Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 121150
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
350 AM PST Mon Feb 12 2018


.Synopsis...
Cooler temperatures this week. A chance of light rain/snow
showers over the mountains this morning, Wednesday and Wednesday
night and late next weekend.

&&

.Discussion...
Upper low over the Great Basin with a shortwave dropping down the
Sierra Cascade range this morning bringing a few light showers.
Snow levels remain quite low at around 3000 feet or less but
precipitation amounts are quite light so impacts should remain
minimal. Temperatures will remain cooler this week than last week
but still come in just a bit above normal for this time of year. A
few light showers will remain possible over the northern Sierra
through tonight as the upper low continues to dig southward.
Surface high pressure building over the Pacific northwest behind
the retreating low will bring a tightening northerly gradient
across norcal. This gradient combined with good upper level
support will bring breezy north winds to the north state today.
Models predict surface gradients of about 8 mb from Medford to
Sacramento. At this time expect winds for the most part to remain
below wind advisory criteria. Surface gradients and windspeeds
should max out this evening then decrease quickly overnight and
during the Tuesday morning hours. High pressure pushing in off the
Pacific will bring dry conditions and fair skies on Tuesday.
Temperatures warm as well on Tuesday to several degrees above
normal.

Another inside slider type trough will drop through the Pacific
Northwest and northeast California on Wednesday. This system will
bring increased cloud cover to most of the north state and a
chance of showers over the northern mountains and Sierra Cascade
range Wednesday afternoon and night. Daytime highs on Wednesday
will drop down to close to normal for this time of year. Another
round of breezy north winds will follow on Thursday with warmer
temperatures and clearing skies.

&&

.EXTENDED DISCUSSION (Friday THROUGH Monday)



Ridge of high pressure will rebuild across interior NorCal late
this week into Saturday as an upper level disturbance exits the
area. As a result, a gradual warming trend and dry conditions are
anticipated. Daytime temperatures will remain 5-15 degrees above
average with Valley highs reaching the mid 60s to mid 70s.

The upper level ridge will be displaced as an upper level trough
drops down from the Pacific NW Sunday into early next week.
However, forecast models are beginning to show better agreement
compared to previous forecast runs. This system could bring snow
and rain to the mountains with snow levels as low as 1500 feet.


&&

.AVIATION...


A weather system will continue to spread scattered showers across
the higher elevations of the northern Sierra Nevada today into Monday
resulting in areas of MVFR/IFR conditions. Snow levels lowering
to 025-050. Local westerly surface wind gusts 15-30 kts 18Z-08Z
today, especially across higher terrain.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$



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