Anyone who ever said that winter weather in California was boring has never experienced a pattern like the one we’re headed for over the next several weeks. After a very prolonged period of benign and mostly dry weather across the entire state brought about by an anomalously and almost bizarrely persistent high-latitude block for much of the winter season thus far, a major shift in the hemispheric flow pattern will being a prolonged period of heavy rainfall and strong winds to the entire state of California. Though there have been a few large storms California over the last few years, the first decade of the new millennium was generally not known for its active weather patterns in our state. The new decade appears to be trying to make up for some lost time in that regard. For the first time in at least several years, a powerful southern stream branch of the jet stream over the Pacific is expected to roar across CA for at least the next two weeks, potentially bringing a tremendous amount of precipitation and frequent strong wind events.
First things first, however. A decent rainmaker moved through Northern California overnight, bringing mostly moderate but locally heavy precipitation. Looking out the window this afternoon, I see the first direct sunlight in weeks here in the fog-plagued Central Valley, but this break will be short-lived as there is a rather potent-looking convective system several hundred miles off the coast. This system will lift northeast and move inland overnight, bringing periods of rain with embedded thunderstorms to much of NorCal. Precipitation could be locally heavy once again due to convective elements. SoCal will stay dry from this system except for perhaps a few light showers in the north. Showers and thunderstorms wane by tomorrow afternoon in the north and the Central Valley will likely see a couple more days of dense Tule fog as a brief quiescent period occurs between Thursday and early Saturday. Later on Saturday, however, the first of a great number of strong to powerful storms will begin approach the coast.
16-day GFS precipitation accumulation. Note that the scale is much larger than on typical precipitation maps.
All this excitement revolves around the southern branch of the jet stream over the Pacific, which is known to be energized by El Nino. Currently, the strong El Nino is reaching its peak in the Eastern Pacific, and now finally appears to be exerting an influence on our weather. The strong jet has been apparent for quite some time out over the open water, but the persistent block had prevented it from reaching the coast. Now that the block has dissolved completely, a 200+ kt jet is barreling towards us. Multiple large and powerful storm systems are expected to slam into CA from the west and northwest over the coming two weeks, all riding this extremely powerful jet stream directly into the state. The jet will itself provide tremendous dynamic lift, in addition to directing numerous disturbances right at the state and supplying them with an ample oceanic moisture source. The jet will be at quite a low latitude over much of the Pacific, so these storms will be quite cold, at least initially. Very heavy rainfall and strong to potentially very strong winds will impact the lower elevations beginning late Sunday and continuing through at least the following Sunday. This will be the case for the entire state, from (and south of) the Mexican border all the way up to Oregon. Above 3000-4000 feet, precipitation will be all snow, and since temperatures will be unusually cold for a precipitation event of this magnitude, a truly prodigious amount of snowfall is likely to occur in the mountains, possibly measured in the tens of feet in the Sierra after it’s all said and done. But there’s a big and rather threatening caveat to that (discussed below).Individual storm events are going to be hard to time for at least few more days, since this jet is just about as powerful as they come (on this planet, anyway). Between this Sunday and the following Sunday, I expect categorical statewide rainfall totals in excess of 3-4 inches. That is likely to be a huge underestimate for most areas. Much of NorCal is likely to see 5-10 inches in the lowlands, with 10-20 inches in orographically-favored areas. Most of SoCal will see 3-6 inches at lower elevations, with perhaps triple that amount in favored areas.
This is where things get even more interesting, though. The models are virtually unanimous in “reloading” the powerful jet stream and forming an additional persistent kink 2000-3000 miles to our southwest after next Sunday. This is a truly ominous pattern, because it implies the potential for a strong Pineapple-type connection to develop. Indeed, the 12z GFS now shows copious warm rains falling between days 12 and 16 across the entire state. Normally, such as scenario out beyond day seven would be dubious at best. Since the models are in such truly remarkable agreement, however, and because of the extremely high potential impact of such an event, it’s worth mentioning now. Since there will be a massive volume of freshly-fallen snow (even at relatively low elevations between 3000-5000 feet), even a moderately warm storm event would cause very serious flooding. This situation will have to monitored closely. Even if the tropical connection does not develop, expected rains in the coming 7-10 days will likely be sufficient to cause flooding in and of themselves (even in spite of dry antecedent conditions).
