Sun, Feb 2nd                 SUPERBOWL SUNDAY!  Patchy Morning Frost at the coldest Stations with mins reaching Critical >28° before cloud coverage reaches inland, with insulating reflectivity’s, raising temps before dawn at most districts.  CONVECTION/THUNDERSTORMS;  The latest charts indicate a -28C cold core Low Pressure upper level ‘devil’ poised offshore near Monterey Bay by afternoon.  It’s final location Sunday will have a profound impact on the potential (or not) of having Thunderstorms over the SJV.  This disturbance has the potential to create convection, if the circulation is close enough to the SJV and if clear or partly cloudy skies allow surface temps to reach convective temps.  The evening Z GFS has backed off slightly as compared to the earlier 12Z morning run.  The strongest convective parameters without a doubt will be located over the Coast Range, with Hail Parameters, and possible Supercell Parameters as well.  While the morning 12Z model run had its location over the Coast Range which would have stimulated stronger updrafts over the SJV, the trend on the evening 0Z model run is for the strongest cells to remain over the Coast Range, or Westside SJV.  If the GFS verifies then Kings Co could be a primary target.  The morning RUC detailed model will have the best look at the potential on this event, and if it should jog 50miles closer to the SJV, then be prepared for stronger Thunderstorms, with Fresno Co southward having the highest convective parameters.  Localized QPF in vicinity of Thunderstorm downdraft downpours could be high.  The chances for convection continues into the evening hours as the cold core moves down the coast.  If strong SE surface winds develop in the SJV then directional shear with a curved hodograph would imply rotating cells which could produce larger sized hail.  Charts at this time do not indicate funnel clouds, but they are not 100% ruled out either.  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 from the PACNW into the Great Basin, while the upper disturbance drops into SOCAL.  Temps over CENCAL remain close to persistence with another night of frost unlikely at most Stations due to either cloud coverage or wind mixing, however the cold spots which are cloud free/wind sheltered should easily reach 32° 




Mon, Feb 3rd                With the trough axis in the Great Basin and High Pressure offshore the NNW flow pattern continues with a frosty morning and fair skies with SJV temps in the 60°’s.  Overnight the High Pressure ridge weakens, which allows a long-fetched Atmospheric River (AR) to begin to flow toward the PACNW from the ITCZ at the Dateline.  Moisture traveling over the dirty ridge allows some cloudiness to reach toward CA.  Temps in the SJV remain into the upper 50°’s to lower 60°’s, with stronger radiational cooling allowing for overnight frost at most SJV Ag Stations.


Tue, Feb 4th                 Morning Frost.  Fair Skies.  The RRR High Pressure ridge axis is positioned near 140W providing CA with a cool/dry NW flow pattern, while a moist flow aims toward the PACNW with warm rains which reach inland overnight, with partly cloudy skies over CENCAL, as temps slowly recover by a few degrees over CENCAL, with less frost in the morning due to partly cloudy skies dropping SE over CENCAL from the PACNW.


Wed, Feb 5th                Clear skies allow for lower morning temps to provide more frost in the morning.  The RRR High Pressure ridge shifts west as a REX configured High over Low pattern develops near the Dateline, with allows for cold air to descent into western Canada and the PACNW.  The strong NW flow pattern over CA keeps most of this cold -34° ARCTIC air kicking SE from WA into the Great Basin as more moisture and rainfall spread southward into NORCAL on the cool NW flow pattern.    Max temps reach the mid 65° commonly, with overnight mins slightly warmed due to increased cloud coverage.   


Thu, Feb 6th                 While the RRR High Pressure ridge still is connected to a very large High Pressure cell over western Siberia, the Bering Sea and most of Alaska, the downwind flank forms a large ARCTIC -34°C cold core over the PACNW covering all of WA and northern OR, producing an increasingly tight NW pressure gradient over CA.  Overnight cold air begins to spill into NORCAL, as the -34°C ARCTIC Low Pressure over the PACNW settles into eastern OR and the -32°C isotherm advects SW to Alturas.  While the storm center is dry, the backside has a water trajectory from the NW which produces clouds and snow showers over the Sierra, with a slight chance that some cold precip could reach into CENCAL with showers.  Meanwhile the REX tucked Low Pressure is situated near 43N at 156W, which is attached to a short-fetched Atmospheric River (AR) which reaches thru Hawaii to the ITCZ.  This AR stops at the apex of the RRR High Pressure ridge west of CA.


Fri, Feb 7th                   A transformation occurs as the REX Low Pressure connects to the cold ARCTIC trough over Western Canada, forming a long-wave trough.  The RRR High Pressure ridge once again begins to retract as a long-fetched AR streams NE into the developing longwave trough evolution.   As the High Pressure ridge axis passes over CA overnight, the organizing AR warm heavy rains reach into the PACNW, then trail SW back toward Hawaii. 


