Thursday, April 20, 2017
A cold Gulf of Alaska storm is currently on our doorstep, and some showers have popped up today in advance of the main storm. While snow levels are currently near 9500′, temperatures will drop this evening and bring snow to the Yampa Valley floor overnight. I would expect to see accumulations on the grassy surfaces by the morning of an inch or two, with a more substantial 4-8” at the higher elevations.
Cool and moist northwest flow will follow for Friday and Saturday. Showers, most likely snow even at the valley bottom, will be heaviest through Friday night, with an additional inch or two expected at the higher elevations.
Decreasing moisture on Saturday will limit the showers, but seasonably cool and still unstable northwest flow will make them most likely in the afternoon.
Sunday should be a spectacular day as temperatures warm under a transient ridge bringing mostly sunny skies.
However, a strong and progressive Pacific jet stream containing several embedded waves will move that ridge of nice weather eastward, with the first weakening wave bringing a chance of light showers by Monday afternoon.
Behind that, a stronger wave moves over the Steamboat Springs area on Tuesday, bringing heavier precipitation and the chance of snow down to the valley floor again.
It does not appear there will be much of a break in the weather as the strongest wave in this series moves across the central Rockies on Wednesday. Additional energy will keep the cool and wet weather around for the rest of the work week, with impressive precipitation accumulations likely across all of Colorado by week’s end.
The timing and details of these waves in the fast Pacific jet stream are notoriously difficult to predict, and I expect changes to the forecast for my next update on Sunday or Monday.