Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 242354
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
354 PM PST Sat Feb 24 2018

.SYNOPSIS...
Below normal temperatures will continue. Snow showers possible
over the mountains into this evening. Additional systems next
week will bring more widespread precipitation. The first system
with very low snow levels will move into the region Sunday night
and Monday.

&&

.DISCUSSION...
A weak system is moving into the Great Basin this afternoon and
may produce some light showers along the western slopes into the
evening hours before drying out. Another cold night is in store
for the interior although temperatures should be a little bit
warmer than this mornings lows.

The next system is looking like it will bring widespread
precipitation to Northern California Sunday night and Monday. This
system will be dropping down from the north and will have a lot
of cold air associated with it. As the system moves south late
Sunday night and Monday morning the models are indicating some
enhancement over the Motherlode. Have issued a winter storm watch
for now due to the amount of snowfall and timing of the event
likely having significant impacts on travel Monday morning over
the Motherlode and western slopes. 2 to 5 inches of snow is
expected above 2000 feet for the Motherlode with lessor amounts
possible down to around 1500 feet.

Further north have issued an advisory since the amounts are
expected to be much lighter but snow levels will drop to 1500
feet...possibly around 1000 feet over Shasta County with some snow
likely accumulating along I-5 north of Shasta Lake.

The system will taper from north to south during the day on Monday
and Monday evening for the southern forecast areas. Some
convective showers with brief heavy precipitation and small hail
may occur behind the front mainly Monday afternoon.

Breezy to locally windy conditions are expected to develop behind
the front on Monday and persist into Tuesday for the valley. The
strongest winds look like they will be over the north and west end
of the valley. Northerly winds will continue on Tuesday but wind
speeds are not expected to be as strong. Tuesday will be a day
in between systems with warmer daytime highs.
&&
.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)



The wet pattern continues through the extended period as another
winter storm is slated to impact the area. Current model runs
bring the storm in a little earlier than previous forecasts. Rain
and snow showers now forecast to impact the higher elevations and
northern counties Wednesday afternoon before spreading to the
valley overnight Wednesday. Heavy precipitation is expected
Thursday throughout the area with another wave of precipitation
moving in Friday into Saturday. Currently, this storm system is
forecast to bring substantial precipitation accumulations to the
area. Liquid precipitation amounts of 0.5 to 1.5 inches in the
valley and 1.5 to 4 inches in the foothills and mountains are
expected. Forecast snow amounts are on the order to 2 to 3 feet at
pass level with significant snowfall possible down to 3000 feet.
Strong winds are forecast with this system, especially over the
mountains, which could bring additional impacts to the mountain
passes. Details are still changing with this weather system this
far out, so stay tuned to future updates on this storm. HEC
&&

.AVIATION...


VFR conditions next 24 hours except local MVFR conditions over
the mountains due to scattered snow showers through 6z Sunday.
Winds less than 12 kts at TAF sites except for gusts up to 20 kts
from KRBL northward through 0z Sunday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 9 PM Sunday to 2 PM PST Monday for
Burney Basin / Eastern Shasta County-Northeast
Foothills/Sacramento Valley-Shasta Lake Area / Northern Shasta
County-Western Plumas County/Lassen Park.

Winter Storm Watch from late Sunday night through Monday evening
for Motherlode-West Slope Northern Sierra Nevada.

&&

$$



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