Storm To Put Small Dent In Severe Drought – Warmth Records Set – Return To Dry, Cooler Weather

The warm temps on Wed were the 20th consecutive day of RECORD-SETTING temps for CA.  Many of those new records during the past 20 days beat those that were set during the Great Drought of 1976, and some broke ALL-TIME RECORDS for the month of January!  A list of the new records for CA during Sun/Mon/Tue/Wed is provided below. 

The most significant single wet storm of the Season is moving thru NORCAL attm, with heavy orographic rains falling into the northern Sierra and 24hr accumulations topping 2 inches at several stations near Tahoe to the Feather River basin.   The storm has tapped into a high PWAT subtropical tap of moisture originating from Hawaii and a developing shortwave disturbance west of Cape Mendocino will drive the system thru CENCAL on Thursday, with brief mod/heavy rainfall, enhancing over the Sierra producing generous precip.  The frontal boundary stalled for about 6hrs over the SAC region which kept a moist flow into the Feather, Yuba and American River basins producing high accumulations.  The latest GFS charts show that this storm is basically the one and only best chance of widespread precip for NOR/CENCAL depicted on the 16 Day GFS charts, as most of the possibilities for rainfall into CENCAL have been edited out, with week #2 turning mostly dry and cooler.  In the meantime, both Coasts continue to set records at opposite extremes; West Coast records for heat with temps +15° above average and CA experiencing the past 20 consecutive days with Record-Setting temps, and the East Coast records for cold being up to -30° below average. 

 The exceptionally warm, dry and stable wx conditions are nearing an end on Wed as the long awaited pattern shift opens the storm door for a few days to receive some much need rainfall into NOR/CENCAL.  Heavy precip of up to 2-3 inches is forecast for the Northern Sierra Wed/Thu with lighter amts spreading into the Southern Sierra Thu and tapering off on Fri.  This puts a small dent into the Severe Drought for NORCAL and has less impact upon CENCAL.  The Record-Setting max temps for CA reached its 20th consecutive day on Wednesday, which is the possible end of an unprecedented stretch of a mid-winter heat wave, that has exacerbated the situation with Severe Drought conditions by producing soaring evapotranspiration rates.  The record-setting temps for the past 20 days have produced a net loss of water thru evaporation of up to 3.50 inches and since Dec 1st has produced a net loss thru evaporation of up to 5.0+ inches for the SJV and Southern Sierra foothill regions below the inversion around 3,000ft.  The is especially relevant for Tulare and Kern Co.  The air has been so dry in the CENCAL region that Bakersfield has had only one day of fog this season, and Fresno has had a FOG FREE season so far, with zero days with fog thus far!  Even during the Great Drought of 1975-77 Fresno had 26/27 days with fog, but not this year!  This is the first time in both BFL and FAT climate history’s to experience such a dramatic reduction of the infamous Tule Fog.  Also, the unseasonably warm record-setting warmth is causing many tree crops to bud very early this year, with Orange, Almond and Peach trees sending out new growth and/or flowering…way ahead of schedule, without the proper seasonal ‘chilling’ required.  The longer range progs show an immediate return to mostly dry but cooler conditions beginning Fri, Jan 31st thru Fri, Feb 14th, with chances of morning frost returning.

CA Dept of Public Health on Jan 28^th identified and offered support to 17 CA communities which may face severe water shortages in the next 60-100 Days, link; http://www.acwa.com/news/water-supply-challenges/cdph-eyes-17-rural-communities-vulnerable-drinking-water-supply-due-dro

On Jan 28^th electronic readings from the Sierra indicated that the Snowpack Water Equivalent (SWEQ) had dipped to 10% of normal to date, with a Statewide SWQE of only 2 inches!  Chart below ↓

The Second 2014 Snow Survey is set for Jan 30, link; http://www.acwa.com/news/water-supply-challenges/second-snow-survey-2014-set-jan-30-conditions-expected-be-dry-despite-p

Mammoth Mt Summit reporting 70mph WSW winds as the storm approaches CENCAL with precip reaching Stockton at midnight with enhancement along the frontal boundary occurring as the front widens from SAC down to Stockton at midnight, with a clearly delineated Mork rain/no rain line along the south flank of the front.   Maximum 45dBz reflectivity on radar observed moving into the Sierra east of SAC. 

