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fxus66 ksto 081216 
afdsto 


Area forecast discussion 
National Weather Service Sacramento California 
415 am PST Thursday Jan 8 2009 


Discussion... 
stratus deck covering the Sacramento Valley and surrounding 
foothills...current satellite shows low clouds beginning to fill in 
over the northern San Joaquin Valley. Cold front is 
moving into the Pacific northwest as precipitation is now being 
picked up by radar along the northern California 
coastline...Crescent City reporting rain in the past hour. Valley 
stratus could persist into late morning for the southern SAC valley 
and northern San Joaquin Valley before the front arrives. 


Best chance for precipitation is in northern California but have 
kept slight chance to chance probability of precipitation in the southern portion of our 
County Warning Area. Front should begin affecting the northern Sacramento Valley 
with light rain by 8-10 am then spread southeastward through the 
day. Models continue to indicate light accumulations. 06z Eta model BUFKIT 
is only forecasting a few hundredths in the valley. Higher 
elevations range 0.1 to 0.3 inches of rain...with just a couple of 
inches of snow accumulation above 5000 feet. Models are consistent 
in moving the front quickly into the Great Basin tonight which 
should leave lingering showers along the Sierra this evening before 
clearing out by Friday morning. 


Enhanced northerly flow will follow the frontal passage with gusts 
20 to 30 miles per hour possible in the valley on Friday. The eastern Pacific 
high will strengthen through the weekend into next week. Current 
models indicate the high pressure ridge will linger along the 
coastline and set up an easterly gradient across the County Warning Area...thus 
expect light to moderate offshore flow through midweek. The main 
forecast issue for this weekend and next week will be whether a low 
level inversion from the ridge will trap moisture and allow the 
development of valley stratus. If the ridge moves over interior 
California instead of staying along the coast...then there's a 
better chance for cooler temperatures under gray skies. For 
now...have kept a sunnier outlook for the extended forecast with 
best chances of valley stratus being limited to the San Joaquin 
Valley. Valley temperatures under the building ridge and...hopefully 
clear skies...should warm up around the low to middle 60s for the 
valley. Model guidance suggests temperatures peaking in the middle to upper 
60s but haven't pushed maximum temperatures that high until the possibility of 
valley stratus plays out this weekend. Jbb 




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Aviation... 
St in SAC valley and adjacent foothills extending northward into Shasta Colorado and 
lake Colorado...keeping visible above 1sm in valley. Much of SAC valley St is 
near IFR ceiling thres...009-012...expect LIFR at krdd. Lack of St in 
northern sj valley allowed LIFR/vlifr conds in fog. Now St is filling in 
northern sj valley...should be overcast by 14z. St top 020-025. Weak cold front moves 
through today with areas -dz/-ra with -sn mainly above 055. Exc impvg 
conds from north to S with frontal passage after 21z. Increasing northerly winds after 09/00z from north 
to S. Winds may have trouble reaching ksck...so potential for IFR in 
fog Friday. Jclapp 




&& 


Sto watches/warnings/advisories....none. 


&& 


$$