A deep trough remained over the West this weekend, keeping temperatures below seasonal normal. Highs at higher elevations were in the 30s, lows were below freezing. A midlevel disturbance and associated surface low moved across the northern West and produced up to 1/2 foot of snow in the northern Great Basin and up to a foot of snow in the Yellowstone region mainly on Saturday. Up to 1 1/2 inches of rain fell at lower elevations in the northern Rockies and nearby Plains. This area of precipitation was enhanced in the Rockies due to upslope flow from a northern Plains low.
Except for areas which received snow this weekend, the Western snowpack is warm. Slow to moderate snowmelt occurred yesterday.
The Western midlevel trough this weekend is lifting northeastward into the northern Plains today. Up to a foot of snowfall is possible at higher elevations in the northern Rockies due to upslope flow. An inch of rainfall is possible at lower elevations.
As the Rockies trough moves out, another moves into the West Coast tomorrow. This slow-moving system will not have very sharp or strong surface features, so light, intermittent precipitation is expected in a continuing cool air mass. Highs at higher elevations will be in the 30s to lower 40s this week, with lows below freezing at middle and higher elevations.
weather.gov
