FOUS11 KWBC 290722
QPFHSD
Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
322 AM EDT Wed Apr 29 2026
Valid 12Z Wed Apr 29 2026 - 12Z Sat May 02 2026
...Central & Southern Rockies... Days 1-3...
A pair of upper-level disturbances; one over the Great Basin and
another approaching the Central Rockies from the north, will work
together to produce a much-needed period of moderate-to-heavy
mountain snow from the WY Rockies on south through the CO/northern
NM Rockies. As these disturbances work together to gradually cause
500mb height falls, a robust 130kt 250mb jet streak will tap into
subtropical moisture at the same time that high pressure building
in over the Northern Plains forces easterly upslope flow into the
Front Range and Sangre De Cristo. Periods of light high-elevation
mountain snow (generally above 9,000ft) will occur Wednesday night,
but as the strong upsloping easterly winds arrive on Thursday,
snowfall rates will intensify along the Front and Park Ranges. The
Palmer Divide above 7,000ft is also likely to see periods of snow
Thursday afternoon, potentially causing some slick travel
conditions as the sun sets Thursday evening. Snowfall rates between
1-2"/hr are likely along the Front Range and Sangre De Cristo
above 9,000 Thursday afternoon and into Thursday night. Snowfall
rates diminish gradually Friday as easterly upslope flow gradually
lessens, but still manages to keep periods of snow in the forecast
for much of the day. A burst of heavier snowfall is likely along
the San Juans above 10,000ft as the trailing 500mb shortwave trough
pivots through the Four Corners region on Friday. Snow finally
tapers off some time Friday night.
WPC probabilities paint a snowy picture over the Central and
Southern Rockies, which is overall a great thing to see given the
ongoing drought and lack of snowpack. The heavier snowfall totals
12") are most likely to occur above 8,000ft along the Front
Range, the above 9,000ft along the Park Range and the Sangre De
Cristo. Some localized totals >20" are possible in the more remote
peaks pf the CO Rockies, including Pike's Peak. Generally 6-12" of
snowfall are likely along the San Juans above 11,000ft. The WSSI
does show mostly Minor Impacts at elevations between
8,000-10,000ft, with localized Moderate to Major Impacts at the
more remote elevations above 10,000ft. Some Minor Impacts are
depicted along I-25 over the Palmer Divide and Raton Pass, so some
locally hazardous travel conditions are possible Thursday
afternoon and evening.
Farther north, some light-to-moderatwe snowfall is likely in the WY
mountain ranges such as the Wind River, Big Horn, and Absaroka.
Most totals will range between 4-8" above 9,000ft with localized
amounts approaching 10" possible. The bulk of the snowfall there
occurs today, although some light snowfall looks to persist into
the first half of Thursday.
The probability for significant icing over one-tenth of an inch is
less than 10 percent.
Mullinax
$$
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