000
FXUS66 KLOX 032159
AFDLOX
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
200 PM PST WED DEC 3 2008
.SHORT TERM (TODAY-SAT)...MARINE LYR SPUN UP TO OVER 2000 FEET THIS
MORNING IN RESPONSE TO AN EDDY CIRCULATION. HOWEVER, A STRONG
OFFSHORE TREND CLEARED THINGS OUT QUICKLY TODAY AND SKIES ARE MOSTLY
SUNNY EVERYWHERE THIS AFTERNOON WITH TEMPS UP SEVERAL DEGREES IN THE
VALLEYS AND TO A LESSER DEGREE THE COAST. IN ADDITION, WEAK OFFSHORE
BREEZES HAVE BEEN REPORTED DOWN TO THE HIGHER VALLEYS AND MOUNTAINS.
TONIGHT AN UPPER LOW WILL DROP SOUTH ALONG THE CALIFORNIA COAST.
MODELS SHOW THE LOW STAYING TOO FAR OFFSHORE TO BRING ANY PRECIP,
HOWEVER IT SHOULD BE CLOSE ENOUGH TO HELP MAINTAIN A DEEP MARINE LYR
S OF PT CONCEPTION WITH OR WITHOUT AN EDDY CIRCULATION. GIVEN THAT
HEIGHTS ARE FALLING PRETTY RAPIDLY TONIGHT WE COULD SEE SOME DRIZZLE
IN SOME AREAS THU MORNING. CONFIDENCE IN CLOUD COVERAGE ALONG THE
CENTRAL COAST NOT QUITE AS HIGH AS MODELS ARE STILL SHOWING A LIGHT
EASTERLY FLOW AT LOW LVLS WHICH MAY KEEP THE CLOUDS OFFSHORE. THE
COMBINATION OF MORE CLOUDS S OF PT CONCEPTION AND STRONG ONSHORE
TRENDS SHOULD CAUSE HIGHS TO DROP 5-10 DEGREES FOR THE COAST AND
VALLEYS. LEFT IN A PARTLY CLOUDY FORECAST FOR THU AFTERNOON AS THERE
IS A CHANCE THAT MARINE LYR CLOUDS WILL HAVE A VERY DIFFICULT TIME
CLEARING, EVEN IN THE VALLEYS.
CONDITIONS REVERSE AGAIN FRIDAY AS THE LOW MOVES WEST AND WEAK
OFFSHORE FLOW RETURNS. WITH HEIGHTS REBOUNDING WE SHOULD SEE QUITE A
BIT LESS MARINE LYR FRI WITH EARLIER CLEARING. HIGHS WILL BE WARMER
AS WELL, THOUGH THE AMOUNT OF WARMING DEPENDS ON THE STRENGTH OF THE
COLD ADVECTION. COAST AND VALLEYS WILL LIKELY SEE 5-10 DEGREES OF
WARMING WHILE AREAS FURTHER INLAND WILL BE ABOUT THE SAME AS THU.
ALTHOUGH NOT ADVISORY LEVEL, LOCALLY GUSTY NORTHEAST WINDS ARE
POSSIBLE INTO THE VALLEYS AND MOUNTAINS.
THE CUTOFF LOW IS EXPECTED TO REMAIN WELL WEST OF THE AREA SAT AS
HIGH PRESSURE BUILDS IN FROM THE NORTH. OFFSHORE GRADIENTS ARE ABOUT
THE SAME, THOUGH UPPER SUPPORT IS MINIMAL. AIRMASS IN GENERAL IS
WARMER AND WE SHOULD SEE A NICE BUMP IN TEMPS ACROSS THE MTNS AND
DESERTS ESPECIALLY. MAY EVEN SEE SOME 80 DEGREE READINGS IN THE
VALLEYS ON SAT.
.LONG TERM (SUN-WED)...THERE WASN`T A SINGLE 12Z MODEL RUN TODAY
THAT SUPPORTED ANY RAIN FOR THIS WEEKEND AND EARLY NEXT WEEK. ALL
THE GFS ENSEMBLE MEMBERS AND EURO RUNS SHOWED THE UPPER LOW
RETROGRADING TO AT LEAST 130W. THE ECMWF CONTINUES TO BE THE CLOSEST
TO THE COAST, BUT EVEN IT`S SOLUTION IS FAR TO WEST TO HAVE ANY
SIGNIFICANT IMPACT LOCALLY. THE OTHER SOLUTIONS ARE WARM AND DRY
WITH NO CLOUDS AND WEAK OFFSHORE FLOW. THE EC SOLUTION COULD BE
CLOSE ENOUGH TO SUPPORT SOME MID AND HIGH CLOUDS ACROSS THE AREA
SUN/MON, AND IT`S NOT QUITE AS WARM AS THE OTHER MODELS. FOR NOW
I`VE DROPPED POPS TO 10 OR LOWER ACROSS THE AREA, LEAVING IN THE
SMALL POSSIBILITY THAT FUTURE MODELS RUNS COULD AGAIN CHANGE THEIR
MINDS. I`VE ALSO WARMED THINGS UP QUITE A BIT, BUT HEDGED A LITTLE
TOWARDS THE COOLER ECMWF. AND IF THE GFS IS CORRECT FOR NEXT TUE/WED
WE COULD BE LOOKING AT RECORD HIGHS WITH A 590 HIGH CENTERERD JUST
TO THE WEST AND GRADIENTS 3-4 MB OFFSHORE. I`VE TRENDED THE FORECAST
WARMER BUT DIDN`T WANT TO GO THAT WARM JUST YET.
&&
.AVIATION...03/1930Z.
LOW CLOUDS AND FOG HAVE CLEARED TO THE COASTLINE AND THE ONLY ISSUE
IS A RATHER THICK LAYER OF HAZE DUE TO WEAK PRESSURE GRADIENTS. THE
HAZE IS THICK ENOUGH TO PRESENT THE ASOS SITES WITH A CHALLENGE IN
DETERMINING THE PRESENCE OF A CEILING. MANY LOCATIONS WERE REPORTING
ONLY 2-3 MILES VISIBILITY IN HAZE. DECIDED TO GO MORE PESSIMISTIC
WITH THE VISIBILITY IN VENTURA/LA COUNTY SITES AS THE PRESSURE
GRADIENTS REMAIN RATHER LIGHT FOR THE NEXT 24 HOURS. LOW CLOUDS AND
FOG WITH MVFR CONDITIONS SHOULD RETURN TO THE COASTAL SITES EARLY
THIS EVENING WITH THE VALLEY TAF SITES GETTING THE CEILING BACK
SHORTLY AFTERWARD...IT WILL NOT TAKE VERY LONG WITH SO MANY
CONDENSATION NUCLEI IN THE ATMOSPHERE.
KLAX...CLEAR SKIES WITH HAZE THROUGH THE AFTERNOON...FOLLOWED BY LOW
CLOUDS AND FOG WITH MVFR CONDITIONS RETURNING TO THE AIRFIELD IN THE
EARLY EVENING. FAIRLY GOOD CONFIDENCE IN THE FORECAST.
KBUR...CLEAR SKIES WITH HAZE THROUGH THE EARLY EVENING...FOLLOWED BY
LOW CLOUDS AND FOG WITH MVFR TO LOCALLY IFR CONDITIONS RETURNING TO
THE AIRFIELD IN THE LATE EVENING. WILL ADJUST THE CURRENT FORECAST
TO BRING THE LOW CLOUDS AND FOG IN AROUND 06Z. FAIRLY GOOD
CONFIDENCE IN THE FORECAST.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
PUBLIC...WOFFORD
AVIATION...SWEET
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