Blizzard and Winter Storm in California, February 29, 2024

Area Forecast Discussion
National Weather Service Sacramento CA
300 AM PST Thu Feb 29 2024

.Synopsis...
Active pattern returns tomorrow into next weekend bringing
widespread precipitation, extremely heavy mountain snow with
blizzard conditions, strong winds, and low elevation (1500-3000)
snow accumulations.

&&

.Discussion...today through Saturday.

Key points of late week-weekend storm:

* Extremely heavy snow with BLIZZARD CONDITIONS expected in the
  Sierra, heaviest this afternoon through Saturday. Storm total
  snowfall into early Sunday is currently projected at 5 to 10+
  feet for elevations above 5,000 feet, locally higher amounts of
  12+ feet are possible at peaks, with significant disruptions to
  daily life likely.

* Mountain travel will be extremely dangerous to impossible,
  especially this afternoon through Saturday.

* Significant snow accumulations are expected above 3000 feet.
  Cold air will drop snow levels down to 1000-2000 by the
  weekend, with light accumulations possible at those levels.

* Wind gusts to 55 to 75 mph are expected over the mountains.
  Expect snow rates of 2-4+" per hour. These will combine to bring
  whiteout conditions with near zero visibility at times beginning
  today, but especially Friday and Saturday.

* Strong winds are forecast in the Central Valley with gusts of
  40 to 55 mph from Yuba City northward today, and from Modesto
  northward on Friday.

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The dry weather will rapidly come to an end early this morning as
the strong winter storm moves into the region with a classic heavy
snow producer for the mountains set to affect the region through
Saturday. Radar shows precipitation currently moving across
northwest California. Snow will develop over the northern Sierra
around sunrise with heavy snow expected by late morning. In the
valley, spotty lighter precipitation will be possible this morning
with a period of moderate to heavy rain expected to move south
during the afternoon with the front, possibly accompanied by a
little thunder. Gusty southerly wind is already picking up across
the region as the surface pressure gradient tightens ahead of the
approaching front. Gusts of 20-30 mph are already being observed
across the northern half of the Sacramento Valley and in the
mountains.

Extremely dangerous to impossible mountain travel is expected
into the weekend. A Blizzard Warning has been issued for the
Northeast Foothills, Motherlode, Sierra, and Western Plumas/Lassen
area above 2000 feet and a Winter Storm Warning has been issued
for the Coastal Range, Shasta County Mountains, and Burney Basin.
Snow rates of 2-4+" inches are expected, with road closures,
white-out conditions and near zero visibilities at times. Very
strong winds, combined with very heavy snowfall could cause
extensive tree damage and extended power outages. Blizzard
conditions are expected through Saturday. Snow levels will start
out around 5000 to 6000 feet today, lowering to 3000 to 4500 feet
Friday, then down to 1000 to 2000 feet Saturday. Total snowfall
will be measured in feet from this event, with the National Blend
of Models (NBM) suggesting 12 feet in the Sierra. Areas along I-5
in Shasta County will likely see up to a foot of snow or more, so
significant travel delays and road closures are possible.

Gusty winds will also bring moderate impacts to the region through
Friday. Strongest winds will be north of Sacramento today, but
will likely spread south on Friday as the next wave moves through.
A Wind Advisory remains in effect.

A few thunderstorms will be possible today as the initial front
moves south this afternoon and evening. The EC Extreme Forecast
Index (EFI) highlights most of interior NorCal for possible
thunderstorm development on Friday and Saturday afternoon, and the
NBM supports this with a 10-20% chance of T-storm development
Friday and Saturday afternoon/evening. Hazards from any T-storms
that develop will include additional gusty winds, small hail,
brief heavy rain and lightning. As for as rainfall goes, much of
the Valley will likely see generally less than 1.50" inches
through Saturday night. The foothills will see 2-4 inches and the
mountains will see 4-8 inches with locally heavier amounts.

The time to prepare for this *significantly* impactful winter
storm is NOW! Mountain travel is HIGHLY discouraged while the
warnings are in effect!

&&

.EXTENDED DISCUSSION (Monday THROUGH Thursday)...
Lingering mountain snow showers possible Monday, otherwise drier
weather expected into Tuesday as short wave ridging moves through.
Upstream short wave troughs progged inland midweek bringing more
widespread light to moderate precip Wednesday into Thursday. NBM
showing snow levels of 2500-3500 feet during this period.

&&

.AVIATION...
Widespread MVFR/IFR with areas LIFR over the mtns next 24 hrs as
Pac storm moves inland. In Central Vly, Sly sfc wind 15-30 kts
with lcl gusts up to 45 knots. Over mtns, areas SWly sfc wind
gusts 40-60 kts. Isolated -tsra possible in N San Joaquin Vly btwn
22z-04z.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 10 AM PST Sunday for Burney Basin /
Eastern Shasta County-Mountains Southwestern Shasta County to
Western Colusa County-Shasta Lake Area / Northern Shasta County.

Wind Advisory until 4 AM PST Saturday for Carquinez Strait and
Delta-Central Sacramento Valley-Motherlode-Mountains
Southwestern Shasta County to Western Colusa County-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Northern
San Joaquin Valley-Shasta Lake Area / Northern Shasta County-
Southern Sacramento Valley.

Blizzard Warning until 10 AM PST Sunday for Motherlode-Northeast
Foothills/Sacramento Valley-West Slope Northern Sierra Nevada-
Western Plumas County/Lassen Park.

&&