Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 061113
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
313 AM PST FRI MAR 6 2015

...NEAR RECORD HOT TEMPERATURES FOR THE BEACHES AND IMMEDIATE
COASTAL LOCALITIES TODAY...

.SYNOPSIS...

A DOMINANT RIDGE OF HIGH PRESSURE WILL PERSIST INTO EARLY NEXT
WEEK. A WARM AND DRY AIR MASS WILL LINGER INTO TUESDAY WITH FAIR
SKIES AND TEMPERATURES ABOVE SEASONAL NORMALS. A COOLING TREND
WITH INCREASING CLOUDS EXPECTED TO BEGIN BY THE MIDDLE OF NEXT
WEEK AS A LOW PRESSURE SYSTEM APPROACHES THE COAST.

&&

.SHORT TERM (TODAY-SUNDAY)...

WATER VAPOR IMAGERY INDICATES A DRY AIR MASS IN PLACE WITH
OFFSHORE FLOW AS A RIDGE OF HIGH PRESSURE ALOFT OVER THE NORTH
COAST OF CALIFORNIA CONTINUES TO BUILD IN THIS MORNING. AT THE
SURFACE...OFFSHORE PRESSURE GRADIENTS CONTINUE TO TREND OFFSHORE
AND GUSTY SANTA ANA WINDS CONTINUE TO INCREASE. WIND GUSTS BETWEEN
35 MPH AND 45 MPH HAVE BEEN PREVALENT EARLY THIS MORNING. WITH
NAM-WRF SOLUTIONS INDICATING BOUNDARY LAYER WINDS INCREASING
FURTHER LATER THIS MORNING...THE WIND ADVISORY WAS EXPANDED TO THE
COASTAL SECTIONS OF LOS ANGELES AND VENTURA COUNTIES...AND THE
SAN FERNANDO VALLEY.

OTHERWISE...OFFSHORE FLOW WILL KEEP A WARM AND DRY AIR MASS IN
PLACE. MODEL SURFACE PRESSURE GRADIENTS CONTINUE TO PERFORM POORLY
WITH THE MODEL SOLUTIONS WANTING TO TREND MORE STRONGLY TOWARDS
AN ONSHORE FLOW PATTERN IN THE AFTERNOON. GOING WITH GRADIENT
TRENDS SEEMS TO BE THE WAY TO GO...AND TEMPERATURES HAVE BEEN
TWEAKED A LITTLE WARMER ALONG THE COAST FOR TODAY. NEAR RECORD
HEAT IS FORECAST FOR THE BEACHES AND IMMEDIATE COASTAL LOCALITIES
TODAY. EVEN WARMER TEMPERATURES ARE FORECAST FOR THE AREA FOR
SATURDAY. RECORD HEAT IS LESS LIKELY AS MOST TEMPERATURE RECORD
LEVELS ARE WARMER FOR SATURDAY. REGARDLESS...A WARM WEATHER
PATTERN WILL BE THE MAIN STORY FOR THE WEEKEND.

MOS GUIDANCE CONTINUES TO BREAK AWAY FROM THE SYNOPTIC PATTERN
FOR SUNDAY. MODELS WANT TO BREAKDOWN THE OFFSHORE FLOW DESPITE
500 MB HEIGHTS AND 1000-500 THICKNESS VALUES CLIMBING. EVEN 850 MB
TEMPERATURES WARM...BUT MODEL SOLUTIONS WANT TOO COOL THE LOWEST
2500 FEET OF THE ATMOSPHERE. TEMPERATURES HAVE BEEN NUDGED UP FOR
SUNDAY AS THERE IS NO REAL UPPER-LEVEL FORCING TO SWITCH THE AIR
MASS TO ONSHORE FROM OFFSHORE.

.LONG TERM (MONDAY-THURSDAY)...

A SLIGHT COOL DOWN LOOKS MORE LIKELY FOR MONDAY WHEN A SHORTWAVE
TROUGH BRUSHES THE AREA...BUT THE AIR MASS WILL STILL BE VERY
WARM. THE COOL DOWN WILL BE VERY SHORT-LIVED AS HIGH PRESSURE
SHOULD REBOUND INTO TUESDAY AND WARM THE AIR MASS ONCE AGAIN.

