Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
245 PM EDT Mon Apr 8 2024

Valid 00Z Tue Apr 09 2024 - 00Z Fri Apr 12 2024


...Colorado/New Mexico...
Day 1...

An upper level shortwave trough will continue to amplify over the
Southwest, with a closed low developing over Arizona by this
evening. As the system drops further southeast and then moves east
along the U.S.-Mexico border, modest divergence to its north and
weak low level convergence will support some light snow over the
south-central Colorado ranges into the Sangre de Cristos this
evening into the overnight -- producing some low end probabilities
for accumulations of 4 inches or more.

Heavier precipitation will develop further to the south over
southeastern New Mexico on Tuesday. As the upper low continues to
track east, strong upper divergence afforded by the left-exit
region forcing and increasing upslope on the backside of the
associated low-to-mid level cyclone will support moderate to heavy
precipitation, with several inches of snow possible over the higher
elevations of the Sacramento Mountains.

...Northwest...
Day 1...

An approaching upper jet out of the northeastern Pacific will
bring in moisture to the Olympics and Washington Cascades overnight
into Tuesday, with downstream snow for the northern Idaho
mountains and northwestern Montana. Progressive flow will move the
moisture through the region and taper off from west to east
starting Tuesday afternoon (WA) into very early Wednesday (MT).
While accumulations of a foot or more are likely over the
Washington Cascades, rising snow levels will keep most of the snow
above pass level and confined to the higher peaks.


The probability of significant snow on days 2 and 3 is less than
10 percent.

For days 1-3, the probability of significant icing of at least
0.25 inches is less than 10 percent.

Pereira