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fxus66 ksto 202155 
afdsto 


Area forecast discussion 
National Weather Service Sacramento California 
300 PM PDT Sat Mar 20 2010 


Discussion... 
made a few tweaks to previous forecast but not much. Biggest 
challenge of the forecast is the next system moving across the area 
late tonight through Sunday evening. Impacts from this system will 
be very minimal as energy is not that impressive and system not too 
cold for low snow level concerns. 


Tonight...forecast area will remain to be dry but will be fair 
amount of clouds around as middle/upper flow remains from the southwest 
ahead of next storm system. This will result in a mild night. 


Sunday...base of upper trough swings through northern California and 
should be some light moisture across northern zones. Have raised 
probability of precipitation into likely category in northern quarter of forecast area. 
Temperatures will cool closer to normal for this time of the year. 


Sunday night into Monday....some energy does push across the area 
particularly on Monday on backside of the upper trough. Airmass 
looks to be pretty dry and stable during this time and the main 
effect of this energy looks to be some localized breezy 
conditions...but will keep the area dry. 


Tuesday and Wednesday...ridging builds back into the area for 
warming and drying. Rasch 


Extended discussion (wednesday through saturday)...upper ridge 
shifts east Wednesday allowing a Pacific front and associated upper 
trough to move across late Wednesday into Thursday. GFS/Gem trending 
wetter but precipitation amounts look light and mainly north of I-80. 
Another weaker short wave prognosticated to move across mainly the north 
some time between late Thursday into Friday morning bringing a 
slight chance of showers over the northern mountains. Short wave 
ridging follows Friday into Saturday. Oper GFS trending faster with 
next frontal system while preferred Gem/European model (ecmwf) hi-res keeping 
interior norcal dry through Saturday. 




&& 


Aviation... 
upper ridge of high pressure will shift eastward tonight and 
tomorrow as a trough approaches the Pacific northwest. South of 
kcic...VFR conditions are expected the next 24 hours with possibly 
some MVFR br towards the northern San Joaquin Valley overnight. 
North of kcic...MVFR/IFR showers will be possible particularly along 
the northern interior mountains from around 18z-06z Sunday. Some 
showers may make it to the krdd/krbl taf sites but should remain 
light. Winds will remain generally light onshore...though local 
southwesterly gusts up to 35kt will be possible towards the Sierra 
crest Sunday. 


&& 


Sto watches/warnings/advisories...none. 


&& 


$$