Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 222108
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
208 PM PDT Fri Mar 22 2024

.Synopsis...
Periods of widespread rain, heavy mountain snow, breezy winds,
and cooler weather return through the weekend with the current
storm system. Additional impactful storms will be possible next
week.

&&

.Discussion...
Current GOES-West satellite imagery shows a band of moisture
associated with the current storm system draped across much of
West Coast. KBBX and KDAX have been flipped over into
precipitation mode as showers are spreading inland across interior
NorCal this afternoon.

This storm system will bring heavy snow to the mountains through
Sunday. The National Blend of Models (NBM) suggests a 50 to 90
percent probability of 12 inches of snow or greater through
Sunday, mainly above 5000 feet. Snow levels will be high
initially, around 6000 to 7000 feet, lowering to around 3500 to
4500 feet tonight and continuing through the weekend. Heaviest
snow rates are expected this evening through tonight with rates
of 1 to 3 inches of snow per hour. The Winter Storm Warning
remains in effect for western Plumas/Lassen Park area and the
northern Sierra, and now includes elevations above 4000 ft as snow
levels have lowered slightly. A Winter Weather Advisory has also
been issued for portions of the north Coast Range and Shasta
County Mountains above 4000 ft from this evening through Saturday
night.

Widespread rain will also return with this system. Expect storm
total amounts of 0.50"-1" in the Valley and 1"-3" in the foothills
and mountains from this afternoon through Sunday. People should
plan for slick roads this weekend. Locally heavier rain amounts
can be expected with any thunderstorms that develop. The NBM
projects a 25 to 40 percent probability of thunderstorm
development today and Saturday, with the best chances in the
afternoon and evening hours. With any thunderstorms that develop,
brief heavy rain, small hail, gusty winds, lightning and even
brief funnel clouds will be possible.

Periods of gusty southerly winds are expected today through
Saturday. Strongest winds will be in the northern/central
Sacramento Valley, adjacent foothills and in the mountains where
the NBM has generally a 45 to 85 percent probability of wind
gusts greater than 40 mph. Gusty winds may cause loose objects to
blow around, difficult driving conditions for high profile
vehicle, and downed branches.

Drier conditions return Sunday afternoon through early next week,
with the exception of light mountain and foothill showers on
Monday. Little to no impacts are expected with these showers. Be
sure to check the weather forecast and current road conditions
before heading out the door this weekend, especially for those
with mountain travel plans! //KH

&&

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
Drier weather on tap Tuesday into early Wednesday as upper level
ridging moves through. Cluster Analysis indicates some
discrepancies in the timing for the next impactful weather, which
should impact us sometime Wed-Thu. This system looks to bring
another round of widespread rain, mountain snow and breezy winds,
all of which appear to be of similar magnitude to this weekend`s
system with similar snow levels. Another impactful weather system
is expected on it`s heels, but timing/details are still very much
uncertain with that one which is progged to impact us next
weekend.

//Peters

&&

.AVIATION...
Periods of MVFR/IFR conditions, with lcl LIFR over mountains,
spreading eastward across interior NorCal after through this
evening. In northern Sacramento Valley, winds 15-25 kts with gusts
around 25-30 knots through 23-00Z today, with gusts less than 25
knots for the rest of the Valley and TAF sites. In mountains,
areas of south to southwest wind gusts up to 40 kts. Snow levels
initially above 6500 feet today, lowering 3500 to 4500 feet
tonight/Saturday morning behind cold front. Isolated thunderstorms
possible after 00Z this evening associated ahead of or along
frontal boundary today. Gusty winds to around 25-30 knots with
additional isolated to scattered thunderstorms Saturday afternoon
as well.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 11 PM this evening to 5 AM PDT
Sunday for Mountains Southwestern Shasta County to Western
Colusa County-Shasta Lake Area / Northern Shasta County.

Winter Storm Warning until 5 AM PDT Sunday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

$$


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