Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 231346
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
321 AM PST SUN NOV 23 2014

.SYNOPSIS...SKIES WILL BE MOSTLY CLEAR ACROSS THE REGION THIS WEEK.
THERE WILL BE AREAS OF GUSTY OFFSHORE WINDS THROUGH WEDNESDAY AS
SURFACE HIGH PRESSURE LINGERS IN THE GREAT BASIN. AN UPPER LEVEL
RIDGE WILL BRING A WARMING TREND TO THE AREA...WITH DAYTIME
TEMPERATURES RISING TO WELL ABOVE NORMAL LEVELS IN MOST AREAS
MONDAY THROUGH THURSDAY. COOLER WEATHER IS EXPECTED FRIDAY AND
SATURDAY AS AN UPPER TROUGH APPROACHES THE WEST COAST.

&&

.SHORT TERM (TODAY-TUE)...N-S PRESSURE GRADIENTS WERE DECENTLY
OFFSHORE THIS MORNING...AND W-E PRESSURE GRADIENTS HAVE FLIPPED FROM
MODERATELY ONSHORE TO OFFSHORE DURING JUST THE PAST 6 HOURS. AN AREA
OF SUBSIDENCE...EVIDENT ON WATER VAPOR IMAGERY...WAS PUSHING INTO
THE REGION. THIS HAS CAUSED A SHARP INCREASE IN WINDS IN THE
MTNS...AND HAS FORCED WINDS INTO LOWER ELEVATIONS OF L.A. AND VTU
COUNTIES. SOLID ADVISORY LEVEL WINDS WERE OCCURRING IN THE MTNS OF
L.A. AND VTU COUNTIES...THE SANTA CLARITA AND SAN FERNANDO
VALLEYS...EASTERN SECTIONS OF THE VTU COUNTY VALLEYS...THE SANTA
MONICA MTNS...AND BELOW PASSES AND CANYONS FROM MALIBU TO THE
HOLLYWOOD HILLS. A FEW LOCATIONS WERE REPORTING WIND GUSTS TO JUST
UNDER HIGH WIND WARNING LEVELS.

GUSTY WINDS ACROSS THE ANTELOPE VALLEY AND ACROSS THE SOUTH COAST OF
SBA COUNTY CONTINUED THIS MORNING...BUT THOSE WINDS ARE EXPECTED TO
DIMINISH BY SUNRISE AS THE LOW LEVEL FLOW TURNS MORE NELY. AS THE
FLOW TURNS MORE NELY...EXPECT GUSTY WINDS TO BECOME MORE WIDESPREAD
IN THE VLYS OF VTU COUNTY AND ACROSS THE VTU COUNTY COASTAL PLAIN.
WINDS SHOULD BEGIN TO DIMINISH SOME BY MID AFTERNOON IN COASTAL
AREAS...BUT SHOULD REMAIN GUSTY THROUGH THE DAY ACROSS THE REMAINDER
OF L.A. AND VTU COUNTIES...WITH THE EXCEPTION OF THE SAN GABRIEL
VLY...WHERE WINDS WILL BE MORE LOCALIZED AND CONFINED TO THE HILLS.

SOME CLOUDINESS AND EVEN A FEW SHOWERS WERE LINGERING ACROSS THE NRN
SLOPES OF THE MTNS OF VTU AND NWRN L.A. COUNTY. ANY SHOWERS SHOULD
END EARLY THIS MORNING. OTHERWISE...JUST SOME HIGH CLOUDS ACROSS THE
REGION TODAY. GOOD COLD AIR ADVECTION SHOULD BRING SEVERAL DEGREES
OF COOLING TO THE MTNS...DESERTS AND INTERIOR VALLEYS TODAY...WHILE
COMPRESSIONAL WARMING WITH THE OFFSHORE FLOW SHOULD OFFSET ANY
COOLING IN LOWER VALLEY LOCATIONS AND ACROSS THE COASTAL PLAIN. IN
FACT...THERE COULD BE A BIT OF WARMING ON THE COASTAL PLAIN.

THE UPPER TROUGH OVER THE ROCKIES TODAY WILL CONTINUE TO MOVE EWD
TONIGHT AND MONDAY AS AN UPPER RIDGE AMPLIFIES JUST OFF THE WEST
COAST. THIS RIDGE WILL MOVE EWD TOWARD THE COAST MON NIGHT AND
TUE...CAUSING HEIGHTS AND THICKNESSES TO RISE. SKIES WILL BE CLEAR
ACROSS THE FCST AREA TONIGHT THROUGH TUE. SFC HIGH PRESSURE IN THE
GREAT BASIN WILL KEEP GUSTY NE WINDS ACROSS MOST OF VTU AND L.A.
COUNTIES. THERE WILL BE A LULL IN THE WINDS DURING THE LATE
AFTERNOON AND EVENING HOURS TODAY AND MONDAY...BUT WINDS SHOULD
INCREASE AGAIN DURING THE LATE NIGHT OR EARLY MORNING HOURS MON AND
TUE. WITH LESS IN THE WAY OF UPPER SUPPORT...IT DOES NOT APPEAR AS
THOUGH IT WILL BE AS WINDY LATE TONIGHT/MON MORNING...AND WINDS MAY
REMAIN JUST BELOW ADVISORY LEVELS...ESPECIALLY IN THE VLYS.
HOWEVER...THERE IS NOT ENOUGH CONFIDENCE TO START TINKERING WITH THE
CURRENT WIND ADVISORIES WHICH ARE IN EFFECT UNTIL MON AFTERNOON IN
THE MTNS AND VLYS OF L.A. AND VTU COUNTIES.

