666 
fxus66 ksgx 081132 
afdsgx 


Area forecast discussion 
National Weather Service San Diego California 
330 am PST Thursday Jan 8 2009 


Synopsis... 
a weak trough of low pressure moving by to the north will bring a 
brief return of the marine layer into early Friday. For the weekend 
through early next week...high pressure off the West Coast and 
moderate offshore flow will bring much drier and warmer conditions 
with strong...gusty winds through and below passes and canyons. The 
offshore winds are expected to weaken early next week. 


&& 


Discussion...for extreme southwestern California including Orange... 
San Diego...western Riverside and southwestern San Bernardino 
counties... 


Short term (today through saturday)... 
a weak trough of low pressure moving by to the north will bring a 
brief return of the marine layer. Patchy stratus has developed along 
the coast in the form of patchy dense fog with Wednesday evening 
aircraft soundings showing the base of a shallow marine inversion 
around 500 feet. The marine layer should deepen some tonight with 
more extensive stratus for southern coastal areas. As this trough of 
low pressure moves east...surface high pressure will develop over 
the Great Basin and high pressure aloft off the West Coast will 
strengthen and expand toward the coast. This will bring warming with 
moderate to locally strong offshore winds for Friday afternoon into 
the weekend. Models have trended weaker and farther east with the 
trough to the east for the weekend. This should result in offshore 
winds not quite as strong as previous model forecasts...but still 
the low end of high wind criteria for northern areas for late Friday 
into Saturday for the windier locations below the Cajon Pass and in 
the Santa Ana Mountains and foothills. 


&& 


Long term (sunday through Wednesday... 
moderate to locally strong offshore flow will continue Sunday...then 
weaken Monday and Tuesday. Strong high pressure aloft will continue 
centered near or just off the California coast with temperatures 
well above seasonal averages for Sunday and Monday...especially west 
of the mountains. Weak onshore flow may return for Tuesday and 
Wednesday with cooling spreading inland from the coast. 


&& 


Aviation... 
081200z...very shallow marine layer early this morning but is 
expected to deepen to around 1500 feet tonight. Areas of fog should 
develop along the coast before sunrise which could bring periods of 
LIFR to coastal airports such as ksan...kcrq and ksna through 16 or 
17z. Stratus/fog should return during the evening moving over 
coastal airports between 04z and 07z then spread inland over The 
Mesas and inland valley areas after midnight. Bases should be around 
800 to 1000 feet mean sea level. 


Above the marine layer...a mostly clear sky with unrestricted 
visibilities will continue through Friday. Horton 


&& 


Sgx watches/warnings/advisories... 
California...high wind watch from Friday afternoon through Sunday afternoon 
for San Bernardino County mountains-San Bernardino and 
Riverside County valleys-the inland Empire-Santa Ana 
Mountains and foothills. 


Pz...none. 


&& 


$$ 


Public...Martin 
aviation/marine...Horton 


National Weather Service on the web at weather.Gov/sandiego