Some late-season rainfall in store for the entire state

It has been an odd rainy season this year in California. Things got off to an early start in October, but rainfall and overall storm activity over the far Eastern Pacific dropped off dramatically during the traditionally wet months of November through February. Since approximately the end of February, however, storms returned to the state of California, bring much-needed rainfall and substantially boosting the previously anemic Sierra snowpack. Still, while recent precipitation has greatly reduced the potential for any serious or widespread water concerns this summer, water-year precipitation remains substantially below average for most of the state.

Source: NWS/NOAA

At the present time, a fairly complex and increasingly active pattern is evolving over the far Eastern Pacific. A cutoff low is currently circulating several hundred miles off of the California coast, which triggered mountain thunderstorms this evening in the moist, warm, and slightly divergent southerly flow on its eastern side. As this low begins to approach the SoCal coast over the next 48 hours, I expect the coverage of showers and thunderstorms to increase. Tomorrow afternoon, a weak perturbation and associated vorticity maximum will lift north over NorCal, likely triggering scattered convection in many places (especially over the mountains). Similar activity could occur on Tuesday, though there doesn’t appear to be a specific focusing mechanism on that day so shower/thunderstorm coverage could be somewhat more limited.

Source: NOAA.

On Wednesday and Thursday, the cutoff low will move inland near the Los Angeles area, bringing a fair bit of rain and possibly thunderstorms to a wide swath of the state. At the same time, a modestly stronger and colder low will begin to approach the state from the northwest. The confluence of these two systems will bring unsettled and potentially active weather over most or all of the state into late Thursday.

Source: NCEP.

Thunderstorm potential is difficult to assess at this point given the complexity of the developing pattern, but there may be lightning observed somewhere in the state each day between now and Friday. Right now, the mountains, the Central Valley, and the coast from the L.A. Basin sourthward appear to have the highest thunderstorm potential this week, but this may change. Stay tuned!

© 2011 WEATHER WEST

  • Nicholas

    Hey its starting to poor buckets here in Whittier. Yet the radar isn’t showing any rain.

  • jeff

    David,
    Be patient and please turn on your spell check.

    • David

      jeff if you dont like my spellng ignored it that one thing i i wont stane on any blog site if you dont like some one spelling this ignored it or dont even say any thing no one is 100% right on all of there spelling

  • sc100

    Already over a foot of snow in the Sierra! This has been a good storm so far.

  • http://www.norcalweather.net/ WxTracker15

    That was quite the afternoon for the Sacramento valley. Had a feeling there would have been some rotating, as hodographs had some very decent curvature and with the few hours of surface heating that occurred after fropa, conditions were perfect for “mini”-supercellular structures.

    • sc100

      That was a wild day yesterday, one of the craziest I can remember. To have one tornado is one thing, but to have five in a couple hours and God only knows how many funnel clouds is a whole different story. I’m glad to see nobody got killed even though some houses got hit pretty bad.

      Also, kudos to you for seriously advertising the possibility of major convective action. The NWS wasn’t really talking about it and the Weather Channel had zero thunderstorm potential over the entire state!

      • http://www.norcalweather.net/ WxTracker15

        Yep, one of the most active days I’ve seen in my time. Even crazier this wasn’t in the later Winter or early Spring.

        Thanks, I feel the NWS is a bit too conservative at times, had to start my own site (norcalweather.net, not to “spam” or advertise the link or anything) and forecast myself to get my opinion out there.

        Hopefully this is a sign to come and we don’t see a dryer than normal winter like the NOAA is forecasting. I don’t really see much to go off of, neutral years are as un-predictable as any other ENSO extreme.

  • Tom in San Diego

    First santa ana of the season down here. Winds are ESE at 8-10 sustained gusts to 15 right now. RH has dropped right down to 10 in the last hour. From NOLF Imperial Beach.

  • http://www.norcalweather.net/ WxTracker15

    Could see some decent rainfall by the middle of next week in northern California once again.

    • sc100

      Yeah, it looks like we could see a pretty active pattern set up for a while starting next week. The season’s starting out pretty well, all things considering. It looks like you guys in Socal will have to wait a while though to get in on the action.

  • Nicholas

    The upper air pattern over the Pacific sure doesn’t look favorable so far for a big fall/winter, and Spring hasn’t been good in years. Still to early to hit that panic button but if you remember a season like an 04-05 you started having good storms in October. This year there was only one with a few locations getting decent totals from isolated thunderstorms.

    • Dan the Weatherman

      This last spring was actually better than the winter. We had more storms from mid-March to the end of April than we had in January and February, and May and June were very pleasant without any major hot blasts.

  • Shady Blues

    I hope this season doesn’t turn out dry. I have been waiting 5 months for the wet season to start again. I want some strong storms. Socal weather blows. I wish I was at the East Coast right now.

