482 
FXUS66 KLOX 270022 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
522 PM PDT MON APR 26 2010

...UPDATED AVIATION SECTION...

.SYNOPSIS...

ON TUESDAY...LOW PRESSURE WILL MOVE INTO THE CENTRAL COAST...AND A 
CHANCE OF RAIN WILL MOVE FROM NORTH TO SOUTH ACROSS THE REGION 
BEFORE EXITING ON WEDNESDAY...WITH GUSTY POST FRONTAL WINDS INTO 
FRIDAY. A LOW WILL COOL FRIDAY OFF...BUT A WARMING TREND IS EXPECTED 
FOR THE WEEKEND. 

&&

.SHORT TERM (TODAY-THU)...A LOW MARINE INVERSION STILL EXISTS ACROSS 
THE SO CAL BIGHT REGION WITH CLOUDS/FOG HUGGING THE COASTLINE SOUTH 
OF PT CONCEPTION. A WEATHER SYSTEM APPROACHING FROM THE NORTHWEST 
TONIGHT WILL LIFT UP THAT INVERSION AS WELL AS PULL THE LOW CLOUDS 
NORTH UP THE COAST. THIS WILL RESULT IN IMPROVING VISIBILITIES ALONG 
THE COAST LATER TONIGHT AS THE CLOUD BASES LIFT BUT WILL BRING LOW 
CLOUDS AND FOG WELL INTO THE VALLEYS BY TUESDAY MORNING. 

THE APPROACHING WEATHER SYSTEM WILL BRING A COLD FRONT THROUGH THE 
AREA TUESDAY AFTERNOON ALONG THE CENTRAL COAST AND TUESDAY EVENING 
AND NIGHT ACROSS LA/VENTURA COUNTIES. THE SCENARIO ISN'T MUCH 
DIFFERENT THAN EARLIER MODELS HAD INDICATED, BUT GIVEN THE 
CONSISTENCY CONFIDENCE IS HIGHER THAT THE CENTRAL COAST WILL GET 
MEASURABLE RAIN WITH THIS SYSTEM. THAT CONFIDENCE DROPS OFF TO THE 
SOUTH AS THE BULK OF THE ENERGY WITH THIS SYSTEM STAYS NORTH AND 
THERE ISN'T MUCH TO HOLD IT TOGETHER. HOWEVER, THE ONE THING THAT IT 
DOES HAVE GOING FOR IT IS A DECENT MOISTURE PLUME AND PW'S RANGE 
FROM 1.3" ACROSS SLO COUNTY DOWN TO ABOUT 1.1" IN THE SOUTH. AS A 
RESULT, EVEN WITHOUT THE GOOD DYNAMICS THAT NORTHERN CALIFORNIA WILL 
GET WITH THIS EVENT, THERE IS A STILL A GOOD CHANCE THAT AT LEAST 
SOME LIGHT RAIN/SPRINKLES WILL FALL ACROSS OUR SOUTHERN ZONES 
TUESDAY NIGHT AND FOR THIS REASON POPS HAVE BEEN INCREASED ALL 
AREAS. NOT MUCH IN THE WAY OF OROGRAPHIC ENHANCEMENT AS THE LOW LVL 
FLOW REMAINS WESTERLY AND I EXPECT RAIN AMOUNTS IN THE SOUTH TO NOT 
EXCEED .10 FOR MOST AREAS. IN THE NORTH PROBABLY A QUARTER TO HALF 
INCH ON AVERAGE. EXPECT HIGHS TO DROP 10-20 DEGREES OVERALL FROM 
TODAY'S LEVELS, THOUGH COASTAL AREAS WON'T SEE MUCH CHANGE SINCE 
IT'S ALREADY BEEN QUITE COOL THERE DUE TO THE PRESENCE OF LOW CLOUDS.

