000
FXUS66 KSGX 201621
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 AM PDT SAT MAR 20 2010
.SYNOPSIS...FAIR AND WARM THIS WEEKEND UNDER HIGH PRESSURE AND WEAK
OFFSHORE FLOW. A LITTLE COOLER ON MONDAY...THEN ON TUESDAY A TROUGH
OF LOW PRESSURE WILL BRING MORE COOLING ALONG WITH INCREASING CLOUDS
AND GUSTY WINDS TO THE MOUNTAINS AND DESERTS. WEAK HIGH PRESSURE
WILL REBUILD FOR MORE WARM DRY WEATHER WEDNESDAY AND THURSDAY...THEN
A LITTLE COOLER AGAIN NEXT FRIDAY AND SATURDAY.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
MOSTLY CLEAR THIS MORNING...EXCEPT FOR SOME SHALLOW MARINE LAYER
CLOUDS AND FOG LINGERING OVER THE COASTAL WATERS AND THE BEACHES.
THIS SHOULD BURN OFF BY 11 AM PDT EVEN AS SOME HIGH CLOUDS STREAMING
OVER SOCAL FROM THE NW. SURFACE HIGH PRESSURE OVER COLORADO WILL
STRENGTHEN THE OFFSHORE PRESSURE GRADIENTS THROUGH EARLY AFTERNOON
WHEN GUSTY EAST WINDS WILL BLOW THROUGH THE EAST-WEST PASSES AND
CANYONS OF RIVERSIDE AND SAN DIEGO COUNTIES. THE OFFSHORE FLOW WILL
ALSO PUSH THE MARINE LAYER OUT TO SEA TONIGHT...BUT THE SHALLOW
MARINE LAYER WITH LOW CLOUDS AND FOG COULD RETURN TO THE COASTAL
WATERS AND THE IMMEDIATE COAST LATE TONIGHT INTO SUNDAY
MORNING...SIMILAR TO THIS MORNING. TEMPERATURES TODAY WILL BE A FEW
DEGREES HIGHER THAN YESTERDAY WEST OF THE MOUNTAINS...BUT BE A
LITTLE LOWER OVER THE MTNS AND DESERTS DUE TO WEAK COLD AIR
ADVECTION. SUNDAY WILL BE WARMER IN IN THE MTNS AND DESERTS AS THE
COLD AIR ADVECTION WEAKENS...AND COOLER WEST OF THE MTNS AS THE
UPPER RIDGE AND THE OFFSHORE FLOW BOTH WEAKEN.
ON SUNDAY NIGHT AND MONDAY...THE UPPER LEVEL RIDGE IS WEAKENED BY A
SPLIT FLOW TROUGH THAT WILL BRING EVEN COOLER WEATHER MONDAY AND
TUESDAY. THE MODELS COME INTO FAIRLY GOOD AGREEMENT...WITH BOTH THE
ECM AND THE GFS INDICATING A COOL BREEZY DAY WITH A DEEPENING MARINE
LAYER ON TUESDAY.
WEDNESDAY THROUGH SATURDAY...A WEAK UPPER RIDGE REBUILDS OVER
CALIFORNIA AS THE TROUGH MOVES EAST...BRINGING FAIR SKIES AND SOME
WARMING ON WED AND THU. ANOTHER LOW PRESSURE TROUGH MOVES IN FROM
THE NW TO AGAIN BRING SOME CLOUDS AND LOWER TEMPS FRIDAY AND
SATURDAY.
&&
.AVIATION...
201630Z...SCT-BKN LOW CLOUDS BASED 300-500 FEET MSL WITH TOPS AROUND
800 FEET MSL OVER THE COASTAL WATERS OTHERWISE CLEAR WITH
UNRESTRICTED VISIBILITIES. AFTER 12Z SUNDAY SCT-BKN LOW CLOUDS
COASTAL WATERS AND INLAND ABOUT 10 MILES BASED 300-500 FEET
MSL...TOPS AROUND 800 FEET MSL...AND VISIBILITIES LOCALLY BELOW 3SM
IN FOG. SMALL
&&
.SGX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...PG
AVIATION...SMALL
