215
FXUS66 KLOX 161009
AFDLOX
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
310 AM PDT WED OCT 16 2013
.SYNOPSIS...
GUSTY OFFSHORE WINDS WILL CONTINUE ACROSS THE USUAL WIND PRONE AREAS
OF LOS ANGELES AND VENTURA COUNTIES THROUGH THIS MORNING...THEN
BEGIN TO DIMINISH THIS AFTERNOON. IT WILL CONTINUE TO BE DRY WITH
SOME WEAK OFFSHORE WINDS THROUGH THE PERIOD. TEMPERATURES WILL COOL
A FEW DEGREES ON THURSDAY AND THEN BOUNCE BACK UP A COUPLE DEGREES
ON FRIDAY AS ANOTHER WEAK OFFSHORE EVENT IS LIKELY LATE THIS WEEK
INTO SATURDAY.
&&
.SHORT TERM (TODAY-FRI)...LATEST SATELLITE IMAGERY INDICATED CLEAR
SKIES ACROSS THE FORECAST AREA AND ADJACENT COASTAL WATERS AS
OFFSHORE FLOW CONTINUES TO DOMINATE THE WEATHER PATTERN TODAY.
SYNOPTICALLY...AN UPPER LEVEL TROUGH WAS DIGGING ACROSS THE FOUR
CORNERS REGION THIS MORNING...WHICH WAS A TAD FARTHER EAST THEN
EARLIER MODELS WERE SHOWING. THIS IN TURN WILL PUSH THE
SURFACE HIGH PRESSURE A BIT FARTHER EAST AND WEAKEN THE SURFACE
PRESSURE GRADIENT BETWEEN LAX-DAG A FEW MILLIBARS.
CURRENTLY...THE OFFSHORE TRENDS ARE SIMILAR TO YESTERDAY...BUT BASED
ON ACTUAL OBS AT THIS TIME...NOT IMPRESSED WITH WHAT IS HAPPENING
WIND WISE EVEN IN THE USUAL WIND PRONE LOCATIONS. FOR NOW WILL LEAVE
WIND ADVISORIES IN PLACE...AS WIND GUSTS SHOULD PICK UP NEAR
SUNRISE. EXPECT MARGINAL STRENGTH OVERALL TODAY WITH MOST WIND PRONE
PASSES AND CANYONS OF THE LA/VTU VALLEYS AND COASTAL AREAS LIKELY
REACHING 35 MPH. MOST OF THE LA COUNTY BASIN WILL NOT EXPERIENCE ANY
WINDS...EXCEPT FOR THE WESTERN PORTION OF THE HOLLYWOOD HILLS NEAR
PACIFIC PALISADES TO LEO CARRILLO BEACHES INCLUDING MALIBU. MOUNTAIN
ZONES WILL EXPERIENCE GUSTS TO 45 MPH THIS MORNING.
WITH SOME ADDITIONAL COOL AIR ADVECTING ACROSS THE ANTELOPE VALLEY
THIS MORNING...HIGH TEMPS WILL CONTINUE TO BE IN THE MID 70S...WHILE
THE COAST AND VALLEYS WILL ONCE AGAIN WARM UP TO THE MID 80S. THE LA
COAST COULD SEE A DEGREE OR TWO OF COOLING THIS AFTERNOON AS A WEAK
SEABREEZE SHOULD DEVELOP IN THE AFTERNOON. THE VENTURA COAST SHOULD
STAY OFFSHORE A TAD LONGER SO HIGH TEMPS SHOULD REMAIN IN THE MID
80S AS WELL. SIMILAR CONDITIONS ARE EXPECTED ACROSS THE CENTRAL
COAST AND THE SANTA BARBARA SOUTH COAST WITH HIGHS ALSO REMAINING IN
THE LOWER TO MID 80S...JUST WITHOUT THE WIND ISSUES.
