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

Valid 00Z Wed May 06 2026 - 00Z Sat May 09 2026

...Central Rockies and High Plains...
Day 1...

...Significant late season snowstorm continues for the Rockies and
Denver Metro through Wednesday evening...

A secondary cold front initially near the WY/CO border will bank
up against the lee side of the Front Range as it presses southward
through the CO High Plains tonight into Wednesday. In the wake of
the front, strengthening low-level upslope east to northeasterly
flow combined with favorable jet dynamics aloft will support
intensifying precip across the CO Rockies, the Denver Metro, and
the I-25 corridor this evening into the overnight hours. Marginal
surface temperatures early on may result in pockets of mixed rain
and snow along with heavier bursts of all snow dependent on precip
rate; however, post-frontal cold advection will drop temperatures
near to below freezing area wide by Wednesday morning, changing any
lingering rain/snow to all snow as snow levels crash to between
4500 and 5000ft. Moderate to heavy snow continues through Wednesday
morning from Cheyenne to Denver through the Front Range as forcing
for ascent maximizes within a fairly deep DGZ. Forcing sags
southward Wednesday afternoon, shifting the focus for moderate to
heavy snow to the Sangre De Cristos and San Juans as snowfall rates
gradually diminish north of the Palmer Divide. Snow mostly
diminishes area wide by Wednesday evening with only a few lingering
showers across the Rockies of southern CO and northern NM into
Wednesday night.

The latest Day 1 WPC probabilities of additional snowfall >4" are
50-80% from Cheyenne southward to the Denver Metro and the Palmer
Divide eastward to I-70 just west of Flagler. Probabilities of >8"
are 50-90% from the Front Range and central Continental Divide
mountains southward to the San Juans and Sangre De Cristos.
Finally, probabilities of >12" are 60-90% for the high higher
elevations of the Front Range including Rocky Mountain NP.

This late season winter storm continues to bring much needed
precipitation to the Central Rockies and High Plains, providing
some relief to places facing severe to extreme drought. With that
being said, the moisture does not come without notable impacts. The
latest WSSI continues to highlight 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 and wet nature of the snow on trees fully
leafed out/in bloom and on power lines could result in tree damage
and power outages. Snow-covered and icy roads will also become a
greater concern as temperatures cool, leading to increasingly
difficult travel (especially over higher mountain passes) overnight
into Wednesday morning's commute.


The probability of significant icing across the CONUS is less than
10 percent.


Miller