180
FXUS66 KSGX 062133
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
230 PM PST TUE JAN 6 2009
SYNOPSIS
FAIR AND A LITTLE WARMER THROUGH MID WEEK UNDER HIGH
PRESSURE. A TROUGH OF LOW PRESSURE APPROACHING FROM THE NORTHWEST
WILL BRING MORE LOW CLOUDS AND FOG WEST OF THE MOUNTAINS AND COOLING
THURSDAY AND FRIDAY. CLEAR SKIES IN OFFSHORE FLOW THIS WEEKEND AND
EARLY NEXT WEEK WITH WARMER DAYS...ESPECIALLY WEST OF THE MOUNTAINS.
LOCAL STRONG GUSTY WINDS AT TIMES LATE FRIDAY INTO EARLY NEXT
WEEK...MAINLY THROUGH AND BELOW MOUNTAIN CANYONS AND PASSES.
DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
SHORT TERM (REMAINDER OF TODAY-FRIDAY)
THERE WERE PATCHES OF
STRATUS NEAR THE S COAST THIS MORNING AND VARIABLE HIGH CLOUDINESS.
EARLY AFTERNOON ACARS SOUNDINGS INDICATED STRONG NNW WINDS ALOFT.
WEAK GRADIENTS.
HIGH CLOUDINESS WILL DECREASE TONIGHT AS THE NLY UPPER JET SHIFTS
FARTHER E. A STRONG UPPER LEVEL RIDGE OF HIGH PRESSURE IN THE ERN
PAC WILL FLATTEN AND SHIFT E THROUGH THURSDAY BRINGING GENERALLY
FAIR WEATHER. THERE COULD BE AREAS OF STRATUS NEAR THE COAST LATE
WEDNESDAY NIGHT AND THURSDAY MORNING AS ONSHORE FLOW STRENGTHENS A
LITTLE. COOL TONIGHT UNDER MOSTLY CLEAR SKIES WITH PATCHY FROST
INLAND. WARMER WEDNESDAY THEN A LITTLE COOLING THURSDAY AS THE HIGH
ALOFT WEAKENS AND ONSHORE FLOW INCREASES. A SHORT WAVE TROUGH
APPROACHING FROM THE NW WILL MOVE THROUGH FRIDAY BRINGING MORE
CLOUDS AND COOLING. CANNOT RULE OUT THE POSSIBILITY OF A FEW LIGHT
SHOWERS AS THIS TROUGH MOVE THROUGH...BUT MOISTURE IS LIMITED AND
POPS TOO LOW TO INCLUDE PRECIP IN THE FORECAST AT THIS TIME. W TO NW
WINDS WILL INCREASE FRI...MAINLY IN THE MOUNTAINS AND DESERTS.
LONG TERM (SATURDAY-TUESDAY)
OFFSHORE FLOW WILL DEVELOP RAPIDLY
IN THE WAKE OF THE PASSING UPPER TROUGH. AN UPPER LEVEL RIDGE OF
HIGH PRESSURE WILL BUILD IN THE ERN PAC AND SLOWLY SHIFT E. THIS
WILL BRING CLEAR SKIES AND WARMING...ESPECIALLY W OF THE MOUNTAINS
WITH MONDAY LIKELY THE WARMEST DAY. THE OFFSHORE WINDS COULD BE
STRONG AT TIMES...ESPECIALLY SATURDAY MORNING THROUGH AND BELOW
MOUNTAIN CANYONS AND PASSES. THE OFFSHORE FLOW WILL CONTINUE BUT IS
EXPECTED TO SLOWLY WEAKEN EARLY NEXT WEEK BASED ON THE ECMWF.
HOWEVER...THE GFS REDEVELOPS STRONG OFFSHORE FLOW AGAIN.
AVIATION
062020Z...MAIN AVIATION WEATHER CONCERN THROUGH 07/0300 UTC IS
TURBULENCE OVER AND TO THE LEE OF THE MOUNTAINS DUE TO
NORTH-NORTHEAST WINDS 15-30 KT IN THE FL100-FL130 LAYER. THESE WINDS
WILL BE DIMINISHING TO LESS THAN 15 KT AFTER 07/0600 UTC. SECONDARY
CONCERN FROM 07/0300-07/1200 UTC...VISIBILITY 3-5SM IN HAZE IN
SHALLOW MARINE LAYER BELOW FL008. AFTER 07/1200 UTC WEAK NORTHEAST
WINDS SHOULD PUSH THE MARINE LAYER OFFSHORE AND CEILING AND
VISIBILITY SHOULD BE UNLIMITED AT ALL AIRPORTS UNTIL 08/0300 UTC
WHEN MARINE AIR RETURNS TO COASTAL AND VALLEY LOCATIONS BELOW FL010.
LOW CEILINGS/VISIBILITY LIKELY TO DEVELOP OVER COASTAL AIRPORTS LATE
WEDNESDAY NIGHT/EARLY THURSDAY MORNING.
SGX WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC...ATKIN
AVIATION...BALFOUR
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