Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
410 PM EDT Fri Oct 19 2018

Valid 00Z Sat Oct 20 2018 - 00Z Tue Oct 23 2018


Day 1...

The probability of significant snow (4 inches or more) is less
than 10 percent.

The probability of significant icing (0.25 inches or more) is less
than 10 percent.

Day 2...

...Central Appalachians...
Guidance continues to show a well-defined shortwave trough digging
southeast from the upper Great Lakes into the Ohio valley and
central Appalachians on Saturday.  Associated lift within the
dendritic growth zone is expected to support snow showers across
portions of the Allegheny mountains Saturday evening, with WPC
probabilities continuing to show some low end probabilities for
accumulations of 4-inches or more.

The probability of significant icing (0.25 inches or more) is less
than 10 percent.

Days 2/3...

...Western U.S....
Models show a broad upper trough drifting east across California
and the Great Basin Sunday and Monday.  Warm temperatures and
limited moisture will greatly hamper the threat for widespread
significant snows, with WPC probabilities only indicating mainly a
very isolated and low end chance for accumulations of 4-inches or
more across some of the higher peaks of the Sierra and central
Rockies.

The probability of significant icing (0.25 inches or more) is less
than 10 percent.

Pereira