Days 8-16, Long Range into Fantasyland OutlookDay 8 begins;


Sat, Feb 8th shows heavy warm rains spread over much of the PACNW and into portion of NORCAL, with clouds and possible showers reaching into the northern portions of CENCAL.  The long-fetched AR moisture supply is severed near Hawaii, as the Longwave Trough retrogrades SW which keeps the AR in place for a long duration heavy rain event into the PACWN. Overnight High Pressure rebuilds over CA which shunts the heavy rains back to the north.  Extremely heavy rains drench the PACNW. 


Sun, Feb 9th shows the High Pressure ridge over CA shifts into the Great Basin which allows the wet trough to spread back into NORCAL with heavy rains as far as Ukiah to Shasta, with clouds/showers down to SFO to Tahoe.  The frontal band stalls over NORCAL, which leaves CENCAL partly cloudy and dry.


Mon, Feb 10th shows little change with the overall synoptic pattern with weak High Pressure over CEN/SOCAL, and a strong/moist SW flow pattern over the PACNW and NWNORCAL.  The pattern continues overnight.


Tue, Feb 11th shows the backside edge of the moisture field nearing NORCAL, as rains begin to taper, and partly cloudy skies continue over CENCAL as the large cyclonic flow continues into most of the West Coast.  Overnight the offshore trough becomes zonal from 160W into the PACNW with heavy rains reaching into OR/NORCAL.


Wed, Feb 12th shows the zonal-type flow pattern continues to advect a moist westerly flow pattern into the PACWN and NORCAL, with partly cloudy skies into CENCAL.  With High Pressure at the Dateline, a new trough digs SW from the Aleutians as a new Atmospheric River (AR) develops from Hawaii NE into the developing trough configuration which brings heavy warm rains into the BC, Canada coastline. 


Thu, Feb 13th shows the new GOA trough deepens at 140W with a subtropical tap AR feeding into the prefrontal warm sector with heavy warm rains continuing into southern BC, Canada and approaching the PACNW.  Overnight the AR is severed to the SW of CA with heavy rains spreading into OR, and partly cloudy skies reaching into NORCAL.


Fri, Feb 14th Valentine’s Day shows the trough axis moving inside of 140W, with heavy rains continuing into the PACNW and with lighter rainfall into NORCAL, and partly cloudy skies reaching into CENCAL.  Overnight a frontal boundary spreads mod rains into CENCAL, and the SJV and Southern Sierra.


Sat, Feb 15th shows the trailing end of the frontal boundary barely reaching into the northern portion of SOCAL, with rains tapering off over CENCAL, while the main trough configuration remains over 130W with the cyclonic flow pattern over the PACNW and NORCAL continuing and another surge of heavy rains reaching into NORCAL, with clouds down to Monterey to YNP.


Sun, Feb 16th shows High Pressure rebuilding offshore at 150W, with the trough pattern shifting inland over the West Coast with continues rains into the PACNW and far NORCAL, with partly cloudy skies into CENCAL.


Mon, Feb 17th shows High Pressure offshore rebuilding and nosing closer toward the West Coast as the trough over the West Coast provides a dry, cool NW flow pattern over CA.  Additional rains ride over the top of the developing ridge an supply Vancouver, BC and the PACNW with more rains while the Fantasyland Forecast ends with a clearing trend for most of CA.



Special Notations;


Forecast guidance continues to suggest that cold ARCTIC air gets within close proximity to CA on Feb 6th, which should be monitored closely.  Charts are also fairly consistent in developing a longwave trough pattern over the NE PAC which brings a long duration heavy rain event into SW Canada, the PACNW and portions of NORCAL during Week #2.  The consistency has been high for heavy precip at least reaching into portions of NORCAL, with varying QPF’s ranging from a min of up to 3 inches to a max suggesting as much as 6-7 inches.  Another consistent message is that CENCAL remains on the southern flank of the activity and either receives light amts of QPF at a min, or moderate amts of rainfall at a max.  The Mork rain/no rain you get none line appears to be somewhere over or near CENCAL during this period.   The two 384hr QPF charts below illustrate the flip/flopping of the models which has been repeating regularly.  We’ll take any precip that we can get, whether it’s over NORCAL or CENCAL, it’s better than High Pressure and clear skies.  The lack of confidence into bringing significant rains into CENCAL at this time of year is troubling, because we should be reaching the peak of the rainy season.   Have a wonderful SUPERBOWL SUNDAY, and watch out for the possible Thunderstorms Sunday!







