FXUS66 KSGX 261128
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
330 AM PST SAT DEC 26 2009

.SYNOPSIS...THE 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 SLOWLY MOVE THROUGH 
MONDAY AND TUESDAY. THIS WILL BRING VARIABLE CLOUDINESS WITH A 
SLIGHT CHANCE OF LIGHT SHOWERS SUNDAY NIGHT INTO TUESDAY NIGHT. 
PARTLY CLOUDY SKIES THROUGH MID WEEK IN DRIER NORTHWEST FLOW ALOFT. 

&&

.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO... 
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.

.SHORT TERM (TODAY-MONDAY)...THERE WAS PATCHY STRATUS NEAR THE COAST 
AND A FEW HIGH CLOUDS THIS MORNING. AIRCRAFT SOUNDINGS SHOWED LIGHT 
WINDS IN THE LOWER 10000 FT WITH INCREASING NW WINDS ABOVE. 
WEAKENING OFFSHORE GRADIENTS FROM THE N AND WEAK ONSHORE TO THE E. 

A SHALLOW MARINE LAYER WILL CAUSE AREAS OF LOW CLOUDS AND FOG THIS 
MORNING. THE FOG COULD BE LOCALLY DENSE ON THE HIGHER COASTAL 
TERRAIN AND FAR WRN SAN DIEGO INLAND VALLEYS. THERE WILL ALSO BE 
PATCHY FROST IN THE COLDER INLAND VALLEYS THIS MORNING. THE MARINE 
LAYER SHOULD LIFT A BIT TONIGHT AND WILL BE DISRUPTED BY HIGHER 
CLOUDS. THE HIGH CLOUDS WILL INCREASE DUE TO A TROUGH APPROACHING 
FORM THE NW. THIS TROUGH WILL WEAKEN AND PUSH THE UPPER RIDGE TO THE 
E AND THEN SPLIT 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 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. 

&&

.LONG TERM (TUESDAY-FRIDAY)...A SHORT WAVE WILL DROP INTO SRN CA  
TUESDAY ON THE W SIDE OF THE DEPARTING TROUGH. THIS WILL MAINTAIN A 
SMALL CHANCE OF LIGHT PRECIP. GENERALLY DRY NW FLOW WILL PREVAIL 
ALOFT WEDNESDAY AND THURSDAY WITH VARIABLE HIGH CLOUDINESS. WEAK 
RIDGING FRIDAY FOR FAIR WEATHER. GRADUALLY WARMER DURING THE SECOND 
HALF OF NEXT WEEK WITH MAX TEMPS REACHING NEAR SEASONAL THURSDAY AND 
FRIDAY. 

&&

.AVIATION...
261000Z...ANY AVIATION PROBLEMS EARLY THIS MORNING WILL BE DUE TO 
SHALLOW MOIST LAYER WEST OF THE MOUNTAINS. EXPECT AREAS OF 3-5SM VIS 
IN HAZE AND FOG...LOCALLY BELOW 2SM IN RADIATION FOG. AREAS OF CIGS 
1K TO 1.5K FT MSL WITH TOPS BELOW FL020 ARE POSSIBLE AS WELL AT 
TIMES THROUGH 17Z. SCT-BKN CIGS NEAR FL200 SHOULD HELP TO LIMIT 
EXTENT OF NOCTURNAL LOWER CLOUDS. OTHERWISE...VFR WITH UNRESTRICTED 
VIS THROUGH SAT. 

.MARINE...
261000Z...A LARGE...LONG PERIOD WEST SWELL IS FORECAST TO MOVE INTO 
THE COASTAL WATERS SUN THROUGH TUE. HIGH SURF ADVISORY CONDITIONS 
ARE PROBABLE SUNDAY AFTERNOON THROUGH TUESDAY.

&&

$$

PUBLIC...ATKIN 
AVIATION/MARINE...JAD