Arctic Air Mass To Bring Near Record Cold
By Rod Hill on 2022-02-19
Arctic air to drop over the Rockies next week and spill into the Northwest as east winds start to blow during the day Tuesday. Bitter cold at times Tuesday through Thursday night with possible snow Thursday night and Friday.
Below is the American GFS model air mass map next Tuesday, the 22nd. The bright purple represents the center of the Arctic air mass where daily temps will be a good 20 degrees below seasonal average over the Rockies and the plains, including Nebraska. This is the batch of air the gorge east winds will be blowing off of and advecting the cold air into the Willamette valley.
The extended 7day forecast model most widely used by forecasters. The bottom line (DPT) shows the dew point forecast. As dry east winds pick up during the day Tuesday, notice the dew points lower to 11 degrees Wednesday morning and hold at 18 degrees Thursday morning and still well below freezing at 27 degrees Friday morning. Gusty east winds will hold temps up a bit, but calmer conditions with clear skies would easily allow for overnight valley temps dropping to near 20 degrees or possibly upper teens Wednesday morning and again Thursday morning.
The Euro model shows a push of warm air advection Thursday night into Friday morning, bringing possible moisture into freezing temps. At this time, some accumulating snow is at least possible next Thursday night and Friday morning, followed by warming daytime temps and rain showers.
A strong cold front with breezy south winds and deep moisture should easily hold next Friday night temps above freezing with rain and rising snow levels back to 4,000 or 5,000 feet Saturday Feb. 26th, which looks like a rain soaker at this time with valley temps in the 40s.
Keep in mind that gusty east winds tend to hold actual air temperatures up a bit, making for a difficult low temperature forecast. The same wind also holds afternoon temps down, especially when advecting cold air from a bitterly cold Arctic air mass dropping south over the Rockies.
At this time, the data supports a widespread hard freeze for 2-3 nights next week. Windy areas near the gorge may see overnight lows hold near 32 degrees or above, while calmer locations report upper teens and record lows.
Keep updated with my 7day forecast,
Rod Hill
Dry, quiet February to continue