Station                         New Record                Old Record__

Barstow-Daggett            0.00 January (Ties)        0.00 set in 1948, 1972, 1976 and 1984

Needles                         0.00 January (Ties)        0.00 set in 1896, 1901, 1912, 1947, 1948, 1971, 1972 and 1976


Highest Minimums

Newport Beach              58°  (Ties)                     58° set in 2003

Laguna Beach                57°                               55° set in 2006

San Diego                      59°                               58° set in 1980

Oceanside                     57°                               55° set in 1986

Chula Vista                    56°                               55° set in 2003

Thermal                        62°                               61° set in 1954

Indio                             62°                               56° set in 1911  Beats a 103 year old record.






Day 1 – 5 QPF:

At 12Z (9am) Saturday thru the period Thursday night (Friday @4am) shows;

Sat shows a few light showers from the Russian River northward along the immediate NORCAL coast up thru the Eel River basin and up into Del Norte Co with >0.1 inch.

Sun shows most of CA has at least some light precip of >0.1 inch, with up to 0.2 inch for the Southern Sierra fro near Tahoe south to the upper Kern River basin, and from Eureka southward along the coast to the LA basin, with up to 0.3 – 0.5 inch over the Sierra, San Joaquin, Kings, and Kaweah River basins, and along the coast from Cape Mendocino southward to the Malibu region, with up to 1 inch of precip from the immediate coastal region of Pt Arena southward to near Cambria.  Max focal point appears to the be the Santa Lucia range near Big Sur. The Great Valley is painted with generally >0.1 inch, however since convection is suggested, amts could be much higher in the pathway of the Thunderstorms which develop stronger updrafts, which charts currently favor in the north and Westside SJV, especially western Merced, Fresno and Kings Co.

Tue shows a dramatic drying trend, with much less spotty rainfall over CA, targeting the Southern Sierra, portions of Orange, San Diego Co, and the NE quadrant of CA with >0.1 inch.  The rest of CA, including the SJV is DRY.

Wed shows a few spots of lingering light showers possibly into the Kings River basin, the upper Pit River basin and again in portions of Orange, Riverside and San Diego Co.

Thu shows some increased shower activity in the NE quadrant of CA from the upper Pit River basin southward into the Feather and Yuba River basins with 0.1 up to 0.2 inch, while of few light showers may continue in the far SW quadrant of CA near Orange and San Diego Co.





Days 6 & 7 QPF thru next Fri/Sat shows light amts of precip across most of CA with at least >0.1 inch, with up to 0.2 inch down most of the Sierra, and coast range from the Russian River southward thru the LA basin with focal points of the max amts of precip showing 0.4 inch near Cape Mendocino, the Kings River basin, and into Orange Co, and up to 0.15 inch at Monterey.

f CA remains DRY.


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

Days 1-8 shows up to 1.25 inch for the NW coastal region, up to 1 inch for the Central Coast, up to 0.5 inch for portions of the interior coast and around the Bay region, with up to 0.1 inch for the Great Valley, except in spots that are affected by Monday’s thunderstorms, with portions of SOCAL showing up to 0.1 to 0.2 inch.

Days 9-16 shows moderate rainfall amts for portions of NORCAL up to 2.5 inches including the NW Coastal region, the Shasta and Feather River basins, with rapidly diminishing amts to the south, with up to 0.3 to 0.5 inch for the Tahoe region, with up to 0.25 inch for the wet spots of the northern SJV and up to 0.6 inch for portions of the Southern Sierra.



Friday’s 0Z 9pm GFS 384hr, 16Day QPF Chart, showing up to 5-6 inches of precip for the NW corner of CA with rapidly diminishing mts to the S and E, with portions of CENCL receiving up to 1 inch in the north to 0.25 inch in the South and with the coastal regions of SOCAL receiving up to 0.25 to 0.5 inch.



Saturday’s 12Z 9am GFS 384hr, 16Day QPF Chart, showing substantial decreases in the forecast QPF’s for CA, ranging from up to 5 inches for the Cape Mendocino north coastal region, with rapidly diminishing amts over NORCAL with up to 1+ inches for portions of the northern SAC Valley and Feather River basin with up to 0.5 inch for the Tahoe region to Monterey Bay and up to 0.25 inch to 0.5 inch suggested for CENCAL, and from zero up to 0.25 inch suggested for portions of SOCAL.







Water Vapor 4KM Image of the West Coast Friday, January 31st, 2014, shows a narrowing ‘Dry Slot’ extending N to S thru the center of CA, sandwiched between 2 separate moist airmasses.  The approaching upper level Low Pressure west of the CA/OR border will be near the CENCAL coast tomorrow with increased moisture and clouds, with possible convection.



Visible Satellite Image of the CA Saturday, February 1st, 2014, shows a fresh mantle of snow over Mt Shasta as well as the higher elevations of the Sierra, with clear skies over CA except for fog into the NW coastal valleys.


Comments and suggestions always welcome.


Atmospherics Group International

Dan Gudgel              Steve Johnson

559-696-9697                559-433-7316