Winter Storm Warning 7, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 AM PST FRI FEB 26 2010

.SYNOPSIS...HIGH PRESSURE ALOFT WILL BRING FAIR AND MILD WEATHER
TODAY WITH OCCASIONAL HIGH CLOUDS. RAIN AND MOUNTAIN SNOW FROM A
PACIFIC STORM WILL SPREAD ACROSS THE REGION LATE TONIGHT AND
SATURDAY. THIS STORM WILL BE FOLLOWED BY DRY...WARMER WEATHER SUNDAY
AFTERNOON THROUGH TUESDAY. THE NEXT TROUGH DEEPENS THE MARINE LAYER
FOR MORE CLOUDS AND A CHANCE FOR SHOWERS TUESDAY NIGHT AND
WEDNESDAY.

&&

.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.

RIDGING ALOFT AND WEAK OFFSHORE FLOW WILL BRING WARMER WEATHER
TODAY...BUT THE WARMING WILL BE TEMPERED A BIT BY FAIRLY THICK
CIRRUS CLOUDS. OFFSHORE SURFACE PRESSURE GRADIENTS AS OF 8 AM WERE
ABOUT -3 MB LAX-DAG AND -2 MB SAN-IPL. THIS WILL GENERATE LOCAL EAST
WINDS OF 15-25 MPH IN AND BELOW THE PASSES AND CANYONS...MAINLY THIS
MORNING.

A STRONG UPPER LOW AND COLD FRONT CURRENTLY OFF THE COAST WILL MOVE
INTO SOUTHERN CALIFORNIA ON SATURDAY...BRINGING RAIN AND MOUNTAIN
SNOW. RAIN WILL BEGIN IN NORTHERN ORANGE AND WESTERN SAN BERNARDINO
COUNTIES AFTER 2 AM...THEN SPREAD ACROSS SOUTHERN RIVERSIDE AND SAN
DIEGO COUNTIES AFTER SUNRISE. THE RAIN WILL CHANGE OVER TO SCATTERED
SHOWERS SATURDAY AFTERNOON IN THE COLD...UNSTABLE AIRMASS BEHIND THE
COLD FRONT. THERE IS JUST ENOUGH INSTABILITY FOR A THUNDERSTORM OR
TWO...MAINLY WEST OF THE MOUNTAINS.

ASIDE FROM TIMING DIFFERENCES WITH THE ONSET OF THE PRECIP...THE
MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS SYSTEM. THAT INCLUDES
THE PRECIPITATION FORECASTS. RAINFALL PROJECTIONS REMAIN UNCHANGED
WITH 1/2 TO 1 INCH IN THE COAST AND VALLEY AREAS...AND 1 TO 2 INCHES
IN THE MOUNTAINS WITH LOCALLY HEAVIER AMOUNTS TO 3 INCHES ON THE
FAVORED SOUTHWEST FACING SLOPES IN THE SAN BERNARDINO COUNTY
MOUNTAINS. RAINFALL WILL GENERALLY BE LESS THAN 1/2 INCH IN THE
UPPER DESERTS AND 1/4 INCH IN THE LOWER DESERTS.

THE SNOW LEVEL WILL START OUT ABOVE 8000 FT TONIGHT...THEN LOWER TO
NEAR 5000 FT NORTH AND 5500 FT SOUTH BY SATURDAY AFTERNOON. TOTAL
SNOWFALL ACCUMULATIONS OF 6 TO 12 INCHES ARE FORECAST ABOVE 6000
FEET IN THE SAN BERNARDINO AND RIVERSIDE COUNTY MOUNTAINS...WITH THE
GREATEST AMOUNTS ABOVE 7000 FT. MOST OF THE PRECIP WILL FALL AS RAIN
IN THE SAN DIEGO MOUNTAINS BUT THE HIGHEST ELEVATIONS MAY EVENTUALLY
GET A ONE OR TWO INCHES OF SNOW SATURDAY AFTERNOON AND EVENING AS
THE SNOW LEVEL LOWERS. DENSE FOG WILL RESTRICT VISIBILITIES IN THE
MOUNTAINS SATURDAY.

