Wx Headline; The exceptionally warm, dry and stable wx continues for a few more days, however, a pattern shift evolving late this week should open the storm door for at least NORCAL and portions of CENCAL to receive some much need rainfall. It does not appear the storm system will deliver as much precip as we’d like, but we’ll take every drop we can get. There are no signs of significant Drought relief, as the storms heading for NOR/CENCAL are progged to produce up to 1-2 inches at the wet spots. Record-Setting max temps during the afternoons continue for several more days as CA heads into its 16th consecutive day with record setting heat. Unbelievable record dry conditions continue to prevail during thru Wed for CEN/SOCAL, with some rainfall expected to reach into NOR/CENCAL, Wed/Thu. The longer range progs show an immediate return to dry but cooler conditions beginning Fri, Jan 31st thru Tue, Feb 11th, with chances of morning frost returning.
STORM DOOR OPENING…at least temporarily! This week a series of disturbances makes an assault on the RRR High Pressure ridge along the West Coast that has kept CA persistently dry for almost 2 months. There is much uncertainty regarding the initial arrival timing of the first storm to reach into NORCAL, with the earliest arrival of #1 storm system on Mon/Tue, Jan 27/28 as the warm/wet system moves eastward rapidly, it does not appear to make it into CENCAL, nor does it leave much precip over NORCAL either because it lacks dynamic lift even though it is loaded with moisture. (what a waste of water!) The potential wetness is there, but the dynamics aren’t for #1 storm, but it does serve to help in breaking down the dominant ridge. The next better chance for rainfall arrives from #2 storm on Wed/Thu, into NOR/CENCAL, with some spillage into portions of coastal SOCAL. Initially warm/wet with heavy Sierra precip forecast late Wed, shift south into CENCAL overnight into Thu. This storm period is not expected produce enough precip to alleviate the severe drought conditions, but we’ll gladly accept whatever we can get. Charts shows a well-defined “Mork rain/no rain you-get-none line” over CENCAL with Fresno receiving ½ the amt from Merced, and Visalia receiving ½ the amt compared to Fresno. It will be very interesting to see the storm totals tallied on Thu/Fri, just in time for the end of the Month of an extraordinary January.
Close up Visible Image of Mt Shasta, illustrating the lack of snowpack on the tallest single peak in CA at 14,179ft, standing over 10,000ft over the surrounding terrain;
24hr Precip Summary highlights to 9am Sunday; none
FORECAST SUMMARIES
Days 1-7;
Sun, Jan 26th The overall synoptic pattern remain similar to the past weeks with a dominant OMEGA shaped High Pressure ridge built across the West Coast of NOAM, with a 570dm center of circulation over the panhandle of Alaska. The western flank OMEGA Low Pressure span a large region of the PAC from the Dateline to about 140W, with a tiny/weak disturbance near Pt Conception allowing the flow of some subtropical moisture to move northward into CA, shrouding portions of CEN/SOCAL with cloudiness, but no rain. A well defined Atmospheric River (AR) from the WPAC is entraining into the giant Low Pressure over the mid PAC loaded with high PWAT moisture content. The disturbance is making headway into the weaker lower portion of the High Pressure ridge aiming for the CA coast. Mild for Jan, temps for CA could largely be governed by the amt and timing of cloud coverage, with light winds.
Mon, Jan 27th The mid PAC storm system continues to make headway into the High Pressure ridge, even though heights remain relatively high over CA, the core of a 1.5 inch PWAT tongue of subtropical moisture reaches the NORCAL coastline with warm air advection rains. Models usually have a difficult time diagnosing these type systems because they lack upper dynamics, but orographic and isentropic upglide lift should be able to produce some warm rains for NORCAL while 576dm High Pressure covers most of CA produces clouds but no rain for CENCAL, with mild temps and light winds continuing.
Tue, Jan 28th The High Pressure over CA intensifies up to 582dm heights along the coast as the ridge axis shifts inland over the PACNW and begins to diminish. The moist SW flow offshore brings heavy rains into the WA coast which trail SW offshore. The warm rains over NORCAL shift northward toward the OR border, with partly cloudy skies and near persistence with temps. Overnight the High Pressure ridge flattens significantly which allows the subtropical moisture stream to sag southward again into NORCAL.
