000
FXUS66 KSGX 200436
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 PM PST WED NOV 19 2008
.SYNOPSIS...A SHALLOW MARINE LAYER WILL CAUSE AREAS OF COASTAL LOW
CLOUDS AND FOG DURING THE NIGHTS AND MORNINGS. FOG WILL BE LOCALLY
DENSE TONIGHT AND THURSDAY MORNING. VARIABLE HIGH CLOUDINESS IN
WESTERLY WINDS ALOFT. UPPER LEVEL LOW PRESSURE WILL BRING MORE
CLOUDS AND COOLING NEXT WEEK.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
.SHORT TERM (TONIGHT-SAT)...THERE WERE AREAS OF LOW CLOUDS AND DENSE
FOG IN THE SAN DIEGO COASTAL AREAS THIS EVENING. CLEAR ELSEWHERE.
THE 00Z NKX SOUNDING HAD A WEAK INVERSION BASED BELOW 1000 FT WITH
DRY WLY WINDS ALOFT. WEAK OFFSHORE GRADIENTS FROM THE N AND ONSHORE
TO THE E.
AN UPPER TROUGH WILL MOVE PAST FAR TO THE N ON THU FOLLOWED BY FLAT
OR WEAKLY CYCLONIC FLOW ALOFT THROUGH SAT. THE MARINE LAYER WILL
REMAIN SHALLOW AND MOSTLY CONFINED TO THE COASTAL AREAS WITH LOCAL
DENSE FOG DURING THE NIGHTS AND MORNINGS. OFFSHORE FLOW WILL DEVELOP
FROM THE N FRI AND TURN OFFSHORE FROM THE NE SAT. THE OFFSHORE FLOW
WILL BE MAINLY GRADIENT DRIVEN AND WEAK. THE STRONGEST WINDS WILL BE
TROUGH AND BELOW THE CAJON PASS AND IN THE SANTA ANA MOUNTAINS WHERE
THEY COULD GUST TO ABOUT 35 MPH FRI MORNING...BECOMING EVEN WEAKER
SAT MORNING. THE OFFSHORE FLOW WILL REDUCE THE MARINE LAYER
CLOUDINESS...ESPECIALLY IN ORANGE COUNTY. A LITTLE COOLER THU...BUT
MAX TEMPS WILL STILL BE 5 TO 10 DEGREES ABOVE SEASONAL INLAND. MINOR
TEMP CHANGES OR SLIGHT COOLING IN THE MOUNTAINS AND DESERTS FRI AND
SAT BUT A LITTLE WARMER W OF THE MOUNTAINS DUE TO THE WEAK OFFSHORE
FLOW. WLY WINDS ALOFT WILL BRING VARIABLE HIGH CLOUDINESS.
&&
.LONG TERM (SUN-WED)...AN UPPER TROUGH IN THE ERN PAC WILL SLOWLY
APPROACH THE W COAST. THIS WILL BRING MORE CLOUDS AND COOLING. THERE
WILL BE A SMALL CHANCE OF SHOWERS BY LATE TUE OR WED BUT THERE IS
STILL A LOT OF UNCERTAINTY THAT FAR OUT AND WILL ONLY INDICATE LOW
POPS FOR NOW.
&&
.FIRE WEATHER...HIGHER RELATIVE HUMIDITIES AND LOWER TEMPERATURES AT
THE COAST WILL BE SPREAD INLAND AS THE OFFSHORE FLOW CONTINUES TO
WEAKEN. THE MOISTENING AND COOLING TREND WILL CONTINUE INTO THU. THE
FLOW REVERSES FRI..AND WEAK OFFSHORE FLOW WILL DEVELOP...WITH THE
MAIN EFFECTS IN THE MOUNTAINS AND VALLEYS. ALTHOUGH CONDITIONS WILL
BE DRY AND WARM...CRITICAL FIRE WEATHER VALUES ARE NOT EXPECTED TO
BE REACHED.
&&
.AVIATION...
200430Z...AREAS OF STRATUS AND FOG WILL OCCUR ALONG THE COAST
OVERNIGHT...MOST PREVALENT IN SAN DIEGO COUNTY. BASES WILL GENERALLY
BE AROUND 400-500 FT MSL WITH AREAS OF DENSE FOG EXPECTED OVER THE
MESAS...HIGHER IMMEDIATE COASTAL TERRAIN AND LOCALLY OVER LOWER
TERRAIN AS WELL. KSAN WILL HAVE VIS MOSTLY ABOVE 2 MILES
OVERNIGHT...BUT KCRQ WILL LIKELY HAVE VIS BELOW 1/2 MILE BY 07Z.
KSNA COULD HAVE DENSE FOG...WITH VIS BELOW 1/2 MILE...AFT 11Z. MOST
AREAS SHOULD CLEAR BY 17Z THU. STRATUS/FOG COULD AGAIN IMPACT
IMMEDIATE COASTAL AREAS THU NIGHT...ESPECIALLY IN SAN DIEGO COUNTY.
ABOVE THE MARINE LAYER...MOSTLY CLEAR SKIES WITH UNRESTRICTED
VISIBILITIES WILL CONTINUE THROUGH THURSDAY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...ATKIN
AVIATION...MAXWELL