MOUNTAIN AND DESERT WINDS WILL RAMP UP LATE TONIGHT AND SATURDAY
MORNING ALONG AND AHEAD OF THE COLD FRONT. LOCAL WIND GUSTS TO 50
MPH ARE POSSIBLE ON THE RIDGES AND DESERT SLOPES. WIND ADVISORIES
WILL LIKELY BE ISSUED LATER IN THE SHIFT.

THE SHOWERS TAPER OFF SATURDAY NIGHT AS THE TROUGH MOVES EAST. A FEW
LINGERING SHOWERS ARE STILL POSSIBLE ACROSS SAN DIEGO COUNTY EARLY
SUNDAY MORNING...OTHERWISE SUNDAY SHOULD BE DRY AND MILD.

.LONG TERM (MONDAY-THURSDAY)...MILD AND DRY MONDAY AND TUESDAY UNDER
HIGH PRESSURE. A WEAK TROUGH TUESDAY NIGHT WILL BRING INCREASING
CLOUDS AND COOLER WEATHER WEDNESDAY ALONG WITH A SLIGHT CHANCE OF
LIGHT SHOWERS. DRY AND A LITTLE WARMER THURSDAY AS THE TROUGH MOVES
EAST.

&&

.AVIATION...
261500Z...MARINE LAYER DEPTH THIS MORNING WAS NEAR SEA LEVEL BUT
SHOULD DEEPEN THIS EVENING TO AROUND 2500 FEET AHEAD OF A STRONG
COLD FRONT EXPECTED TO MOVE INTO THE NORTHWEST PART OF THE AREA LATE
TONIGHT AND MOVE SOUTHEAST THROUGH THE AREA SATURDAY MORNING. COLD
FRONT SHOULD PASS THROUGH KSAN BETWEEN 18Z AND 21Z ON SATURDAY.

MOSTLY MID AND HIGH LEVEL CLOUDS OVER THE AREA TODAY. LOWER STRATOCU
BROKEN TO OVERCAST LAYERS WITH BASES BETWEEN 1500 AND 2500 FEET MSL
MOVING IN THIS EVENING AND OVERNIGHT. PRECIPITATION SHOULD MOVE OVER
THE AREA BETWEEN MIDNIGHT AND 12Z SAT. MOUNTAINS BECOMING OBSCURED
IN CLOUDS AND PRECIPITATION TONIGHT.  HORTON

&&

.SGX WATCHES/WARNINGS/ADVISORIES...

SPECIAL WEATHER STATEMENT. SEE LAXSPSSGX.

WINTER STORM WATCH ABOVE LATE TONIGHT THROUGH SATURDAY EVENING ABOVE
6000 FT IN THE SAN BERNARDINO AND RIVERSIDE COUNTY MOUNTAINS. SEE
LAXWSWSGX.

&&

PUBLIC...SCV
AVIATION...HORTON

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN DIEGO CA
425 AM PST FRI FEB 26 2010

CAZ042-043-048-050-055>058-060>062-270000-
ORANGE COUNTY COASTAL AREAS-
SAN DIEGO COUNTY COASTAL AREAS-
SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-
SAN DIEGO COUNTY VALLEYS-
SAN BERNARDINO COUNTY MOUNTAINS-
RIVERSIDE COUNTY MOUNTAINS-
SANTA ANA MOUNTAINS AND FOOTHILLS-
SAN DIEGO COUNTY MOUNTAINS-
APPLE AND LUCERNE VALLEYS-
COACHELLA VALLEY-
SAN DIEGO COUNTY DESERTS-
425 AM PST FRI FEB 26 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ALL OF EXTREME SOUTHWESTERN
CALIFORNIA.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH FRIDAY

A PACIFIC STORM WILL BRING LOCALLY HEAVY RAIN...ISOLATED
THUNDERSTORMS...GUSTY WINDS AND MOUNTAIN SNOW SATURDAY. HIGH SURF
WILL ELEVATE THE RIP CURRENT RISK.

.SPOTTER INFORMATION STATEMENT...SKYWARN SPOTTER ACTIVATION MAY BE
REQUESTED SATURDAY.

MOEDE