  • Dan the Weatherman

    The thing that is concerning to me this year is the combination of large scale factors in play right now. We have a combo of -PDO, +AMO, and Neutral ENSO together that in the past has led to some really awful seasons such as 1960-61 and 2001-02. Weak El Nino with these same conditions led to 1958-59 and 2006-07, although I can’t remember when exactly the PDO went back to negative in 2006 or 2007. This doesn’t necessarily mean that this winter will be dry or as dry, but I don’t feel particularly comfortable with this combination of factors. I wish that El Nino would have developed this summer and strengthened this fall, as opposed to fizzling out before it really was able to get its act together.

    • http://www.norcalweather.net/ WxTracker15

      Models are not looking good for the first half of November. Hopefully this changes as we head into the month and models are just highly focused in on Sandy.

  • Nicholas

    November 2005, 2006, and 2009 where all quite dry and warm for Southern California. If the GFS is right we might be in store for another November like that.

  • http://weatherwest.com Daniel Swain

    This blog’s not dead, I promise! There will be a formal update during the next significant weather event in CA. Unfortunately, that doesn’t appear to be on the horizon at the moment. If nothing happens within the next two weeks, there’ll be some sort of post anyway…

    • http://www.norcalweather.net/ WxTracker15

      Noticed that the 12z GFS and current 00z ECMWF (waiting for 12z) have some agreement with a cold trough around the 9th of next month… it doesn’t look very wet, but it’s something.

      • Shady Blues

        Its on the 18z GFS too. I don’t like those kind of storm tracks….reminds me off 2006-2007. They bring more cold and wind than rain.

        • Dan the Weatherman

          I would hate to see a repeat of 2006-07 as well. While the cold was interesting that year, it was just WAY too dry rainfall-wise for my liking.

          • Tom in San Diego

            Yes, wasn’t that the one that started out promising, and then we had that the mega alpha block from hell that seemed to last all winter?
            Chance of a shower next week, but it really going to be a hat trick – if at all.

  • Nicholas

    It would be interesting of that solution came to be. Odder things have taken place.

  • Sunchaser

    Looks like So Cal will get some much needed rain towards the end of the week ..yay finally…hope it doesn’t fall apart….lol

    • Dan the Weatherman

      I am seeing that as well and am hoping that it actually occurs as opposed to being a figment of the models’ imagination.

    • sc100

      It looks like we’ll get more cold than moisture but I’m looking forward to the chillier temperatures. It’ll feel more like fall around here. And it’s always interesting to see how low snow levels get with these systems.

      • Shady Blues

        I don’t know about that. The rainfall totals with this storm do not look impressive. As many of have said before, this is going to be a dry and cold storm. Not the kind of storm I would like to see.

  • redlands

    I wouldnt want another 2006-2007 rain season — my station in Redlands, Ca only got 4.30 — the 2001-2002 was even worse with only 2.78 –

    • sc100

      Yeah, I remember that 2001-2002 year was brutal for Socal. A friend of mine from Socal said it seemed like it only rained a couple days the entire year.

  • Dan the Weatherman

    Both 2001-02 and 2006-07 were absolutely miserable for Socal in terms of rainfall and I am hoping that this year is not a repeat of either one of those years.

  • Nicholas

    As I said on another message board this storm keeps tracking more East. The cold and the Wind might be the headline over the rain.

  • redlands

    Was 92 in Redlands, Ca today 11-4-2012 —-got up to 93 on the other thermometers

  • Sunchaser

    It was 94 here in Glendale today another toasty day…..NWS AREA FORECAST DISCUSSION still indicating a big change towards the end of the week…will it rain or not that is the question..

  • Nicholas

    Thought we where going to hit the big 100 today. Only made it to 94 but impressive none the less. The sad system at the end of the week might turn into a true inside slider :(.

  • redlands

    Was a toasty 96 in Redlands, Ca on November 5 2012 — which ties the record — ties the record from 1988 —— Got close to 100 — its now 63 at 815pm . Did anyone see the smoke from the fire in Cajon Pass —- it put out alot of smoke —- at first i thought it was smog from Los Angeles — put then realized it was from the Cajon Pass Area — it closed both sides of the freeway

    • Dan the Weatherman

      It was very warm here in Orange with highs near 90 or low 90s and is still mild here tonight despite being no wind. I saw some smoke from the Devore (Cajon Pass) fire to my north and west, but it wasn’t overhead.

  • http://www.norcalweather.net/ WxTracker15

    I’ve noticed the GFS, it’s ensembles, and the long range version of the ECMWF indicate a very active period between around the 15th – 22nd at least. If any of the current solutions were to be correct, northern and possibly even central California may have some hydrology issues.

    • http://www.norcalweather.net/ WxTracker15

      lol.. and as soon as I feel confident enough to mention it, it gets pushed back in time and nearly dropped.

