Area forecast discussion 
National Weather Service San Diego California 
920 PM PST Wednesday Feb 22 2012 


Synopsis... 
fair and warm weather will continue through Friday...but with a 
little lower daytime temperatures. Locally gusty offshore winds 
could develop early Friday morning...mainly in and below the passes 
and canyons in the coastal foothills. The winds will weaken by 
Friday afternoon. Cooler with breezy conditions Saturday through 
Monday with low clouds and fog returning to the coastal areas during 
the nights and mornings. 


&& 


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


High clouds continue to stream over socal this evening. The 
afternoon nkx sounding shows a dry atmosphere with northwest winds below 
and NE winds above about 5000 feet. Surface pressure gradients remain 
offshore to the north and onsgore to the east with -3 mb san-tph and +2 mb 
san-ipl. 


The upper level high pressure ridge will weaken only slightly 
Thursday and Friday and at the same time a coastal eddy will form 
over the coastal waters. This will develop some coastal clouds early 
Thursday and again early Friday...but the low clouds are unlikely to 
spread inland since the surface pressure gradients remain offshore and 
even increase Friday morning. The increasing offshore gradients will 
also produce some gusty northeast winds in the coastal foothills 
below canyons and passes. Wind gusts could approach 45 miles per hour at times 
on Friday morning. 


The overall pattern will shift from ridging to troughing over the 
western states starting Saturday as a series of three major 
shortwave troughs move through the east Pacific Ridge and establish a 
trough over the western states by next Wednesday. Lifting dynamics and 
moisture remain north of US for the entire period so we will stay 
dry...although cool and breezy at times. The first wave will move 
into the Pacific northwest and northern cal on Sat. It will bring a 
noticeable cooling trend and bring strong and gusty west winds 
mainly for the mountains and deserts. This wave moves out on 
Sunday...but we will continue in cyclonic flow aloft which will keep 
the cool air mass over US. The second wave arrives Monday with 
similar properties to the first...but less windy. Models differ with 
the timing and track...but the third wave is expected to move 
through northern cal around Wednesday. This one looks windy like the 
Saturday wave. Models seem to agree that the overall pattern shifts 
back to one dominated by an upper ridge over the east Pacific/West Coast later 
next week for warmer weather. 


&& 


Aviation... 
230415z...few-sct clouds at or above 20kft mean sea level through Thursday afternoon. 
Patchy 3-5sm visibility in br/haze near the coast and over the coastal 
waters 08z-15z. Stratus/fog with bases near 500 feet mean sea level and visibility 2sm 
or less may return to the coastal airports as early as Thursday 
evening...however confidence in timing is low. 


&& 


Sgx watches/warnings/advisories...none. 


&& 


$$ 


Public...pg 
aviation...sunset