24hr Precip Summary highlights to midnight Wednesday as follows; 2.32 Huysink, 2.20 La Porte, 2.09 Alpine Mdws, 2.04 Forni Ridge, 1.88 Greek Store, 1.80 Blue Canyon, 1.75 Donner Lake, 1.64 Gold Lake, 1.52 Alleghany, 1.40 Bucks Lake, 1.37 Brush Crk, 1.32 Bald Mtn, 1.30 Rollins Reservoir, 1.17 Manzanita Lake, 1.16 Humbug, 1.15 De Sabla, 1.12 Gasquet, Fort Dick, Sugar Pine, 0.96 Bucks Crk, 0.92 Four Trees, Cavelo 0.86 Crescent City, 1.08 Orick, 1.00 Miranda, Leggett, 0.88 Strawberry Valley, 0.84 Sierraville, 0.77 Friend Mt, 0.76 Pacific House, 0.75 South Lake Tahoe, 0.74 Arcata, 0.72 Ruth Lake, 0.71 Lake Davis, 0.68 Black Springs, 0.61 Englebright Dam, 0.60 Hillcrest, Oroville Dam, 0.59 Big Hill, 0.58 Farad, 0.57 Lassen Lodge, 0.56 Taylor Ridge, Georgetown, Willits, Bridgeville, 0.52 Honeydew, Antelope Lake, 0.51 Markleville, 0.48 Hoopa, Elk Valley, Snow Mt, 0.46 Dorrington, 0.41 Somes Bar, 0.40 Saddle Camp, Battle Ridge, Auburn, 0.38 Ash Valley, Quincy, 0.37 Oroville, 0.36 Trinity, 0.35 Pilot Hill,  0.34 Redding, 0.30 Ukiah, 0.29 Chico, 0.28 Shasta Dam, 0.25 Arnold, 0.24 Marysville, 0.20 Brandy Crk, Yorkville, 0.19 Reno, 0.18 Camanche, Campo Seco, 0.17 Lincoln, 0.14 Mt Elizabeth, New Hogan, 0.12 McCloud Dam, Fair Oaks, 0.11 Rancho Cordova, 0.08 Alturas, 0.05 Weed, Red Bluff, SAC Exec, 0.04 Elk Grove, Ione, Stateline, 0.02 Vacaville, 0.01 Corning, Santa Rosa, Napa, Concord, Brentwood, SJ, Moffett, Stockton

Streamflows for the Truckee River at Truckee showing an uptick Wednesday from heavy warm rains, increasing by more quadruple the Streamflows in just a few hours;

Meanwhile further south on Wednesday under partly cloudy skies with no rainfall, the Middle Fork San Joaquin River at Devils Postpile continues to flow at a record low flow of 10cfs, (a trickle) easily beating the prior Low Flow record set in 2012 of 29cfs, a decrease of 65% from the previous record.  The Tuolumne River above Hetch Hetchy also recording another day of record Low Flows, with 17cfs, beating the previous Low Flow Record of 38cfs set in 2007 by a decrease of 30% from the prior record.  The Salinas, Carmel, Santa Maria and Santa Ynez rivers along the coast have dried up, with zero flows reporting.

FORECAST SUMMARIES

Days 1-7;

Wed, Jan 29^th              While High Pressure over CA continues to flatten, a weak shortwave trough ripples eastward imbedded within the mean flow pattern toward CA, carrying a rich subtropical Atmospheric River (AR) of moisture with PWAT’s of up to 1.2 inch moving onshore over NORCAL producing occasionally mod/heavy warm precip which gradually sags south.  While 576dm heights still cover most of CA the pressure gradient tightens over NORCAL with an increasing WSW flow pattern which brings a narrow frontal boundary into NORCAL that intensifies rainfall rates overnight in a narrow band that stretches WSW to ENW across the Feather, Yuba and American River basin, as the progression of the front nearly stalls out due to a wave development offshore west of SFO.  Generous warm-type rains finally are breaking the exceptionally long dry spell for NORCAL.  Temps over CENCAL governed by the amt and timing of increasing cloud coverage, with widespread 70°’s and light winds which increase overnight. The GFS targets the Sierra from the Feather basin down to YNP with heavy precip overnight which slowly sag south by morning.  Higher elevations of the northern Sierra could see 1-3 feet of snowfall around Lake Tahoe from this event.  That is a sight for sorry eyes!

