Record Temps . . Cooling Saturday . . Warming Wednesday

Surface High Pressure of 1026mb over NV combined with an inverted surface 1016mb Pressure trough over the SJV is drawing hot/dry air downslope into the SJV. With gusty SE winds in the South Valley downsloping quickly into the SJV aiding adiabatic heating in addition to the subsidence heating that is occurring from the High Pressure ridge over the West Coast, max temps soared in the South Valley region with the max SJV temp of 99°recorded at the Comanche Station with winds up to 47mph recorded at the CHP Grapevine Station producing reduced visibilities down to about 2+miles. R/Humidities and dewpoints have dropped into the single digits in the southern SJV and Kern Mts, prompting a Red Flag Warning. In addition to the SE winds in the South Valley, gusty NE winds are also blowing across the Sierra which are also downsloping into the Eastside foothills. Mammoth Mt reporting NE winds to 33mph blowing down the San Joaquin River canyon, which is producing a dewpoint 6° and R/Humidity of 8% at the High Sierra Station near Florence Lake! This is certainly not the best news for the forest moisture content as well as the meager Sierra snowpack. The entire State of CA produced record-setting heat at key stations which have the some of the oldest records on the West Coast…including San Francisco, Los Angeles, Santa Barbara and even at Crescent City! The warm/dry flow pattern should continue thru Thursday, then gradually diminish on Friday and Saturday as the High Pressure retracts southward. Although SJV temps will remain near persistence on Thu/Fri, expect a cooling trend to initiate on Sat with a big drop occurring on Sunday by about -12° to -15°. Gusty NW winds will accompany the cool down beginning late Sunday thru Tuesday, and by next Tuesday the cooling trend bottoms out with mid 70°’s common, which is slightly below average for this time of year. A warming trend begins on Wednesday, May 7^th.

500mb chart showing the 582dm High Pressure ridge built northward into WA State, with a +2.5 Standard Deviation Anomaly over SW Canada and NW WA, which produced record-setting heat.

Red Flag Warning; Kern Co mts region for very low R/Humidities remaining below 10% for up to 10 hrs or reaching as low as 5% with temps in the 90°’s in foothills and in the 70°’s above 4000ft. Rapid Fire spread and extreme fire behavior could occur.

Memo regarding a recent EL NINO publication that is being circulated; The CPC continues to show a high confidence forecast for a warm phase ENSO event this fall/winter…Water Year 2015. Please remember that the evolution of the El Nino is just beginning and is far from complete. Therefore no one knows whether or not the event will be weak, medium or strong. A weak or medium event has NO signal for CA! It has a 50% chance of producing another dry season or it also has a 50% chance of producing a wet season. The only well defined El Nino signal is during a strong event, which has in the past brought copious amts of rainfall to much of CEN/SOCAL. So at this time it remains unknown what “type” of ENSO event is upcoming. Therefore we strongly urge you to disregard any attempt by a forecaster to call the shots for this upcoming Water Year. If you believe the recent garbage issued yesterday with regards to an early ‘preliminary outlook’ for El Nino you are being very foolish. Forecasters who are issuing detailed analysis forecast for next fall and winter are making claims that could be applied to any winter season. Please do NOT fall for this hype, it is a reckless attempt to impress someone, but has made a fool out of the author and that is putting it mildly. It is being widely condemned by the experts involved in ENSO to make such claims.

FORECAST SUMMARIES

Days 1-7;

Thu, May 1^st The large scale features over the PAC basin show a highly amplified pattern which includes 2 separate High Pressure ridges and 2 separate troughs. The trough/ridge/trough configuration centered at 160W is an OMEGA block, so the downstream features are slow to move, including the High Pressure ridge over the West Coast. The West Coast ridge has reached its apex and is beginning to shrink southward, with the 582dm height dropping from southern BC, Canada down to southern OR by Thu afternoon, while the offshore downsloping flow pattern over CA slowly diminishes as compared to the strong strength exhibited on Wednesday.

MAX MIN

Fri, May 2^nd As the 582dm heights continue to fall over CA, a strong 540dm Low Pressure storm center approaches the Olympics region with a SW flow pattern evolving over the PACNW. Overnight as the 582dm heights push offshore SOCAL lower pressures move inland over NORCAL, with increasing onshore marine breezes beginning to cool off much of NORCAL, while CEN/SOCAL continue to bake another day.

MAX MIN

Sat, May 3^rd The pressure falls over NORCAL slow down dramatically and level off, while pressures over SOCAL remain higher. The PACNW storm brings heavy precip into the WA coastline, with lighter rains reaching into OR and clouds crossing the CA/OR border. Temps over CENCAL drop by a few degrees as compared to Friday with increased winds late evening along the Westside SJV in response to a surge of marine air reaching into the Coastal passes and gaps.

MAX MIN

Sun, May 4^th Pressures over NOR/CENCAL drop slightly as the PACNW trough digs further southward. This increases the amt of marine air entering the interior of CA bringing significantly cooler temps. Clouds and showers reach into NORCAL and the Northern Sierra down to near Tahoe.

MAX MIN PRECIP

Mon, May 5^h The PACNW trough digs southward into NORCAL with 558dm heights reaching across the CA/OR border, with -24°C isotherm reaching Yreka and Alturas, vort energy spreads southward producing shower activity into the Sierra down to near the Kings and Kaweah River basins with snowfall at the higher elevations. Overnight the -26°C cold core drops into NE CA near Alturas accompanied with moderate vort energy which keeps showers going over portions of NORCAL and into the Sierra. Winds pick up throughout the SJV.

