Melor remnants to bring major (record-breaking) CA storm?

Well, if you had asked me yesterday, I would have guessed that this potential event would already be in the early stages of fizzling out before it even started. Such is the tendency of early-season storms in this part of the world. At least for the time being, however, the event slated for early next week shows no signs of falling apart. Very much on the contrary–all the major computer models have (in the past several runs) significantly ramped up both precipitation totals and the potential for strong winds at the surface. The ECMWF has had much more consistency than the GFS in forecasting the potential for heavy precip and strong winds in NorCal during this event, but the most recent 00z run of the GFS is a real show-stopper. This run, in particular, brings truly phenomenal rainfall accumulations to all of NorCal over a 36-48 hour period–on the order of a foot or more. Keep in mind that the GFS does not really have sufficient resolution to incorporate the crucial orographic effects of precipitation in CA and as a result almost always underestimates basin-averaged precip during strong storms. Also very much of note is the significant potential for strong to very strong winds ahead of the cold front. A very large and deep low–perhaps sub 970 mb–is expected to deepen off the WA coast by Monday. 850 mb winds are forecast by the 12z ECMWF to exceed 75 kts over coastal Oregon and 65 kts over Norcal. The 00z GFS is now in agreement with the ECMWF forecast, perhaps even a little stronger. Were the storm to pan out exactly as indicated by the 00z GFS, it would probably the the strongest October storm ever in CA. Certainly, the rainfall output of the GFS would suggest that daily (and probably monthly) October records would be obliterated all across NorCal. As always, keep in mind that this system is still a good 5-6 days from reaching the coast, and the forecast will likely change quite a bit between now and then. Even so..the potential for a storm of this magnitude in CA in October is extremely unusual, and it bears close watching. SoCal may be spared much significant weather from this system aside from some light precipitation, but there has been a distinct shift southward with model forecasts thus far. Again: stay tuned.

What is causing this highly anomalous storm potential so early in the season? Former super typhoon Melor, now a tropical storm off the north coast of Japan after striking near Tokyo as a category 1 storm, is currently being absorbed into the Westerlies. A large volume of moisture has already been sheared off of the decaying tropical cyclone and is traversing the Pacific at this time. The remnant circulation of the typhoon is expected to become the surface low of the new extratropical cyclone that may cause all of the action next week. As mentioned previously, this is not dissimilar to the setup of the Columbus Day Storm of 1962. There is no indication that this storm will even approach the magnitude of that storm in terms of maximum wind speed, but it’s also important to keep in mind that that benchmark event affected WA and OR most severely, leaving NorCal with only moderate damage (which has since been repeated in subsequent storms in the intervening decades). In terms of its effect on CA, the storm next week very well could be similar.

Another slightly more technical note: all the models are showing a truly incredible degree of isentropic lift over NorCal during the warm frontal passage and even right up to near the cold front itself. Not only will this tend to dramatically enhance orographic effects, but there may also be an enhanced chance of convection associated with it. In addition, the new GFS has a 150 kt jet streak over CA with the left exit region over–you guessed it–NorCal. Pretty cool stuff for October, I will say…

  • Tom in San Diego

    The UJEAS thingy is modeling the same followed by a monster ridge of equal size for week 4. Logical.

    Be nice for Socal to at least get a shower or two out of it, Im sure we’ll get some wind and a heightened sea state, but well have to see how it developes. Im guessing given the time of year, it will most likely stay north, but as you point out its still a 5 day horizon.

  • Tom in San Diego

    We are due to get underway next month for some blue water ops between Station November and Sitka – Prince Edward Sound and Seward. Could be interesting.
    And cold.

  • http://www.wunderground.com/blog/Inyo/show.html Inyo

    wow, I just saw that run, pretty amazing if that pans out. Figures something like this would happen after I leave…

    Meanwhile, in the long term, the -10 isobar is getting near Vermont at the same time that light precipitation is in the area. Not hard to guess what that might mean…

  • nicholas

    Looks like So Cal could pick up a mighty drizzle storm at best if this pans out…

  • http://www.wunderground.com/blog/Inyo/show.html Inyo

    i dunno, looked pretty impressive to me, from the last run, also would have snow flurries at my location in 1 week.