Thu, Jan 30^th               Flat pressures over CA produce an onshore flow with a W directional component, as cold air and dynamics remain stretched west to east over NORCAL.  The 700mb charts show heavy precip which has been aimed at Tahoe trails off to the SW and diminishes to the south over CENCAL.  Precip slowly spreads further into CENCAL throughout the day and overnight, with much cooler temps due to overcast skies, with winds increasing from the south up to 15mph.  It will be very interesting to see how this storm behaves, as it reaches into CENCAL, which is like a dried-up sponge.  As the flow pattern aloft switches to the NW, cold air drops the snowlevels with several moist impulses moving thru CA on the backside of the trough as it begins to depart CA.  Temps range in the 60°’s with a few 70°’s in the South Valley.

Fri, Jan 31^st                 END OF JANUARY!  Skies gradually clear in the morning with a slight chance of a few showers, with lingering upslope activity continuing into the Sierra diminishing later.  As the trough axis continues to move into the Great Basin, cooler/drier air from the NW advects into CA.  Temps continue to cool over CA as the storm departs, leaving partly cloudy skies with SJV temps ranging from the upper 50°’s in the north to the lower 60°’s in the south.  If skies clear more rapidly, then overnight frost is possible in the coldest locations.

Sat, Feb 1^st                   Patchy morning frost possible in the coldest regions.  With the High Pressure ridge axis at 140W another shortwave trough with a small upper level devil, digs toward NORCAL from the NW, attached to a small moisture field as the flow pattern over CA turns NNW, with cooler temps.  Overnight the upper level devil moves close enough to the NORCAL coast to bring renewed shower activity from SFO northward with partly cloudy skies over CENCAL which may allows for another frost event overnight.

Sun, Feb 2^nd                 The weakening trough over CA slowly dries out, with a few lingering showers over the Sierra and cooler temps.  The RRR High Pressure ridge intensifies at 140W as cold air from the ARCTIC dives in to the PACNW reaching Portland, OR by afternoon.  Overnight the RRR High Pressure ridge shifts eastward and deflects the ARCTIC blast over the PACNW into the Great Basin, while temps over CENCAL remain close to persistence with another night of frost. 

Mon, Feb 3^rd                With the trough axis in the Great Basin and High Pressure offshore the NW flow pattern continues with frosty mornings and fair skies with SJV temps in the 60°’s.  Overnight the High Pressure ridge weakens, which allows a long-fetched Atmospheric River (AR) begin to flow toward the PACNW. 

Tue, Feb 4^th                 The RRR High Pressure ridge is positioned at 130W providing CA with a cool/dry NW flow pattern, while initiating a moist flow into the PACNW with warm rains.  With partly cloudy skies over NORCAL, CENCAL is mostly fair, as temps slowly recover over CENCAL, with less frost in the morning due to partly cloudy skies dropping SE over CENCAL from the PACNW.

Days 8-16, Long Range into Fantasyland Outlook; Day 8 begins;

Wed, Feb 5^th shows the RRR High Pressure ridge remaining offshore, with a NNW flow pattern over CA with some moisture riding over the top of the ridge and then dropping into NORCAL with a few clouds also reaching into CENCAL, but no rain.  Overnight the High Pressure steepens close to the West Coast which produces a N flow pattern aloft, advecting colder temps into the region with clear skies and probably more frost overnight.

Thu, Feb 6^th shows a REX High over Low configuration over Alaska and the GOA, with weak High Pressure near the CA coast keeping CA fair and dry as a trough digs southward into SOCAL, producing a stronger NNW flow pattern over CA. Overnight the pressure gradient allows for increased winds from the NW with cool/dry conditions continuing.

Fri, Feb 7^th shows the trough in the Great Basin kicks east as the High Pressure ridge near the West Coast remains dominant, with fair skies and cool temps for CA.

Sat, Feb 8^th shows the RRR High Pressure ridge shifts inland over CA as a Low Pressure storm drops south from the GOA, aided by a new High Pressure ridge over the Dateline region supplying cold air from the Bering Sea to fill the GOA Low Pressure storm.  A moist SW flow develops offshore west of the PAC NW with rains reaching into the BC, Canada coast down to OR.  Partly cloudy skies reach into NORCAL.  Overnight heavy rains reach into BC, Canada and the  WA coast, with lighter rains reaching into OR/NORCAL and partly cloudy skies reaching into CENCAL.

