms.

  • Xerophobe

    I’ll let you guys discuss it. The dynamic and stat averages are hanging in there a little below +1.0 pretty much the same as last month. The CPC consensus has mostly been a little bit less than the dynamic and stat averages for this year.

    • ApocalypseNow

      Seems the question is now neutral vs. weak; such a strong contrast to probable strong Nino we were banking on just a couple of months ago. Regardless, there is still a prediction for above normal precipitation the upcoming fall and winter. Do you see a repeat of 2004-2005 or more of a repeat of 2012-2013? I wouldn’t mind a repeat of fall of 2012 when we had some decent rains from October through December but do not care to repeat any part of 2013.

      • Xerophobe

        Looking back at the models I think only one or two breached +1.5 which would have put it in the “strong” category. Avg. to weak is under +1.0. and Moderate is +1.0 to +1.4 for El Nino. The “super” was based on nothing other than the huge Kelvin and comparing that to 1997. All those bouys were placed after 82-83 El Nino and became operational in ’94 I think. There could have been a ‘super’ if a few more decent Kelvins were generated and the atmosphere kicked in gear to further support the upwelling. There are really only a couple of models that are looking at neutral conditions.

        i think timing of the peak ONI is very important for possible above average precip. or at least an average winter season. The models all seem to forecast a peak ONI near early December which i think is pretty optimal for an average to weak +ENSO. Also MEI can be an indicator along with a peak ONI in early December.

        I’m really skeptical of the CFSv2 precip anomaly forecasts for our winter. JAMSTEC (Japan’s version of NOAA I guess) does have above average for CA this winter but the map I was looking at was a world view not just North America. I don’t have a guess for precip, i just look at the data.

        Daniel has been great with his analysis. I’d lean on his expertise more than my ego!

      • http://www.weatherwest.com/ Weather West

        Not really–we’re still looking at a likely/very El Nino event, probably of moderate strength (though the possibility remains for anything from a weak to a strong event). Recent atmospheric conditions are finally starting to look a little more favorable/coupled with a warm ocean. I’ll update this weekend.

        • Dan the Weatherman

          What is important to me is that CA receives significant rain this next season as opposed to this ridiculous dryness we have been suffering through the last two years.

    • theboreworms

      The last two El Niño events were slow to get going as well, and the ONI only peaked at 0.8 (in ASO, no less) in the 2004-5 event that soaked SoCal. So I still think there’s decent hope for some better precip, although of course it’s not like everything depends only on the ONI. Really hoping to see some sort of breakdown of the RRR early this fall…

      Side note – I love doing it myself but it’s so funny and (mostly) pointless to micro-analyze these day-by-day updates of such a complex and slowly-evolving system. Really eager to get past fire season and see how things play out.

      • craig matthews

        I like your side note. I do it all the time…micro-analyze almost by the hour. But in doing that it becomes an emotional roller coaster for me. Getting my hopes up on one model run, or one satellite frame, or someone’s latest positive discussion. Only to find that I am let down by “the forecasts” more often then not.

      • Xerophobe

        Good point about ONI, thanks! Yup, I do what Craig does and you are suggesting. This is interesting and I like to dig into it and also look at different viewpoints as well as models and forecasts. I have a looong way to go. Craig….hang in there but I get it all too well what you are saying…

  • xeren

    i’m liking this august precip forecast for CA

    https://twitter.com/WSI_Energy/status/490165378170236928

    • geopower

      90% more than average in a month that on average has negligible precipitation, is still pretty negligible.

      • xeren

        oh yeah, good point :(

        • ApocalypseNow

          Problem with monsoons is that west of the mountains, it brings more dry lightning than significant rain. As much as some of us might be “amused” by the rare sound of thunder and sight of lightning here, it will cause lightning strikes causing fires if there isn’t substantial rain to put out those fires.

          • http://www.weatherwest.com/ Weather West

            Dry thunderstorms–especially this year–have a tremendous destructive potential (given the drought and associated fire potential). One clarification in terminology: individual storms are not “monsoons.” A monsoon–in this case, the North American Monsoon–is a seasonal reversal of the prevailing circulation (wind) pattern on the large scale brought about by summer heating in the Sonoran Desert region. The monsoon can bring thunderstorms, but thunderstorms themselves are not the monsoon. :)

      • http://www.weatherwest.com/ Weather West

        my point exactly! Still, this would suggest a good chance at getting at least one monsoonal/tropical remnant event with measurable precip nearly everywhere.

      • Kamau40

        Excellent point!!

    • Kamau40

      I’m seeing strong signs of convective precipitation events(at least one or two) for Ca. during the month of Aug. Earlier this week, I have also been pointing out the CFS long range models have been predicting that possibility for awhile now.

