023 
fxus66 khnx 211728 
afdhnx 


Area forecast discussion 
National Weather Service San Joaquin Valley - Hanford California 
928 am PST Sat Nov 21 2009 


Synopsis...expect cooler temperatures today in the wake of the cold 
front that passed through the area. High pressure will return with 
dry conditions and gradually warming temperatures through the end of 
the week. 


&& 


Discussion... 


Typical upslope clouds banked along the north and west facing 
slopes of the Tehachapi Mountains this morning with some light 
precipitation expected as the trough moves through today. Current forecast 
looks on track as some clouds are expected to develop across the 
Sierra crest today. Fog is expected to develop in the valley 
tonight. Temperatures will be below normal today and tonight. 


Previous discussion... /issued 257 am PST Sat Nov 21 2009/ 


Discussion...initial frontal boundary has pushed well into Kern 
County and a expected the precipitation was rather light. Radar 
does continue to show some northward bound echoes from Fresno 
north into Yosemite and this scenario is most likely caused by a 
secondary shortwave trough now pushing rapidly across northern 
California. In the very fast flow across northern California, 
forecast models race yet another short wave across the north state 
tonight however this feature should pass well to the north of the 
Hanford forecast area. For the next several hours the isolated 
rain and snow showers over the east San Joaquin Valley and the 
Sierra will continue and then decline by sunrise. Meanwhile, over 
Kern County the upslope flow will wring out some precipitation 
along the Tehachapi and Grapevine area mountains. Beginning later 
Sunday a ridge of high pressure is projected by all models to 
build over California and this will quite effectively push the 
storm track well north into the Pacific northwest. Through 
Wednesday good agreement remains between the GFS and European model (ecmwf) models 
in keeping the ridge in place however on Thanksgiving, the European model (ecmwf) 
breaks down the ridge and drives a shortwave trough into northern 
California while the GFS keeps the strong anticyclone in place. For 
central California it will be dry either way into the weekend. At 
this point I don't see any travel problems for the big 
Thanksgiving travel period outside of morning fog in the San 
Joaquin Valley. Will need to watch just if and how widespread the 
fog might get under a ridge in late November. 


&& 


Aviation... 
low clouds are very slowly eroding across the Tehachapi Mountains 
and adjacent foothills. Mountain wave clouds evident on visb Sat 
this morning on the southeastern side of the tehachapis. Low clouds 
also slow to erode across the southern extent of the Sierra. Some 
rain/snow showers also possible in the upslope sections of the 
southern Sierra and tehachapis through 22z this afternoon. These 
clouds should scatter out this afternoon but will be slowest in the 
tehachapis. Gusty winds to affect the taf sites this afternoon...with 
g20kts or so likely. Valley fog likely at the terminals tonight with 
LIFR predicted at only kvis for now and IFR to MVFR at the other 
sites. 


&& 


Air quality issues... 
none 


&& 


Hnx watches/warnings/advisories... 
none. 


&& 


$$ 


Public...jdb 
AVN/fw...Brotherton 


Weather.Gov/Hanford