Quantitative Precipitation Forecast
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QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
411 AM EDT Sun Mar 24 2024

Valid 12Z Sun Mar 24 2024 - 12Z Wed Mar 27 2024

...The West/Four Corners...
Days 1-3...

A longwave trough encompassing most of the western U.S. will
continue to produce rounds of heavy mountains snow today and into
early Monday morning. While snow will be winding down in California
throughout the day on Sunday, a vigorous 500mb vorticity max moving
through the Four Corners region will induce PVA aloft and stream a
plume of 850-500mb moisture flux into the Mogollon Rim, the Gila
Mountains, the Wasatch, the Colorado Rockies, and both the Sangre
De Cristo and San Juans of northern New Mexico. Snowfall rates will
be heaviest in the Colorado and New Mexico Rockies where higher
elevations >8,000ft will witness the best upslope enhancement. WPC
PWPF shows high chances (>70%) for snowfall totals >8" in most of
the Colorado and northern New Mexico Rockies, while probabilities
are closer to moderate levels (40-60%) in the tallest peaks of the
Wasatch, Mogollon Rim, and Gila Mountains. The WSSI shows Minor to
Moderate Impacts throughout all these ranges through Sunday night,
with the Gila and San Juans sporting some localized Major Impacts
at their crests. Snow will gradually wind down Monday morning as
the best upper level support moves east into the Plains, but some
residual Pacific moisture throughout the West may result in
localized moderate-to-heavy snow showers along the Rockies and as
far west as the Great Basin. Meanwhile, a persistent onshore flow
in the Pacific Northwest will produce some snow in the Cascades and
Olympics on Monday, but snowfall rates will be manageable for these
ranges. This may all change by Wednesday as the next Pacific storm
system approaches the Washington coast with a renewed influx of
Pacific moisture on its way that may bring more heavy snow to the
Olympics, Cascades, and as far south as the Sierra Nevada.

...Northern Rockies & High Plains, Central Rockies, Upper
Midwest...
Days 1-3...

**Major Winter Storm to Impact Northern High Plains to the Upper
 Midwest into Early This Week**

This morning, a deepening surface low in eastern Colorado and a
deepening 700mb low over western Nebraska will funnel copious
amounts of Gulf of Mexico moisture northward into the Northern
Plains and Upper Midwest. A deformation axis of snow will take
shape over eastern Montana, northern Wyoming, and the Dakotas,
while strong 850-700mb WAA generates thumping snow rates from
northern Iowa and southern Minnesota to western Wisconsin. Latest
WPC Snowband Probability Tracker (SPT) does depict snow bands that
will likely produce 1-2"/hr snowfall rates late Sunday morning and
into Sunday afternoon, with some cases where as high as 3"/hr are
possible. As Sunday unfolds the Central Plains will located
beneath the divergent left-exit region of a 250mb jet streak in
northern Mexico, while the right-entrance region of a 250mb jet
streak over southern Ontario maximizes the intense vertical ascent
atop the atmosphere. This allows for the surface low in the Central
Plains to drop to exceptionally deep levels (sub-980mb by Sunday
evening). On the backside of the deepening 700mb low, strong
northeasterly upslope flow and a potent cold front will allow for
heavy snow to break out along the Front Range of the Colorado
Rockies and the Palmer Divide Sunday evening, followed by the
Sangre De Cristo and as far south as Raton Pass Sunday night into
early Monday morning. Latest WPC SPT shows some instances where
2-3"/hr snowfall rates may ensue with concerns of rapid snow
accumulation on roads and significantly reduced visibilities into
early Monday morning. Similar snowfall rates may occur in west-
central Nebraska and northwest Kansas as the warm conveyor belt
wraps around the northwest flank of the low. The ascent is so
strong at low-mid levels that instances of thundersnow are possible
Sunday night into Monday morning in some localized cases.

Monday morning will see the storm system track northeast towards
eastern Nebraska with strong 850mb WAA in the Upper Mississippi
Valley ultimately causing a change over from snow to an icy wintry
mix at first, then to all rain in southern Minnesota, northern
Wisconsin, and the U.P. of Michigan by Monday afternoon. This will
cut down snowfall totals but the icy wintry mix of sleet and
freezing rain could still lead to hazardous travel conditions
Monday morning. Meanwhile, in the eastern Dakotas and northern
Minnesota, snow will remain the primary precip type with strong
wind gusts >40 mph causing blizzard conditions through Monday
evening. The expansive deformation axis of snow will pivot over
these areas Monday night with snow also falling through eastern
Nebraska and northern Kansas. By Tuesday morning, the storm will be
over the Upper Mississippi Valley with the swath of heavy snow
traversing much of Minnesota and the Upper Missouri river Valley.
Snow will finally taper off from southwest to northeast Tuesday
afternoon and be well into southern Canada by early Wednesday
morning.

The latest WSSI shows Major impacts in northeastern South Dakota,
southeastern North Dakota, much of central Minnesota, and the
Minnesota Arrowhead. These areas also sports high chances (>70%)
for snowfall totals >12" for the duration of this winter storm.
There are even low-to-moderate chances (30-50%) for >18" in
northeast South Dakota and along the coast of the Minnesota
Arrowhead. WPC PWPF also depicts high chances (>70%) for snowfall
totals >8" in northern Nebraska, central South Dakota, and
northwest Wisconsin. West-central Nebraska features moderate-to-
high chances (50-70%) for >6" of snow to go along with whipping
wind gusts surpassing 45 mph. Farther south, the Colorado Front
Range, Palmer Divide, and Sangre De Cristo have moderate-to-high
chances (50-70%) for >6" of snowfall through Monday morning. Expect
hazardous travel in these affected areas Sunday and through Monday
with blowing and drifting snow causing higher snow drifts and
significantly reduced visibilities.

Mullinax

***Key Messages for Northern Plains Winter Storm***

--A high-impact winter storm unfolding

An extensive storm system will continue to develop today,
producing widespread heavy snow and gusty winds that will persist
over parts of the Northern Plains and Central Plains as well as Upper
Midwest through early this week.

--Widespread heavy snow expected

Heavy snow will expand into the Northern Plains and Upper Midwest
today and continue into Tuesday. Heavy snow is also expected in
parts of the Central Plains Sunday night into Monday. There is a
high chance (>70%) of at least eight inches of snow extending from
northern Nebraska and central South Dakota northeastward to
central Minnesota and northwestern Wisconsin.

--Hazardous impacts due to snow, snow load, and wind

Heavy snow and gusty winds will produce areas of blowing and
drifting snow and possible blizzard conditions Sunday into Monday.
This will result in hazardous travel including road closures.
Strong winds and heavy, wet snow on trees and power lines may
damage trees and cause power outages.

--Strong wind gusts in the Central and Southern Plains

Wind gusts over 50 mph on Sunday may result in power outages,
blowing dust with reduced visibility, difficult travel, and
property damage. Critical fire weather conditions are forecast
today over the Southern High Plains.





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