    • craig matthews

      Where I live, one tenth of an inch of rain in August is considered about 200 percent of normal for the month. But I guess it depends on where you live too. Sierra could get pounded with re occurring wet thunderstorms. That would at least help some of the dryness up there.

      • xeren

        yeah, even if it doesn’t help reservoir levels, those trees in the eastern sierra are hurting – a good soak could go a long way for the health of the environment up there

        • Dan the Weatherman

          If a heavy thunderstorm forms over a reservoir and is slow moving, that could help the water level at least a little if the rain is heavy enough. We certainly need every drop of rain we can get at this point to help out with all the vegetation that is being stressed by this drought.

          • http://www.weatherwest.com/ Weather West

            Conditions are so dry at this point that there is virtually no runoff occurring except for extremely localized sheetwash during the heaviest convective downpours. The biggest impact would be in temporarily reducing fire risk, although the associated lightning most likely more than outweighs the effect of precip.

      • Xerophobe

        Good point about how much the rain bucket would tip for most of CA in August.

  • craig matthews

    Here we go again. What appears to be another monsoon surge coming soon to atleast the southern half of California sometime this weekend. That is one large upper level low southwest of California on that model run. Question though as to whether there is any cold air aloft associated with it, or if its just a sub tropical circulation that is hanging out between 2 ridge centers. But we shall see what forms. It is interesting to see these monsoon surges occur back to back.

    • Kamau40

      Craig-
      Now, this is starting become very interesting. This is a nice huge blob of monsoonal moisture feed even right to the Bay Area by Sun. This something we did not see coming several days ago. Maybe this time here in Nor. Cal, as Dan(Weather West) pointed out a couple of days ago, we will see some convective activity. This is the second moisture surge in less than a week. I really think this is a good sign of things to come. Thanks for posting the model trend.

  • Kamau40

    This is an excellent article regarding the current state of the developing El Nino. Another robust oceanic Kelvin Wave is currently developing and has already begun. This event is by no means fading as many people believe. See article below:
    http://www.wsi.com/blog/energy/el-nino-update-el-nino-is-not-dead-and-model-forecasts-call-for-a-future-period-of-warming-this-fall/

  • lightning10

    Something I have always questioned is how do you get strong upper level winds in the middle of summer time? Tonight/tomorrow sounds like a chance of Showers or thunderstorms even near the coast for So Cal. Yet they are saying that it will push through rather fast. This isn’t January :-/

    • http://www.weatherwest.com/ Weather West

      Winds are always driven by temperature differences, so strong upper-level winds (at any time of year) are driven by steep temperature gradients above the surface. Since the summertime upper-level winds are actually from east to west during monsoonal surge/easterly wave events, this means that temperatures must locally be increasing as you go north. This is the opposite of what normally occurs during most of the year (including winter), where things get colder pretty quickly as you go north (and winds blow from west to east as a result).

      • lightning10

        Thanks !

      • Zepp

        Don’t you mean pressure gradients? I thought temperature gradients were secondary, even incidental to those.

        • http://www.weatherwest.com/ Weather West

          That’s strictly true, but the pressure (or density) gradients in the Earth’s atmosphere are mostly driven by temperature variations. This is true for everything from global-scale phenomena like the jet stream (driven by the decrease in temperature from equator to pole in each hemisphere) to the diurnal sea breeze cycle in California (driven by the west-to-east warming of lower-atmospheric temperatures during the daytime).

          • Zepp

            I just realized you were talking about localized convective systems. My mistake.

  • Kamau40

    Take a look at what the models are projecting to happen to the new moisture surge within the next 36hrs. It has more progressive throughout much of the state including the coastal sections by Sun and even making it all the way up here in Nor. Cal. The local forecast is also now including the possibility for convective activity this time. Things could get interesting over the weekend. Stay Tuned!
    http://mag.ncep.noaa.gov/Image.php?fhr=036&image=data%2Fnam%2F00%2Fnam_namer_036_500_rh_ht.gif&model=nam&area=namer&param=500_rh_ht&group=Model+Guidance&preselected_formatted_cycle_date=20140719+00+UTC&imageSize=M&ps=model

    • http://www.weatherwest.com/ Weather West

      Yep. I have a feeling that Saturday night might get interesting in NorCal.

    • so.cal.storm.lover

      Is there any lift to support thunderstorms in valleys and coast of nor cal and so cal.

      • Kamau40

        The local weather statement has not yet mentioned any lift or dynamics to support thunderstorm possibilities. However, with that low off the So.Cal coast along with an impulse forecasted to move northwestward and if there is enough heating of the day, we cannot rule out that possibility to see thunderstorm activity over the next 24-48hrs.

