000
FXUS66 KLOX 232334
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
435 PM PDT WED JUL 23 2008

UPDATED AVIATION SECTION

.SHORT TERM (TODAY-SATURDAY)...
TEMPS RUNNING ABOUT ON PAR FROM YESTERDAY...AS ONSHORE GRADS AND
THICKS ARE RELATIVELY UNCHANGED. STRATUS HAS CLEARED QUITE A BIT OFF
THE LA/VTU CO COAST...BUT IS HANGING IN PRETTY CLOSE TO THE CENTRAL
COAST AND SBA SOUTH COAST. MARINE LAYER WILL BE TRICKY TONIGHT. THE
DEPTH SHOULD SHRINK EVERY SO SLIGHTLY AS ONSHORE GRADS WEAKEN A BIT
AND HEIGHTS INCREASE. BASED ON THE FACT THAT THE STRATUS SPREAD
COMPLETELY INTO THE VALLEYS EARLY THIS MORNING...MENTIONED SOME LOW
CLOUDS AND FOG ONCE AGAIN IN ALL COAST AND VALLEY ZONES TO PLAY IT
SAFE...THOUGH WOULD NOT BE SURPRISED TO SEE CLOUDS ONLY IN THE
COASTS AND THE SAN GABRIEL AND SANTA YNEZ VALLEYS BY DAYBREAK THU.

WITH THE SMALLER MARINE LAYER AND WEAKENING ONSHORE GRADS...STRATUS
SHOULD BURNOFF RATHER QUICKLY THU MORNING. THE HIGH PRESSURE
CENTERED OVER NEW MEXICO WILL GET PINCHED OFF INTO TWO AS HURRICANE
DOLLY MOVES TO THE NORTHWEST. ADD THE WEAKENING ONSHORE GRADS TO THE
EQUATION...AND 950MB TEMPS AND THICKS SHOULD BOOST NICELY...
RESULTING IN THU AND FRI BEING CONSIDERABLY WARMER THAN TODAY AND
YESTERDAY. NAM SHOWING JUST UNDER 40C 950MB TEMPS IN THE ANTELOPE
VALLEY... WHICH WOULD SUGGEST TEMPS WELL ABOVE 100 FOR THE FAR
INTERIOR SECTIONS OF THE AREA. THERE SHOULD STILL BE A SEABREEZE IN
THE AFTERNOON WHICH WOULD LIMIT THE WARMING SOME OVER THE COAST AND
COASTAL VALLEYS. EVEN STILL...TEMPS SHOULD BE ABOVE NORMAL
EVERYWHERE TO CLOSE OUT THE WORK WEEK.

WITH HIGH PRESSURE NUDGING WESTWARD AND NW MEXICO MOISTENING UP
AHEAD OF DOLLY...THERE IS STILL A POSSIBILITY OF SOME MONSOONAL
MOISTURE MOVING UP INTO THE AREA. MODELS HAVE BEEN TRENDING LATER
AND SOMEWHAT DRIER WITH THIS SURGE...AND DECIDED TO REMOVE POPS FROM
THE LA/VTU MTN AND DESERTS FOR FRI AS A RESULT...BUT KEPT THEM
RIDING FOR THE WEEKEND. THE SITUATION LOOKS SIMILAR TO LAST
WEEK...WITH A PLUME OF MOISTURE GETTING ADVECTED INTO SOUTH ERN CA
WITH THE EDGE OF THE PLUME JUST TO THE EAST OF LA COUNTY. LIKE LAST
WEEK AS WELL...THE SOUTHEAST FLOW IS SHORT-LIVED AS THE FOOT OF A
RATHER LARGE TROUGH PUSHES INTO NRN CA SAT NIGHT...AND SHIFTS THE
FLOW SOUTHWESTERLY LATER ON SUN. WILL KEEP AN EYE ON THIS
SITUATION...BUT AT THIS POINT IT DOES NOT LOOK TOO FAVORABLE OF OUR
AREA...JUST LIKE LAST WEEK.

TEMPS-WISE SAT IS VERY TRICKY...AS THE NAM INCREASES ONSHORE GRADS
ON SAT WHILE THE GFS WAITS UNTIL SUN. BASED ON THE 12Z WATER VAPOR
PATTERN...THE GFS INITIALIZED MUCH BETTER THAN THE NAM AND AM GOING
TO LEAN HEAVIER ON THE GFS AS A RESULT. IF THE NAM PROVES CORRECT
HOWEVER...TEMPS WOULD DECREASE MUCH MORE THAN THE CURRENT FORECAST
SUGGESTS.

.LONG TERM (SUNDAY-WEDNESDAY)...
AS ONSHORE FLOW INCREASES ON SUN AND HIGH PRESSURE ALOFT
WEAKENS...TEMPS SHOULD DECREASE ON SUN AND STAY ABOUT THE SAME ON
MON. ONCE THE PREVIOUSLY MENTIONED TROUGH MOVES OUT OF CA...HIGH
PRESSURE WILL BEGIN TO BUILD BACK INTO CA ON TUE...AND TEMPS SHOULD
BEGIN TO WARM UP A BIT MORE OVER THE INTERIOR PORTIONS. DECENT
ONSHORE FLOW WILL MODERATE THAT WARMING ALONG THE COAST AND COASTAL
VALLEYS HOWEVER. THERE IS A SHOT OF MID-LEVEL MOISTURE LINGERING
AROUND ON SUN AND LEFT THE SLIGHT CHANCES OVER THE LA/VTU CO MTNS
AND DESERTS GOING...BUT THE MODEL TRENDS ARE SCALING BACK THE
POSSIBILITY. AS THE HIGH PUSHES BACK WESTWARD TUE AND WED...THERE IS
ANOTHER WINDOW FOR SOME MID-LEVEL SOUTHEAST FLOW RETURNING...BUT DID
NOT BITE ON THIS QUITE YET OTHER THAN KEEPING 10 POPS GOING THROUGH
THE EXTENDED.

&&

.AVIATION...23/2330Z.
MARINE LAYER HAS DECREASED TO ABOUT 1000 FEET...WHICH HAS BEEN THE
NORM FOR THE PAST SEVERAL DAYS DURING THE LATE AFTERNOONS. LOW
CLOUDS HOLDING THEIR OWN ALONG THE CENTRAL COAST AND AROUND POINT
CONCEPTION TO SANTA ROSA ISLAND. EXPECT STRATUS TO REDEVELOP TONIGHT
FOR ALL COASTAL AREAS DUE TO A WEAK EDDY CIRCULATION ACROSS THE
BIGHT. ONSHORE GRADIENTS ARE JUST AS STRONG AS 24-HOURS AGO AND A
SIMILAR MARINE LAYER WILL RESULT IN CLOUDS PUSHING INTO THE VALLEYS
AGAIN LATE TONIGHT.

KLAX...GOOD CONFIDENCE IN CLEAR SKIES UNTIL LATE EVENING WHEN MVFR
CIGS/VSBYS WILL REDEVELOP...MAINLY AFTER 05Z.

KBUR...GOOD CONFIDENCE IN CLEAR SKIES UNTIL LATE TONIGHT WHEN IFR
CIGS/VSBYS RETURN TO THE VALLEYS...MAINLY AFTER 09Z.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

PUBLIC...KITTELL
AVIATION...BOLDT

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NWS LOX Office Area Forecast Discussion