Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
425 AM EDT Sat Oct 20 2018

Valid 12Z Sat Oct 20 2018 - 12Z Tue Oct 23 2018


Day 1...

...Central Appalachians...
A potent shortwave rounding a trough over the Great Lakes today
and crosses the Central Appalachians tonight. Lift from the trough
and topography of the Allegheny Plateau allow snow for higher
elevations with saturation and lift in the dendritic growth zone.
WPC blend probabilities for four inches are in the moderate range.

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

Days 2/3...

...Western U.S....
An upper trough drifts east across California and the Great Basin
Sunday and Monday. Warmth from southwesterly flow below the trough
and limited moisture will limit the significant snow threat to the
highest elevations of Utah on Sunday, spreading into Colorado and
Wyoming on Monday. WPC blend probabilities only indicate very
isolated moderate chance for accumulations of 4-inches or more
across the higher peaks of Utah and the central Rockies.

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

Jackson