447 
fxus66 khnx 192102 
afdhnx 


Area forecast discussion 
National Weather Service San Joaquin Valley - Hanford California 
202 PM PDT Sat Jul 19 2008 


Discussion...a mostly sunny and dry afternoon across our area 
today as the result of an upper ridge over The Four Corners area. 
Temperatures have been generally running 3-5 degree f above yesterday in 
the central and south San Joaquin Valley and 1-2 degree f above yesterday 
elsewhere in our County warning forecast area. WV indicating the tropical moisture fetch 
is retrograding westward into southeastern California today. An upper low 
center near 46n/140w is prognosticated by the 12z models to track eastward 
to near the norcal coast tonight then remain quasi-stationary 
Sunday and Monday. This feature may pick up some of the monsoonal 
moisture to our southeast and spread some of it into the 
southeastern portion of our County warning forecast area as noted by middle level relative humidity forecasts. 
Convective available potential energy and Li/S will be favorable for cumulus buildups and at least 
isolated afternoon thunderstorms over the Tulare and Kern County 
mountains as well as across the Kern deserts. Another impact this 
low will have is that the marine layer will continue to build 
along the coast and with p-grads expected to strengthen Sunday 
night and Monday...a healthy push of marine air will make it/S way 
inland through the Delta and into the central and South Valley. 
This will keep winds up a bit across the valley Sunday night and 
also keep temperatures near climatology on Monday. The low is expected to 
push inland Monday night and Tuesday a trough crosses the Pacific northwest. 
This will bring a drier westerly flow across central California and push 
the monsoonal moisture well to the east of our area. The majority 
of the medium range models indicate the dry onshore flow pattern 
continuing over central California through Thursday before the south 
central Continental U.S. Ridge retrogrades westward on Friday and 
Saturday...possibly allowing for the return of monsoonal moisture 
into our area as the tropical fetch pushes westward. Since the 
models seem to be underestimating the effects of the expected 
marine intrusion on Monday night...will keep temperatures below mex 
guidance during the extended period but still slightly above 
climatology. 


&& 


Aviation...VFR conditions can be expected across the central 
California interior through 00z Monday...except a possible isolated 
thunderstorm in the Kern County desert Sunday afternoon. 


&& 


Air quality issues... 
on Sunday July 20 2008... unhealthy in Tulare County. Unhealthy 
for sensitive groups in Fresno... Kern... Kings... Madera and 
Merced counties. 
Further information is available at valleyair.Org 


&& 


Hnx watches/warnings/advisories...none. 


&& 


$$ 


Public...ds 
AVN/fw...jdb 


Weather.Gov/Hanford