Details on timing and strength are still being tossed around with regards to the arrival of a storm system into CA Wed/Thu
Wed, Jan 29th The High Pressure over CA continues to flatten, but builds further west at 150W as a weak shortwave trough ripples eastward toward CA. 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 which intensifies overnight as the progression of the front nearly stalls due to a wave development offshore west of SFO. Generous warm-type rains finally break a long dry spell for NORCAL. Temps over CENCAL will be governed by the amt and timing of increasing cloud coverage, with light winds. The GFS targets the Sierra from Tahoe to YNP with heavy precip overnight while the NAM waits until Thu. Higher elevations of the northern Sierra could see 1-2 feet of snowfall.
Thu, Jan 30th Flat pressures over CA produce an onshore flow with a WSW directional component, as cold air and dynamics remain stretched west to east over NORCAL, with 700mb charts showing heavy precip aimed at Tahoe which trail off to the SW and diminish to the south over CENCAL. Precip slowly spreads further into CENCAL and increases overnight, with much cooler temps due to overcast skies, with winds increasing from the south up to 15mph. Timing on the arrival is faster by 6 hrs according to the GFS as compared to the WAF. It will be very interesting to see how this storm behaves, as it reaches into CENCAL, which is like a dry-up sponge.
Forecast Chart at 700mb showing Winds and Moisture arriving into CENCAL Thursday.
Fri, Jan 31st 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. 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, especially north.
Sat, Feb 1st Patchy morning frost possible in the coldest regions. With the High Pressure ridge axis at 140W another shortwave trough digs into NORCAL from the north, lacking moisture as the flow pattern over CA turns NNW, with cooler temps.
Days 8-16, Long Range into Fantasyland Outlook; Day 8 begins;
Sun, Feb 2nd shows the RRR High Pressure ridge rebuilding at 140W as troughing still is over the SWCONUS producing a N flow pattern for CA, advecting drier air into the region. As the ridge rebuilds the moist subtropical storm track shifts due north back into southern Alaska.
Mon, Feb 3rd shows the RRR High Pressure ridge offshore the WCONUS, with the storm track moving over the top of the ridge and bringing rains back into the BC, Coastline, while CA develops an offshore NNE flow pattern as drier air moves back into CA.
Tue, Feb 4th shows more the of same with High Pressure offshore CA, and moisture riding over the top of the ridge reaching into WA, with the dry N –NE flow over CA continuing.
Wed, Feb 5th shows the High Pressure ridge producing a NW flow over CA as some moisture spills into OR and NORCAL. Overnight a minor disturbance travels into the Great Basin, with some cloudiness perhaps reaching into CENCAL as it moves to the east. A massive High Pressure cell forms over the ARCTIC region, which sends an ARCTIC airmass southward along the eastern flank of the ridge, down thru western Canada.
Thu, Feb 6th shows the RRR High Pressure ridge extending from offshore northern Baja NNW beyond the ARCTIC circle. It’s huge! Cold air from western Canada deflects slightly to the SE and dives into the Rockies.
Fri, Feb 7th shows the RRR High Pressure ridge narrows considerably, especially along the east side, which allows ARCTIC air to dive southward into the WCONUS, with much colder temps for CA, including increasing freezing temps overnight.
Sat, Feb 8th RRR High Pressure ridge hold offshore and up into the ARCTIC region with the downwind flank bringing ARCTIC air southward thru western Canada into CA, as temps continue to lower, with more freezing temps.
Sun, Feb 9th as the base of the ridge is pinched off, two separate Low Pressure systems begin to merge; 1) in the mid PAC at 40N 160W and 2) an ARCTIC Low Pressure over SW BC, Canada and the Olympic Peninsula. Thankfully the flow pattern over CA veers to the NW and begins to modify the cold temps. Overnight the two Low Pressure areas continue to merge, forming a longwave trough that extends WSW to 170W. A weak subtropical moisture plume flows northward into the flow pattern reach CA, bringing increasing cloudiness to CA.
Mon, Feb 10th shows the longwave trough pattern continues to develop with the addition of one more Low Pressure circulation at the Dateline connecting to the longwave configuration which now extends from BC, Canada SW to past the Dateline. At the same time an impressive long-fetched Atmospheric River (AR) also forms to the south of this newly forming boundary which begins to flow into the PACNW and NORCAL overnight. The GFS has been attempting to develop this longwave trough for several days out at Day 15/16, which keeps being delayed out to Day 15/16 each day. If this feature did form and if the alignment was over CA, and if it lasted for a week, then copious amts of rainfall could emerge and put a potential dent into the drought, but that is wishful thinking for a lot of if’s and it’s way out there in Fantasyland or beyond.
