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Area forecast discussion 
National Weather Service San Joaquin Valley - Hanford California 
821 PM PDT Monday Oct 6 2008 


Update... 
clear conditions across the region this evening. Little in the way 
of clouds development this afternoon over the mountains. 24 hour 
temperature trends running a few degrees warmer as 500mb heights 
rise due to an upper ridge offshore. Gradients remain weak 
offshore resulting in much lighter winds this evening. Expect 
warmer overnight lows in the valley. However mountain locals may 
be bit more difficult. Less cloud cover...drier dew points...and 
light winds will provide for better radiational cooling conditions. 
Thus some mountain locales will be cooler tonight from south of 
Kings Canyon to the High Desert. Do not plan on any updates. 


&& 


Previous discussion...flat upper ridge will continue to build into 
California Tuesday with a warming trend and clear skies. Further warming is 
slated for Wednesday as 850 mb temperatures inch up another couple of degrees/c 
though thickness and 500 mb height forecasts level out. Changes in the 
Pacific and western U.S. Take hold Thursday as a longwave ridge 
builds into the Gulf of Alaska...in-turn sending shorwave trough energy 
digging south into the west. This is where models begin to show 
considerable uncertainty...which continues into Sat. The 
operational GFS is an outlier in that it takes energy into The 
Rockies and digs it south toward the 4-corners Sat. The Euro on 
the other hand...digs energy directly south across California Friday 
afternoon before moving toward the central rockies. Just by their 
nature...sliders typically tend to be farther west and thus the 
forecast has been sided more toward the Euro. This means significantly 
cooler by Sat...if not Friday as well. While various model outputs 
for temperatures were used in creating grids...the GFS mex MOS was 
completely ignored as unrealistic. But forecast temperatures may still be too 
high if the Euro is completely right. While sliders are typically 
dry across central California...there is enough cold advection and low- 
level upslope forcing (on the east slopes) in the southern Sierra to 
have a few snow showers along the crest Friday afternoon into Sat. 
Little if any accumulations will occur. 


The pattern is expected to be progressive...with some form of 
ridging building back into the west by the first of the week. 
Began a warming trend sun which accelerates Monday with mainly clear 
skies. 


&& 


Aviation...VFR conditions will prevail across the central California 
interior through 06z Wednesday. 




&& 


Air quality issues... 
none 


&& 


Hnx watches/warnings/advisories... 
none. 
&& 


$$ 


Public...mv 
AVN/fw...Dudley 


Weather.Gov/Hanford