686 
FXUS66 KLOX 232152
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
145 PM PST MON NOV 23 2009

.SYNOPSIS...

GUSTY OFFSHORE WINDS AND CLEAR SKIES SHOULD SEND TEMPERATURES IN THE 
AFTERNOONS TO WELL ABOVE THE SEASONAL NORMALS THROUGH THURSDAY. A 
COLD FRONT WILL CROSS THE REGION ON FRIDAY AND WILL SHARPLY DROP THE 
TEMPERATURES. HIGH PRESSURE WILL BUILD IN ON SATURDAY...AND 
WINDS WILL SHIFT OFFSHORE ON SUNDAY FOR MOSTLY CLEAR SKIES AND A 
WARMING TREND.

&&

.SHORT TERM (TONIGHT-THU)...MAIN WEATHER FOCUS IS THE DEVELOPING 
SANTA ANA ACROSS SOUTHERN CAL AND THE STRENGTH OF THE WIND GUSTS... 
WARM TEMPERATURES AND LOW HUMIDITIES FOR THE NEXT FEW DAYS. THE 
OFFSHORE WINDS KICKED IN EARLIER THAN EXPECTED TODAY AND 
TEMPERATURES HAVE ZOOMED ABOVE FORECASTS AS A RESULT. PRESSURE 
GRADIENTS OF -5.0MB LAX-DAG AND -10.6MB LAX-TPH CONTRIBUTED TO THE 
INCREASED OFFSHORE WINDS. STRONGEST GUSTS HAVE OCCURRED ALONG THE 
SANTA CLARA RIVER VALLEY AND NEARBY FOOTHILLS... AND ACROSS CANYON 
COUNTRY TOWARD THE SAN FERNANDO VALLEY. GUSTS OF 30 TO 40 MPH HAVE 
BEEN COMMON WITH STRONGEST WINDS OVER 60 MPH AT WILEY RIDGE...OUR 
NOTORIOUSLY WINDY SPOT. WRF MODEL LOW-LEVEL WINDS (AROUND 2K FT) 
INCREASE TO NEARLY 40KT JUST AFTER DARK ACROSS VENTURA COUNTY AND 
REMAIN STRONG THROUGH TUESDAY MORNING. THEREFORE...EXPECT WINDS TO 
BECOME MORE WIDESPREAD AND STRONGER ACROSS VENTURA AND LOS ANGELES 
COUNTIES TONIGHT. WILL CONTINUE ALL WIND ADVISORIES AND COASTAL 
AREAS SHOULD RAMP UP INTO THIS CATEGORY THIS EVENING AS PLANNED. 
MINIMUM TEMPERATURE FORECASTS ARE CHALLENGING FOR THE NEXT THREE 
NIGHTS AND WILL DEPEND SOLELY ON WIND-SHELTERING AND COULD MAKE FOR 
LARGE SPREADS IN SHORT DISTANCES. 

WINDS TEND TO WEAKEN IN THIS TYPE OF PATTERN BY LATE MORNING OR 
EARLY AFTERNOON...SO WILL LET ADVISORIES RIDE UNTIL THIS TIME FRAME 
ON TUESDAY. IT IS HIGHLY LIKELY THAT ADDITIONAL WIND ADVISORIES WILL 
BE REQUIRED FOR TUESDAY NIGHT AND POSSIBLY WEDNESDAY NIGHT. HAVE 
RAMPED UP TEMPERATURES IN THE WINDIER LOCATIONS THROUGH THANKSGIVING 
DAY. STILL DO NOT BELIEVE RECORDS ARE REACHABLE...BUT READINGS WILL 
PUSH UPPER 80S TO LOWER 90S ON THE WARMEST DAYS OF WEDNESDAY AND 
THURSDAY. OFFSHORE WINDS CONTINUE THROUGH THURSDAY MORNING WITH A 
WEAK ONSHORE SEABREEZE ATTEMPTING TO DEVELOP LATE IN THE DAY. THERE 
IS STILL A HEIGHTENED FIRE WEATHER CONCERN THROUGH THURSDAY DUE TO 
THE PERSISTENT SANTA ANA CONDITIONS...WARMER TEMPERATURES...POOR 
HUMIDITY LEVELS AND DRYING FUELS. A STRONGER SANTA ANA EVENT WOULD 
TIP THE SCALES TOWARD FIRE WEATHER WATCHES AND/OR WARNINGS. 

.LONG TERM (FRI-MON)...GOOD MODEL CONSISTENCY NOW WITH A LOW PRES 
TROUGH MOVING ACROSS THE WEST COAST ON FRIDAY. TEMPERATURES WILL BE 
A GOOD 15-20 DEGREES COOLER WITH DECENT HUMIDITY RECOVERY AS 
NORTHERLY WINDS RETURN TO THE REGION. THIS SYSTEM LOOKS DRY AND WILL 
BLOW OUT ANY LOW CLOUDS ALONG THE COAST. THERE COULD BE A REPEAT OF 
UPSLOPE CLOUDINESS ON THE NORTH SLOPES OF THE MOUNTAINS ALONG WITH A 
FEW SPRINKLES BEHIND THE STORM SYSTEM LATE FRIDAY OR SATURDAY. THE 
RIDGE BECOMES QUITE AMPLIFIED OVER THE EASTERN PACIFIC OCEAN ON 
SUNDAY AS A SURFACE HIGH DEVELOPS OVER THE GREAT BASIN TURNING OUR 
WINDS BACK TO OFFSHORE. FAIRLY GOOD CONFIDENCE IN THIS SCENARIO SO 
HAVE TRENDED TEMPERATURES BACK TO ABOVE NORMAL FOR DAYS 6-7. WE 
COULD ALSO BE LOOKING AT A STRONGER SANTA ANA WIND EVENT BY SUNDAY 
NIGHT-MONDAY. 

&&

.AVIATION...23/1950Z.
VFR CONDITIONS WILL CONTINUE THROUGH TUESDAY...EXCEPT LATE NIGHT AND 
EARLY MORNING DENSE FOG AT KPRB. WIND SHEAR COULD BE A PROBLEM FOR 
KSBP...KBUR AND MAYBE KVNY DUE TO OFFSHORE WINDS.

KLAX...VFR CONDITIONS THROUGH TUESDAY.

KBUR...VFR CONDITIONS THROUGH TUESDAY. PERIODS OF LOW LEVEL WIND 
SHEAR.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).

&&

$$

PUBLIC...BOLDT
AVIATION...SWEET
SYNOPSIS...SETO

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