An ominous “Pineapple Express” connection, GFS model
In addition to very heavy precipitation, powerful winds may result from very steep pressure gradients associated with the large and deep low pressure centers expect ed to begin approaching the coast by early next week. Though it’s not clear at the moment just how powerful these winds may be, there is certainly the potential for a widespread damaging wind event at some point, and the high Sierra peaks are likely to see gusts in the 100-200 mph range (since the 200kt jet at 200-300 mb will essentially run directly into the mountains at some point). The details of this will have to be hashed out as the event(s) draw closer.
In short, the next 2-3 weeks (at least) are likely to be more active across California than any other 2-3 week period in recent memory. The potential exists for a dangerous flood scenario to arise at some point during this interval, especially with the possibility of a heavy rain-on-snow event during late week 2. In some parts of Southern California, a whole season’s worth of rain could fall over the course of 5-10 days. This is likely to be a rather memorable event. Stay tuned.
Tags: El Nino, Flooding, Major, Rain, Snow, Storm, Wind, Winter
Looks to be very interesting, reminds me of the 1979-1980 event, if not potentially worst this time around. Time will tell, soon.
I think everyone is in the kind of “believe it when we see it mode”. California is long overdo for something historic weather wise.
Nicholas – I would have to agree with you — believe it when I see It !!!!
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1242 PM PST TUE JAN 12 2010
AZZ001>003-036-CAZ519>527-NVZ014>022-131100-
NORTHWEST PLATEAU-LOWER COLORADO RIVER VALLEY-NORTHWEST DESERTS-
LAKE MEAD NATIONAL RECREATION AREA-EASTERN SIERRA SLOPES-
OWENS VALLEY-WHITE MOUNTAINS OF INYO COUNTY-
DEATH VALLEY NATIONAL PARK-WESTERN MOJAVE DESERT-
EASTERN MOJAVE DESERT-MORONGO BASIN-CADIZ BASIN-
THE UPPER COLORADO RIVER VALLEY OF EASTERN SAN BERNARDINO COUNTY-
ESMERALDA AND CENTRAL NYE COUNTY-LINCOLN COUNTY-
NORTHEAST CLARK COUNTY-WESTERN CLARK AND SOUTHERN NYE COUNTY-
SHEEP RANGE-SPRING MOUNTAINS-LAS VEGAS VALLEY-
SOUTHERN CLARK COUNTY-
1242 PM PST TUE JAN 12 2010 /142 PM MST TUE JAN 12 2010/
IT IS TOO EARLY TO PINPOINT EXACTLY WHERE
AND WHEN THE MAIN IMPACTS WILL OCCUR…BUT THE OVERALL PATTERN IS
SIMILAR TO THE ONE WHICH AFFECTED THE WEST COAST IN JANUARY OF
1995…WHICH WAS ALSO AN EL NINO PERIOD. LAS VEGAS RECEIVED THREE
INCHES OF RAIN…NEARLY THREE QUARTERS OF THE YEARLY AVERAGE…IN
JANUARY 1995.
“The models are virtually unanimous in “reloading” the powerful jet stream and forming an additional persistent kink 2000-3000 miles to our southwest after next Sunday. This is a truly ominous pattern, because it implies the potential for a strong Pineapple-type connection to develop. Indeed, the 12z GFS now shows copious warm rains falling between days 12 and 16 across the entire state.”
That is the kind of pattern that brought San Diego the “50 year” floods we experienced in 1916, and about every 20 odd years since; ’67, ’81 and ’93, being in recent memory. Where a northwest storm and a southwest jet join up. If this kind of thing developes, hang on to your skivvies !
Naw, not going to happen Tom. The Models have already backed off on that idea.
Right?
Not much.