GLOBAL ANOMALIES
Global SST Anomaly Comparison charts between Dec 25th, 2013 and Jan 15th, 2014, 20 Days later; shows the +3° Anomaly in the NE PAC basin is still the dominant globe feature by far. There are some subtle differences noted;
1) The +3° anomaly core has shifted slight east, closer to the coast of NOAM,
2) The -1.5° anomaly along the West Coast is virtually gone
3) The +1° to +1.5° anomaly on the south flank has spread to include more of the Hawaii region
4) The previous clearly defined thermal gradient ribbon pathway between Japan and the West Coast is no longer valid as a new thermal gradient ribbon could developing between the cooler anomaly SW of Hawaii and the huge +3° EPAC anomaly to the far NW. Therefore the inferred Jet Stream projected pathway is not as well defined as it was on Dec 25th.
5) Our forecast that the +3° anomaly would be around for a while is validating, whether that means the dry pattern will continue or shift remains to be seen, but the chart could imply that since the +3° core is closer to the West Coast the Jet Stream could follow
6) A new small-sized +2° anomaly has formed south of Newfoundland, near a thermal gradient ribbon, which could influence the activity of the Hudson Bay Low, which is one of, if not THE major feature regarding the stable, non-progressive pattern. If the Hudson Bay Low shifts then the rest of the boxcars upstream could also shift.
7) The large-sized +3° anomaly will continue to be the primary general focus area for the Jet Stream and Low Pressure enhancement in the NE PAC for quite some time, whether the Jet continues its zonal-type flow pattern across the WPAC as it has done for the past 2months or it finds a new trajectory to aim for the +3° anomaly remains to be seen.
8) The ENSO region remains in a neutral to slightly more negative cool El Nino phase in the latest Jan 15thchart, and has been lacking significant contributions or influence to the West Coast NOAM wx so the major player this year has been and is likely to remain the +3° anomaly in the NE PAC for quite some time.
500mb Height Anomalies; The Chart below shows the 500mb Geopotential Height Anomaly for the period Oct 1st 2013 to Jan 22nd, 2014 depicting the general area in the NE PAC basin which has had the RRR High Pressure ridge blocking pattern. Note that this anomaly is positioned close to where the +3° SST anomaly is located in the NE PAC basin, but primarily along the eastern portion of the SST anomaly.
Special Notations;
If records are set again Sunday it will mark the 16th consecutive day of RECORD-SETTING temps for CA. Many new records continue to beat those that were set during the Great Drought of 1976, and some have broken ALL-TIME RECORDS for the month of January! A list of the new records for CA during Fri/Sat is provided below for Days 14 and 15 of consecutive record-breaking temps. When was the last time that Statewide records were broken for 15 or 16 consecutive days, either hot or cold?
Forecast guidance continues to advertise a significant pattern change as the PAC RRR High Pressure at 140W encourages a wet subtropical disturbance to slide into NOR/CENCAL on next Wed/Thu. This feature has a high probability of giving a dose of rainfall to NOR/CENCAL. However there is a lot of spread with important embedded details so some aspects of the forecast could be subject to considerable error. One uncertainty is associated with the EPAC energy as it heads toward the West Coast, with possible incorporation of the subtropical moisture into the system adding complexity to the forecast. As this energy nears the West Coast there is barely any clustering at all among the Operational models and ensembles at the surface with forecasts ranging between a vigorous Low Pressure circulation to a weak wave with a variety of tracks and timings. At the very least we favor leaning more with the slower models due to the direction aloft this energy is initially traveling… heading directly into the strong RRR High Pressure ridge. The latest GFS charts show that this storm the one and only chance of precip for CENCAL currently showing on the 16 Day GFS charts, the rest of the possibilities for rainfall into CA have been edited out, with week #2 turning dry and cooler. The PACNW and NORCAL could see moderate amts of rainfall with the potential for enhanced orographics depending upon the currently very uncertain details of mid level and surface evolution in the storm development late Wed into Thu. Expected QPF’s for CENCAL currently range from 0.25 inch up to 0.70 inch, which is enough water to compensate for about 3 to 6 days worth of evapotranspiration experienced this past week. In the meantime, both Coasts continue to set records at opposite extremes; West Coast records for heat with temps +15° to +20° above average and CA with 15 Days of consecutive Record Setting temps, and the East Coast records for cold being up to -30° below average.
