266 
FXUS66 KSTO 101650
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
950 AM PDT Wed Oct 10 2018

.SYNOPSIS... 
Weak weather systems will bring a few light showers to the Sierra
today and Thursday. Locally breezy north to east wind today into 
Friday. Temperatures remain near normal through Friday, then 
slightly above normal this weekend.

&&

.DISCUSSION...
Interior NorCal sandwiched between high amplitude ridging in EPAC
and deep longwave troughing over U.S. Water Vapor imagery showing
short wave trough dropping into NorCal under northerly flow aloft.
Visible showing clouds associated with this wave and also a patch
of fog from around Mather, southwest to Freeport and south to
near Lockeford. This is currently restricting visibility at KMHR.
Fog should be short lived as boundary layer becomes mixed later 
this morning. Models show some light showers possible over higher
elevations of the Sierra Nevada this afternoon into evening as 
vort max digs through CWA. Light snow is possible over Sonora, 
Ebbetts, and Carson passes. Locally breezy northerly wind possible
today in Shasta county and Northern Sacramento Valley.

Additional short wave trough drops south and digs offshore 
Thursday as upper ridging builds into the PacNW. Models keep a 
threat of showers over the Sierra Nevada with light snow again 
possible over the passes, above 8000 feet. NEly flow aloft 
develops over NorCal with locally gusty north to east wind. 
Strongest wind, gusts to around 30 mph, expected northern and 
western portions of the Sacramento Valley, east slopes of Coastal 
Range, eastern foothills and favorably oriented canyons of Western
Plumas mountains and Sierra Nevada. Drying downslope flow will 
lower humidities.

Offshore trough develops into upper low Friday and digs Saturday as
upper ridging continues to build over NorCal. Locally breezy wind
persists into Friday morning then gradient weakens some. Near 
normal temperatures today into Friday, then about 3 to 5 degrees 
above normal forecast this weekend.

PCH

&&

.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)
Upper ridge over the eastern Pacific and west coast will keep the
forecast area under fair skies and dry conditions through the 
extended period. Overall, daytime highs should remain near to a 
little above normal. Upper level and surface pressure gradients 
should produce light northerly breezes through the extended period
but nothing that looks particularly strong at this time. These 
north winds will, however, keep daytime humidity values on the low
side for this time of year so fire risk will remain moderate most
areas during the extended forecast period. 


&&

.AVIATION...
Isold MVFR/IFR conds in Fog vcnty KMHR til 18z otrw mainly VFR 
conds nxt 24 hrs for Intr NorCal. Isold MVFR poss Siernev Crest in
-shra/-shsn aft 21z til 06z. Lcl Nly sfc wnd gsts to 20 kts in 
ptns of nrn and wrn Sac Vly tda.


&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$