Weather

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afdhnx 


Area forecast discussion 
National Weather Service San Joaquin Valley - Hanford California 
905 PM PDT Wednesday Aug 27 2008 


Update...skies remain clear this evening as a ridge continues to 
build over the west. Maximum temperatures saw a 3-5 degree-f rise today 
from that of Tuesday afternoon...with a forecast rise of an 
addition 2-4 degree-f expected on Thursday. Model forecast the ridge axis 
over the West Coast by Thursday evening with temperatures peaking 
on Friday. Forecast on track with current thinking so no updates 
needed on temperatures elements. While the atmosphere becomes 
slightly unstable on Thursday...the lack of middle level moisture 
will maintain dry conditions during the afternoon hours over the 
high country. Will maintain the possibility of precipitation over the 
mountains on Friday as moisture surges up from the Desert 
Southwest on Friday. Forecast on track with weather elements as 
well so therefore...will make no updates to the forecast this 
evening. 


Previous discussion...ridge continues to build over central California with 
temperatures warming 2-5 degrees most places and some locations up 
as much as 7-9 degrees above yesterday at this time. As heights 
continue to rise Thursday and 850mb temperatures rise another 2c. 
Thus will see a few more degrees warming all areas Thursday and 
will remain well above normal Friday. Do not expect any records 
and conditions are dry enough to keep the heat index below the air 
temperatures. Monsoonal moisture will have a hard time working its 
way north into the Sierra. GFS indicates that 500mb winds will 
turn a little more south-southeasterly Friday which could let a 
little moisture begin to work its way northward. Have left the 
slight chance probability of precipitation in the mountains and desert for Friday and 
Saturday...with the best chance looking like Saturday. 


An upper trough is forecast to move out of the Gulf of Alaska 
Saturday and begin lowering heights across central California. However 
do not see much cooling Saturday in the pre-trough environment and 
little if any increase in the onshore surface gradients. Big 
change in temperatures will occur Sunday as the upper trough moves 
inland and 500mb heights lower some 100 meters from Friday 
afternoon over central California...and 850mb temperatures drop 5-7 degrees/c from 
Saturday to Sunday. This should result in Sunday maximum temperatures 10 degrees 
or so lower than Saturday. As the trough moves in...moisture will 
be pushed eastward...ending any threat of thunderstorms in the 
Sierra. The trough shifts eastward Monday but another weaker trough 
moves across the pacnw/northern California Tuesday. Even with the second trough 
heights and 850mb temperatures rebound slightly allowing 
temperatures to warm just a few degrees for middle of next week. 


&& 


Aviation...VFR conditions will prevail across the central 
California interior through 00z Friday. 




&& 


Air quality issues...on Thursday August 28 2008... 
unhealthy in Fresno...Kern and Tulare counties. Unhealthy for 
sensitive groups in Kings...Madera and Merced counties. Further 
information is available at valleyair.Org 


&& 


Hnx watches/warnings/advisories...none. 


&& 


$$ 


Public...Molina 
AVN/fw...Dudley 


Weather.Gov/Hanford