The models have been reducing precip across socal too. :/
Not really. See 18z run for further elucidation…that’s a lot of purple shading over SoCal…
Daniel 10ft or more of snow all so i have more
000
WWUS86 KSTO 132210
SPSSTO
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SACRAMENTO CA
210 PM PST WED JAN 13 2010
CAZ013>019-063-064-066>069-141300-
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 PST WED JAN 13 2010
…INTERIOR NORTHERN CALIFORNIA TRANSITIONS TO A WETTER WEATHER
PATTERN NEXT WEEK…
A VERY STRONG JET STREAM IS MAKING ITS WAY ACROSS THE PACIFIC AND
WILL TRANSITION INTERIOR NORTHERN CALIFORNIA INTO A WETTER WEATHER
PATTERN NEXT WEEK. AS A RESULT…AN EXTENDED PERIOD OF MUCH NEEDED
SIGNIFICANT PRECIPITATION IS EXPECTED. A RELATIVELY WEAK STORM MOVES
THROUGH SATURDAY…THEN MUCH STRONGER AND WETTER SYSTEMS WILL BEGIN
SUNDAY AND CONTINUE INTO NEXT WEEK. ALTHOUGH TIMING OF INDIVIDUAL
STORMS IS DIFFICULT AT THIS POINT…IT LOOKS LIKE EVERY 24 TO 36
HOURS A SYSTEM WILL MOVE THROUGH. RAINFALL TOTALS BY THE END OF NEXT
WEEK COULD EXCEED 5 TO 10 INCHES IN THE LOWER ELEVATIONS WITH SNOW
AMOUNTS OF 10 FEET OR MORE POSSIBLE OVER THE HIGHER SIERRA
NEVADA. SNOW LEVELS WILL GENERALLY BE AROUND 4000 TO 5500 FEET
BUT AT TIMES COULD DROP INTO THE FOOTHILLS. THERE IS ALSO LIKELY
TO BE PERIODS OF BREEZY TO WINDY CONDITIONS AND TRAVEL INTO THE
MOUNTAINS IS LIKELY TO BE IMPACTED.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
425 PM PST WED JAN 13 2010
BESIDE THE RAIN…WIND WILL BE THE OTHER STORY AS SEVERAL
AREA OF DEEP LOW PRESSURE WILL FORM NEAR THE BC AND WASHINGTON COAST
THROUGH NEXT WEEK HELPING TO BRING A STRONG SURFACE GRADIENT ACROSS
THE CWA. GFS/DGEX BOTH BRING IN 60-70 KT 850 MB WINDS TO SECTIONS OF
THE CWA TUESDAY NIGHT THROUGH WEDNESDAY SUGGESTING THAT WINDS COULD
BE VERY GUSTY
wait i have more
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
255 PM PST WED JAN 13 2010
SURFACE LOWS ASSOCIATED WITH THESE STORMS ALSO APPEAR STRONG WITH
POTENTIALLY A 970S MB LOW REMAINING OFF THE COAST OF OREGON. IN
SUMMARY…WE MAY BE LOOKING AT AN EXTENDED PERIOD OF MODERATE TO
HEAVY RAIN AND STRONG SOUTHERLY WINDS AT LOWER ELEVATIONS…AND
HEAVY SNOW AND BLOWING SNOW OVER THE MOUNTAINS. CONTINUE TO STAY
TUNED AS THE DETAILS AS WE CONTINUE TO REFINE THE DETAILS. DANG
000
FLUS46 KMTR 132302
HWOMTR
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
302 PM PST WED JAN 13 2010
CAZ006-505>513-516>518-528>530-141600-
SAN FRANCISCO-
COASTAL NORTH BAY…INCLUDING POINT REYES NATIONAL SEASHORE-
NORTH BAY INTERIOR VALLEYS-NORTH BAY MOUNTAINS-
SAN FRANCISCO BAY SHORELINE-SAN FRANCISCO PENINSULA COAST-
EAST BAY INTERIOR VALLEYS-EAST BAY HILLS AND DIABLO RANGE-
SANTA CRUZ MOUNTAINS-SANTA CLARA VALLEY…INCLUDING SAN JOSE-
SOUTHERN SALINAS VALLEY…ARROYO SECO…AND LAKE SAN ANTONIO-
SANTA LUCIA MOUNTAINS AND LOS PADRES NATIONAL FOREST-
MOUNTAINS OF SAN BENITO AND INTERIOR MONTEREY COUNTY INCLUDING
PINNACLES NATIONAL MONUMENT-
NORTHERN SALINAS VALLEY…HOLLISTER VALLEY…AND CARMEL VALLEY-
NORTHERN MONTEREY BAY-SOUTHERN MONTEREY BAY AND BIG SUR COAST-
302 PM PST WED JAN 13 2010
THIS HAZARDOUS WEATHER OUTLOOK IS FOR SAN FRANCISCO BAY AREA AND
MONTEREY BAY AREA.
.DAY ONE…WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT
PARTLY CLOUDY SKIES WITH AREAS OF PATCHY FOG ARE EXPECTED TONIGHT.
SOME LOCATIONS MAY HAVE DENSE FOG ESPECIALLY OVER THE NORTH AND
EAST BAYS.
