Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 300439
Area Forecast Discussion
National Weather Service Sacramento CA
939 PM PDT THU SEP 29 2016
Significant cooling trend through the weekend with daytime highs
15 to 25 degrees below normal Sunday. Chance of showers and
isolated thunderstorms Sunday into Monday. Drier Tuesday into
Thursday with a warming trend.
Temperatures are running cooler this evening by 2 to 9 degrees.
The delta breeze remains moderate this evening with the marine
layer near 1200 feet along with patches of low clouds in the Bay
Area. This is helping to bring cooler air into the interior along
with the continued synoptic cooling for the trough.
The winds will continue to be moderate on Friday through the delta
and stronger throughout the interior than today. Continued cooling
will occur with temperatures for the valley only warming into the
70s during the day while the mountains will warm into the 60s to
The trough will continue to deepen on Saturday bringing some
cooling to the interior with the greatest cooling occurring in
the mountains which will have highs in the 50s and 60s.
Sunday is the day when we are expecting the front to move through
the area with rain or showers moving through from north to south
during the day. The GFS is indicating a stronger front with some
steady rain while the NAM brings a more showery pattern to the
area and less rainfall. Both models indicate post frontal chances
for thunderstorms Sunday afternoon and evening. Precipitation
amounts remain uncertain due to varying model strengths but
several inches of snow look possible near Sierra pass levels with
up to 5 or 6 inches locally for some of the higher peaks. Sunday
will not be a good day to go hiking in the higher elevations of
the Sierra Nevada.
.EXTENDED DISCUSSION (Monday THROUGH Thursday)
The upper level low quickly shifts east into the Great Basin by
Monday. Cool northerly flow aloft takes hold across the region on
Monday, but there still may be enough residual moisture for a few
showers. Overnight temperatures will likely be on the cool side
for a few nights, with 40s across the Central Valley and 20s
possible over higher terrain.
Drier weather is expected by the middle of next week as the
eastern Pacific ridge rebuilds into California. High temperatures
are expected to warm back to near normal levels, though overnight
lows may remain on the cooler side.
VFR conditions across Valley terminals the next 24 hours.
Southerly onshore wind continue across the Valley through Friday,
with local gusts up to 25 kt during the afternoon. Near the Delta
and over higher terrain...higher gusts are possible.