Sun, Feb 9^th shows the broad trough in the GOA enlarges with increased onshore flow into the BC, Canada coast down to NORCAL, with partly cloudy skies down to SAC.  This continues overnight.

Mon, Feb 10^th shows the broad trough in the GOA shifts eastward into the Alaskan panhandle and the PACNW coast with continued heavy rains flowing inland into ID.  Skies over NORCAL begin to clear out as the westerly onshore flow continues.  Overnight the heavy rains continue into the southern BC, Canada coast down to Portland, OR.

Tue, Feb 11^th shows little synoptic scale changes with weak/flat High Pressure over CA, allowing a strong onshore flow pattern to continue into the same region to the north, while CA remains fair/dry.

Wed, Feb 12^th shows a significant change occurs with regards to a newly developed Atmospheric River (AR) attachment originating from Hawaii flowing NE into the trough configuration in the GOA.  This feature dramatically increases the rainfall rates and broadens the aerial coverage of rains over SW Canada, the PACNW and far NORCAL.  Overnight heavy rains are depicted moving onshore into NORCAL, down to Santa Rosa fed by the rich moister-laden Atmospheric River (AR)

Thu, Feb 13^th shows the Atmospheric River (AR) water hose connection is severed with the trailing end continuing to move into NORCAL, with partly cloudy skies down to Fresno.  Heavy rains over NORCAL gradually diminish, with some light rains possibly reaching into CENCAL.  Meanwhile large Low Pressure is circulating over the GOA with the moist onshore flow continuing to bring mod rains into the PACNW.

Fri, Feb 14^th Valentine’s Day shows weak/flat High Pressure over CEN/SOCAL, as a tight pressure gradient over the PACNW and NORCAL continues to bring mod/cool rains into SW Canada, the PACNW and far NORCAL thru the end of the GFS Fantasyland forecast realm.

Special Notations;

TEMPS

NEW RECORD TEMPS

Sunday

Station                         New Record                Old Record__

South Lake Tahoe          54°                               52° set in 2003

Madera                         69°                               66° set in 2007

Fresno                         72°                              70° set in 1940  Sets the 9^th Day in January with temps at or above 70°, beating the prior record in 1948

Hanford                         69°                               67° set in 2007

Oak Dwntwn                  73°                               72° set in 1984

SJ/Moffett                      70°                               69° set in 2011

San Rafael                     68°                               66° set in 1976

SJ Dwntwn                    71°                               70° set in 2011

SFO                              66°   (Ties)                    66° set in 1984

Livermore                     72°   (Ties)                    72° set in 1918   A 96 year old record

Stockton                        69°                               66° set in 2012

Modesto                        68°   (Ties)                    68° set in 1940

Monday

Station                         New Record                Old Record__

South Lake Tahoe          54°                               52° set in 2003

Merced                          67°                               59° set in 2007

Madera                         69°                               62° set in 2007

Hanford                         70°                               62° set in 2007 

Bakersfield                    70°   (Ties)                    The 11^th Day in January with temps at or above 70° set in 1948

Record High Minimums

San Diego                      58°   (Ties)                    58° set in 1980

Thermal                        54°   (Ties)                    54° set in 1984

Indio                             62°                               56° set in 2013

Tuesday

Station                         New Record                Old Record__

Merced                          70°                               61° set in 2000

Madera                         70°                               63° set in 2009

Hanford                         71°                               65° set in 2009

SAC Exec                       70°                               66° set in 1976

SAC Dwntwn                  70°  (Ties)                     70° set in 1984

Stockton                        69°                               67° set in 1976

Modesto                        70°                               67° set in 1976

Sandberg                       65°  (Ties)                     65° set in 1993

Wednesday

Station                         New Record                Old Record__

South Lake Tahoe          54°   (Ties)                    54° set in 2012

Reno                             65°                               64° set in 1986

SJ/Moffett                      68°   (Ties)                    68° set in 1989

Stockton                        68°                               66° set in 2007

Modesto                        69°                               68° set in 1928   Breaks a 86 yr old record

Merced                          70°                               63° set in 2001