Water Year 2013-14 is now the record driest to date in California history as illustrated in the chart below ↓
Minimum Temp Days below 32° chart; averaged since Nov 27th, 2013 to Jan 25th, 2014 showing the number of Days below 32°, with portions of the SJV depicted with 40-50 nights with Freezing Temps!
Evaporation rates this week have soared, peaking on Friday at over 0.25 inch in the South Valley region and Southern Sierra due to the super dry downsloping adiabatically heating air mass with 0.2 inch PWAT’s and dewpoints into the single or negative digits. That adiabatically heated airmass set 2 records in one day for Bakersfield! Moisture loss thru evaporation for the past 10 Days over CENCAL ranges from 1 inch to 1.55 inches, which is far more than any SJV Station has received this rainfall year, and adds to the 4.5 inch deficit thru evaporation that has occurred during the dry December 1st to Jan 15th. So basically CENCAL is about minus 5-6 inches in the negative for rainfall in the middle of the rainy season and heading into the end of the 7th month of the rainfall year.
Folsom Lake storage past 3 years graph;
Some LOW Streamflows examples
Station Current (cfs) Previous Record LOW FLOW (cfs)
Carson 2.14 45 set in 1977
Eel Mid Fork 31 79 set in 1977
Eel/Scotia 164 342 set in 1977
Mattole/Petrolia 47 58 set in 1977
Russian/Healdsburg 26 51 set in 1977
Scott 57 86 set in 1977
Klamath/Klamath 3110 3840 set in 1977
Pit 1030 1240 set in 1991
Yuba 103 108 set in 1977
White 4.4 5.5 set in 1991
Tule 4.4 9.6 set in 2007
San Joaquin/Mid Fk 7.7 20 set in 2012
Tuolumne Abv/HH 16 42 set in 2007
Salinas/Salinas 0.0 0.0 set in 1991
Carmel 0.0 0.0 set in 1977
Sierra Precip Indexes;
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TEMPS
NEW RECORD TEMPS
Friday
Station New Record Old Record__
Merced 73° 63° set in 2007 Beats the prior record by +10°
Madera 77° 65° set in 2009
Fresno 78° 73° set in 1953 Also ties the Record High Max for January, set in 1986
Hanford 77° 65° set in 2009
Bakersfield 79° 77° set in 1946 Breaking a 68 year old record
Bakersfield 68° 53° set in 2009 This set a new ALL-TIME JANUARY RECORD HIGH MIN, beating 62° on Jan 13, 1980
Crescent City 69° 68° set in 2006
SAC Dwntwn 79° 70° set in 1984 This set a new ALL-TIME JANUARY RECORD, beating 74° set on Jan 31st, 1976
Stockton 74° 69° set in 1976
Modesto 73° 68° set in 1976
Oxnard 57° 55° set in 1930 Breaking an 84 yr old record
Santa Maria 82° (Ties) 82° set in 1951 This is the 9th day of 80° or more, breaking the previous record of 6 days set in 1976
Paso Robles 76° 73° set in 2011
Burbank 80° Marks the 13th day in January with 80° or more beating the prior record of 12 days in Jan 2003
Saturday
Station New Record Old Record__
Fresno 75° 70° set in 2005 and 1936 This also ties the record number of 70° days in January set in 1948
Merced 72° 65° set in 2007
Madera 74° 69° set in 2007
Hanford 74° 68° set in 2007
Ukiah 77° 72° set in 1980
Redding 78° 73° set in 2011
Red Bluff 78° 71° set in 1984
SAC Dwntwn 74° 71° set in 1899 Beats a 115 year old record!
SAC Exec 74° 67° set in 1987
Stockton 72° 68° set in 1987
Modesto 73° 67° set in 1997
OAK Dwntwn 73° 72° set in 2011
SJ/Moffett 72° 70° set in 2011
Gilroy 77° 71° set in 2007
Salinas 78° 76° set in 2011
San Rafael 70° (Ties) 70° set in 1948
OAK 70° (Ties) 70° set in 2011
SJ 71° (Ties) 71° set in 1948
Record High Mins
Laguna Beach 60° 59° set in 1935
San Diego 62° 60° set in 1969
Elsinore 55° (Ties) 55° set in 2013
Riverside 60° 58° set in 1914 Beats a 100 year old record!
