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000
FXUS66 KLOX 250330
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
830 PM PDT FRI MAY 24 2013

.SYNOPSIS...
A LOW PRESSURE AREA WILL CONTINUE THROUGH TUESDAY BRINGING NIGHT
THROUGH MORNING CLOUDS AND FOG. BREEZY CONDITIONS WILL OCCUR
IN THE MOUNTAINS AND DESERTS ON SUNDAY AND MEMORIAL DAY. THERE WILL BE
POSSIBLE PRECIPITATION FROM MONDAY NIGHT TO EARLY WEDNESDAY MORNING.
THE AFTERNOON TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH
TUESDAY... THEN A WARMUP WILL START MIDWEEK WITH TEMPERATURES GOING
ABOVE THE SEASONAL NORMALS BY THE WEEKS END.

&&

.SHORT TERM (TONIGHT THROUGH MONDAY)...
SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA
THIS EVENING. PERSISTENT UPPER LEVEL TROUGH ALONG WEST COAST WILL DEEPEN
THROUGH THE WEEKEND ACROSS CALIFORNIA. THIS WILL MAINTAIN A STRONG
ONSHORE FLOW PATTERN AT THE SURFACE ALONG WITH A DEEP MARINE LAYER.
LATEST ACARS SOUNDING SHOWING MARINE LAYER DEPTH AROUND 3000 FEET...BUT
THE INVERSION IS QUITE WEAK. WHILE THE LATEST 00Z NAM MODEL CONTINUES
TO SHOW A GOOD SURGE OF LOW LEVEL MOISTURE ALL THE WAY TO THE LOWER
COASTAL SLOPES...THE BIG QUESTION MARK IS WHETHER OR NOT THE INVERSION
WILL BE STRONG ENOUGH TO FORM AN ORGANIZED AREA OF LOW CLOUDS. WILL
CONTINUE WITH CURRENT FORECAST BRINGING LOW CLOUDS ACROSS MUCH OF
LOS ANGELES AND VENTURA COUNTIES...POSSIBLY REACHING THE SBA SOUTH
COAST BY MORNING. ALSO...EXPECTING LOW CLOUDS AND FOG TO BECOME MORE
SOLID ALONG THE CENTRAL COAST AS WELL OVERNIGHT. WITH THE MARINE LAYER
EXPECTED TO DEEPEN SLIGHTLY BY MORNING...SHOULD SEE SOME LOW CLOUDS
AND FOG SPREAD INTO THE LOWER COASTAL SLOPES OF THE SAN GABRIELS.
BY SATURDAY AFTERNOON...SKIES SHOULD GENERALLY TURN MOSTLY SUNNY...HOWEVER
SOME LOW CLOUDS WILL LIKELY LINGERING ACROSS SOME IMMEDIATE COASTAL
AREAS. CONTINUED MILD TEMPERATURES THROUGH THE HOLIDAY
WEEKEND...WITH VALLEYS GENERALLY REMAINING IN THE 70S.

*** FROM PREVIOUS DISCUSSION ***

BY SUNDAY...THE MARINE LAYER LOOKS TO BEHAVE SIMILARLY TO
SATURDAY...BUT WITH A LITTLE DEEPER INLAND PUSH THANKS TO STRONGER
ONSHORE GRADIENTS. BY THE AFTERNOON HOWEVER...INCREASING NORTHWEST
FLOW WILL HELP TO CLEAR THINGS OUT BETTER...WITH NEARLY ALL AREAS
CLEAR BY THE AFTERNOON. THIS FLOW WILL ALSO RESULT IN SOME DOWNSLOPE
WARMING...ESPECIALLY OVER SOUTHERN SBA COUNTY. THE WIND ITSELF WILL
FLIRT WITH ADVISORIES OVER THE I-5 CORRIDOR AND SANTA YNEZ
RANGE...BUT SHOULD STAY BELOW ADVISORY THRESHOLDS.

BY MEMORIAL DAY MONDAY...THE WINDS WILL BE STRONGER...AND ADVISORIES
LOOK LIKELY BY THE LATE AFTERNOON FOR THE I-5 CORRIDOR...SRN SBA
COUNTY...CENTRAL COAST...AND ANTELOPE VALLEY. THIS SHOULD
SIGNIFICANTLY DISRUPT THE MARINE LAYER...AND BRING A LITTLE WARMING
TO COASTAL AREAS. MOUNTAINS AND NORTHERN AREAS HOWEVER WILL BE
COOLER...AS THE AIRMASS COOLS IN ADVANCE OF AN APPROACHING UPPER
LEVEL TROUGH.

