Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 272245
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
245 PM PST Thu Nov 27 2014
Mild Thanksgiving will give way to a wet Friday and weekend.
Slick roads and snow above 6000 feet may cause travel delays.
Unfortunately a lot of uncertainty remains with next storm system
arriving sometime in the Monday through Thursday time frame, periods
of wet weather are possible next week.
Warm and dry Thanksgiving day today with some mid and high clouds
with a weak ridge over the area. Temperatures will peak in the
mid to upper 60s in the valley and upper 40s to low 60s in the
mountains this afternoon, which is about 6 to 12 degrees above
normal. Friday temperatures will cool with highs in the mid 50s
to mid 60s in the Valley and 40s to mid 50s in the mountains as an
upper level trough approaches the area. Saturday will be cooler
with highs in the low to mid 50s in the Valley and 30s to mid 40s
in the mountains.
Precipitation will start moving into the Coastal range and the
Northern Sacramento Valley Friday by noon and spread southeast to
around the I-80 corridor around midnight and in the Northern San Joaquin
Valley Saturday morning as the jet and 1.3 in Precipitatable water
plume sag south. A band of precipitation may be around the I-80
corridor Saturday morning bringing wet roads and snow over the
Sierra passes for possible travel delays. Precipitation is expected to
continue into Saturday evening with some weak upward motion and moisture.
Snow levels will be around 7500 ft (near pass level in the Sierra)
Friday evening and drop down to around 5500 ft Saturday morning.
Several inches of snow are possible above 6000 ft by Saturday
evening. Rainfall amounts are expected to be around a quarter to
three quarters in the Valley and generally around an inch to an
inch and a half in the mountains by Saturday evening.
Precipitation will probably continue at least at times on Sunday
but there is more uncertainty in the amounts. There is variability
in the models with the ECMWF with the strongest wave but all have
a little lift and some moisture for a chance of precipitation.
.Extended Discussion (Monday through Thursday)
Models showing brief ridge building over NorCal Monday...have
lowered precip chances a few percent to show this trend. May need
to lower more in the future if models continue with this drier
solution. Euro and Gfs diverge on Tuesday/Wednesday with GFS
faster and wetter than Euro. Will keep a blend of the two going
with slight weighting to the wetter GFS. Roles are reversed
Thursday/Friday as Euro shows a wet system moving through
California with the GFS much drier. Needless to say much
uncertainty and low confidence exists in the extended forecast
especially with timing. Although...the pattern is shifting to a
much wetter one.
BKN-OVC high clouds today with VFR/MVFR conditions with generally
light winds expected across TAF sites on Thanksgiving. Local
MVFR/IFR conditions are possible around Sacramento and Stockton
due to BR/FG aft 10z until 18z Friday. Lowering ceilings and
precipitation possible with areas of MVFR conditions by Friday
afternoon around KRDD and KRBL.