      • http://www.norcalweather.net/ WxTracker15

        The GFS is at it again, now pushed up to next weekend.

  • David

    when was the last time this site was updated?

    • Dan the Weatherman

      April 22, 2012.

      • Dan the Weatherman

        That is for a full blog update.

  • Dan the Weatherman

    Looks like some of the coldest air of the season for Socal behind the late week storm, as low temperatures in inland Orange County may be down into the 40s late this weekend and early next week with some 30s possible in the inland valleys.

  • Nicholas

    Got a decent rain shower this morning. I think this slug of moisture from the south could bring more rain then the low itself.

  • Tom in San Diego

    Yeah, we got one too Nicholas, 0 dark thirty, nice shower for South Bay San Diego. area.

  • http://www.norcalweather.net/ WxTracker15

    The GFS and it’s ensemble mean continue to indicate a very wet storm (at least for northern/central California) between the 17th – 20th. The (12z) ECMWF looks like it’s trying to follow it… but lagging in time.

    • sc100

      Yeah, that thing’s looking huge. Let’s hope it stays together.

      • http://www.norcalweather.net/ WxTracker15

        Arg, 18z/00z GFS runs and the ensembles are now trending much dryer… the 12z ECMWF latched onto the wetter side, hoping the 00z ECMWF continues the wet trend, and not the GFS’s dryer solution.

  • alan

    Managed to pick up 1.20″ since 4pm thursday with a trace amount overnight wed. Temps dropped steadily from a high of 45 yesterday to 34 right now, been a steady light to moderate rainfall all night, just stopped right now.

  • redlands

    Alan — You live in Running Springs ??? Redlands Ca here — You didnt get any snow ???? I got 0.30 for Thursday 11/8 and another 0.08 for Friday 11/9 — for a total of 0.38 — was suprised to get that amount — i was figuring my area – Redlands would only get bout 0.05 – 0.12 —- As of 656pm hi of 61.8 — low of 49.2 — presently 49.4 — Did you get some high winds Alan ???

    • alan

      That’s weird I had typed that it snowed a couple inches after the rain. Not much winds with the rain, Thursday afternoon we had some strong gusts and again with the snow.

  • Nicholas

    0.20 from this storm so far. I guess some of the more advanced computer models have been showing thunderstorms for Southeast LA County and have been protestant on it for tonight. So far nothing has taken place.

    • http://www.norcalweather.net/ WxTracker15

      The HRRR has been having some issues lately, it seems… was down for a few days and magically came back online last night in time for this post-frontal convective stuff. It also didn’t verity well in northern California, and usually it does great.

  • http://www.norcalweather.net/ WxTracker15

    This site should be turned into a forum, since there is a decent amount of commenting, but not much overall blog updating (no harm intended, I understand that time can be hard to come by).

    • Dan the Weatherman

      There used to be more frequent updates, especially during more active weather periods such as now. It may be that Daniel has a much busier schedule now than he used to and has not had a chance to post as often.

  • Dan the Weatherman

    This is easily the coldest night of the season so far down here in Orange as it is between 50 and 51 right now outside my bedroom window.

    We went from summer to winter in about a week’s time and the weather today was a lot like a December day and there was a cool crispness to the air that hasn’t been felt here since last winter.

    • Dan the Weatherman

      .06″ fell here in Orange on Thursday, which is the first measurable rain of the fall. It appears that the most precipitation occurred in the far inland valley areas nearer to the mountains and the mountain areas. Julian and Lake Arrowhead both got over an inch of rain over the last 2 days, which were the highest totals I could find on the NWS climate summaries.

  • Tom in San Diego

    58 at NOLF Imperial Beach this morning:
    4 Broken
    8 to 12 Scattered
    Humidity55%
    Wind SpeedNW 14 MPH
    Barometer30.05 in (1017.4 mb)
    Dewpoint42°F (6°C)
    Visibility10.00 mi in scattered showers
    Few showers this afternoon and clearing.

    Looks like were getting the better share of rain again continuing from last year with this pattern of outside sliders.

  • Nicholas

    A real nice loop today showing the cold air quickly moving over the area. Looks something you would see in January.

  • Nicholas

    Made it Dow. To 42 in Whittier this morning. It could get colder tonight.

  • sc100

    Next weekend is looking interesting again.

    • http://www.norcalweather.net/ WxTracker15

      Yep, depending which model wins the fight is right that is.

      • Shady Blues

        The drier one haha.

  • Tom in San Diego

    46 this morning. Getting kinda wintry for this time of year, heck it was warmer in my hometown in Ohio.

  • redlands

    Redlands, Ca Weather Update —- Low for Nov-10 was 38 — a record at my station for the day — low for Nov-11 33 which is a record for the day — presently its 44.1 at 813pm — lowest temp recorded at my station is 29 for November

  • http://weatherwest.com Daniel Swain

    New blog, believe it or not… ;)