FXUS66 KSGX 072145
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
230 PM PST MON DEC 7 2009
.SYNOPSIS...
A STRONG PACIFIC STORM WILL BRING RAIN TODAY. HEAVY SNOW AND NEAR
BLIZZARD CONDITIONS ARE LIKELY IN THE SAN BERNARDINO MOUNTAINS ABOVE
6000 FEET...AND IN THE SAN JACINTO MOUNTAINS ABOVE 7000 FEET. STRONG
AND GUSTY WINDS ARE POSSIBLE WITH THE PASSAGE OF THE COLD FRONT THIS
AFTERNOON...ESPECIALLY IN SAN DIEGO COUNTY. THE STORM WILL EXIT
TUESDAY...BUT A MOIST FLOW OFF THE PACIFIC WILL BRING A CHANCE FOR
MORE RAIN LATE THURSDAY INTO THE WEEKEND.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
WIDESPREAD STRATIFORM RAIN CONTINUES OVER THE FORECAST AHEAD OF AN
APPROACHING COLD FRONT. SNOW IS FALLING ABOVE 5500 FT. WINDS ARE
INCREASING ALONG THE SAN DIEGO COAST WITH GUSTS TO 44 MPH BEING
REPORTED AT 130 PM.
A BROAD...COLD TROUGH WILL MOVE EASTWARD THIS AFTERNOON AS A 140 KT
JET PASSES OVER SOUTHERN CA. LIGHT TO MODERATE PRECIP WILL BECOME
HEAVY AS A COLD FRONT APPROACHES THIS AFTERNOON...THEN TAPER OFF
THIS EVENING AS THE FRONT MOVES EAST.
REGARDING THE WIND THREAT...A DEEPENING SURFACE LOW WILL MOVE ASHORE
IN SAN DIEGO COUNTY EARLY THIS AFTERNOON. AHEAD OF THIS SURFACE
LOW...A 60-70 KNOT LOW LEVEL JET WILL BRING GUSTY SOUTH WINDS AND
HEAVY RAIN TO SAN DIEGO COUNTY. THE STRONGEST WINDS WILL OCCUR
DURING THE EARLY AFTERNOON HOURS WITH LOCAL GUSTS TO 60 MPH
POSSIBLE...MAINLY ALONG THE COAST AND IN THE FOOTHILLS. AS THE COLD
FRONT MOVES EAST...STRONG GUSTY WINDS WILL DEVELOP IN THE MOUNTAINS
AND DESERTS. WINDS WILL CONTINUE IN THE MOUNTAINS AND DESERTS
OVERNIGHT INTO TUESDAY MORNING BEFORE WEAKENING.
IN THE MOUNTAINS...HEAVY SNOW IS EXPECTED AT THE HIGHER ELEVATIONS.
STRONG WARM AIR ADVECTION AHEAD OF THE SURFACE LOW AND COLD FRONT
WILL CAUSE SNOW LEVELS TO RISE TO ABOUT 6000 FT IN SBD COUNTY...TO
GREATER THAN 7000 FT OVER SAN DIEGO COUNTY EARLY THIS AFTERNOON.
SNOW LEVELS WILL THEN PLUMMET BEHIND THE FRONT TO 3000 FT OR LOWER
LATE THIS EVENING. BETWEEN ONE AND TWO FEET OF SNOW IS POSSIBLE IN
THE SAN BERNARDINO AND RIVERSIDE MOUNTAINS ABOVE 6000-6500 FEET.
STORM TOTAL RAINFALL ESTIMATES ARE FOR ABOUT 1 TO 2 INCHES IN THE
FLATS...2 TO 4 INCHES ON THE COASTAL MOUNTAIN SLOPES...UP TO 1/2 AN
INCH IN THE DESERTS. PRECIPITATION WILL QUICKLY DIMINISH AFTER THE
FRONT MOVES THROUGH IN THE EVENING...EXCEPT AT HIGHER ELEVATIONS
WHERE STRONG WEST WINDS WILL CONTINUE UPSLOPE PRECIPITATION. MON
NIGHT IS WHEN THE SAN DIEGO COUNTY MOUNTAINS COULD SEE SEVERAL
INCHES OF SNOW. SOME LIGHT PRECIPITATION COULD LINGER IN THE SAN
DIEGO MOUNTAINS THROUGH TUE MORNING BEFORE COMPLETELY DRYING OUT.
OTHERWISE PARTLY CLOUDY AND CONTINUED BREEZY AND COOL.
ANOTHER SYSTEM FROM THE CENTRAL PACIFIC IS EXPECTED BY LATE THU INTO
FRI WITH LIGHT TO MODERATE RAIN POSSIBLE. MOIST WEST FLOW WILL
CONTINUE A CHANCE FOR SHOWERS INTO THE WEEKEND. SLIGHTLY LESS
RAINFALL IS NOW EXPECTED WITH THE NEXT SYSTEM VS WHAT HAS FALLEN
TODAY.
&&
.AVIATION...
072030Z...COLD FRONT EXPECTED TO PASS THROUGH ANYTIME BETWEEN 22Z
AND 01Z. BROKEN TO OVERCAST LAYERS BETWEEN 1500 AND 3000 FEET MSL
WITH LOCALLY LOWER BASES BELOW 1000 FEET MSL VICINITY OF THE FRONT
IN THE MODERATE TO HEAVY SHOWERS. VISIBILITIES MOSTLY BETWEEN 3 TO 5
MILES IN LIGHT TO MODERATE PRECIPITATION EXCEPT BELOW 3 MILES IN
HEAVY SHOWERS. GUSTY SOUTHWEST WINDS EXPECTED JUST AHEAD OF THE
FRONT BETWEEN 25 AND 45 KNOTS BECOMING WEST 15 TO 30 KNOTS BEHIND
THE FRONT. TOPS TO FL200 AT TIMES. MOUNTAINS OBSCURED IN CLOUDS AND
PRECIPITAION. CEILINGS AT KPSP COULD GO BELOW THE VOR/GPS APROACH
MINIMUMS AT TIMES THROUGH THE AFTERNOON IN SHOWERS. EXPECT MOSTLY
BROKEN STRATOCU CONDITIONS LATE TONIGHT INTO WEDNESDAY MORNING THEN
BREAKING UP DURING THE DAY ON WEDNESDAY. HORTON
&&
.MARINE...
A STRONG COLD FRONT WILL BRING HAZARDOUS SEAS AND WINDY CONDITIONS
TODAY THROUGH TUESDAY MORNING. THERE WILL BE A GALE WARNING FOR THE
INNER AND OUTER WATERS THROUGH TUESDAY MORNING. A RAPID RISE IN
WESTERLY SWELL WILL ACCOMPANY THE FRONT MONDAY EVENING...THEN
DECREASE EARLY TUESDAY. A HIGH RIP CURRENT RISK WILL DEVELOP THIS
AFTERNOON AS SWELL AND SURF RISE RAPIDLY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING...SEE LAXWSWSGX.
HIGH WIND WARNING...SEE LAXNPWSGX.
GALE WARNING...SEE LAXMWWSGX.
FLASH FLOOD WATCH...SEE LAXFFASGX.
HIGH SURF ADVISORY...SEE LAXCFWSGX.
&&
$$
PUBLIC...SCV
AVIATION/MARINE...HORTON