Madera                         72°                               66° set in 2003

Hanford                         72°                               65° set in 2003

Sandberg                       67°                               64° set in 1976, 1971; The 21^st day in January with temps at or above 60°, old record of 11 days in 1971

Lancaster                      77°                               71° set in 1976

Palmdale                       76°                               72° set in 1976

PRECIPITATION FORECAST

Day 1 – 5 QPF:

At 12Z (9am) Wednesday thru the period Sunday night (Monday @4am) shows;

Wed shows up to 2.5 inches for the wet spots of the Feather River basin, with up to 2 inches for the Feather to the American River basin, with up to 1 inch from Mt Lassen south to YNP and along the wet spots of the Shasta basin and the NW coastal region, with up to 0.75 inch covering all of the NW Coastal region, the Shasta region and the Sierra southward to the NF of the San Joaquin basin, with up to 0.5 inch covering all of NORCAL down to Santa Cruz, Stockton, to the SF of the San Joaquin basin, with up to 0.2 inch Monterey Bay to Modesto to the Kings basin, with up to >0.1 inch from Cambria to Porterville.

Thu shows the bulk of precip shifts south into CENCAL with up to 1 inch for the Sierra Crest from I-80 corridor south to the NF San Joaquin basin, with up to 0.75 inch from the Yuba basin southward to the Kaweah basin, with up to 0.5 inch from the Feather basin south to the upper Kern basin and along the Central Coast along the Santa Lucia’s, with up to 0.2 -0.3 inch for most of the Great Valley from Chico south to Visalia.  The Westside of the Great Valley is suggested to have a rainshadow with only 0.1 inch possible.  SOCAL has 0.1 inch up to 0.2 inch into the higher terrain with Big Bear and the wet spots receiving up to 0.5 inch.

Fri shows light amts of precip into the northern counties and thru the Sierra, with chances of showers into the eastern portions of the SJV and most of SOCAL where the San Gabriel’s receive up to 0.2 inch.

Sat shows a few possible lingering showers over Inyo Co

Sun shows most of CA is DRY, except for some coastal showers from Monterey south to Ventura Co with up to 0.2 inch along the immediate coastline with amts diminishing further inland and across the Tehachapi Mts down into the coastal region of SOCAL.

5DAY ACCUMULATION CHART:

Days 6 & 7 QPF thru next Mon/Tue shows light amts of precip over portions of NORCAL of up to 0.1 inch, while the rest of CA remains DRY.

16-Day QPF estimates (from the 12Z GFS) for;

Days 1-8 shows a precip target focal point of up to 3.5 inches near Lake Tahoe with amts diminishing north and south of that point with up to 2 inches from the Feather River basin south from the Tuolumne River basin, with up to 1 inch extending south to YNP, with up to 0.5 inch for most of the Sierra and near the Eastside of the Great Valley and from the Bay region to Monterey Bay, with up to 0.25 inch over all of NOR/CENCAL and the SOCAL coastal region, with up to 0.1 inch for the desert region.

Days 9-16 shows up to 1 inch for NORCAL north of Chico, with up to 0.5 inch north of SAC and up to 0.25 inch north of Modesto, and 0.1 inch for Madera and >0.1 inch for the southern SJV.  SOCAL remains dry.

Wednesday’s 12Z 9am GFS 384hr, 16Day QPF Chart, showing up to 3 inches targeted for the wettest regions of NORCAL with diminishing amts southward into CENCAL with up to 0.25 to 0.50 inch for CENCAL, with up to 1 inch for the Southern Sierra, and generally showing >0.1 inch for SOCAL.

SATELLITE

Water Vapor 4KM Image of the West Coast Wednesday, January 29^th, 2013, shows a moist WSW subtropical flow pattern entering NORCAL and slowing spreading into CENCAL, while High Pressure offshore near SOCAL diminishes.

Visible Satellite Image of the CA Wednesday, January 29^th, 2013, shows the moist WSW subtropical flow pattern bringing significant clouds and rainfall into portions of NORCAL, especially focused upon the Ukiah to Feather River basin.  Partly cloudy skies are on the increase over CENCAL, while SOCAL remains mostly clear.

If you have any questions please call or text at any time of day or night. 

Comments and suggestions always welcome.

Atmospherics Group International

Dan Gudgel              Steve Johnson

559-696-9697                559-433-7316