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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Monday
• 
• High: 65 °
• Low: 47 °
• Chance of T-Storms

• Tuesday
• 
• High: 61 °
• Low: 43 °
• Partly Cloudy

• Wednesday
• 
• High: 63 °
• Low: 43 °
• Partly Cloudy

• Thursday
• 
• High: 68 °
• Low: 47 °
• Partly Cloudy

• Friday
• 
• High: 70 °
• Low: 47 °
• Clear

Area forecast discussion 
National Weather Service San Diego California 
925 PM PST sun Feb 12 2012 


Synopsis... 
wintry weather returns to Southern California this week. A storm on 
Monday will bring cool...windy weather with scattered showers and a 
chance for thunderstorms through Tuesday morning. A second system 
will bring a chance for more showers Wednesday and Wednesday night. 
A gradual warming and drying trend will occur later this week...but 
another cold storm may affect the region Sunday. 


&& 


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


Water vapor imagery shows the next trough of low pressure off the 
norcal coast this evening...barreling southward toward the Bay area 
where the rain has already begun. A narrow band of high precipitable 
water of >0.80" ahead of this trough will shift south overnight and 
take aim at Southern California tomorrow. This middle level moisture 
feed together with the saturated low levels already in place over 
socal will give most areas a good shot at precipitation tomorrow. 
Rain will start off light...with heavier showers during the 
afternoon and evening as the atmosphere destabilizes. 


The cold core upper low tracks down the California interior Monday 
night to near Las Vegas Tuesday morning. 500 mb temperatures begin to fall 
Monday afternoon and slide all the way down to -26 over socal Monday 
night...with cold air instability showers and isolated thunderstorms 
continuing into Monday night. This cold storm will lower snow levels 
to 5000-5500 feet in the San Bernardino Mountains tomorrow afternoon 
where a Winter Weather Advisory is in effect. Snow will also fall 
over the Riverside and San Diego County mountains with highest 
totals over the Riverside County mountains. As the cold core spreads 
south Monday night the snow levels will fall to 4000-4500 feet. 


The other concern with this system will be the strong winds. A 75 knots 
500 mb jet core tracks directly over socal Monday evening...with 50 
knots winds at 700 mb (10kft). Winds will be strongest over the 
mountains...deserts and over the coastal waters. High Wind Warning 
and advisories are posted for the mountains and deserts...and gale 
warnings will go in effect Monday afternoon over the coastal waters. 


The trough starts moving east Tuesday...but it will still be a cold 
day with showers tapering off in the morning. Without any strong low 
level dry air intrusion behind the front residual showers may linger 
over some of the mountain ranges into the afternoon. 


On Wednesday...the GFS and European model (ecmwf) are in good agreement with the next 
cold upper trough sweeping across socal during the day. The nam12 is 
a surprising outlier. It tracks the storm over Utah as an inside 
slider...a 500 mile departure from the preferred GFS/ec solutions. 
This trough is slated to arrive Wednesday and bring another round of 
rain...wind...cold and mountain snow through Wednesday night. 


We get a brief break in the weather Thursday and Friday with high 
pressure bringing dry...warmer weather and offshore flow. But 
the long range models show the potential for a third winter storm 
next Sunday or Monday. 


&& 


Aviation... 
130400z...west of mts...sct-bkn low clouds with bases varying from 
2000 to 4000 feet mean sea level and tops to 7000 feet. Cloud coverage will 
continue to increase and fill in over the valleys and coastal areas 
through early Monday morning with broken-overcast ceilings and bases between 2000 
and 3000 feet mean sea level. Clouds and fog over the foothills and along the 
coastal slopes will reduce visible to 1sm or less locally and obscure 
higher terrain. Not much clearing expected Monday morning...but 
bases will rise as the frontal system approaches by early afternoon. 


Mts and deserts...westerly winds 20 to 30 knots with higher gusts over 
the ridges with associated uddfs...low level wind shear and mountain waves downwind over the 
deserts. Scattered middle-level clouds as the system moves through Monday PM. 


&& 


Marine... 
another storm system moving south through California will increase winds 
over the coastal waters again Monday afternoon. West to northwest winds 
of 20 to 30 knots with gusts to 40 knots are possible in the 
bight...along with combined seas building to 7 to 12 feet. The gale 
watch has been upgraded to a Gale Warning for Monday afternoon through 
Tuesday morning for both the inner an outer waters. 


The surf will decease slightly through Monday afternoon...then increase 
again Monday night when a large short-period swell moves through the 
coastal waters. A high surf advisory will likely be needed for San 
Diego County Monday night through Tuesday. 


&& 


Sgx watches/warnings/advisories... 
California...High Wind Warning from noon Monday to 3 am PST Tuesday for the 
Coachella Valley...Riverside County mountains...San Diego 
County deserts...San Diego County mountains. 


Wind Advisory until noon PST Monday for the Coachella Valley... 
Riverside County mountains...San Diego County deserts...San 
Diego County mountains. 


Wind Advisory from noon Monday to 3 am PST Tuesday for the apple 
and Lucerne valleys...San Bernardino County mountains. 


Winter Weather Advisory from noon to 10 PM PST Monday above 5000 
feet for the San Bernardino County mountains. 


Pz...Gale Warning from 4 PM Monday through 10 am Tuesday for the 
inner and outer coastal waters. 


&& 


$$ 


Public...moede 
aviation/marine...ts