  • http://weatherwest.com/current_weather Daniel Swain

    The storm looks even MORE impressive on current model runs–surface winds are now explicitly progged at 55 kts, without channeling enhancements…and we’re still looking at 5-10 inches of rainfall in some places…

  • redlands

    Daniel — so what does this mean for Southern California ??? Any rain, drizzle — I wont believe it till i see it — so many predicted flop storms

  • http://www.wunderground.com/blog/Inyo/show.html Inyo

    the last run had a half an inch for so-cal but like Daniel said the runs have been trending south so it could be more, especially in the mountains.

  • Norcal44

    Wow, this storm is starting to look really promising. I’ve never seen anything like this in the fall, let alone mid Oct. VERY impressive. 00z GFS spit out nearly 10in of rain for my area in 48 hours. Even the new 12z is showing 7.5in. Could be some MAJOR flooding issues next week in NorCal. As far as precip goes, this storm is looking very similar to the 1962 Columbus Day Storm.

  • Dan the Weatherman

    Those rain amounts mentioned for Norcal of 5-10 inches sounds really unrealistic for this early in the season. I will believe it when I see it, but I will continue to watch the situation closely. The latest NWS discussion out of Los Angeles / Oxnard does mention the possibility for drizzle for LA and the increased probability of rain next week, but San Diego NWS indicates that it may reach only as far south as Santa Barbara. It is still rather early to see any significant rain in Socal anyway, as we are still in Santa Ana season which comes just before the rainy season.

  • Dan the Weatherman

    Speaking of the Columbus Day Storm of 1962, I hope this season does not resemble 1962-63, which was a La Nina year. According to records, Los Angeles only received about 8.3 inches of rain for the season and no rain of any significance fell until late January, 1963. Los Angeles only received only about .1″ to .15″ of rain in October, which meant that the Columbus Day Storm largely bypassed the area or missed altogether.

  • nicholas

    California had 2 very impressive storms in October of 2004. I remember the first storm of that season was one of the most windy I can remember for the Whittier area. I woke up one or two times that night/early morning and felt the air rushing up under the house in my room. It was quite amazing. My dad stayed up most of the night and was worried that some of the big trees near my house was going to fall on the house.

    Here is one of the trees that fell and this was taken the day after the that storm in October. I think its a pine tree a ton of them in Whittier. Inyo might know what its called.
    http://img.photobucket.com/albums/v681/packerfan10/DSC00056.jpg?t=1255033817

  • Norcal44

    It’s definitely a possibility to recieve 5-10in of rain in NorCal with a moisture plume originating from once a very strong (cat 5.) typhoon. The Columbus Day Storm originated from a much weaker tropical cyclone then brought widespread 5-10in of rain to NorCal and strong winds. The models have been unbelievevably consistent as well. They started showing this storm a good 10 days out.

  • Tom in San Diego

    Well, the saner heads are prevailing at NWS San Diego, and they are not going with a wet prog yet, for next week. Citing the tendency for model waffling this far ahead. I would concur. Living on the drier side end myself, Im not going to fall for it either. Well get some rain later, but Id really be surprised if this one delivered this far south this early. Besides I’d rather play gold this weekend before it gets hot again.

  • Tom in San Diego

    Ceiling and visibility unrestricted today, id guess its in the low to mid 70′s, really nice day.

  • David

    what are the ch of seeing High Wind Warnings for the valley for this storm????

    SPECIAL WEATHER STATEMENT
    NATIONAL WEATHER SERVICE SACRAMENTO CA
    210 PM PDT THU OCT 8 2009

    CAZ013>019-063-064-066>069-091230-
    SHASTA LAKE AREA / NORTHERN SHASTA COUNTY-
    BURNEY BASIN / EASTERN SHASTA COUNTY-NORTHERN SACRAMENTO VALLEY-
    CENTRAL SACRAMENTO VALLEY-SOUTHERN SACRAMENTO VALLEY-
    CARQUINEZ STRAIT AND DELTA-NORTHERN SAN JOAQUIN VALLEY-
    MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE COUNTY-
    CLEAR LAKE/SOUTHERN LAKE COUNTY-
    NORTHEAST FOOTHILLS/SACRAMENTO VALLEY-MOTHERLODE-
    WESTERN PLUMAS COUNTY/LASSEN PARK-
    WEST SLOPE NORTHERN SIERRA NEVADA-
    210 PM PDT THU OCT 8 2009

