FXUS66 KLOX 121201
AFDLOX
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
400 AM PST THU FEB 12 2009
...ADDED LONG TERM AND AVIATION DISCUSSIONS...
.SHORT TERM...
A PARTLY CLOUDY AND COOL DAY TODAY IN THE WAKE OF YDYS COLD FRONT.
THERE IS A SLIGHT CHANCE OF SOME SHOWERS OVER THE CENTRAL COAST AS
WELL AS SOME MORNING SNOW SHOWERS OVER THE NORTH SLOPES WHICH
INCLUDES I-5 THROUGH THE GRAPEVINE. A BREEZY DAY TOO...AS THE COOL
AIR POURS IN. WITH FAVORED WEST FLOW THE ANTELOPE VALLEY WILL SEE
ADVISORY LEVEL GUSTS STARTING AROUND MID MORNING.
TONIGHT ANOTHER COLD FRONT WILL BEGIN ITS MARCH TO SOUTHERN
CALIFORNIA. BOTH THE NAM AND THE GFS FORECAST THE FRONT TO STAY TO
THE NORTH OVERNIGHT. THIS WILL ALLOW FOR ANOTHER ROUND OF VERY COLD
OVERNIGHT LOWS AS THE SURFACE HEAT IS LOST INTO THE PARTLY CLOUDY
SKIES.
BOTH THE NAM AND THE GFS ARE A LITTLE MORE AGGRESSIVE WITH THE FRONT
FRIDAY WHICH WILL ENTER THE CENTRAL COAST A BIT PAST DAWN AND THEN
REACH L.A. COUNTY BY EARLY OR MID AFTERNOON. BEHIND THE FRONT RAIN
WILL TAPER TO SHOWER STARTING IN THE LATE AFTERNOON OVER THE CENTRAL
COAST AND THEN LATE EVENING OVER L.A. COUNTY. RIGHT NOW IT LOOKS
LIKE THIS SYSTEM WILL DROP A HALF INCH TO AN INCH ALONG THE COASTS
AND VLYS AND A INCH TO TWO INCHES IN THE FOOTHILLS AND MOUNTAINS.
THERE IS A BRIEF BURST OF SOUTH FLOW SO IT IS NOT OUT OF THE
QUESTION FOR THE SANTA YNEZ RANGE AND THE WESTERN VENTURA COUNTY
COASTAL SLOPES COULD SEE UP TO 3 INCHES OF RAINFALL. THIS IS QUITE
THE COLD SYSTEM AND SNOW LEVELS WILL BE DOWN TO BETWEEN 3000 AND
4000 FEET WHICH WILL DEFINITELY AFFECT MOUNTAIN TRAVEL.
RAIN WILL TAPER OFF TO SCATTERED SHOWERS BEHIND THE FRONT OVERNIGHT
FRIDAY INTO EARLY SATURDAY MORNING. THIS WILL END THE SIGNIFICANT
PRECIPITATION...BUT A POST FRONTAL TROF WILL KEEP SOME SHOWER
ACTIVITY GOING SATURDAY WITH MOST OF THE SHOWER ACTIVITY ACROSS THE
CENTRAL COAST. 500 MB HEIGHTS WILL ONLY BE NEAR 554DM SO LOOK FOR
ANOTHER VERY COOL DAY.
ALL EYES ON SATURDAY NIGHT AND SUNDAY AS THE BIGGEST STORM OF THE
SEASON BEARS DOWN ON SOUTHERN CA. CURRENT MDLS DELAY THE ONSET OF
PRECIP FROM EARLIER RUNS. THE GFS IS ABOUT 6 HOURS FASTER THAN THE
NAM AND BRINGS RAIN TO THE CENTRAL COAST OVERNIGHT WHILE THE NAM
WAITS UNTIL DAWN. THE FRONT SWEEPS THROUGH THE AREA SUNDAY AND
SHOULD LIKELY BE VERY IMPRESSIVE. IT WILL LIKELY HAVE A 4 TO 6 HOUR
BAND OF MODERATE TO HEAVY RAIN...IT WILL LIKELY HAVE A BROAD AREA OF
SOUTH WINDS THAT WILL GREATLY ENHANCE PRECIPITATION ON THE COASTAL
SLOPES. THE WINDS WITH THIS SYSTEM WILL GUST TO AROUND 30 MPH OVER
THE COASTS AND VLYS TO 50 MPH IN THE MOUNTAINS. SNOW LEVEL WILL BE
NEAR 5000 FEET. THE STORM WILL EXIT THE CENTRAL COAST LATE IN THE
AFTERNOON OVER THE CENTRAL COAST AND OVERNIGHT FOR L.A. COUNTY.
