Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 012207
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
207 PM PST SUN MAR 1 2015

.SYNOPSIS...

A MOIST AND UNSTABLE AIR MASS IN PLACE FROM A COLD UPPER LOW
PRESSURE SYSTEM WILL BRING SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS TO THE AREA THROUGH MONDAY. A WEAKER STORM SYSTEM
WILL FOLLOW ON ITS HEELS LATER MONDAY ALLOWING FOR LINGERING
SHOWERS INTO EARLY TUESDAY. DRY AND WARMER WEATHER IS EXPECTED
LATE TUESDAY THROUGH FRIDAY.

&&

.SHORT TERM (TONIGHT-WEDNESDAY)...

A COLD CUTOFF TROUGH OF LOW PRESSURE CENTERED NEAR POINT
CONCEPTION CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON. THIS
TROUGH IS DRIFTING SLOWLY SOUTH AND EAST...AND WILL REMAIN OVER
THE REGION INTO MONDAY. A MOIST AND UNSTABLE AIR MASS WILL PERSIST
OVER THE AREA. RADAR AND SATELLITE IMAGERY INDICATE SHOWERY
ACTIVITY BECOMING MORE WIDESPREAD AND NUMEROUS AS PREVIOUSLY
SURMISED WITH DAYTIME HEATING. CONVECTIVE STORMS WILL CONTINUE
INTO THE EVENING HOURS AS CYCLOGENESIS OCCURS. WITH THE LOW
FREEZING AND SNOW LEVELS...THERE IS POTENTIAL FOR SMALL HAIL AND
GRAUPEL...POSSIBLY ACCUMULATING AT TIMES AS THE STORM CORES ARE
RATHER INTENSE THIS AFTERNOON. LOCALIZED FLOODING IS POSSIBLE TOO
ESPECIALLY IN LOW-LYING AREAS. RECENTLY BURN AREAS WILL BE
MONITORED CLOSELY AS RATES COULD REACH CRITICAL THRESHOLDS FOR
MUD AND DEBRIS FLOWS...SUCH AS THE COLBY...POWERHOUSE...AND
SPRINGS BURN AREAS.

AN UPSTREAM KICKER TROUGH ALONG THE BRITISH COLUMBIA COAST WILL
DROP SOUTH INTO THE REGION THROUGH MONDAY AND DISPLACE THE
SLOW-MOVING CUTOFF TROUGH BETWEEN MONDAY AND TUESDAY. GFS
SOLUTIONS HOLD ONTO THE IDEA THAT THE TROUGH MAY MOVE OFFSHORE
AND HAVE LITTLE IMPACT FOR THE AREA. NAM-WRF SOLUTIONS ARE
STARTING BUY INTO THIS IDEA. POPS HAVE BEEN DECREASED AND WEATHER
HAS BEEN SCALED BACK SOMEWHAT IN-LINE WITH THIS IDEA.

NORTHEAST FLOW ALOFT ON THE LEE SIDE OF THE KICKER TROUGH TUESDAY
WILL PERMIT AN OFFSHORE FLOW PATTERN TO DEVELOP AND BRING A WARMER
AND DRIER AIR MASS FOR LATE WEEK. RIDGING ALOFT WILL REENFORCE AND
BUILD IN BEHIND THE TROUGH WEDNESDAY...AND BRING ADDITIONAL
WARMING AND DRYING FOR THE REGION.

.LONG TERM (THURSDAY-SUNDAY)...

RIDGING ALOFT WILL REENFORCE AND BUILD IN BEHIND THE TROUGH
SOMETIME BETWEEN THURSDAY AND FRIDAY. ADDITIONAL WARMING AND
DRYING IS LIKELY FOR THE REGION...BUT IT COULD BE DELAYED BY A
DAY DEPENDING UPON WHAT HAPPENS WITH ANOTHER WEAK WAVE DROPPING
SOUTH IN THE NORTHERLY FLOW ALOFT. BY FRIDAY...AN OMEGA BLOCKING
RIDGE SHOULD ESTABLISH FOR THE WEEKEND. THE WARMEST DAY AT THIS
TIME APPEARS TO BE SATURDAY WHEN THE RIDGE CENTER IS OVERHEAD. THE
RIDGE SHOULD LINGER INTO EARLY NEXT WEEK.

&&

.AVIATION...01/1745Z.

AT 1745Z...THERE WAS NO MARINE INVERSION AT KLAX.

OVERALL...LOW CONFIDENCE IN 18Z TAF PACKAGE. UNSTABLE AIR MASS WILL
CONTINUE TO GENERATE SCATTERED SHOWERS AND EVEN THE POSSIBILITY OF
AN ISOLATED THUNDERSTORM JUST ABOUT AT ANY TAF SITE THROUGH THIS
EVENING. IN TERMS OF CIG/VSBY RESTRICTIONS...CONDS WILL LIKELY VARY
BETWEEN VFR AND MVFR...WITH A GOOD CHANCE OF MVFR CIGS BEING
PREDOMINATE THIS AFTERNOON/EVENING...EXCEPT 30 PERCENT CHANCE FOR
LIFR/IFR FOR KPRB THROUGH 19Z

KLAX...LOW CONFIDENCE IN 18Z TAF. CONFIDENCE IN TIMING OF ANY MVFR
CIGS THRU THE PERIOD IS LOW. THERE IS A SLIGHT CHANCE OF TSTMS
THROUGH THIS EVENING.

KBUR...LOW CONFIDENCE IN 18Z TAF. CONFIDENCE IN TIMING OF ANY MVFR
CIGS THRU THE PERIOD IS LOW. THERE IS A SLIGHT CHANCE OF TSTMS
THROUGH THIS EVENING.

&&

.MARINE...01/950 AM.

HIGH CONFIDENCE IN WINDS REMAINING BELOW SMALL CRAFT ADVISORY LEVELS
THROUGH EARLY TUESDAY MORNING. ON TUESDAY...THERE IS A CHANCE OF
NORTHWEST WINDS INCREASING TO SMALL CRAFT ADVISORY LEVELS ACROSS THE
OUTER WATERS. 30 PERCENT CHANCE FOR THE WESTERN PORTION OF THE SBA
CHANNEL TUESDAY AFTERNOON.

MAIN ISSUE IN THE SHORT TERM WILL BE THE CONTINUED THREAT OF
THUNDERSTORMS THROUGH MONDAY EVENING. WITH ANY THUNDERSTORMS THAT
DEVELOP...THERE WILL BE THE POTENTIAL FOR BRIEF GUSTY WINDS...SMALL
HAIL AND EVEN A WATERSPOUT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...HALL
AVIATION/MARINE...CK
SYNOPSIS...HALL

WWW.WEATHER.GOV/LOSANGELES





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