.DAYS TWO THROUGH SEVEN…THURSDAY THROUGH TUESDAY
A SERIES OF STORMS ARE EXPECTED TO ROLL ACROSS THE SAN FRANCISCO
AND MONTEREY BAY REGIONS. AFTER SOME LIGHT RAIN ON SATURDAY THE
FIRST LARGE STORM IS FORECAST TO SPREAD MORE SUBSTANTIAL RAIN
INTO OUR AREA LATE SUNDAY INTO MONDAY. ADDITIONAL STORMS ARE THEN
EXPECTED FOR MUCH OF NEXT WEEK. DUE TO MANY DAYS OF RAINFALL
ACCUMULATION…HYDROLOGIC CONCERNS ARE EXPECTED. IN ADDITION…THESE
STORMS ARE FORECAST TO PRODUCE STRONG WINDS BOTH OVER THE WATER
AND LAND WHICH MAY TRIGGER BOTH WIND ADVISORY AND WARNING PRODUCTS
TO BE ISSUED.
Of course the details are going to change quite a bit from run to run. Things should get a little more clear in the next few days.
dont for get i was the 1st too see this on the mode runs so dont say i did not tell you so
Major pattern change still on track. I will update on Friday.
O.o I am going to start building my boat soon if the 12z was right. Look this is insane. I can only recall one other time since I have started looking at the models seeing that 3 inch bullseye right over the area, that was way out like at day 8.
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_slp_108s.gif
Yes, the 12z depicts a very scary scenario for SoCal, especially considering it is only 4 days out. The latest GFS appears to be picking up on the idea of SoCal getting most of the energy over the next 10 days, rather than NorCal. I think this scenario makes more sense considering how deep the trough looks to be. The greatest dynamics appear to begin in NorCal begining Sunday, then shift south to SoCal and San Diego by later in the week. This isn’t to say that NorCal will not see any rain, or strong winds as I believe this area will also see a healthy dose of both. Just as of right now, I see SoCal getting hit the hardest with what looks to be damaging flooding rains, and mud slides over the next 7-10 days.
About time we get the hardest.
Interesting Incident in So. Cal. Brush Fire, Tenaja Fire in the Mountains west of Temecula. 50 acres with potential of 200 plus sending air craft and engine strike teams. winds 15 to 25 MPH. The winds are to pick up tonight 60 to 80 mph in favorite canyons and 30 to 50 in the foothills and valleys. The ole santa ana giving its last big blow before the big rains.
Like the old timers used to say: Rain 3 days after a santa ana.
‘Nuther gorgeous day. No ceiling, no layer, no fog. It was 77 degrees on the bayside of Pt Loma around noon, 74 cliffside.
ALONG THE WEST COAST THERE ARE AT LEAST 3 TO 4 SURGES COMING INTO
THE WEST COAST IN THE FAST PAC FLOW THIS PERIOD EACH WITH ROUNDS
OF HVY PCPN. AT THIS TIME THERE IS REASONABLE AGREEMENT ON THE
SHORTWAVES EMBEDDED IN THE FLOW TO COME IN AROUND
SAT-SUN..MON..TUES AND ANOTHER THURS-FRI WITH MORE TO FOLLOW.
MONDAYS SURGE HITS THE ENTIRE COAST FROM VANCOUVER SOUTH TO PT
CONCEPTION BUT THEN AS THE HTS FALL AND THE JET CORE SHIFTS SWD
THE TARGET AREA WILL BE MORE INTO CENTRAL CA AND SRN CA TUES
ONWARD. THIS EVENT HAS THE POTENTIAL TO APPROACH OR RIVAL THE
JAN/FEB 1998 EL NINO EVENT IN CENTRAL CA AND THE JAN 1995 TIME
FRAME FOR SOCAL. QPF TOTALS FROM MODEL GUIDANCE ARE VERY HIGH WITH
AN OVERALL RANGE OF 7-12 LIQUID INCHES DURING THIS FORECAST PERIOD
OVER COASTAL REGIONS/SIERRA. EXPECT CONSIDERABLY HIGHER AMOUNTS
OVER A MULTIDAY PERIOD WITH 10-20 INCH MOUNTAIN AMOUNTS WITH EVEN
HIGHER OVER FAVORABLE TERRAIN. SIERRA MOUNTAIN SNOWS MAY BE IN THE
8-12 FOOT RANGE. AS THE JET CORE SHIFTS SOUTHWARD THE HEAVIER PCPN
WILL BE MORE CONCENTRATED INTO SRN CA WHERE SIMILAR RAINFALL
NUMBERS MAY OVER ESPECIALLY OVER FAVORABLE TERRAIN. SOME LOCAL
FAVORED TERRAIN AREAS WILL MOST LIKELY APPROACH 20 INCH LIQUID
AMOUNTS DURING THIS PERIOD WITH THE EVENT CONTINUING PAST OUR 7
DAY RANGE YIELDING EVEN HIGHER TOTALS. VERY HVY SNOWS CAN BE
EXPECTED OVER HIGHER TERRAIN AND A FLOODING/MUDSLIDE PROBLEMS
APPEAR LIKELY. A HEAVY RAIN THREAT FOR AZ APPEARS IN STORE THURS
INTO SAT. SEE CPC THREATS ANALYSIS AND LOCAL NWS OFFICE
STATEMENTS/ADVISORIES AND EVENTUALLY WARNINGS. HIGH CONFIDENCE
EVENT WITH PAC RECON REQUESTED.
