Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 170511
Area Forecast Discussion
National Weather Service Sacramento CA
911 PM PST Mon Jan 16 2017
Dry through Tuesday, then a series of winter storms will begin
Wednesday and continue into early next week.
Fog is expected to set up again starting late this evening for
the overnight hours. A similar cycle as occurred today is
expected for the overnight and Tuesday with the cleared areas
starting to see some fog during the late evening hours showing
improvement as ceilings form...most likely during the mid to late
morning hours and a little later than what occurred today. Along
the fringes of the low cloud area that will form we should see
some dense fog so have updated the forecast to include a mention
into the lower elevations of the motherlode. The height of the
ceilings should be close to 1500 ft tonight.
Tuesday night we may see some overrunning of precipitation over
the north but Wednesday is when the main part of the storm and the
first of a series of winter type storms moves into the region.
The models indicate light rain start during the morning for the
southern areas but the heavier rains will start in the afternoon
and evening. Dry air over the mountains will help to make sure
snow starts out below pass levels and stays below pass levels
during the day. Snow levels lowering Wednesday night down to
around 3500 to 4500 feet...2500 feet over Shasta County.
The system looks like a decent winter storm with the higher
totals focused over the north. Though Thursday afternoon (0.75)
to (1.25) inches of rain is expected in the central valley with up
to (2.00) inches in the north. (1.00) to (3.50) inches for the
foothills and mountains with the higher totals over Butte County
and Western Shasta County. (18.0) to (24.0) inches of snow can be
expected near major pass levels with (3.0) to (6.0) inches
between 4000 and 5000 feet.
Snow levels will remain fairly low and near the above mentioned
levels through Thursday with showers continuing through the day.
Locally lower snow levels may occur if convective showers develop
during the day.
.EXTENDED DISCUSSION (Friday THROUGH Monday)
A couple Pacific frontal systems impact interior northern
California Friday into Monday with wind, rain, and mountain snow.
The first system impacts the area with some decent precip totals
and strong wind with the potential for some snow into the upper
foothills Friday night into Saturday. Scattered showers possible
Saturday, tapering off Saturday night as weak upper ridging moves
through. Another wet Pacific system progged to impact the area
Sunday into Monday bringing more significant rain and wind along
with relatively low elevation snow.
Friday into Monday: The Shasta county mountains could see 3 to 5
feet of new snowfall above 2500 feet while the Sierra and Coastal
Range could accumulate 2 to 4 feet above 3500 to 4000 feet.
MVFR stratus and/or IFR fog is lifting this afternoon over
foothills south of I-80 and adjacent Sac/SJ Valley areas.
Widespread IFR/LIFR conditions in stratus/fog will likely
redevelop tonight into early morning over southern Sac and
northern SJ Valley with IFR and patchy LIFR northward of Sutter
Buttes. Slow erosion of stratus/fog will keep it around into mid
Tue afternoon for interior Valley. JClapp
Winter Storm Watch from Wednesday afternoon through Thursday
morning for West Slope Northern Sierra Nevada-Western Plumas