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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Monday
• 
• High: 59 °
• Low: 49 °
• Chance of T-Storms

• Tuesday
• 
• High: 59 °
• Low: 47 °
• Chance of Rain

• Wednesday
• 
• High: 61 °
• Low: 49 °
• Chance of Rain

• Thursday
• 
• High: 65 °
• Low: 49 °
• Chance of Rain

• Friday
• 
• High: 65 °
• Low: 49 °
• Clear

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


Synopsis... 
cool and unsettled weather will continue across the region through 
Wednesday night...with showers possible...mainly west of the 
mountains. Moderate to strong and gusty west winds will also 
continue across the mountains and deserts. As the next system digs 
over the region Monday afternoon and evening...a slight chance of 
thunderstorms will also be possible as well as higher elevation 
snow. A gradual warming and drying trend will occur later this 
week...but another system will approach the region late Saturday and 
Sunday. 


&& 


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


Water vapor imagery will continue to show the next trough of low 
pressure moving inside of 130 west this afternoon...which will dig 
across California on Monday. In the meantime...composite radar 
imagery still shows some light showers over the San Diego area...and 
this threat will continue through the night at the marine layer 
moves back in across the region. However...expect widespread 
showers to develop across the region tomorrow during the day...as 
this next system approaches the region. This will be a much colder 
system...with 850 mbs temperatures falling to between 0 and 2 
degrees c by Monday afternoon and well below zero by Monday night. 
The 700 mbs temperatures also fall to between -8 and -11 degrees c 
by Monday night...which suggest that snow levels will likely fall 
below 4000 feet during the overnight hours...and may be locally 
lower with the heavier showers. There is also enough instability 
with this system...that a slight chance of thunderstorms will be 
possible Monday afternoon and evening. 


The real question with this next system will be with the 
precipitation amounts? At this time...most of the models continues 
to show a relatively shallow moisture layer...with precipitable 
water values falling from a peak of 0.8 inches Monday morning to 
around 0.4 inches or less by Monday afternoon. Therefore...the 
marine layer will once again be the likely moisture source...and 
that precipitation amounts will once again be on the light side. 
However...given the instability...it is probable that some moderate 
or heavier showers will develop. The 06 and 12z local WRF show this 
happening...especially along the coastal slopes...where amounts may 
be upwards to a half inch. If this happens...some of the mountain 
areas could see a decent amount of new snow fall. Therefore...have 
issued a Winter Weather Advisory for the San Bernardino Mountains. 
The Riverside County mountains will also see some snow...and may 
need to consider an advisory for this area later. 


The other concern with this system will be with the winds in the 
mountains and deserts. At this time...it appears that the onshore 
gradients will be tighter tomorrow...with upper level wind support 
at 850 mbs increasing to between 35 and 55 knots. The 700 mbs winds 
support is even stronger...ranging between 50 and 60 knots. 
Therefore...upgraded the high winds watches to High Wind Warning for 
the Riverside and San Diego mountains and deserts. The upper level 
support does not look as strong over the San Bernardino 
Mountains...and given the more westerly trajectory...have decided to 
issue a wind advisories for the northern mountains and deserts. 


Although showers will linger across the area on Tuesday...drier 
conditions will develop by Tuesday night. Models are continues to 
struggle with the next upper level low for the Wednesday or Thursday 
time frame. At this time...the 12z GFS seems to be the most 
consistence over the past few runs...tracking the system down the 
California coast and bringing more precipitation to the region on 
Wednesday and Wednesday night. However...it is still the most 
westward of the models. Although the 00z European model (ecmwf) took a more inside 
track...dropping the low across the intermountain west Wednesday and 
into the Desert Southwest Wednesday night. Although it still a more 
inside track...the 12z run once again brought the system back over 
Southern California. The 12z UKMET also has splits the difference 
between these tracks. Therefore...have once again added probability of precipitation back 
into the forecast for Wednesday and Wednesday night. 


The extended models then gradually warm and dry things out for the 
remainder of the work week...but are now hinting that another trough 
will dig over the region for late Saturday and into Sunday. 


&& 


Aviation... 
122130z...west of mts...sct-bkn low clouds with bases varying from 
2000 to 4000 feet mean sea level and tops to 7000 feet. Clouds and fog will 
continue over the foothills and along the coastal slopes through 
tonight...reducing visible to 1sm or less locally and obscuring higher 
terrain. After 03z expect increasing coverage over the valleys and 
coastal areas with broken-overcast ceilings and bases between 2000 and 3000 feet 
mean sea level. Partial clearing from the coast inland Monday morning after 
18z...with clouds and fog lingering over the coastal slopes into 
the afternoon. 


Mts and deserts...westerly winds over the ridges around 20kt and 
gusty with associated uddfs...low level wind shear and mountain waves downwind over the 
deserts. 


&& 


Marine... 
another storm system moving south through California will increase winds 
over the coastal waters again on 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 10 feet. A gale watch has 
been issued for Monday afternoon through Tuesday morning. 


The surf will decease slightly into Monday...then increase again on 
Tuesday when a large short-period swell moves through the coastal waters. 


&& 


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 watch from Monday afternoon through Tuesday morning for the 
waters from San Mateo Point to the Mexican border extending 
30 to 60 nm out including San Clemente Island. 


Gale watch from Monday afternoon through Tuesday morning for the 
coastal waters from San Mateo Point to the Mexican border 
and out 30 nm. 


&& 


$$ 


Public...Palmer 
aviation/marine...pg