Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 121218
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
418 AM PST Thu Dec 12 2013
Temperatures are on a gradual warming trend into next week. There
is a slight chance of showers over the Coastal Range and western
Shasta County Mountains tonight/early Friday as a weak system
brushes the area. The potential for another weak system exits for
northern California next Wednesday.
.Short Term Discussion (Today through Sunday)...
Strong high pressure over the region is keeping the region clear
near normal afternoon temperatures and slightly below normal
overnight temperatures. The pattern shifts inland as a system
approaches the region later today. The system splits and northern
CA will be on the southern periphery of the upper level dynamics
tonight. Some cloud cover tonight will also help modify the
airmass over northern California and warm up the lows enough to
get rid of any hard freeze concerns. The thermal belt areas will
have lows in the 30s to mid 40s but most foothill valley locations
will only cool off into the lower 30s.
A ridge will build over the region behind that system Friday into
Sunday to keep the region dry with gradually warming afternoon
temperatures and cool nights with no significant threat of any
.Extended Discussion (Monday through Thursday)
A high pressure ridge over the west coast will keep fair skies
over the CWA Monday and Tuesday with daytime highs about 10
degrees above season normals. An upper low off the SoCal coast is
likely to spread high cloudiness over the north state at times.
Winds under the ridge will remain mainly light northerly. A trough
of low pressure dropping out of the Gulf of Alaska is forecast to
bring a little cooling on Wednesday with a slight threat of light
showers over the northern mountains. Model timing varies but
trough axis passage through NorCal generally expected Wednesday
night providing the best chance of light mountain precip.
Northerly flow behind the trough on Thursday should bring an end
to the shower threat. Breezy northerly winds will bring continued
cooler temperatures on Thursday but still a little above normal
for this time of year.
VFR next 24 hours except MVFR southern Sacramento valley and
northern San Joaquin valley in haze or light fog. Weak frontal
system will bring clouds at or above 10k ft after about 06z Friday
north of Sacramento. Winds variable generally below 15 knots.