FOR TONIGHT INTO THURSDAY...WINDS WILL COME TO AN END AS SFC
GRADIENTS BECOME MORE NEUTRAL. THEREFORE OVERNIGHT TEMPS WILL COOL
DOWN AND AREAS LIKE THE ANTELOPE VALLEY AND PORTIONS OF THE INTERIOR
SAN LUIS OBISPO VALLEYS WILL EXPERIENCE TEMPS INTO THE MID 30S WHERE
SOME PATCHY FROST WILL BE POSSIBLE. THE ONSHORE FLOW WILL INCREASE
SOME THU BUT NOT EXPECTED TO BE STRONG...SO BEST COOLING WILL OCCUR
ACROSS COASTAL AREAS. THERE WILL BE A FEW DEGREES OF COOLING
INLAND...HOWEVER EXPECT A FEW DEGREES OF WARMING ACROSS THE FAR
INTERIOR AREAS INCLUDING THE ANTELOPE VALLEY.
THURSDAY NIGHT INTO FRI...ANOTHER WEAK SHORTWAVE IS EXPECTED TO PUSH
ACROSS THE GREAT BASIN WHICH WILL CAUSE A BRIEF PERIOD OF WEAK
OFFSHORE FLOW FRIDAY MORNING. EXPECT BEST WARMING ACROSS THE COAST
AND VALLEYS AS USUAL WITH THIS WEAK LOOKING SANTA ANA EVENT WITH
WARMEST TEMPS REACHING THE LOWER TO MID 80S AND COOLER FOR THE
INTERIOR AREAS. EXPECT SKIES TO REMAIN CLEAR THROUGH FRI.
.LONG TERM (SAT-TUE)...THE GFS AND ECMWF MODELS ARE SHOWING SUBTLE
DIFFERENCE THROUGH THE LONG TERM. OVERALL...WEAK OFFSHORE SHOULD
PERSIST INTO SATURDAY ACROSS THE COAST AND VALLEYS...WITH SOME
COOLING LIKELY FOR AREAS N OF POINT CONCEPTION...BUT CONTINUED WARM
OFFSHORE CONDITIONS ACROSS LA/VTU COAST AND VALLEYS. ON SUNDAY...THE
EC MODEL SHOWS A VERY WEAK CUTOFF LOW DEVELOPING OFF THE SO CAL
COAST WITH A WEAK UPPER TROUGH BEGINNING TO DEEPEN OFF THE
CALIFORNIA COAST BY BOTH MODELS. BY MONDAY BOTH MODELS INDICATE A
WEAK UPPER TROUGH PUSHING ACROSS THE COASTAL WATERS OF CALIFORNIA
WHICH SHOULD BRING SOME MARGINAL COOLING ACROSS THE ENTIRE REGION.
THERE WILL LIKELY BE SOME KIND MARINE LAYER STRATUS ALONG THE
COASTAL AREAS BY EARLY NEXT WEEK.
&&
.AVIATION...16/1000Z
CLEAR SKIES AND VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. SOME
LOW-LEVEL WIND SHEAR AND MDT UDDF POSSIBLE..PARTICULARLY IN AND NEAR
THE FOOTHILLS OVERNIGHT/WED MORNING.
KLAX...HIGH CONFIDENCE IN CAVU CONDS THROUGH THE PERIOD. ANY EAST
WINDS SHOULD REMAIN BELOW 7 KNOTS. THERE IS A 20 PERCENT CHANCE OF
MODERATE LOW LEVEL WIND SHEAR AND TURBULENCE BETWEEN 10Z AND 16Z.
KBUR...VERY HIGH CONFIDENCE IN CAVU CONDS THROUGH THE PERIOD. THERE
WILL LIKELY BE SOME LOW-LEVEL WIND SHEAR AND MDT UDDF NEAR THE
AIRPORT BETWEEN 08Z AND 16Z.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
&&
$$
PUBLIC...KAPLAN
AVIATION...DB
WWW.WEATHER.GOV/LOSANGELES