Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
352 PM EDT Thu May 09 2019

Valid 00Z Fri May 10 2019 - 00Z Mon May 13 2019



...Central Rockies and the Sierra Nevada...

Disorganized positively tilted longwave trough will amplify Friday
as a mid-level low closes off near Southern California. Backing
flow ahead of an this upper trough will direct a series of low
amplitude shortwaves across Colorado into Friday  In addition,
models show increasing divergence across Colorado along the right
entrance region of an upper jet amplifying over the central High
Plains, while low-level flow continues to direct upslope into the
terrain of CO and the Sierra.  However, snow levels are expected
to increase which will help keep heavier amounts contained largely
to areas above 9000 ft in the Sawatch, San Juan, Sangre de Cristo,
and Sierra Nevada ranges - where WPC guidance is indicating a
Slight Risk for additional accumulations of a foot or more during
the Day 1 period (ending 00Z Saturday).  Snow showers are forecast
to continue into early Sunday, however the potential for
additional heavy snow is expected to diminish as the weekend
progresses, with lingering accumulations expected predominantly in
the San Juans.

The probability of significant icing is less than 10 percent.

Weiss