Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 AM EST Wed Feb 22 2023

Valid 12Z Wed Feb 22 2023 - 12Z Fri Feb 24 2023

...Significant coast-to-coast winter storm will continue to produce both
heavy snow and impactful freezing rain across the West and Northern Tier
of the country...

...Widespread very strong, gusty winds expected across the West and
adjacent High Plains through Wednesday...

...Heavy rain with the potential for scattered flash flooding and severe
weather for the Midwest and Plains Wednesday...

...Widespread record-breaking warmth expected in the East with much below
average cold in the Northern Plains/West...

The arrival of a large arctic air mass from Canada interacting with an
energetic upper-level pattern and multiple frontal systems forecast to
move through the country this week will bring numerous weather hazards and
highly anomalous temperatures coast-to-coast, with almost all of the
country experiencing some form of notable weather. Widespread heavy snow
will continue to expand across the West and Northern Tier of the country.
Ample moisture associated with a pair of Pacific fronts will combine with
increasingly warm and moist air streaming in to the east from the Gulf of
Mexico, clashing with the arctic air surging in from Canada to fuel heavy
snow rates.  Storm total snowfall of 1-2 feet, locally higher, is expected
for most of the mountain ranges across the West. The snow will begin to
taper off to the north Wednesday and focus further south through Thursday.
The heavy accumulating snow should be limited to higher elevations in the
mountains, with a lighter rain/snow mix for the interior valleys. Moderate
to locally heavy rain as well as some thunderstorms are forecast for the
lower elevations of the immediate West Coast, spreading southward from the
Pacific Northwest Wednesday to the California coast Thursday. Snow will
begin to mix in with the rain for lower elevations of the Pacific
Northwest as temperatures cool overnight Tuesday into Wednesday, and there
is even a chance to see some light snow in the central California valleys
Wednesday night.  In addition, a deep low pressure system moving through
the Great Basin/Central Rockies and trailing cold front will bring
widespread very strong, gusty winds of 50-60 mph, locally as high as 80
mph in favorable terrain locations, to California, the interior Southwest,
and the Southern High Plains. These winds have prompted an Elevated Risk
of fire weather from the Storm Prediction Center for the Southern High
Plains Wednesday-Thursday, with areas of blowing dust also expected. There
will be little to no break from the active weather in California as
another Pacific storm system is forecast to approach the coast late
Thursday, with continued lower elevation rain/higher elevation snow
chances.

An axis of heavy snow will also continue to expand eastward across the
Northern Plains into the Upper Midwest/Great Lakes Wednesday as a strong
low pressure system consolidates in the lee of the Rockies and moves
northeastward across the Plains then into Midwest. A wide swath of storm
total snowfall over a foot is likely from South Dakota eastward through
southern Minnesota, northern Wisconsin, and the Upper Peninsula/northern
Lower Peninsula of Michigan.  Snow totals may approach 2 feet in southern
Minnesota. Heavy snow rates of 1-2" per hour and gusty winds will produce
blizzard/whiteout conditions, making travel treacherous to impossible and
potentially leading to scattered power outages.  Snow will begin to stream
into the Interior Northeast/New England late Wednesday into Thursday as a
low pressure wave develops along a slowing warm front extending eastward
across the Midwest/Mid-Atlantic.  A swath of 4-8 inches of snow is
forecast from Upstate New York into central New England, with locally
higher totals over a foot for the higher elevations including the
Adirondacks and the Green and White Mountains.  A heavy wintry mix of
snow, sleet, and freezing rain is expected just to the north of the warm
front and south of the heavy snow axis across the upper Mississippi Valley
and into the lower Great Lakes, with lighter accumulations extending
eastward into the Central/Northern Appalachians and southern New England. 
Ice accumulations of 0.1-0.25", locally 0.5"+, are possible, especially
across lower Great Lakes Wednesday-Thursday. Gusty winds will increase the
risk of power outages and tree damage.

Widespread showers and thunderstorms are forecast to develop in the
system's warm sector along the warm front and southward along a dry
line/Pacific cold front from the Southern Plains northeast into the Middle
Mississippi and Ohio valleys and Lower Great Lakes on Wednesday.
Anomalously high moisture streaming northward from the Gulf will help
storms to produce locally heavy rain rates. There is a Slight Risk of
Excessive Rainfall (level 2/4) from northeast Missouri into northern
Illinois, northern Indiana, and southern Michigan where these heavier rain
rates as well as the tendency for multiple storms to track over the same
areas may lead to some scattered instances of flash flooding. Strong
low-level and deep-layer shear as well as very marginal, but sufficient
instability have also prompted a Slight Risk of severe weather (level 2/5)
from the Storm Prediction Center from central Oklahoma northeastward
through central Missouri for the chance some storms may produce damaging
winds. Winds will be quite blustery as well, with gusts of 35-45 mph
possible for the Mississippi/Ohio Valleys.

Besides the numerous weather hazards expected this week, another major
story will be the significantly anomalous warm temperatures for February
over the East and cold temperatures over the West.  Highs
Wednesday-Thursday will soar into the 70s and 80s from the Southern Plains
east into the Southeast, Midwest, and Mid-Atlantic. These highs on
Thursday will be particularly anomalous for the Ohio Valley and
Mid-Atlantic, where temperatures 40+ degrees above average will feel more
like June than February. Many record-tying/breaking highs are forecast,
some by several degrees. The forecast temperature gradient from the
Mid-Atlantic into New England Thursday is worth noting, as highs in the
80s in Virginia drop to the single digits in northern Maine. In stark
contrast, temperatures will be running 20-30 degrees below average over
the Northern/Central Plains and much of the West. Many
record-tying/breaking minimum high temperatures are possible over the
West, with highs in the 20s and 30s for the Pacific Northwest, 30s and 40s
for northern California, 50s for central/southern California.  Bitterly
cold temperatures from the negative single digits into the teens are
forecast for the Northern Central Plains, with wind chills dropping as low
as 20-30 degrees below zero.

Putnam/Kong


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php