MAX MIN PRECIP

Tue, May 6^th The trough shifts into the Great Basin with the backside north flow pattern advecting cool/dry air southward into NORCAL with clearing skies and breezy conditions locally producing cool temps and partly cloudy skies for the lowlands and cloudy skies and showers into the Sierra.

MAX MIN PRECIP

Wed, May 7^th While the bulk of the Low Pressure trough exits into the Rockies, a portion of the trough lags behind, offshore SOCAL. This inhibits the warming trend by providing an extension of the cool/dry north flow pattern into CA for an additional day.

MAX MIN PRECIP

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

Thu, May 8^th shows the trough continues to dig SE into Baja and NW Mexico, with a continuation of the northerly breezes over CA which produce offshore winds for SOCAL. Meanwhile further north a strong/moist onshore flow pattern brings additional rainfall into the PACNW and far NORCAL near the OR border with cloudiness reaching as far south as Monterey to near Tahoe. Overnight High Pressure noses into NORCAL and OR, thus shunting the moist flow northward.

Fri, May 9^th shows strong High Pressure returns to CA, with 582dm heights spreading west to east running from Cape Mendocino southward to near Long Beach moving east, while further west of CA a 588dm High Pressure cell forms far west of San Diego.

Sat, May 10^th shows the High Pressure continues to build over the West Coast, with 582dm heights covering all of CA and most of AZ. With subsidence aloft and weak winds, temps over CA rise rapidly.

Sun, May 11^th shows High Pressure over CA weakening over NORCAL, while the 582dm heights run from SFO to near Tahoe, with persistence for CEN/SOCAL temps remain warm. Overnight pressures begin to fall again.

Mon, May 12^h shows the formation of a weak long-wave trough evolving offshore west of CA, while the High Pressure ridge shifts east into the Rockies, thus producing a S-SW flow aloft over CA. Currently the charts show no moisture associated with this pattern…just warm air from the subtropics spreading over CA.

Tue, May 13^th shows the High Pressure ridge migrating eastward into the Central CONUS, as a weak trough configuration develops over BC, Canada and the PACNW. The flow aloft over CA continues to be SW, with no moisture, just warm air advecting into the State.

Wed, May 14^th shows a -28°C cold core Low Pressure storm center drops southward into eastern WA/OR and the ID border region which drags a weak cold front into NORCAL which is hardly recognizable except for the wind shift to the north and a few clouds to near Mt Shasta. The rest of CA enjoys mild/dry wx with temps near seasonal averages.

Thu, May 15^th shows the modified -24°C cold core dropping southward to near SLC, with the backside isothermic barrier shoved up against the eastern Sierra with breezy conditions along the Sierra Crest region along with some cloudiness and perhaps a few showers in the High Country.

Fri, May 16^th shows the SLC Low Pressure storm ejects into the Midwest, creating havoc with SEVERE Thunderstorms into the High Plains and Midwestern States. This has the typical signature of another major tornado outbreak for the folks in the Midwest. Meanwhile High Pressure moves into CA with fair/mild conditions and a warming trend.

NEW CA RECORDS …HEAT!

Station New Record Old Record__

Crescent City 78° 75° set in 1958 Beats a 56 year old record

San Francisco 90° Ties 90° set in 1996

Salinas 93° Ties 93° set in 1996

King City 97° 96° set in 1996

San Rafael 89° Ties 89° set in 2013

Los Angeles 89° 90° set in 1996

Long Beach 94° 90° set in 1996

Camarillo 94° 93° set in 1996

Oxnard 93° Ties 93° set in 1996

Santa Barbara 90° 80° set in 1993 Blows the old record away by +10°!

Santa Maria 98° 96° set in 1996

San Diego 94° 87° set in 1996

Newport Beach 92° 86° set in 1921

Laguna Beach 95° 92° set in 1981

Vista 96° 95° set in 1996

Elsinore 59° 57° set in 1981 High Min

Campo 52° 50° set in 1995 High Min

Palm Springs 73° 69° set in 2001 High Min

Indio 72° 70° set in 1992 High Min

Medford, OR 92° 86° set in 1981

PRECIPITATION FORECAST

Day 1 – 5 QPF:

At 12Z (9am) Wednesday thru the period day Sunday night (Monday @5am);

7 Day QPF Chart; shows rains into the far NW coastal region of CA with up to 1.25 inches for the Smith River basin. Amts rapidly diminish further south with only 0.1 inch for the Southern Sierra. The Great Valley and most of CENCAL and SOCAL remain dry.

16-Day QPF estimates (from the 0Z GFS model) for;

Days 1-7; shows rains into the far NW coastal region of CA with up to 1.5 inches for the Smith River basin. Amts rapidly diminish further south with only 0.1 inch for the Southern Sierra. The Great Valley and most of CENCAL and SOCAL remain dry.

Days 8-16; shows only 0.25 inch of precip falls into the NW coastal region of Del Norte Co, with lesser amts into Humboldt Co, with the remainder of CA staying dry.

GFS 384hr, 16Day QPF Chart shows very little moisture offered for CENCAL and dry conditions for the 16 Day period for SOCAL. NORCAL receives up to 0.75 inch near the OR border region with rapidly diminishing amts further south.

EVAPOTRANSPIRATION

Weekly Evapotranspiration rates for the local 7 Counties shows up to 1.75 inch near Merced, up to 1.95 inch in western Kings Co and up to 2.31 inch near Ridgecrest during the next 7 Days. The Sierra Crest evaporation loss ranges from 1.20 inch in the upper Tuolumne River basin up to 1.93 inch near Isabella.

SATELLITE

Water Vapor 4KM Image of the West Coast Wednesday, April 30^th, 2014, shows a large dome of High Pressure over the West Coast, with high clouds offshore moving due north around the blocking High Pressure.