FOUS11 KWBC 050849
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
449 AM EDT Tue May 5 2026

Valid 12Z Tue May 05 2026 - 12Z Fri May 08 2026

...Central/Southern Rockies and Adjacent High Plains... Days 1-2...

Confidence continues to increase for impactful snow through the
Denver Metro in addition to CO Rockies.

A post-frontal low level convergence zone near the WY/CO border
merely drifts south through tonight before picking up some
southward speed Wednesday with the passage of a southern stream
shortwave trough currently over SoCal and a northern stream
reinforcing trough. A tight baroclinic zone through this low-level
boundary shifts south over CO and banks on the lee-side of the
Front Range today. This brings snow down to the I-25 corridor
tonight. Precip intensity increases today as left exit dynamics
strengthen from a SWly jet over NM to the central Plains and
upslope easterly flow becomes more pronounced as high pressure
builds down the Plains in the wake of the cold front.

Snow levels reach 6000ft late this afternoon from the Palmer
Divide and north before dropping below a mile high during the
evening hours. Moderate precip rates occur late tonight through
Wednesday morning from Denver through the Front Range with quick
bursts of wet snow. The focus for the snow will shift to the
Sangre De Cristo and San Juans Wednesday afternoon as snowfall
rates gradually diminish north of the Palmer Divide. Snow rates
quickly drop off Wednesday evening as the northern stream shortwave
trough pushes onto the central Plains.

Day 1 snow probs for additional >6" are 50-80% for the Wind River,
Bighorns, Laramie, and Medicine Bow Mtns in WY. Day 1.5 snow probs
for >6" are 40-70% from Cheyenne down I-25 through the greater
Denver metro and on the Palmer Divide. Meanwhile, probs for >12"
are >80% for the Front Range and Park Range. Day 2 snow probs for

6" are 50-80% for the Sangre de Cristos/San Juans and 40-70% for

the Raton Mesa.

This winter storm will produce much needed precip in the drought-
stricken Central Rockies and High Plains. However, unlike last
week's event which had less snowfall and was confined to the higher
elevations, this event is more significant and will have notable
impacts. The latest WSSI highlights widespread Moderate Impacts
for the I-25 corridor from Cheyenne through Denver and the Palmer
Divide and Major Impacts for the Front Range including Rocky
Mountain NP. The heavy/wet nature of the snow on trees fully
leafed out/in bloom and on power lines could result in tree damage
and power outages.

The probability for significant icing over one-tenth of an inch is
less than 10 percent across the CONUS.

Jackson
$$
--- MultiMail/DOS
* Origin: Project Scorpio TEST (618:250/6)