    …WET AND WINDY WEATHER MONDAY THROUGH WEDNESDAY…

    ABUNDANT MOISTURE FROM RECENT SUPER TYPHOON MELOR IN THE WESTERN
    PACIFIC IS HEADING TOWARDS THE WEST COAST OF THE U.S. NWS COMPUTER
    MODELS COMBINE THIS MOISTURE WITH A POWERFUL JET STREAM AND DEVELOP
    A STRONG STORM THAT MOVES INTO THE AREA EARLY NEXT WEEK. THIS STORM
    HAS THE POTENTIAL TO PRODUCE A SIGNIFICANT AMOUNT OF PRECIPITATION
    FOR INTERIOR NORTHERN CALIFORNIA LATE MONDAY THROUGH WEDNESDAY ALONG
    WITH STRONG WIND.

    CURRENTLY…PRECIPITATION LOOKS TO BEGIN IN THE COASTAL RANGE
    MONDAY AFTERNOON SPREADING OVER INTERIOR NORTHERN CALIFORNIA BY
    MONDAY EVENING. PERIODS OF HEAVY PRECIPITATION ARE POSSIBLE MONDAY
    NIGHT THROUGH TUESDAY
    WITH MORE SHOWERY WEATHER LIKELY TUESDAY
    NIGHT INTO WEDNESDAY. PRECIPITATION AMOUNTS FROM MONDAY THROUGH
    WEDNESDAY IN THE CENTRAL VALLEY COULD EXCEED 2 INCHES WITH 3 TO 7
    INCHES POSSIBLE IN THE FOOTHILLS AND MOUNTAINS. SNOW LEVELS ARE
    EXPECTED TO REMAIN HIGH THROUGH THE EVENT…GENERALLY ABOVE 7000
    FEET.

    VERY STRONG WIND COULD ACCOMPANY THIS STORM…ESPECIALLY MONDAY
    NIGHT THROUGH TUESDAY AFTERNOON. AT THIS TIME IT APPEARS WINDS IN
    PORTIONS OF THE CENTRAL VALLEY COULD REACH SUSTAINED SPEEDS OF 40
    MPH WITH HIGHER GUSTS. WIND IN THE FOOTHILLS AND MOUNTAINS COULD
    BE STRONGER WITH GUSTS TO 60 MPH OR MORE. WINDS OF THESE SPEEDS CAN
    CAUSE PROPERTY DAMAGE AND DOWN BRANCHES OR TREES.

    MAIN STEM RIVERS AND STREAMS ARE RUNNING LOW FROM THE SUMMER AND
    ARE NOT EXPECTED TO HAVE SIGNIFICANT IMPACT. HOWEVER EXCESSIVE
    RUNOFF FROM HEAVY RAINFALL COULD PRESENT FLOODING ISSUES FOR
    SMALLER STREAMS AND TRIBUTARIES ALONG WITH URBAN AREAS. IN
    ADDITION…HEAVY PRECIPITATION FALLING ON BURN SCAR AREAS FROM
    PAST FIRES COULD LEAD TO DEBRIS FLOWS.

    THIS STORM HAS THE POTENTIAL TO PRODUCE SIGNIFICANT PRECIPITATION
    AND STRONG WIND FOR INTERIOR NORTHERN CALIFORNIA EARLY NEXT WEEK.
    LOOK FOR MORE DETAILED STATEMENTS TO BE ISSUED AS THE TIME DRAWS
    CLOSER. CONTINUOUS WEATHER INFORMATION IS AVAILABLE FROM THE
    NATIONAL WEATHER SERVICE ON NOAA WEATHER RADIO OR FROM THE
    INTERNET AT: http://WEATHER.GOV/SACRAMENTO.

    and look at this part PORTIONS OF THE CENTRAL VALLEY COULD REACH SUSTAINED SPEEDS OF 40
    MPH

    Daniel is this for real??

  • David

    i think the mts likt 8 too 9,000 i think the mts snow fall could be any where from 5 too 10ft of snow fall from this storm

    ok may be not 10ft but i think more like 5 too 7ft of snow

    what do you think Daniel sounds about right ??

  • http://www.wunderground.com/blog/Inyo/show.html Inyo

    Nicholas, it may be an Italian Stone Pine.