OFFSHORE GRADIENTS ARE FORECAST TO INCREASE MON NIGHT/TUE
MORNING...PEAKING AT OVER 7 MB OFFSHORE BETWEEN KLAX AND KDAG. WITH
ANOTHER BURST OF SUBSIDENCE SPREADING INTO THE REGION...EXPECT WINDS
TO BE STRONGER TUE MORNING...LIKELY REQUIRING ADVISORIES ACROSS MOST
OF VTU COUNTY AND A GOOD PORTION OF L.A. COUNTY. MAX TEMPS WILL BE
UP SEVERAL DEGREES BOTH MON AND TUE...AND WILL BE WELL ABOVE
NORMAL...AT LEAST IN COASTAL AND VALLEY AREAS. CRITICAL FIRE CONDS
ARE LIKELY TO DEVELOP ACROSS MUCH OF L.A. AND VTU COUNTIES LATER
TODAY...WITH FIRE DANGER LIKELY PEAKING ON TUE AS TEMPS RISE AND
HUMIDITIES FALL...AND A BURST OF STRONGER WINDS IS EXPECTED.

WITH CLEAR SKIES AND VERY LOW RELATIVE HUMIDITIES...IT WILL BECOME
QUITE CHILLY AT NIGHT...ESPECIALLY ACROSS INLAND SECTIONS WHERE THE
WIND DROPS OFF. FREEZE WATCHES MAY BE NEEDED FOR THE ANTELOPE VALLEY
FOR LATE MON NIGHT AND EARLY TUE MORNING.

.LONG TERM (WED-SAT)...THE UPPER RIDGE AXIS WILL DRIFT RIGHT ACROSS
THE FORECAST AREA ON WED. LOW LEVEL GRADIENTS WILL REMAIN STRONGLY
ENOUGH OFFSHORE FOR SOME GUSTY WINDS AGAIN ACROSS MUCH OF L.A. AND
VTU COUNTIES...BUT WINDS SHOULD REMAIN BELOW ADVISORY LEVELS. MAX
TEMPS WILL LIKELY ACTUALLY EDGE UPWARD A FEW DEGREES IN MOST
AREAS...WITH THE POSSIBLE EXCEPTION OF THE IMDT COAST. THE UPPER
RIDGE SHOULD BEGIN TO FLATTEN AND SHIFT EWD ON THANKSGIVING
DAY...BUT IT SHOULD BE ANOTHER WARM DAY...ESPECIALLY AWAY FROM THE
BEACHES WHERE MAX TEMPS WILL REMAIN AS MUCH AS 10 DEGREES ABOVE
NORMAL. HEIGHTS AND THICKNESSES WILL FALL MORE SIGNIFICANTLY ACROSS
THE REGION ON FRI AS AN UPPER TROUGH BEGINS TO APPROACH THE WEST
COAST AND SFC PRESSURE GRADIENTS TURN ONSHORE. EXPECT MORE
SIGNIFICANT AND WIDESPREAD COOLING ON FRI...ALTHOUGH TEMPS WILL
STILL LIKELY BE A BIT ABOVE NORMAL. THE UPPER TROUGH WILL MOVE INTO
THE PAC NW AND NRN CA SAT. LOW CLOUDS/FOG MAY RETURN TO MOST COASTAL
AND VLY AREAS...AND THERE WILL LIKELY BE SEVERAL MORE DEGREES OF
COOLING ON SAT. IT LATER MODEL RUNS REMAIN CONSISTENT...A SLIGHT
CHANCE OF RAIN MAY HAVE TO BE ADDED TO THE FORECAST FOR AREAS N OF
PT CONCEPTION FOR SAT AFTERNOON.

&&

.AVIATION...23/12Z...

AT 0915Z AT KLAX...A WEAK INVERSION WAS LOCATED AT THE SURFACE WITH
THE TOP AT 1200 FEET AT 15 DEGREES C.

OVERALL...MODERATE TO HIGH CONFIDENCE IN THE 12Z TAFS.  AT KPRB
THROUGH 18Z VLIFR/LIFR CONDITIONS.  AT KSBA THROUGH 14Z THERE IS A
SIXTY PERCENT CHANCE OF LOW LEVEL WIND SHEAR AND AT KBUR AND KVNY
THROUGH 20Z THERE IS A TWENTY PERCENT CHANCE OF LOW LEVEL WIND
SHEAR.  THROUGH 20Z PERIODIC GUSTY N TO E WINDS ACROSS THE REGION.
OTHERWISE AND ELSEWHERE VFR CONDITIONS WILL PREVAIL.

KLAX...MODERATE TO HIGH CONFIDENCE IN THE 12Z TAF.  VFR CONDITIONS
WILL PREVAIL THROUGHOUT THE FORECAST PERIOD.  THROUGH 20Z PERIODIC
GUSTY N TO E WINDS.

KBUR...HIGH CONFIDENCE IN THE 12Z TAF.  VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE FORECAST PERIOD.  THROUGH 20Z PERIODIC GUSTY NE WINDS
WITH A TWENTY PERCENT CHANCE OF LOW LEVEL WIND SHEAR.

&&

.MARINE...23/300 AM PST...
MODERATE NORTHWEST WINDS WILL CONTINUE OVER THE OUTER WATERS THROUGH
LATE TONIGHT WITH SOME WEAKENING MIDDAY.  WEAK TO MODERATE OFFSHORE
FLOW NEARSHORE DURING THE OVERNIGHT HOURS THROUGH TUESDAY ESPECIALLY
FROM MALIBU TO SANTA MONICA.  LARGER SEAS WILL AFFECT THE CENTRAL
COAST AND SOUTH TO SAN CLEMENTE ISLAND THROUGH LATE TONIGHT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING (SEE LAXRFWLOX).
FIRE WEATHER WATCH (SEE LAXRFWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&

$$

PUBLIC...DB
AVIATION/MARINE...KJ
SYNOPSIS...DB

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