089 
FXUS66 KLOX 221127
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
330 AM PST TUE FEB 22 2011

.SYNOPSIS...

A COLD AIR MASS WILL KEEP TEMPERATURES BELOW SEASONAL NORMALS THROUGH
WEDNESDAY WITH PARTLY CLOUDY CONDITIONS PREVAILING. OUR NEXT WEATHER 
SYSTEM WILL BRING A CHANCE OF PRECIPITATION TO THE REGION THURSDAY 
NIGHT THROUGH SATURDAY...WITH LOW ELEVATION SNOW.
 
&&

.SHORT TERM (TODAY-THU)...
PARTLY TO MOSTLY CLOUDY TODAY AS LOTS OF MID AND HIGH CLOUDS STREAM 
OVER THE AREA OUT FROM A RETROGRADING UPPER LOW CURRENTLY A COUPLE 
HUNDRED MILES TO THE WEST OF POINT CONCEPTION. 545 DM THICKNESS IS 
ABOUT 7 DM BELOW NORMAL AND MAX TEMPS WILL BE 5 TO 10 DEGREES BELOW 
NORMAL.

WEDNESDAY IS NO MORE EXCITING. THE UPPER SLOW SWINGS SOUTH AND SLIPS 
UNDER THE AREA INTO MEXICO. THERE WILL BE A LITTLE MORE SUNSHINE AS 
THE FLOW PATTERN TURNS TO THE NW DURING THE AFTERNOON. THKNS REMAINS 
NR 545 DM AND MAX TEMPS WILL REMAIN 5 TO 10 DEGREES BELOW NORMAL.

WEDNESDAY NIGHT THE GFS AND NAM SHOW AN INFLUX OF 975MB MOISTURE 
STREAMING INTO THE SAN GABRIEL VLY UP FROM ORANGE COUNTY THIS 
MOISTURE WILL TRAVEL UP THE FOOTHILLS AND COULD PRODUCE A SHOWER OR 
TWO THROUGH THURSDAY MORNING. SOME PATCHY LOW LEVEL CLOUDS MAY ALSO 
FORM BUT OVERALL IT WILL BE PARTLY CLOUDY THROUGH THURSDAY MORNING. 

DURING THE DAY THURSDAY A VERY COLD UPPER TROF WILL MOVE OUT OF 
WASHINGTON STATE AND BEGIN ITS TREK SOUTHWARD. IT WILL NOT AFFECT 
THE WEATHER MUCH DOWN HERE WHERE IT WILL REMAIN PARTLY CLOUDY AND 
COOL WITH MAX TEMPS REMAINING NEAR 60 ACROSS MUCH OF THE COAST AND 
VLY AREA.

.LONG TERM (FRI-MON)...
THE 00Z GFS AND 00Z EC WERE A LITTLE OUT OF PHASE WITH EACH OTHER 
OVER THE COURSE OF THIS STORM BUT THE 06Z GFS HAS COME INTO PHASE 
WITH THE EC. BY FRIDAY AFTERNOON THE UPPER LOW WILL BE JUST W OF 
CRESCENT CITY...REACHING THE BAY AREA BY SATURDAY AFTERNOON...AND 
THEN OVER THE ANTELOPE VLY EARLY SUNDAY MORNING. A CHANCE OF RAIN 
WILL OVERSPREAD THE AREA FRIDAY MORNING STARTING ALONG THE CENTRAL 
COAST...THE CHANCE OF RAIN WILL CONTINUE ALL DAY SATURDAY AND THEN 
END OVERNIGHT INTO EARLY SUNDAY MORNING. IF GFS AND EC KEEP IN THIS 
CLOSE AGREEMENT AND CONTINUE THIS PATTERN FORECAST WORDING WILL HAVE 
TO MOVED UP TO LIKELY IN THE AFTERNOON UPDATE. THE OTHER IMPORTANT 
FACTOR WITH THIS STORM IS THE AMOUNT OF COLD AIR IT WILL BRING WITH 
IT. THKNS START OUT AT 546DM FRIDAY AFTERNOON...FALL TO 539 DM 
SATURDAY AFTERNOON AND THEN PLUNGE TO 525 DM EARLY SUNDAY. (THE MDLS 
USUALLY OVER DO THE COLD AIR IN THE EXTENDED PERIOD SO THESE 
REMARKABLE NUMBERS MAY COME IN A LITTLE WARMER) SNOW LEVELS WILL BE 
VERY LOW AND WILL AFFECT THE MOUNTAIN PASSES AND INTERIOR VALLEYS.
MAX TEMPS WILL BE 15 TO 20 DEGREES BELOW NORMAL.

THE LOW PULLS OUT SUNDAY. BOTH THE EC AND THE GFS AGREE THAT MOST OF 
SUNDAY AND MONDAY WILL BE DRY. A LITTLE RIDGE BUILDS IN AND WHILE 
SUNDAY WILL BE COOL IT WILL WARM MONDAY.

&&

.AVIATION...22/1130Z.

VFR CONDS EXPECTED ALL TAF SITES THRU PERIOD. STRATOCU DECK AROUND
050 SHOULD DISSIPATE THIS AFTERNOON. NO SIGNIFICANT WIND ISSUES.

KLAX...HIGH CONFIDENCE IN 12Z TAF.

KBUR...HIGH CONFIDENCE IN 12Z TAF.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

PUBLIC...RORKE
AVIATION...RAT
SYNOPSIS...KAPLAN

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