    As for this storm, it could be pretty interesting in nor-cal. in so-cal i doubt it compares with the very wet October 2004 storms, but if it goes further south, it could. There have been cases where remnant tropical systems drenched so-cal in October, but usually from the east pacific.

  • David

    i no you this started this blog Daniel but vary soon here be for the weekend is done you may have too give us other full update on this storm

    looks like this storm is comeing in a little more S then forcast

  • nicholas

    David the storm looks even better on the 0z :)

  • Dan the Weatherman

    It is looking more likely that Socal (Los Angeles Basin including Orange County) will receive at least some rain Tuesday or Wednesday, so this may be our first rain of the season. It will not likely be heavy down here like it will be in the Bay Area, but it is still too early to tell. It looks as if Santa Ana winds may follow later in the week toward the weekend after the storm passes.

  • Norcal44

    SFO NWS Discussion

    HEAVY RAIN
    STRONG GUSTY WINDS SHOULD LAST THROUGH WED EVENING THEN SHOULD SEE
    WINDS AND RAIN DIMINISH AS THE FRONT PASSES SOUTH. EURO AND 00Z GFS
    INDICATING PWS APPROACH 2 IN OFFSHORE CENTRAL CA WITH WINDS AT THE
    925 MB LEVEL OF 55 TO 60 KTS. THIS IS A VERY POTENT COMBINATION
    AND SHOULD PRODUCE COPIOUS AMOUNTS OF RAIN AT THE HIGHER ELEVATIONS
    WITHIN THE FORECAST AREA. FIVE TO EIGHT INCHES OF RAIN FOR THE
    PERIOD MONDAY NIGHT THROUGH WED MORNING ARE CERTAINLY POSSIBLE WITH
    LOCALIZED AMOUNTS OF CLOSE TO 10 IN. THE KEY WILL BE HOW LONG THIS
    ATMOSPHERIC RIVER OF VERY HIGH MOISTURE LINGERS OVER ANY GIVEN
    LOCATION. WITH SOME GOOD UPPER DYNAMICS ASSOCIATED WITH 155KT 200
    MB JET SHOULD EXPECT LOWER ELEVATIONS OUTSIDE ANY SIGNIFICANT RAIN
    SHADOWING TO RECEIVE 1 TO 3 INCHES OF RAIN AND POSSIBLY MORE.
    TRYING TO DRAW ANALOGIES TO PREVIOUS EVENTS IS ALWAYS TRICKY. WE
    HAVE LOOKED AT RECENT EVENTS LIKE JAN 4-5 2008 AND DEC 12, 1995 AS
    CLOSE COUSINS TO WHAT MODELS ARE FORECASTING. THIS STORM HAS HIGHER
    MOISTURE SUPPLY BUT MAY NOT HAVE AS SIGNIFICANT A WIND COMPONENT.
    AGAIN WE ARE STILL SEVERAL DAYS OUT AND TRYING TO PINPOINT EXACT
    IMPACTS ARE DIFFICULT. WILL UPDATE THE SPS THIS AFTERNOON TO TRY AND
    HIGHLIGHT EXPECTED IMPACTS OF WHAT IS EXPECTED TO BE A VERY
    SIGNIFICANT EVENT…ESPECIALLY FOR THE FIRST STORM OF THE YEAR.

    Amazing that a storm in Oct. is on the same level as the Jan. 4th 2008 storm. That was a really strong storm for my area. I recieved 5″ of rain and wind gust to 80mph. We lost power for over a week.

  • http://weatherwest.com/current_weather Daniel Swain

    This is one of those rare events that just keeps looking more and more impressive as it get closer. The 6z GFS was less impressive, only forecasting a “strong” storm, instead of a record-breaking and massive one. The 12z GFS is back on track in indicating a rather unprecedented October storm. In fact, the 12z run may be the most dynamically powerful and perfectly phased iteration yet. The most recent GFS run now indicates 1 or 2 75-80 kt wind barbs at 850 mb–which would, if it pans out, would lead to potentially destructive winds at the surface, with gusts in favored locations well above 70 mph (and perhaps above 80 mph). This is looking like it will probably be at least as strong as the January 2008 event in NorCal, and possibly approaching the magnitude of the December 1995 event. Usually, during powerful storm events, we either get extremely strong winds or extremely heavy rainfall, but usually not both at the same time. Certainly, relatively strong winds can coincide with very heavy rainfall and vice versa, but this storm has the potential to bring rather extreme amounts of both. The 12z GFS also shows the potential for 5-10 inches of rain in parts of the Bay Area over a 24-48 hour period, with the potential with 3-6 inches in only 12 hours. This presents a large flash flooding threat, even in the absense of antecedent wet conditions or burn scars. Also…the models have been bringing an increasing amount of rain and wind to more southern parts of the state. While an extreme event is not expected there…it now appears there may be enough rainfall to cause flash flooding in burn areas and perhaps put the brakes on the fire season. There will be a full update over the weekend. One thing that is truly remarkable is the consistency with which the models have been indicating a truly unusual and extreme event–with the exception of the 6z GFS today, every single control run of the GFS and ECMWF have been indicating almost the same thing for several days (and the most recent 12z does, as well). Stay tuned…