Escondido 59° 57° set in 2013
Alpine 57° 55° set in 1969
Idyllwild 49° 44° set in 2013
Campo 55° 55° set in 1995
Palm Springs 63° 57° set in 2012
Thermal 56° (Ties) 56° set in 2013
Indio 61° 59° set in 2013
PRECIPITATION FORECAST
Day 1 – 5 QPF:
At 12Z (9am) Sunday thru the period Thursday night (Friday @4am) shows; Sun DRY. Mon shows most of CADRY, as light rainfall occurs in the far north, with >0.1 inch from the Eel River NE to near Susanville, with 0.2 inches for the Klamath River basin in northern Humboldt Co and all of Del Norte Co, with up to 0.5 inch for the higher elevations of the Smith River basin.
Tue shows CA DRY, with rains over the NW spreading further south than on Mon. With >0.1 inch from Clear Lake N _E to near Susanville, with up to 0.2 inch for the Eel River basin NE into the Shasta River basin, with up to 0.5 inch for most of Humboldt Co, with up to 1 inch for most of Del Norte Co. Wed shows the southern half of CA isDRY, with general rainfall over the northern half with up to >0.1 inch from the Bay region east to Livingston to Mammoth, with up to 0.2 inch from the north Bay region and most of NORCAL, down the Sierra to the Tuolumne River basin, with up to 0.5 inch from the Eel River basin northward and into the Shasta River basin and down the Sierra to near the Stanislaus River basin, with up to 1 inch for the northern Sierra down to Tahoe, and along the NW Coastal region. Thu shows rains spreading into CEN/SOCAL while NORCAL dries out. With up to 1 inch for the Santa Lucia’s along the Central Coast and in the Sierra from the Feather River south to the Kern River basin, with up to 1.5 inches of liquid equivalent reaching into the higher elevations of the Sierra Crest from YNP north to Tahoe, with up to 0.5 inch falling into the Eastside of the Great Valley and down to Isabella, and along the coast range from Santa Cruz south to the Santa Barbara coast and east into the San Gabriel Mts. The Westside of the SJV receives up to 0.2 inches and the drier sections of SW and SE Kern Co have >0.1 inch with the same amts for the North Coast region.
5DAY ACCUMULATION CHART:
Days 6 & 7 QPF thru next Fri/Sat shows up to 0.4 inch for the far NW Coastal region over to the Shasta Basin and down the Sierra to the Kings River, with 0.25 inch as far south as the Bay region and with >0.1 inch from SAC north in the Great Valley.
16-Day QPF estimates (from the 12Z GFS) for;
Days 1-8 shows up to 1.5 to 2 inches for the wet spots of NORCAL and the northern Sierra, with up to 1+ inch for the Southern Sierra near YNP diminishing to 0.8 inch for the northern Kern River basin, with up to 0.7 inch for the Eastside of the northern portion of the Great Valley diminishing to 0.4 inch for the Eastside of the southern SJV, with only >0.1 inch for the drier portions of Kern Co.
Days 9-16 shows CA DRY
Saturday’s 0Z 9pm GFS 384hr, 16Day QPF Chart, with up to 2 inches for the NW Coastal region, up to 1 inch for the I-80 corridor northward and into the Sierra down to YNP, up to 0.5 inch from Monterey Bay to Modesto, up to 0.25 inch from Morro Bay to the Southern Sierra and >0.1 inch from near Oxnard across the Tehachapi Mts.
Sunday’s 12Z 9am GFS 384hr, 16Day QPF Chart, showing up to 1.5 inches for the northern Sierra with perhaps up to 1 inch for the Sierra near YNP and lighter amts to the south, with diminishing amts up to 0.50 inch for the northern SJV dropping to 0.1 inch for Kern Co.
SATELLITE
Water Vapor 4KM Image of the West Coast Sunday, January 26th, 2013, shows high level moisture streaming over portions of CA from the WSW with a minor disturbance moving toward the SOCAL coast. Further west is another storm system which may impact NORCAL on Tue/Wed with warm subtropical rains.
Visible Satellite Image of the CA Sunday, January 26th, 2013, shows variable cloudiness moving inland over portions of CEN/SOCAL while most of NORCAL remains clear.
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Comments and suggestions always welcome.
Atmospherics Group International
Dan Gudgel Steve Johnson
559-696-9697 559-433-7316