        • so.cal.storm.lover

          http://www.wunderground.com/DisplayDisc.asp?DiscussionCode=SGX&StateCode=CA&SafeCityName=Temecula The morning discussion mentions sufficient lift and instability!

          • Kamau40

            The local weather statement so far for Nor Cal does not mention thunderstorm chances. Your local weather statement in San Diego mentions mu cape values from 400-600 j/kg which is a high sufficiency of lift and instability to produce high based thunderstorm activity. The latest models has been projecting that activity to move into Nor. Cal late tonight into Sun.

          • so.cal.storm.lover

            Nothing here in temecula yet. The clouds cleared out after a 15 minute rain ban a few hours ago ever since then its been sunny and hot which could enhance surface heating and thunderstorms may develop.

    • Xerophobe

      Good point about dogs and other animals. My dog knows when I act strange too.

  • http://www.weatherwest.com/ Weather West

    High-res NAM has a band of convection over most of NorCal late Saturday night.

    • Bandini

      I cancelled an overnight backpacking trip I had planned into Desolation wilderness for tomorrow night, NOAA has increased thunderstorm chances for the Sierra through the weekend, and it’s been so active I figure I’ll just monitor the Doppler and stay dry at home!

      • TheNothing

        Love hiking Desolation wilderness, even camped atop Pyramid peak once.

      • Kamau40

        Great idea!! Looks like things will get quite active over the weekend with the incoming moisture surge.

    • so.cal.storm.lover

      Would that convection band move through so cal first?

      • xeren

        Ugh is social getting screwed again?

        • so.cal.storm.lover

          Hopefully not.

  • Kamau40

    Monsoonal flow will stay with us until about Tue. However, from middle of next week onward, I also look at the latest model trends, it looks like another big subtropical continental high is very likely to re-establish itself once again. This means the potential for more hot temperatures and the possibility of another round of monsoonal surge to start the process all over again. Review Howard’s discussion from this morning below:
    http://mammothweather.com/

  • Ian Alan

    Light rain showers on and off in San Bernardino mnts – 67F and just a few hundredths so far

  • Xerophobe

    Click the link to see the .gif animation and here’s a pic of the latest Kelvin. Should be another one up soon. Seems another one (kelvin) finally popping through above New Guinea. http://tinyurl.com/phs6xka

    The eastward extent of the Kelvin we’ve been watching is at the equatorial dateline. Might this be the beginning of atmospheric teleconection or at least a slackening of trades near the dateline? Also I see cyclonic activity at about 4°N x 160°E. It would be cool if it moved east or crossed the equator?? rather than North.Can cyclones cross the equator? If so, it would seem beneficial to +ENSO??

  • Utrex

    The CFS forecast for zonal winds shows a WWB developing very soon. Looks to be a bit similar to the one at around April 10-15.

    http://www.atmos.albany.edu/student/macritch/realtime/filteredhovs/75S75N_6_5_uwnd850.png

  • http://www.weatherwest.com/ Weather West

    Thunderstorms now developing in the San Joaquin Valley. Tonight may see a much more widespread thunderstorm outbreak across NorCal, possibly including Sac Valley and Bay Area as storms move in from the southeast. I’m planning on having two updates this weekend–one short one for the monsoonal activity, then a longer one late Sunday on the drought.

    • Bob G

      In my parr of Central Valley southwest of modesto no clouds but definately can feel increase in humidity this afternoon

  • lightning10

    All this stuff that is shafting So Cal today will explode over No Cal. There monsoon has been better this year.

    • Dan the Weatherman

      Here in Orange and surrounding areas where I have been today it hasn’t rained at all despite quite a thick mid-level cloud deck for the first half of the day before becoming partly cloudy in the afternoon. The clouds helped to keep the temperatures in the 70’s to possibly near 80.

  • Kamau40

    Latest local weather statement has finally mentioned slight chance of thunderstorms late tonight for Nor.Cal/Bay Area. The humidity and dew point levels are up and I definitely feel. This means we should see some convective activity!!
    http://www.wunderground.com/DisplayDisc.asp?DiscussionCode=MTR&StateCode=CA&SafeCityName=Napa

  • TheNothing

    I took a time lapse video of some cumulonimbus cloud formation over the Sierras near Truckee before my battery died, enjoy. Click on the link for the video.

    https://www.flickr.com/photos/100185958@N02/14715121493/

  • Dogwood

    A few pelty rain drops moments ago in San Jose. And the sky was on fire with orange rain shafts.

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