Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 261701

901 AM PST Fri Dec 26 2014

Mainly dry weather will continue for the next few days, with
north winds and frosty overnight lows. Stronger north winds and a
few mountain showers may be possible for early/middle next week.


Northern California remains under dry northerly flow between a
strong eastern Pacific ridge and deep trough over the Rockies. An
impressive amount of subsidence is noted on WV satellite imagery,
allowing for clear skies and locally breezy north winds especially
along the western Sacramento Valley. Most locations are running a
bit cooler than 24 hours ago, though those that stayed well-mixed
with north winds are running warmer than yesterday.

High temperatures should remain fairly consistent the next few
days as we see little modification to our airmass. Look for highs
in the lower to mid 50s across the Valley through the weekend,
with 30s and 40s over the mountains. These forecast highs are
within a few degrees of normal.

Pressure gradients are forecast to relax later today and
especially tonight. The combination of lighter winds and clear
skies will allow for strong radiational cooling, and will likely
lead to the coldest temperatures of the season thus far. Look for
lows to drop down to around or slightly below freezing across the
Valley and foothills. 10s and 20s are forecast for the mountains
and colder mountain basins. A frost advisory has been issued for
Saturday morning, with tonight expected to be the first widespread
frost of the season across the Valley.



.Extended Discussion (Tuesday through Friday)

The extended forecast continues to look cool and/or breezy, with
little potential for precipitation except for light snow showers
up in the Sierra early this week.

A cold trough originates from Alaska/northwestern Canada and drops
down into northern California late Monday or Tuesday. This system
deepens and spreads westward over the area, bringing cold air into
the region. Lower level thickness values bottom out Wednesday
and/or Thursday. Breezy winds are expected on Tuesday into
Wednesday, and may reach wind advisory levels with sustained winds
of 25 mph with stronger gusts. The winds should keep the
atmosphere mixed in the Valley and limit frost and colder

By Wednesday/Thursday, the trough closes off and drops to the
south and east. Winds weaken allowing colder temperatures in the
Valley. The best chance for frost and freezing valley temperatures
will likely be Thursday/Friday mornings when winds subside,
especially on the less windy eastern side of the valley. Highs in
the mountains will remain cold through the later half of the week.



VFR conditions today. Local breezy northeast surface
wind gusts in the mountains to 30kt. Breezy/gusty north winds
return again today for the valley with clear skies.   JClapp


.STO Watches/Warnings/Advisories...
frost advisory from 4 am to 9 am pst saturday carquinez strait
and delta...central sacramento valley...northern sacramento
valley...northern san joaquin valley...southern sacramento


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