FXUS66 KLOX 150311
AFDLOX
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
715 PM PST MON DEC 14 2009
.SYNOPSIS...
A WEAK RIDGE BUILDING INTO SOUTHWESTERN CALIFORNIA WILL MAINTAIN DRY
CONDITIONS FOR THE BEGINNING OF THE WEEK...WITH A SLIGHT WARMING
TREND. THE TAIL END OF A FRONTAL SYSTEM COULD BRING LIGHT RAIN TO
FAR NORTHERN SECTIONS OF SAN LUIS OBISPO COUNTY LATE WEDNESDAY OR
WEDNESDAY NIGHT...THEN DRY OFFSHORE FLOW WITH A WARMING TREND FOR
THE END OF THE WEEK.
&&
.SHORT TERM (TONIGHT-THU)...A WEAK RIDGE OF HIGH PRESSURE HAS BUILT
IN ACROSS THE REGION IN THE WAKE OF THE COLD FRONT THAT IS NOW
LOCATED ACROSS ERN AZ AND WRN NEW MEXICO. THERE WAS SOME RESIDUAL
MOISTURE THAT LINGERED ACROSS PORTIONS OF THE CWA TODAY...BUT
LATEST SATELLITE IMAGERY INDICATED ONLY VARIABLE HIGH CLOUDS MOVING
THROUGH THE REGION AS A WEAK DIRTY RIDGE BUILDS IN BEHIND THE
EXITING TROUGH.
TEMPS WARMED UP JUST A FEW DEGREES IN MOST AREAS WITH MOST COASTAL
AND VALLEYS IN THE UPPER 50S TO LOWER TO MID 60S. THIS WARMING TREND
WILL CONTINUE INTO TUE AS WEAK OFFSHORE FLOW WILL PERSIST OVER THE
NEXT FEW DAYS. ALTHOUGH THICKNESS LVLS WILL CONTINUE TO RISE THROUGH
THE WEEK...BY WEDNESDAY THE WEAK RIDGE IN PLACE WILL BECOME MORE
ZONAL AS A WEAK COLD FRONT BEGINS TO PUSH DOWN INTO NRN CAL. THE
MOISTURE ASSOCIATED WITH THIS WEAK COLD FRONT WILL BEGIN TO WEAKEN
AND WASH OUT AS IT REACHES THE MOST NORTHERN PORTION OF THE FORECAST
AREA. THERE IS A SLIGHT CHANCE OF SHOWERS ACROSS THE NW PORTION OF
SAN LUIS OBISPO COUNTY FOR WED. ALTHOUGH THE RIDGE FLATTENS OUT
WED...WEAK OFFSHORE GRADIENTS WILL PERSIST THROUGH MUCH OF THE DAY
KEEPING TEMPS SLIGHTLY WARMER ONCE AGAIN ON WED.
BY WED NIGHT INTO EARLY THU MORNING...THE LAX-DAG SFC GRADS ARE
FORECASTED TO BE AROUND -5MB. THIS SHOULD TRANSLATE INTO CONTINUED
WARMING INTO THU ACROSS THE VALLEYS AND COASTAL AREAS WITH NEAR
ADVISORY LEVEL WINDS POSSIBLE WED NIGHT INTO THU MORNING ACROSS THE
USUAL LA/VTU COUNTY MTN AND VALLEY WIND PRONE NE-SW PASSES AND
CANYONS. WITH THIS INCREASING OFFSHORE FLOW...HIGH TEMPS WILL REACH
THE LOWER TO MID 70S. WHILE AREAS N OF POINT CONCEPTION SHOULD WARM
UP INTO THE UPPER 60S TO AROUND 70...EXCEPT THE SANTA YNEZ VALLEY
SHOULD REACH THE MID 70S AS WELL. TEMPS SHOULD BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR.
THERE IS NO MENTION OF LOW CLOUDS OVER THE NEXT FEW DAYS ALONG THE
COAST...BUT SFC GRADS WILL BE NEAR NEUTRAL THE NEXT FEW EARLY
MORNINGS. THEREFORE...SOME RANDOM STRATUS COULD DEVELOP NEAR THE
COAST...BUT NOT THAT CONFIDENT AS THE INVERSION WILL BE QUITE WEAK
TONIGHT THROUGH WED.
.LONG TERM (FRI-MON)...GOOD AGREEMENT IN EXTENDED MODELS ADVERTISING
ANOTHER WARM OFFSHORE DAY ON FRIDAY...BUT THEN MODELS BEGIN TO
DIVERGE. ON SATURDAY AND SUNDAY...THE ECMWF CONTINUES TO MAINTAIN AN
UPPER LEVEL HIGH PRESSURE SYSTEM OVER THE AREA...WHILE THE GFS BRINGS
A WEAK TROUGH THROUGH THE AREA. PER COORDINATION WITH SURROUNDING
OFFICES...HAVE OPTED FOR DRIER ECMWF SOLUTION DUE TO ITS GREATER
RUN-TO-RUN CONSISTENCY. BY MONDAY...THE ECMWF SHOWS A WEAK TROUGH
OFF THE COAST OF CALIFORNIA THAT COULD BRING IN SOME CLOUD COVERAGE.
&&
.AVIATION...15/0100Z.
HIGH CONFIDENCE IN TAFS THROUGH TUESDAY. MODERATE CONFIDENCE FOR IFR
CIGS FOR KPRB LATE TONIGHT INTO TUE MORNING. LOW CONFIDENCE THAT
RANDOM IFR/MVFR STRATUS COULD DEVELOP NEAR KLAX AFTER 10Z THROUGH
15Z THIS MORNING.
KLAX...HIGH CONFIDENCE IN TAF EXCEPT 20 PERCENT CHANCE OF IFR/MVFR
CONDS DEVELOPING AFTER 10Z THROUGH 15Z THIS MORNING.
KBUR...EXPECT CAVU CONDITIONS THROUGH TUE.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
ABOVE NORMAL SURF (SEE LAXCFWLOX).
&&
$$
PUBLIC...KAPLAN/GOMBERG
AVIATION...KAPLAN
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