May 21, 2021 – Weather system centered over Nevada will continue to bring cooler temperatures, foothill and mountain showers along with a few afternoon thunderstorms through Saturday. Dry with breezy north winds in the valley today. The higher elevations will see some late season snowfall accumulations. Dry and milder weather returns Sunday.
The central part of the low is over Nevada with wrap around moisture spreading over the Sierra Nevada. More rain and snow showers likely later today over the mountains and foothills.
Dry with breezy north winds continuing for the valley with temperatures becoming warmer but still cooler than seasonal normals. Winds should generally peak between 10 and 20 mph with gusts between 20 and 30 mph today with a few locally stronger winds in places. Snow levels will rise during the day to near pass levels before lowering in the evening to around 6000 feet.
Saturday should be a repeat of Friday but with slightly higher snow levels ranging from 6500 to 7500 feet and a little less activity that should stay over the mountains. Winds will be lighter in the valley but northerly during the day.
On Sunday the low moves far enough east for the showers to diminish over the mountains and remain dry. Dry with weak ridging and warmer temperatures to start the work week with temperatures warming into the 85 to 90 range in the valley.
The warmup will be short lived for most areas as a low pressure system moves through the region on Tuesday. Some shower chances will start late Monday over the north and northern mountains as the low begins to move into the region.
Extended discussion (Tuesday through Friday)
Models are in very good agreement this morning with the progression of the low. Both the GFS and the European are indicating the low pressure system will progress through the region on Tuesday and conditions in the mountains and north end of the valley becoming dry again for Wednesday.
I would not be surprised if we see a few thunderstorms as the low moves through given the time of year and warmer surface conditions. Cluster analysis has the trough over the area as well but keeps a weak trough over the region through the remainder of the extended period. This may indicate temperatures near seasonal normals for that time period and with no indication of any precipitation at this time.