LAXAFDSGX (05/14/13 0426)

FXUS66 KSGX 141129
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
400 AM PDT TUE MAY 14 2013

.SYNOPSIS...
A COMPACT LOW PRESSURE SYSTEM WILL MOVE INLAND THROUGH CENTRAL 
CALIFORNIA TODAY WITH A SECOND TROUGH OF LOW PRESSURE MOVING INLAND 
ALONG THE WEST COAST THURSDAY AND FRIDAY. THIS WILL BRING COOLING 
THROUGH FRIDAY WITH NIGHT AND MORNING COASTAL LOW CLOUDS AND FOG 
RETURNING AND EXTENDING INTO THE FAR INLAND VALLEYS FOR THURSDAY AND 
FRIDAY. HIGH PRESSURE OFF THE SOUTHERN CALIFORNIA COAST WILL BRING A 
WARMING TREND FOR NEXT SUNDAY AND MONDAY.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

.SHORT TERM (TODAY THROUGH THURSDAY)...
A COMPACT LOW PRESSURE SYSTEM OFF THE CENTRAL CALIFORNIA COAST WILL 
MOVE INLAND THROUGH CENTRAL CALIFORNIA TODAY. A SECOND LARGER 
TROUGH OF LOW PRESSURE WILL MOVE INLAND ALONG THE WEST COAST 
THURSDAY AND FRIDAY.

SURFACE OBSERVATIONS SHOW THE MARINE INFLUENCE HAS RETURNED NEAR THE 
SAN DIEGO COUNTY COAST BENEATH A STRONG SHALLOW MARINE INVERSION. 
HIGHER RESOLUTION MODELS CONTINUE TO SHOW STRATUS DEVELOPING ALONG 
THE SAN DIEGO COUNTY COASTAL STRIP BY SUNRISE AND PERSISTING FOR A 
FEW HOURS. THE DENSE FOG ADVISORY ISSUED FOR THE SAN DIEGO COUNTY 
COAST FOR 4 AM THROUGH 9 AM WAS DONE ON THE BASIS THAT THIS WILL 
OCCUR EVEN THOUGH SATELLITE IMAGERY STILL SHOWS NO STRATUS NEAR THE 
SAN DIEGO COUNTY COAST. 

THE RETURN OF STRONGER ONSHORE FLOW WILL BRING COOLING FOR MOST 
AREAS TODAY WITH GREATEST COOLING WEST OF THE MOUNTAINS. THE 
STRONGER ONSHORE FLOW WILL ALSO BRING GUSTY SOUTHWEST TO WEST WINDS 
TO AROUND 45 MPH FOR THE MOUNTAINS AND DESERTS FOR LATE THIS 
AFTERNOON THROUGH LATE TONIGHT. 

THE LARGER AREA OF STRATUS BEYOND THE OFFSHORE ISLANDS WILL SPREAD 
INLAND THIS EVENING AND PUSH INTO PORTIONS OF THE INLAND VALLEYS BY 
WEDNESDAY MORNING. STRATUS WILL EXTEND INTO THE FAR INLAND VALLEYS 
BY THURSDAY MORNING.

COOLING WILL CONTINUE FOR WEDNESDAY AND THURSDAY WITH THURSDAY HIGH 
TEMPERATURES 15 TO 20 DEGREES COOLER THAN MONDAY FOR MOST AREAS... 
EXCEPT AROUND 10 DEGREES COOLER FOR THE LOWER DESERTS.

&&

.LONG TERM (FRIDAY THROUGH SUNDAY)...
THE TROUGH OF LOW PRESSURE MOVING INLAND ALONG THE WEST COAST WILL 
BRING COOLEST TEMPERATURES FRIDAY WITH SLIGHT WARMING FOR SATURDAY 
WITH NIGHT AND MORNING COASTAL LOW CLOUDS AND FOG EXTENDING ON THE 
LOWER COASTAL SLOPES. WARMING FOR SUNDAY AND MONDAY WITH A SHALLOWER 
MARINE LAYER WITH HIGH PRESSURE OFF THE SOUTHERN CALIFORNIA COAST.

&&

.AVIATION...
140900Z...CLEAR AND VFR CONDITIONS WILL CONTINUE TODAY AND TONIGHT 
EXCEPT AT THE COAST. PATCHY FOG WILL REDEVELOP ALONG THE COAST EARLY 
THIS MORNING WITH MEDIUM CONFIDENCE THAT IT WILL IMPACT COASTAL 
AIRPORTS BETWEEN 12-15Z...MOST LIKELY AT KSAN. CIGS WILL BE 100-400 
FEET ASL WITH VIS AOB 3SM AND POSSIBLE LIFR CONDITIONS DURING THAT 
TIME. LOW CLOUDS NOT AS LOW WILL RETURN THIS EVENING BETWEEN 01-05Z 
AT COASTAL AIRPORTS WITH CIGS AROUND 1000-1200 FEET ASL AND MOVE 
INTO KONT AFTER 08Z. POCKETS OF STRONG AND GUSTY WESTERLY WINDS ARE 
EXPECTED THIS AFTERNOON AND TONIGHT THROUGH MOUNTAIN PASSES INTO 
ADJACENT DESERTS...POSSIBLY CREATING LLWS IN VCNTY OF KPSP.

&&

.FIRE WEATHER...
CONTINUED HOT AND DRY FOR THE MOUNTAINS AND DESERTS TODAY BUT WITH A 
COOLING AND SLIGHT MOISTENING TREND. LOWEST HUMIDITIES OF 10 TO 15 
PERCENT ON THE DESERT MOUNTAIN SLOPES AND 5 TO 10 PERCENT IN THE 
DESERTS. STRONG GUSTY SOUTHWEST TO WEST WINDS WITH GUSTS TO AROUND 
45 MPH FOR THE MOUNTAINS AND DESERTS FOR LATE THIS AFTERNOON THROUGH 
LATE TONIGHT. THIS WILL CAUSE LOCALLY HAZARDOUS FIRE WEATHER 
CONDITIONS FOR LATE THIS AFTERNOON THROUGH LATE THIS EVENING... 
MAINLY ALONG DESERT MOUNTAIN SLOPES. A TROUGH OF LOW PRESSURE NEAR 
THE WEST COAST WITH STRONGER ONSHORE FLOW WITH BRING GREATER COOLING 
AND HIGHER HUMIDITIES FOR WEDNESDAY THROUGH SATURDAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT WEDNESDAY    
     FOR THE APPLE AND LUCERNE VALLEYS...COACHELLA VALLEY...         
     RIVERSIDE COUNTY MOUNTAINS...SAN BERNARDINO COUNTY              
     MOUNTAINS...SAN DIEGO COUNTY DESERTS...SAN DIEGO COUNTY         
     MOUNTAINS.

     DENSE FOG ADVISORY UNTIL 9 AM PDT THIS MORNING FOR THE SAN      
     DIEGO COUNTY COASTAL AREAS.

PZ...NONE.

&&



PUBLIC...17
AVIATION/MARINE...MM