Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
313 PM EDT Fri May 10 2019

Valid 00Z Sat May 11 2019 - 00Z Tue May 14 2019


...Mountains of the West...

Cutoff mid-level low near Southern California this evening will
drift southward tonight and gradually begin to eject eastward into
early next week. Persistent southwest flow aloft in response to
this system will continue to drive high PWAT into the west, with
left exit region diffluence within a jet maximum rotating around
this trough producing ascent. Snow levels will be quite high,
9000-10000 ft or more most of the area, confining any heavy snow
to only the highest terrain of the Sierra of California, Ranges of
Colorado, and Big Horns in Wyoming. In these ranges, WPC
probabilities are moderate for 4 inches on day 1, with
accumulations above 8 inches possible in the San Juans. As the
upper low ejects eastward, forcing will gradually wane, and only
light accumulations are forecast beyond day 1, again confined to
the highest terrain of the San Juans and Sangre De Cristos.

The probability of significant icing is less than 10 percent.

Weiss