FXUS66 KSGX 261729
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 AM PST SAT DEC 26 2009
.SYNOPSIS...THE SHALLOW MARINE LAYER WILL CAUSE PATCHY FOG NEAR THE
COAST DURING THE NIGHTS AND MORNINGS THROUGH SUNDAY. UPPER LEVEL LOW
PRESSURE APPROACHING FROM THE NORTHWEST WILL MOVE THROUGH MONDAY AND
TUESDAY. THIS WILL BRING VARIABLE CLOUDINESS WITH A SLIGHT CHANCE OF
LIGHT SHOWERS SUNDAY NIGHT THROUGH TUESDAY NIGHT. DECREASING CLOUDS
LATER NEXT WEEK IN DRIER NORTHWEST FLOW ALOFT.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
TODAY THROUGH TUESDAY...SCT LOW CLOUDS LINGER THIS MORNING OVER THE
COASTAL AREAS WITH MID AND HIGH CLOUDS INCREASING AS AN UPPER LEVEL
TROUGH APPROACHES FROM THE NW. THE MORNING NKX SOUNDING SHOWS A WEAK
INVERSION AT ABOUT 1500 FT WITH LIGHT SOUTHERLY WINDS BLO 10000 FT
AND INCREASING NW WINDS ABV. SFC PRESSURE GRADIENTS CONTINUE TO
TREND ONSHORE. THE MARINE LAYER SHOULD LIFT A BIT TONIGHT AND WILL
BE DISRUPTED BY HIGHER CLOUDS. THE HIGH CLOUDS WILL CONTINUE TO
INCREASE AS THE TROUGH MOVES IN FORM THE NW. THIS TROUGH WILL WEAKEN
AS IT PUSHES THE UPPER RIDGE TO THE E AND SPLITS AS IT MOVES ONSHORE
WITH MUCH OF THE ENERGY GOING INTO NRN BAJA. LOW LEVELS IN MOST
AREAS WILL REMAIN FAIRLY DRY WITH WEAK OFFSHORE FLOW RETURNING FOR A
TIME ON MONDAY. HOWEVER...THERE WILL BE MORE MID AND HIGH LEVEL
MOISTURE AND LOW ENOUGH HEIGHTS FOR A SMALL CHANCE OF LIGHT PRECIP
LATE SUNDAY THROUGH MONDAY. TEMPS WILL REMAIN A LITTLE BELOW
SEASONAL AVERAGES IN MOST AREAS. THERE COULD BE A LITTLE WARMING W
OF THE MOUNTAINS MONDAY IN THE WEAK LOW LEVEL OFFSHORE FLOW. A SHORT
WAVE WILL MOVE SWD INTO SRN CA TUESDAY ON THE W SIDE OF THE
DEPARTING TROUGH. THIS WILL MAINTAIN A SMALL CHANCE OF LIGHT PRECIP
THROUGH TUESDAY.
WEDNESDAY THROUGH SATURDAY... GENERALLY DRY AND WEAKLY CYCLONIC NW
FLOW ALOFT WILL PREVAIL WEDNESDAY AND THURSDAY WITH VARIABLE HIGH
CLOUDINESS. WEAK RIDGING FRIDAY AND SATURDAY FOR FAIR WEATHER.
GRADUALLY WARMER DURING THE SECOND HALF OF NEXT WEEK WITH MAX TEMPS
REACHING NEAR SEASONAL THURSDAY THROUGH SATURDAY.
&&
.AVIATION...
261700Z...A COUPLE OF INVERSIONS...ONE NEARLY SURFACE BASED AND ONE
AROUND 1800 FT MSL WERE OCCURRING THIS MORNING. THE ONE AT 1800 FT
MSL SHOULD EVENTUALLY DOMINATE AND RESULT IN SCT/LOCALLY BKN
CONDITIONS NEAR THE COAST AT THAT HEIGHT...INCREASING AFTER 03Z
TONIGHT. PATCHY VIS BELOW 5 MILES WILL OCCUR...THOUGH NO DENSE FOG
IS EXPECTED TONIGHT/EARLY SUNDAY. ABOVE THE MARINE LAYER...MOSTLY
BKN CLOUDS ABOVE FL150 WILL OCCUR THROUGH SUNDAY.
&&
.MARINE...
261700Z...A LARGE...LONG PERIOD WEST SWELL IS FORECAST TO MOVE INTO
THE COASTAL WATERS SUN THROUGH TUE DUE TO A DEEP NORTH PACIFIC STORM
THAT HAS BEEN OCCURRING THE PAST FEW DAYS. A HIGH SURF ADVISORY WILL
BE ISSUED THIS AFTERNOON FOR SUNDAY AFTERNOON THROUGH MONDAY. SURF
WILL BE ABOVE NORMAL INTO TUESDAY BUT PROBABLY BELOW HIGH SURF
ADVISORY CRITERIA.
&&
$$
PUBLIC...PG
AVIATION/MARINE...MAXWELL