.LONG TERM (MONDAY NIGHT THROUGH FRIDAY)...
THE PREVIOUSLY MENTIONED TROUGH LOOKS TO HAVE A FRONTAL SYSTEM THAT
WILL SUSTAIN ITSELF ENOUGH TO BRING CHANCES OF RAIN TO OUR AREA.
BEING VERY UNSEASONABLE FOR ALMOST JUNE...THE MODELS ARE STRUGGLING
ON THE TRACK OF THE SYSTEM. THE ECMWF DIGS THE CORE OF THE TROUGH
ALL THE WAY INTO SOUTHEAST CALIFORNIA...WHILE THE GFS KEEPS IT UP IN
NEVADA. WHILE THIS DIFFERENCE ADDS A LOT OF UNCERTAINTY AS TO THE
AMOUNT OF RAIN THAT COULD RESULT FROM THIS...CONFIDENCE IS GROWING
FOR AT LEAST SOME PRECIPITATION. WITH THE FLOW STAYING
NORTHWESTERLY...THE BEST CHANCES ARE NORTH OF POINT CONCEPTION AND
ON THE NORTHERN MOUNTAIN SLOPES OF LA/VTU COUNTIES. AT THIS
POINT...THE TIMING OF ANY RAIN WOULD BE MONDAY NIGHT AND
TUESDAY...BUT BEING SO UNSEASONABLE...THE TIMING WILL LIKELY BE
TWEAKED OVER THE NEXT COUPLE OF DAYS.

IF THE ECMWF IS CORRECT...WE COULD BE LOOKING AT 0.1-0.5 INCHES OF
RAIN NORTH OF POINT CONCEPTION...WITH 0.01-0.10 INCHES TO THE SOUTH.
IF THE GFS PANS OUT...NORTH OF POINT CONCEPTION WOULD SEE 0.01-0.10
INCHES...WHILE OTHER AREAS WOULD BE HARD PRESSED FOR ANYTHING
MEASURABLE. SO AT THE END OF THE DAY...IT ISNT A LOT OF RAIN...BUT
QUITE SIGNIFICANT CONSIDERING THE TIME OF THE YEAR.

TEMPERATURES WILL BE DOWN TO NO SURPRISE ON TUESDAY WITH AMPLE CLOUD
COVER. THE MARINE LAYER SHOULD TAKE A HIT HOWEVER...AND WEDNESDAY
SHOULD BE MOSTLY STRATUS FREE. TEMPERATURES WILL UP A COUPLE OF
DEGREES AS A RESULT...EXCEPT OVER INTERIOR AREAS.

WEAK RIDGING SHOULD FOLLOW INTO THE END OF NEXT WEEK...WITH A
RE-ESTABLISHMENT OF THE MARINE LAYER AND ASSOCIATED LOW CLOUDS AND
FOG. TEMPERATURES WILL GO UP AWAY FROM THE COAST...AS WE SHOULD
FINALLY REACH OR EXCEED NORMALS BY FRIDAY. MEANWHILE...GUSTY BUT
JUST SUB-ADVISORY NORTHWESTERLY FLOW LOOKS TO PERSIST...AS IS
TYPICAL FOR THIS TIME OF THE YEAR.

&&

.AVIATION...24/2340Z.
SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS THE REGION LATE THIS
AFTERNOON. LATEST ACARS DATA SHOWING MARINE LAYER DEPTH BETWEEN 3000 AND
3500 FEET ACROSS LA BASIN...BUT INVERSION IS RATHER WEAK. WITH ONSHORE
FLOW STILL FAIRLY STRONG AND INVERSION EXPECTED TO STRENGTHEN A BIT
OVERNIGHT...LOOKING FOR FAIRLY SOLID COVERAGE OF LOW CLOUDS ACROSS COASTAL
AND VALLEY AREAS OVERNIGHT INTO SATURDAY MORNING. MOSTLY MVFR CIGS
EXPECTED AT COASTAL/VALLEY AIRFIELDS.

KLAX...HIGH CONFIDENCE OF VFR CONDITIONS THIS EVENING. MODERATE CONFIDENCE
OF MVFR CIGS DEVELOPING OVERNIGHT...+/- 2 HOURS FROM PROJECTED 08Z
TIME FRAME. LIGHT SOUTHEAST WINDS EXPECTED WITH EDDY CIRCULATION BUT
WIND SPEEDS EXPECTED TO REMAIN LESS THAN 10 KT.

KBUR...HIGH CONFIDENCE OF VFR CONDITIONS THIS EVENING. MODERATE
CONFIDENCE OF MVFR CIGS DEVELOPING OVERNIGHT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
GALE WATCH (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&

$$

PUBLIC...GOMBERG/KITTELL
AVIATION...GOMBERG
SYNOPSIS...SETO

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