Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 020445
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
945 PM PDT WED APR 1 2015

.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE MOVING INLAND ACROSS NEVADA WILL BRING
GUSTY WEST WINDS TO THE MOUNTAINS AND DESERTS TONIGHT. SLIGHTLY
WARMER THURSDAY UNDER HIGHER PRESSURE ALOFT...FOLLOWED BY GREATER
WARMING FRIDAY AND GUSTY NORTHEAST WINDS IN THE FOOTHILLS AND
MOUNTAIN PASSES. A COLD LOW PRESSURE TROUGH WILL BRING COOLER
WEATHER...GUSTY WINDS AND A SLIGHT CHANCE FOR SHOWERS EARLY NEXT
WEEK.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

THE 500 MB TROUGH OVER CENTRAL CALIFORNIA THIS EVENING WILL MOVE SE
INTO SOUTHERN NEVADA TONIGHT. A SPEED MAX ROUNDING THE BASE OF THE
TROUGH OVER SOUTHERN CALIFORNIA WILL BRING GUSTY WEST WINDS TO THE
MOUNTAINS AND DESERTS TONIGHT WHERE A WIND ADVISORY REMAINS IN
EFFECT THROUGH 8 AM THURSDAY.

A 2 DEGREE CELSIUS INVERSION THIS EVENING WILL REMAIN FAIRLY WEAK
OVERNIGHT DUE TO COLD AIR ADVECTION ALOFT WITH THE TROUGH. SCATTERED
LOW CLOUDS WEST OF THE MOUNTAINS THIS EVENING WILL SLOWLY EXPAND IN
COVERAGE OVERNIGHT...BUT THE COVERAGE WILL PROBABLY NOT BE AS
UNIFORM AS LAST NIGHT.

ON THURSDAY...SURFACE HIGH PRESSURE STARTS TO BUILD OVER THE
NORTHERN GREAT BASIN AND THAT WILL GENERATE WEAK NORTHERLY WINDS IN
THE CAJON PASS AND ADJACENT AREAS. STRONGER AND MORE WIDESPREAD
OFFSHORE WINDS WILL DEVELOP THURSDAY NIGHT INTO FRIDAY MORNING. THE
00Z WRF WIND FIELD IS SIMILAR TO THE 18Z RUN AND FORECASTS A WEAK TO
MODERATE OFFSHORE WIND EVENT WITH GUSTS OF 35-45 MPH IN THE
FOOTHILLS AND THROUGH THE PASSES. THE OFFSHORE FLOW WILL PUSH THE
SHALLOW MARINE LAYER OFF THE COAST FOR A SUNNY AND MUCH WARMER DAY
FRIDAY WITH COASTAL AND VALLEY HIGHS IN THE 80S TO NEAR 90.

SATURDAY WILL BE ANOTHER WARM DAY AS THE OFFSHORE FLOW TRANSITIONS
TO ONSHORE FLOW AHEAD OF A TROUGH DEEPENING ALONG THE WEST COAST.
THIS TROUGH WILL BRING ABOUT 10 DEGREES OF COOLING SUNDAY ALONG WITH
STRONGER ONSHORE FLOW AND A MUCH DEEPER MARINE LAYER SUNDAY NIGHT
AND MONDAY. THE LONG RANGE GFS AND ECMWF ALSO PROJECT SMALL CHANCES
FOR SHOWERS OVER SOUTHERN CALIFORNIA MONDAY NIGHT INTO TUESDAY. THE
TROUGH MOVES EAST WEDNESDAY FOLLOWED BY WEAK RIDGING AND
WARMER DAYS THURSDAY AND FRIDAY.

&&

.AVIATION...

020430Z...COAST/VALLEYS...AREAS OF BKN-OVC STRATUS WILL OCCUR MAINLY
IN THE SAN DIEGO COUNTY COASTAL AND VALLEY AREAS AND IN THE INLAND
EMPIRE THROUGH 17Z THU...WITH LOCAL BKN STRATUS IN ORANGE COUNTY
MAINLY 09Z-17Z THU. MOST CIGS WILL BE 2000-2500 FT MSL WITH TOPS TO
3000 FT MSL...AND SOME OF THE AIRPORTS WILL ALTERNATE BETWEEN SCT
CONDITIONS AND A BKN/OVC CIG OVERNIGHT. MOST VIS WILL REMAIN ABOVE 5
MI. AFTER 16Z THU...MOSTLY CLEAR SKIES WILL PREVAIL...LIKELY
CONTINUING THU NIGHT.

MOUNTAINS/DESERTS...AREAS OF GUSTY WEST WINDS WILL OCCUR...MAINLY
ALONG THE DESERT MOUNTAIN SLOPES AND THROUGH MOUNTAIN
PASSES...THROUGH 15Z THU. LOCAL SURFACE GUSTS 40-50 KT WILL OCCUR.
OTHERWISE...MOSTLY CLEAR SKIES WILL PREVAIL WITH UNRESTRICTED VIS
EXCEPT LOCAL VIS BELOW 5 MI IN BLOWING DUST THROUGH 15Z THU IN THE
DESERTS.

&&

.MARINE...

930 PM...COMBINED SEAS NEAR 10 FEET...STEEP WAVES...AND NORTHWEST
WIND GUSTS LOCALLY OVER 20 KT WILL CONTINUE THROUGH THURSDAY MORNING
OVER THE OUTER COASTAL WATERS. A SMALL CRAFT ADVISORY CONTINUES
THROUGH THURSDAY MORNING FOR THE WINDS AND SEAS. SEE LAXMWWSGX FOR
DETAILS. HIGH SEAS AND MODERATELY STRONG NORTHWEST WINDS WILL LIKELY
RETURN SUNDAY THROUGH NEXT WEDNESDAY.

&&

.SKYWARN...
SKYWARN ACTIVATION WILL NOT BE NEEDED THURSDAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY THROUGH 8 AM PDT THURSDAY FOR APPLE AND
     LUCERNE VALLEYS-RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO
     COUNTY MOUNTAINS-SAN DIEGO COUNTY DESERTS-SAN DIEGO
     COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING.

PZ...SMALL CRAFT ADVISORY THROUGH 11 AM PDT THURSDAY FOR
     WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER
     EXTENDING 30 TO 60 NM OUT INCLUDING SAN CLEMENTE ISLAND.

&&

$$

PUBLIC...MOEDE
AVIATION/MARINE...MAXWELL


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