FXUS66 KSGX 090530
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 PM PST TUE DEC 8 2009
.SYNOPSIS...PARTLY CLOUDY AND COOL THROUGH WEDNESDAY WITH AREAS OF
FROST POSSIBLE OVERNIGHT. INCREASING CLOUDS AND MILD THURSDAY WITH A
CHANCE OF LIGHT RAIN DEVELOPING AND LINGERING OFF AND ON THROUGH
FRIDAY. MODERATE RAIN IS POSSIBLE LATE SATURDAY THROUGH SUNDAY. DRY
AND TURNING WARMER NEXT WEEK UNDER BUILDING HIGH PRESSURE.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
THERE WERE AREAS OF STRATUS WEST OF THE MOUNTAINS THIS EVENING WITH
INCREASING HIGH CLOUDS ALOFT. THE 00Z KNKX SOUNDING SHOWED A
RESIDUAL 5000 FT DEEP MOIST LAYER WITH DRY NORTHWEST FLOW ALOFT.
EXPECT AREAS OF STRATUS WEST OF THE MOUNTAINS TONIGHT...MAINLY OVER
SAN DIEGO COUNTY. HIGH CLOUDS WILL ALSO BE MOVING IN AS WELL. IT
WILL BE ANOTHER CHILLY NIGHT WITH PATCHY FROST IN AREAS WHERE THERE
ARE FEWER CLOUDS. A BIT WARMER TOMORROW AS HEIGHTS/THICKNESS REBOUND
UNDER FAIR SKIES.
THE SATELLITE IMAGERY SHOWS ANOTHER SYSTEM OUT OVER THE PACIFIC W OF
130W WHICH SHOULD BEGIN TO AFFECT CA ON THU. WEAK WARM AIR ADVECTION
COULD CAUSE LIGHT STRATIFORM RAIN TO FALL AS EARLY AS MID DAY. MODEL
CROSS SECTIONS SHOW AN INCREASE IN MOISTUE BETWEEN 850-700 MB WITH
LESS MOISTURE BELOW. THE LOW LEVELS DO NOT BECOME SATURATED UNTIL
FRIDAY MORNING. BASED ON THE LATEST GUIDENCE...LIGHT RAIN COULD
START AS EARLY AS THURSDAY AFTERNOON WITH THE ONSET OF WEAK WARM AIR
ADVECTION...BUT IS MORE LIKELY ON FRIDAY AS A SURAFCE LOW MOVES INTO
CENTRAL CA AND THE LOW LEVELS BECOME SATURATED. ESTIMATED RAINFALL
AMOUNTS ARE FOR ABOUT ONE QUARTER INCH AT THE COAST AND IN THE
VALLEYS...AND UP TO ONE HALF INCH IN THE MOUNTAINS.
MOIST WESTERLY FLOW CONTINUES OFF THE PACIFIC THROUGH THE WEEKEND...
AND THE MODELS INDICATE ANOTHER SYSTEM MAY AFFECT THE STATE BY LATE
SAT OR SUN. THE ECMWF IS ABOUT 12 HOURS QUICKER THAN THE GFS...BUT
BOTH INDICATE THE POTENTIAL FOR A GOOD RAIN EVENT. SNOW LEVELS WOULD
BE FARILY HIGH...BUT THE HIGHER RESORT TOWNS IN THE SAN BERNARDINO
MOUNTAINS SHOULD BE COLD ENOUGH FOR SNOW.
THE MOIST ZONAL PATTERN OFF THE CENTRAL PACIFIC IS REPLACED BY
RIDGING OVER THE EPAC REGION EARLY NEXT WEEK. THIS SHOULD ENSURE DRY
WEATHER AND WARMING THEN.
&&
.AVIATION...
090300Z...MOSTLY CLEAR THIS EVENING WITH A FEW STRATUS AROUND AND
VSBY ABOVE 7SM. HIGH CLOUDS BEGINNING TO SPREAD OVER SOCAL TONIGHT.
BASES OF STRATUS AROUND 4500 FT MSL WITH TOPS AROUND 5K FT. NOT MUCH
CHANGE WITH INCREASING HIGH CLOUDS WEDNESDAY.
&&
.MARINE...
090300Z...A LARGE LONG PERIOD WEST NORTHWEST SWELL IS FORECAST TO
MOVE IN WEDNESDAY WITH WAVES UP TO AROUND 10 FT. THE LARGE SURF IS
EXPECTED TO CONTINUE THROUGH FRIDAY. HIGH SURF ADVISORY FROM
WEDNESDAY MORNING THROUGH FRIDAY AFTERNON. THE SWELL WILL BE UP TO
AROUND 5 TO 6 FEET IN THE INNER WATER TO 7 TO 9 FEET IN THE OUTER
WATERS DURING THAT PERIOD.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY...SEE LAXCFWSGX.
&&
$$
PUBLIC...SCV
AVIATION/MARINE...WHITLOW
