300 
fxus66 ksgx 211031 
afdsgx 


Area forecast discussion 
National Weather Service San Diego California 
330 am PST Sat Nov 21 2009 


Synopsis...residual moisture will cause areas of low clouds and 
dense fog west of the mountains this morning and patchy coastal low 
clouds tonight. Otherwise...mostly clear. Warmer through the middle 
of next week under high pressure with weak offshore flow. 


&& 


Discussion...for southwest California including San Diego... 
Orange...southwest San Bernardino and West Riverside counties. 


Short term (today-monday)...there were patches of low clouds and 
dense fog west of the mountains this morning and variable high 
cloudiness. Early morning aircraft soundings indicated increasing 
westerly winds aloft. Onshore gradients with about 4 mb san-ipl. 


The departing upper trough will leave behind a little low level 
moisture for areas of low clouds and patchy dense fog west of the 
mountains this morning. There could also be patchy coastal low 
clouds and fog tonight and variable high cloudiness through Sunday. 
Locally windy across the mountain ridges today. Dry northwest flow with 
slowly increasing heights will develop later today and continue 
through Sunday. Cool today with maximum temperatures about 3 to 7 degrees below 
seasonal averages in most areas. Clear and warmer Monday under high 
pressure with weak offshore flow. 


&& 


Long term (tuesday-friday)...upper ridging and weak offshore flow 
will continue through middle week. This will maintain generally clear 
skies with a warming trend. Thursday should be the warmest day in 
most areas with maximum temperatures about 5 to 10 degrees above seasonal 
averages inland from the coast. There will be local gusty winds 
through and below mountain canyons and passes at times but they are 
expected to remain below advisory strength with most gusts less than 
35 miles per hour. Cooler Friday as a trough moves through to the north and onshore 
flow returns. The long period of warm dry offshore flow will 
increase the fire weather hazard Monday through Thursday. 


&& 


Aviation... 
211020z...moist layer west of the mountains will result in areas of 
IFR/MVFR visible/ceilings at times through 15z Sat. Scattered-broken ceilings will vary 
from 1.5k to 3.5k feet mean sea level overnight...with tops rising to fl050 on 
Sat. Ceiling detail and timing uncertain at various taf sites. Expect 
any areas of broken-overcast ceilings to scatter near the coast after 17z on 
Sat...but remain backed up against some coastal slopes and foothills 
through the day...locally obscuring the terrain above 3k feet. 
Widespread 1-3sm visible in fog should mix out to 5sm or more by 17z. 
Otherwise...most areas will experience VFR conditions by 18z on Sat. 
Local 25-30 knots west winds will be possible over the ridges through 
18z...resulting in some mountain waves immediately downstream 
over the desert slopes...diminishing by afternoon. 


&& 


Sgx watches/warnings/advisories...none. 


&& 


$$ 


Public...atkin 
aviation...jad