Frost Advisory 17, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
325 AM PST MON DEC 9 2013

.SYNOPSIS...
HIGH PRESSURE BUILDING OVER NEVADA AND UTAH WILL CREATE STRONG GUSTY
NORTHEAST WINDS TODAY THROUGH EARLY TUESDAY MORNING...DECREASING
MIDDAY TUESDAY. THE DRY...COOL AIR WILL KEEP DAYTIME HIGH
TEMPERATURES WELL BELOW NORMAL DURING THE EARLY PART OF THE WEEK.
TEMPERATURES WILL MODERATE DURING THE LATTER PART OF THE WEEK AND
INTO NEXT WEEKEND AS THE AIRMASS WARMS.

&&

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

A BLAST OF COOL WINTERTIME AIR HAS BEEN SETTING UP OVER THE
PLATEAU...AND IS EXPECTED TO MOVE INTO SOUTHERN CALIFORNIA OVER THE
NEXT COUPLE OF DAYS. THE LOCAL WRF SPREADS STRONG NORTHEAST WINDS
OVER MANY OF THE WIND PRONE AREAS TODAY...AND INTO THE MORNING HOURS
ON TUESDAY. THIS WILL BE A RATHER COOL EVENT WITH TEMPERATURES BELOW
NORMAL. THERE IS AN UPPER LOW JUST OFF THE COAST WHICH COULD BRING
SOME HIGH CLOUDS AT TIMES. THE BUFKIT SOUNDINGS SHOW CONTINUED
DRYING OVER THE NEXT COUPLE OF DAYS AS THE COOL DRY AIR MOVES IN
FROM THE NORTHEAST. FROSTY CONDITIONS ARE EXPECTED TO ACCOMPANY THIS
PATTERN.

LOOKING OUT TOWARD THURSDAY AND FRIDAY THE LOW CONTINUES TO HANG
AROUND ON THE DETERMINISTIC ECMWF MODEL. THE ENSEMBLE MEAN IS MORE
LIKE A WEAK TROUGH...BUT NO SIGNIFICANT EFFECT ON SOUTHERN
CALIFORNIA WEATHER IS EXPECTED FROM THIS LOW. TEMPERATURES COULD
CREEP BACK TO NEAR NORMAL LATE IN THE WEEK...AND REMAIN NEAR NORMAL
INTO NEXT WEEKEND.

&&

.AVIATION...
091000Z...MOSTLY CLEAR WITH UNRESTRICTED VSBY TODAY AND TONIGHT.
AREAS OF NORTHEAST WINDS 20-25 KTS GUSTING TO 50 KTS DEVELOPING THIS
MORNING AND CONTINUING...BUT WEAKENING THROUGH TONIGHT. THIS WILL
RESULT IN A PERIOD OF LLWS AT KONT AND KSNA THIS MORNING BEFORE
THOSE WINDS SURFACE THERE AFTER 15Z. STRONG UPDRAFTS/DOWNDRAFTS AND
AREAS OF LLWS OVER THE MOUNTAINS AND ADJACENT COASTAL FOOTHILLS.

&&

.FIRE WEATHER...
SEVERAL HOURS OF CRITICAL OR NEAR CRITICAL FIRE WEATHER CONDITIONS
ARE LIKELY TODAY MOUNTAIN AREAS AS WELL AS IN AND BELOW WIND PRONE
CANYONS. SURFACE NORTHEAST WINDS OF 25 MPH WITH GUSTS OVER 35
MPH...AND RH OF 10-15 PERCENT FOR SEVERAL HOURS ARE EXPECTED DURING
THE DAY. THESE CONDITIONS WILL SUBSIDE SLIGHTLY OVERNIGHT...THEN
RETURN ON TUE...BUT WEAKER. RECENT RAINS IN SOME AREAS AND
TEMPERATURES IN THE 50S WILL HELP TO LIMIT THE WILDFIRE THREAT.

&&

SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING THROUGH TUESDAY MORNING FOR
THE ORANGE COUNTY COASTAL AREAS...SAN BERNARDINO COUNTY
MOUNTAINS...SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE
INLAND EMPIRE...SANTA ANA MOUNTAINS AND FOOTHILLS.

WIND ADVISORY THROUGH TUESDAY MORNING FOR THE SAN DIEGO COUNTY
VALLEYS...RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY
MOUNTAINS...COACHELLA VALLEY.

FROST ADVISORY TIL 9 AM PST TODAY FOR
THE COACHELLA VALLEY...SAN BERNARDINO AND RIVERSIDE COUNTY
VALLEYS-THE INLAND EMPIRE...SAN DIEGO COUNTY DESERTS...SAN
DIEGO COUNTY VALLEYS.

&&

PUBLIC...SMALL
AVIATION/MARINE...MM