STRONG WEST TO NORTHWEST FLOW WILL DEVELOP BEHIND THE FRONT TUESDAY 
NIGHT INTO WEDNESDAY AND I EXPECT A LOT OF OUR FORECAST AREA TO BE 
COVERED IN WIND ADVISORIES BY WED AFTERNOON. ANOTHER COOL DAY ON TAP 
WITH LOWER ELEVATION HIGHS MAINLY IN THE 60S. LEFT IN A SMALL CHANCE 
OF SHOWERS NORTH OF PT CONCEPTION AS A WEAK IMPULSE MOVES IN FROM 
THE NORTHWEST, AND SIMILAR FOR ALL THE MOUNTAINS DUE TO UPSLOPE FLOW 
AND LINGERING MOISTURE. SNOW LEVELS WILL START OUT QUITE HIGH AND 
PROBABLY WON'T LOWER BELOW 7000 FEET UNTIL MOST OF THE SYSTEM IS 
LONG GONE. AS A RESULT, I DON'T EXPECT MUCH IN THE WAY OF 
ACCUMULATING SNOW BELOW 7000 FEET.

VERY SLIGHT WARMING EXPECTED THURSDAY, ESPECIALLY SOUTH OF PT 
CONCEPTION. BUT STILL QUITE BREEZY AND WIND ADVISORIES WILL STILL 
LIKELY BE NEEDED IN SOME AREAS, ESPECIALLY CENTRAL COAST AND 
ANTELOPE VALLEY.

.LONG TERM (FRI-MON)...MODELS AGREE THAT THERE WILL BE A COUPLE OF 
INSIDE SLIDER SYSTEMS DROPPING THROUGH THE GREAT BASIN FRI-MON, 
THOUGH THE TIMING OF THESE SYSTEMS IS CONSIDERABLY DIFFERENT BETWEEN 
THE EC AND GFS. NO PRECIP IS EXPECTED, BUT CONFIDENCE IN DAY TO DAY 
WINDS AND TEMPS IS LOW DUE TO INCONSISTENCIES IN THE MODELS. HAVE 
OPTED TO NOT MAKE TOO MANY CHANGES TO THE WEEKEND FORECAST AND LEFT 
THE WARMING TREND IN TACT, ESPECIALLY FOR LOWER ELEVATIONS AS 
OFFSHORE FLOW SHOULD HELP THERE.

&&

.AVIATION...26/0022Z.
AT COASTAL TERMINALS NORTH OF POINT CONCEPTION...THERE IS A 40 
PERCENT CHANCE OF LIFR TO IFR CONDITIONS TONIGHT BETWEEN 07Z AND 
15Z. AT COASTAL TERMINALS SOUTH OF POINT CONCEPTION...IFR CONDITIONS 
WILL LIKELY PERSIST THROUGH AT LEAST 09Z TONIGHT...THEN LIFT INTO 
THE MVFR CATEGORY BETWEEN 09Z AND 15Z. VFR CONDITIONS HAVE A CHANCE 
OF DEVELOPING AFTER 18Z. AT LOS ANGELES COUNTY VALLEY 
TERMINALS...IFR TO MVFR CONDITIONS WILL SPREAD IN BETWEEN 10Z AND 
12Z AND DISSIPATE BETWEEN 15Z AND 17Z.

KLAX...IFR CONDITIONS WILL PERSIST THROUGH AT LEAST 07Z 
TONIGHT...THEN LIFT INTO THE MVFR CATEGORY BETWEEN 07Z AND 11Z. VFR 
CONDITIONS HAVE AN INCREASING CHANCE OF DEVELOPING AFTER 18Z 
TUESDAY...WITH A 30 PERCENT CHANCE OF VFR CONDITIONS AFTER 21Z.

KBUR...VFR CONDITIONS WILL PERSIST THROUGH 10Z TONIGHT...THEN IFR TO 
MVFR CONDITIONS SHOULD SPREAD INTO KBUR AND VICINITY BETWEEN 10Z AND 
12Z TUESDAY. VFR CONDITIONS SHOULD REDEVELOP BETWEEN 15Z AND 17Z 
TUESDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...WOFFORD
AVIATION...SWEET
SYNOPSIS...SETO

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