Unseasonable Warmth in West to Fade by Next Week

By Brian Lada, Meteorologist

February 20,2015; 10:16PM,EST

 

 

While much of the West has experienced warm weather over the first three weeks of February, changes are on the way that will last through the balance of the month.
A shift in the weather pattern will usher colder, more seasonable air across the region during the weekend that is expected to last into next week.
Some snow will accompany the arrival of the cold air, but it should mainly be limited to the higher terrain the northern Rockies and Cascades on Saturday, followed by the Sierra and Wasatch Mountains on Sunday.

The air moving into the West shouldn't be as cold as the air in the East, but it will quickly knock down temperatures to more seasonable levels.
This colder air is not expected to penetrate the entire region, however, as above-average warmth holds over the Desert Southwest.
RELATED:
Interactive Radar
Forecast Temperature Maps
Western Weather Blog
The front delivering the colder air is expected to stall by early next week, lingering over a zone stretching from the Sierra Nevada to the Colorado Rockies.
This will allow snow to fall over the mountains in this area for 24 to 48 hours.
This is good news for ski resorts in the region that have received below-normal snowfall this season due to the persistent dry and mild pattern that has held over the West through most of this winter.

City	Temperature Departure
Salt Lake City	+14.4
Helena, Montana	+13.2
Casper, Wyoming	+11.2
Flagstaff, Arizona	10.8
Boise, Idaho	+10.7
Las Vegas	+10.1

This table shows the temperature departures for several cities across the West from Feb. 1 through Feb. 19.
This month has been unusually warm for most locations across the West.
This is the result of a persistent weather pattern that resulted in a large dome of high pressure sitting over the region, promoting dry and mild conditions.
While this change in the pattern will yield lower temperatures, temperature departures for the month are likely to end the month of February above normal.
Unfortunately, this change in the weather pattern will not bring an uptick in the rainstorms which are much needed in the West due to the ongoing drought.