Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
348 PM EDT Wed Mar 13 2024

Valid 00Z Thu Mar 14 2024 - 00Z Sun Mar 17 2024

...Central Rockies, Southern Rockies, and the Southwest...
Days
1-3...

***Significant and long lasting winter storm to produce heavy snow
 across much of the terrain of the central and southern Rockies,
 with impactful snowfall likely into the lower elevations of the
 High Plains as well.***

Snow will spread south from the northern into the central Rockies
and then intensify over the central Rockies through the evening
into the overnight hours. Shortwave energy will continue to eject
east along the leading edge of a broad, amplifying trough centered
over the Intermountain West. Broad-scale ascent east of the
trough, coupled with moist post-frontal upslope flow in the wake
of the ejecting wave will support heavy mountain snow, spreading
south from Wyoming into Colorado. With rates expected to exceed 2
in/hr in some locations, heavy accumulations are likely along the
Front Range and the Palmer Divide beginning tonight, before
extending farther south into the northern Sangre de Cristos on
Thursday. For the 24 hr period ending 00Z Fri, WPC PWPF shows
probabilities for accumulations of a foot or more exceeding 70
percent for much of the Front Range and Foothills. This includes
the western portions of the Denver Metro. With the exception of
the higher elevations along the Palmer Divide, guidance continues
to a show pretty tight gradient, with marginal temperatures
keeping amounts in check east of the I-25 corridor.

Snow will diminish from north to south across eastern Colorado,
while spreading south into the southern Rockies Thursday evening
and overnight. While the heaviest accumulations are expected to
fall in the Day 1 period, WPC PWPF does show that additional
locally heavy amounts of 8 inches or more are likely for portions
of the Front Range and the Sangre de Cristos on Day 2 (ending 00Z
Sat).

Meanwhile, back to the west, the previously noted upper trough
will continue to amplify, with a closed low developing over the
Great Basin tonight. This low is expected to settle into the lower
Colorado Basin on Thursday, where it is forecast to remain into
the weekend. Tapped by deep southwesterly flow, the upper low is
expected to spread anomalous moisture across the Four Corners,
fueling high elevation heavy snow over the region beginning late
Thursday. Areas impacted are likely to include the southern Utah
mountains, the Kaibab Plateau in northern Arizona, and along the
Mogollon Rim into the White Mountains in central Arizona. WPC PWPF
shows at least moderate probabilities (greater than 40 percent)
for accumulations of 8 inches or more across these areas. The low
will slowly shift east, bringing locally heavy, high-elevation
snow into the central New Mexico ranges late Friday into Saturday.

The probability of receiving at least 0.1" ice is less than 10%
across the CONUS through Day 3.


Pereira


**Key Messages for the March 13-16 Winter Storm can be found on
 our website at https://www.wpc.ncep.noaa.gov**