  • redlands

    I hope we get some decent amount of rain out of this storm — I was looking at my weather records for Redlands, Calif — Redlands received 6.07 of rain in October of 2004 — the average which i have like 27 years of data for October is 0.64 — with that amount of 6.07 raising the average – which would be lower without that large amount — That amount ranks at 7th largest monthly amount overall– impressive amount

  • nicholas

    Oh no the 6z and 12z looks like we are back to just a stronger marine layer with a drizzle storm for So Cal.

  • redlands

    Was looking more into October 2004 — Redlands, Ca received 9 days of rain — on Oct – 17 0.85 20th — 2.59 27th 2.09 — these are big amounts for Redlands — maybe not for other amounts but real impressive for the Redlands area —

  • nicholas

    Who wants to rent a car and get away from the drizzle part of the storm and go north into the best part of the storm?

  • redlands

    Am not gonna get too excited bout this approaching storm — my are will be lucky to get a few drops — wont get excited till i see it happen — when they predict big storms it trns into a big flop — wehen there predicting a small storm it turns into a biggie storm

  • nicholas

    One interesting thing about the NAM 18z was the placement of tropical moisture near Baja. It shows it at hour 84. That sort of looks like a new feature. If that moisture worked into the cold front I bet So Cal would be looking at more then just what the GFS shows. The 18Z came in a little better then the bone dry 12Z.

  • Tom in San Diego

    Redland I agree, models are flip flopping on every run for us.
    I’d say mostly dry, slight chance for Orange and N SD county.

    Of course what the models are NOT flip flopping on is a major high ridge, week after next.

  • Dan the Weatherman

    The models seem to seldom disagree on building any type of ridge down here no matter what time of year it is, but they sure flip-flop on storms, though.

  • David

    i think we may see rain fall rates never be for seen here in ca

    i think it will be raining 1 too 3″ per hr

  • http://weatherwest.com/current_weather Daniel Swain

    Given a PW plume of around 2 inches, it would be physically impossible to rain at 3 in/hr. Granted, this storm may produce very high rain rates, but “very high” in the context of CA is around 0.5-0.75 in/hr (and perhaps up to 1 in/hr very locally) for several hours. Everything is still on track for a monster storm in NorCal…

  • redlands

    How is it looking for Southern California — looks like a 40% chance but there delaying the storm

  • redlands

    now its only 20 % chance — guess i should forget any thoughts of rain

  • redlands

    Just watched a weather on tv and its stating 1-2 inches in southern calif — is that really accurate — noaa stating only a 20% chance — whats up

  • nicholas

    Its all come down to this. If you are in So Cal you want the GFS to win out. If you are in No Cal you want the Euro to win. :)

  • nicholas

    Here is some great data for the bay area. Might bring back some memory’s. This is the bay areas strongest storms. http://ggweather.com/basi_archive.htm

  • Shady Blues

    Recent runs of GFS have dramtically increased rain amounts in southern california. It is now 1-2″ of rain! what a big change over a couple of days! hopefully this southward trend continues for increased rainfall in southern california.

  • redlands

    Nicholas — great stats — concerning for the Bay area – San Francisco — Wow gust to 110 mph — Redlands, Ca dont have that kinda wind gust — maybe in San Bernardino Cajon Pass , Rialto Fontana — So whats the new info on this storm

  • Tom in San Diego

    No way, nicht, nada, naga hatchi. Mostly cloudy for us. Too far north and too high, plus we got a small high dome coming in Monday.

  • redlands

    so u dont think any rain will fall tom ???