Since when do they do a RECON on winter storms…!??!!? i thought they were for tropical storms and hurricanes? are these storms next week that powerful???
Like, I said, this extended event is looking more and more serious, especially for southern California. It’s possible we’ll get a 2-3 day break around days 11-13, and then this whole pattern repeats itself. If that happens, we’ll have even more trouble. As it is, I expect a fairly serious flooding situation to develop over at least parts of the state during the next 7 days. Individual storms still hard to pinpoint, and the models may be handling individual impulses poorly, but overall a very heavy rain and wind event is still on track for the entire state. Most recent 2 runs of GFS had phenomenal SoCal rainfall totals–on the order of 10 inches or more for lower elevations…
If its to good to be true right… The 0z not quite as impressive.
Just a note: I have no problem with people re-posting content from this site elsewhere on the internet (in fact, I encourage it), but please remember to include either a link back to Weather West or a mention of the site by name.
Thanks,
Daniel
I honestly cant believe the totals that there predicting — ive seen various totals — think abc7 said inland empire receiving like 14 inches tops — i saw a prediction saying the deserts receiving 1.5-3.5 of rain — i think that prediction is cost to what Redlands, Ca will receive — hopefully more
redlands will receive much more being below gorgonio. I’d like to see specifically which areas they are stating will receive significantly more precip due to orographical enhancement (30″+). Are we talking areas along the rim like Crestline, rimforest, blue jay?? Seems like running springs will see more than 4′-8′ snow if just down the road is getting 30″ rain….
(new timer here! Need a place to talk weather if you all don’t mind, I live the San Bernardino Mnts @ 6300′, can’t wait! but also nervous…)
Alan — where in the mountains do u live ???? my aunt lives in Angeles Oaks ?? Am in Redlands, Ca
In ’93, they predicted 2 to 3 inches; 10 days later we had 19 inches measured, and where I live near the Tijuana slough, over 10 million in crop and property losses. and half of Tijuana’s uncollected rubbish.
We’ve built flood walls, levees and sewage intercepts since then, but the poblem of overgrowth, now protected thanks to the environmental nuts, remains, we’ll seew hat happens this time.
San Diego afternoon watch has mentioned in their forecast discussion, a rex block forning(ed) in the SW Texas/N., Mexico region, and has set back their prog. for any heavy stuff until Tuesday, but still leaving the chance for rain in for Sunday.
I wont make another monster cut and paste as there are enough of those on here already.
I remember these Rex Blocks and Mexican highs pop up in the past and watched the weather systems past to the north and all we got was high clouds, this rex block is not good news for us in S.D. This will most likely keep the Jet north of us. I am hoping the jet will smash the Rex. The problem is I have seen this happen to much over the past.
Looking at the bright side there is a lot of energy out there to move Rex east. Will go with that.
Update on the way by late PM. Things still quite on track…
Ken’s right, I dont think its going to make much difference, after Monday. NWS SD admits as much.
As a matter of fact, NWS SD didn’t even mention the rex block pattern in their afternoon discussion. It was the mid-morning discussion where that was stated, and the latest forecast calls for a 40% chance of rain here in Orange County by Sunday and 70% by Sunday night.
Please let the rain come — no blocking the storms
This posting was excerpted and passed around the nation, popularly (but inaccurately) attributed to the USGS and CalFire. Right now there are literally thousands of webpages, dating from about the 14th to the 17th of January that have portions of this text showing.