355 
fxus66 khnx 202110 
afdhnx 


Area forecast discussion 
National Weather Service San Joaquin Valley - Hanford California 
210 PM PDT Sat Mar 20 2010 


Synopsis... 
a ridge of high pressure along with above normal temperatures and 
dry conditions will prevail through this weekend and continue 
through next week. 


&& 


Discussion...even as high clouds roll over central California... 
a ridge of high pressure will continue to dominate the region. 
Current upper air analysis continues to show the axis of the 
upper ridge over California. The clouds were being produced by a 
weather disturbance trying to ride over the ridge. Even with the 
clouds overhead...temperature across the valley were still able rise by 
several degree-f over this time on Friday. Current location of the 
upper low is near 45n/133w and shows a trajectory toward the 
Pacific northwest. Short range forecasts show the upper trough lifting 
toward western Canada as the ridge flattens slightly. Models show 
about a 60 meter drop in 500mb heights in the next 24 hours. This 
will allow for 4-6 degree-f of cooling across the district but keep 
maximum values in the 70s over the San Joaquin Valley. Winds will not 
be an issue on Sunday as surface pressure gradients from sfo to 
las remain light and under 5mb. By Monday...models show a split 
flow pattern with a cutoff low down toward the west of Baja California 
California. While the southern piece of energy will track toward 
northern Mexico...the northern piece of energy will move across as 
an inside slider. Models are having timing problems with the 
introduction of the inside slider over the southern Sierra Nevada. 
Will go with the slower NAM solution and keep a mention of precipitation 
over the mountains on Tuesday. Therefore...will still see dry and 
warm conditions on Monday ahead of the upper trough expected to 
influence the area beginning Monday night. Will not expect much 
in the way of precipitation from this inside slider...but winds may 
become an issue. Currently...the forecast is calling for a slight 
chance of precipitation over the higher terrain of the Sierra Nevada on 
Tuesday. 


By Wednesday...models begin to show the split flow merging back 
together over the Great Basin. Yet...any significant energy will 
remain east of the district with only clouds remaining over 
central California. On Thursday...models show the cutoff low and 
weak trough continuing to consolidate as it moves into The Four 
Corners area. A ridge pattern will move back over the West Coast 
at this time. After a slight drop in temperatures toward 
midweek...temperatures may rise again by the end of the period. 
Will keep the longer term dry as models show no significant 
moisture source moving into the area for the next seven days. 


&& 


Aviation... 
VFR conditions will prevail across the central California interior 
through 00z Monday...except for some local MVFR conditions in br/haze 
in the San Joaquin Valley between 06z and 20z Sunday. 


&& 


Air quality issues...none. 


&& 


Hnx watches/warnings/advisories...none. 


&& 


$$ 


Public...Molina 
AVN/fw...jeb 
synopsis...pj 


Weather.Gov/Hanford