274 
fxus66 khnx 061621 
afdhnx 


Area forecast discussion 
National Weather Service San Joaquin Valley - Hanford California 
921 am PDT Sat Sep 6 2008 


Update... 
offshore pattern continues to provide clear and dry conditions this 
morning. Smoke from a fire in Sierra Forest has been infiltrating 
into the valley overnight and will likely result in hazy 
conditions today. Profilers show 1-2c degrees warming at lower 
levels with soundings indicating 1-3c degrees warmer from 3kft- 
10kft. 12z vandenberg sounding indicates stronger easterly flow 
with lighter flow towards Oak. This should provide drier conditions 
towards the tehachapis and warmer temperatures region wide. Do not 
plan on a morning update. 


&& 


Discussion...unlike the East Coast, the weather over central 
California is about as tranquil as it gets. Very high amplitude 
east Pacific Ridge continues to dominate the pattern and the hot 
weather will continue through the weekend. Water vapor imagery 
shows a little residual middle level moisture over the area however 
any convection over the Sierra will be squashed by the subsidence 
under the ridge. As for temperatures, today will be as hot as 
Friday and in many locations another 1-2 degrees of warming will 
occur. On Sunday conditions will show change as the hot airmass 
will remain in place. Forecast models do begin to show some change 
in the pattern as a shortwave trough is prognosticated to drop southward 
into northern California and then "wash out" over central 
California Sunday night and Monday. The main affect of this 
feature will be to lower heights and allow for some cooling. The 
extent of the cooling is questionable however as although the 
models keep a weak 500 mb low over the area Monday and Tuesday the 
mean east Pacific Ridge will linger off the west. All in all 
continued quiet weather to continue through Wednesday. By Thursday 
and Friday the European model (ecmwf) model develops a Rex block pattern with the 
associated high over northern California and the low located about 
500 miles west of Point Conception. This pattern would be 
favorable for a southerly flow and possible subtropical moisture 
entrainment into the region...if any is available. For now will 
add some additionally clouds to the Sierra and Kern Mountains however 
will keep the probability of precipitation out of the forecast for now. This could change 
if further model solutions back up a tropical surge situation. 






&& 


Aviation...VFR conditions will prevail across the central California 
interior through 18z Sunday. 




&& 


Air quality issues... 
on Saturday September 6 2008... unhealthy for sensitive groups in 
Fresno... Kern... Kings... Madera... Merced and Tulare counties. 
Further information is available at valleyair.Org 


&& 


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


$$ 


Public...mv 
AVN/fw...jeb 


Weather.Gov/Hanford