THE FORECAST CONTINUES TO BE PROBLEMATIC FOR MID-TO-LATE NEXT
WEEK. AS TYPICALLY WITH MOISTURE TO THE SOUTHWEST OF THE
AREA...THE MODEL SOLUTIONS ARE STRUGGLING TO HANDLE THE SURGE OF
MOISTURE NORTHEASTWARD. GFS SOLUTIONS TAKE A DRY STANCE IN
KILLING A RATHER MOIST AIR MASS ON THE DOOR STEP OF SOUTHERN
CALIFORNIA BETWEEN WEDNESDAY AND THURSDAY...WHILE ECMWF AND GEM
SOLUTIONS SEEMS MORE INLINE WITH KEEPING A RATHER MOIST AIR MASS
IN PLACE FOR THE REGION. GEM SOLUTIONS ARE THE MOST AGGRESSIVE
WITH THE MOISTURE...AND KEEP A MOIST PATTERN LINGERING INTO THE
WEEKEND. NAEFS ANOMALIES INDICATE PRECIPITABLE WATER VALUES ALMOST
TWO STANDARD DEVIATIONS ABOVE THE MEAN. WHILE IT IS BECOMING MORE
APPARENT THAT PRECIPITATION SHOULD IMPACT NORTHERN AND CENTRAL
CALIFORNIA...HOW FAR SOUTH THE MOISTURE AND INSTABILITY MAKE IT IS
LESS CERTAIN. POPS HAVE BEEN TRENDED HIGHER FOR AREAS NORTH OF
POINT CONCEPTION...BUT REMAIN LARGELY UNCHANGED SOUTH OF POINT
CONCEPTION. IF THERE IS A POSITIVE TO THE MODEL SOLUTIONS...RUN-
TO-RUN CONSISTENCY ISSUES WITH TIMING ARE DISAPPEARING.

&&

.AVIATION...06/1030Z.

AT 1030Z...THERE WAS NO MARINE INVERSION AT KLAX.

OVERALL...HIGH CONFIDENCE IN 12Z TAF PACKAGE. OFFSHORE FLOW WILL
KEEP ALL SITES VFR THROUGH THE PERIOD. WITH THE OFFSHORE FLOW...THERE
IS A GOOD CHANCE OF MODERATE TURBULENCE/LLWS AT TIMES FROM THIS
MORNING THROUGH MID-AFTERNOON ACROSS VENTURA AND LOS ANGELES
COUNTIES (ESPECIALLY THROUGH/NEAR THE PASSES AND VALLEYS). FOR LATE
TONIGHT/SATURDAY MORNING...THE OFFSHORE FLOW IS EXPECTED TO BE A BIT
WEAKER...BUT LIGHT/MODERATE TURBULENCE/LLWS WILL STILL BE POSSIBLE.

KLAX...HIGH CONFIDENCE IN 12Z TAF. THERE IS A 30% CHANCE OF LIGHT
TURBULENCE/LLWS 12Z-22Z TODAY.

KBUR...HIGH CONFIDENCE IN 12Z TAF. WITH OFFSHORE FLOW...MODERATE
TURBULENCE/LLWS IS LIKELY 12Z-22Z TODAY.

&&

.MARINE...06/230 AM.

FOR THE OUTER WATERS...HIGH CONFIDENCE IN WEAK NORTHWEST WINDS TODAY.
FOR TONIGHT...THE NORTHWEST WINDS WILL INCREASE AND CONTINUE AT MORE
MODERATE LEVELS THROUGH SUNDAY. THERE WILL BE A 40% CHANCE OF WINDS
INCREASING TO SMALL CRAFT ADVISORY LEVELS TONIGHT THROUGH SUNDAY...WITH
THE STRONGEST WINDS LIKELY IN THE AFTERNOON AND EVENING HOURS. THE
NORTHWEST WINDS ARE EXPECTED TO WEAK A BIT MONDAY AND TUESDAY...AND
SMALL CRAFT ADVISORY CONDITIONS ARE NOT EXPECTED.

FOR THE INNER WATERS...MODERATE CONFIDENCE IN NORTHEAST WINDS REACHING
SMALL CRAFT ADVISORY LEVELS FROM VENTURA SOUTH TO SANTA MONICA THIS
MORNING THROUGH MID-AFTERNOON. THE NORTHEAST WINDS WILL BE A BIT
WEAKER TONIGHT/SATURDAY...WITH ONLY A 20% CHANCE OF SMALL CRAFT
ADVISORY LEVEL WINDS. ELSEWHERE ACROSS THE INNER WATERS THROUGH
SATURDAY...WEAK NORTH TO NORTHEAST FLOW WILL PREVAIL DURING THE
NIGHT AND MORNING HOURS...WITH WEAK WEST TO NORTHWEST FLOW IN THE
AFTERNOON HOURS. FOR SUNDAY THROUGH TUESDAY...HIGH CONFIDENCE IN
WESTERLY WINDS REMAINING BELOW SMALL CRAFT ADVISORY THRESHOLDS.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...HALL
AVIATION...RAT
MARINE...RAT
SYNOPSIS...HALL

WWW.WEATHER.GOV/LOSANGELES





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