SHOWERS WILL LINGER IN ITS WAKE. AT THIS TIME THE RAINFALL FORECAST
CALLS FOR 1 TO 3 INCHES OF RAIN OVER THE CSTS AND VLYS WITH 2 TO 5
INCHES IN THE MOUNTAINS...AND LOCALLY HEAVIER AMOUNTS IN THE MOST
FAVORED SOUTH FACING FOOTHILL COASTAL SLOPE LOCATIONS.
.LONG TERM...
LONG RANGES MDLS...WHICH HAD BEEN IN REASONABLE AGREEMENT UNTIL
NOW...DIVERGE QUICKLY AFTER SUNDAYS FRONT. EC CLEARS THINGS OUT
FAIRLY QUICKLY MONDAY BUT GFS BRINGS IN ANOTHER SHOT OF RAIN WITH A
FAIRLY DYNAMIC POST FRONTAL TROF. ON TUESDAY THE EC BRINGS A LITTLE
FRONT THROUGH THE AREA WHILE THE GFS FORECAST MOIST WEST FLOW INTO
THE CENTRAL COAST. WED/THU THE GFS STICKS TO THE PREVIOUS THINKING
AND DRIVES ANOTHER VIGOROUS FRONT THROUGH THE AREA...BUT THE EC
SHOVES THE ENTIRE FRONT NORTHWARD AS IT BUILDS A STRONG RIDGE INTO
THE AREA FROM THE SOUTH. GIVEN ALL OF THIS CONFUSION BROADBRUSHED
THE LONG RANGE FORECAST WITH MOSTLY CLOUDY SKIES AND A CHANCE OF
SHOWERS.
&&
.AVIATION...
12/1200Z.
WEAK COLD FRONT THAT PUSHED THROUGH THE CENTRAL COAST LAST NIGHT HAS
WEEKEND AND MOVED EASTWARD. MODERATE CONFIDENCE FOR VFR CONDS WITH
LOC MVFR CONDS ACROSS THE NRN SLOPES OF MTNS THIS MORNING AND SOME
IFR VSBYS NEAR KSMX THIS MORNING AS WELL. GUSTY W WINDS WILL AFFECT
KPMD AND KWJF AS WELL THROUGH THIS AFTERNOON. ANOTHER FRONT WILL
BEGIN TO AFFECT THE AREA ON FRIDAY.
KLAX...LOW CONFIDENCE FOR MVFR VSBYS TO DEVELOP BEFORE SUNRISE...BUT
MODERATE CONFIDENCE FOR VFR CONDS THROUGH THIS EVENING...WITH LOCAL
MVFR CIGS THIS MORNING. GOOD CONFIDENCE FOR GUSTY W WINDS TO PERSIST
THROUGH THIS EVENING. GUSTS TO 25 KNOTS POSSIBLE. NO SOUTH OR
EASTERLY COMPONENT EXPECTED TODAY.
KBUR...LOW/MODERATE CONFIDENCE FOR MVFR CIGS TO DEVELOP EARLY THIS
MORNING...WITH MAINLY VFR CIGS BY LATE MORNING. GUIDANCE BRINGS IN
MAINLY WEST TO NORTHWEST WINDS TO NEAR 12 KNOTS THIS AFTERNOON.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
PUBLIC...RORKE
AVIATION...KAPLAN
