AgWeatherNet Weekly Weather Outlook Monday Update for February 22 to February 28, 2021

An active week followed by potentially drier pattern for the weekend

Mark Ingalls, AgWeatherNet Intern
Joe Boomgard-Zagrodnik, AgWeatherNet Postdoctoral Research Associate

Synopsis:

A cold front is expected to lower snow levels back below pass level Monday evening with heavy snow expected in the mountains overnight. This cold front and westerly flow behind it should keep rain showers in place for Washington lowlands through Tuesday except in the Columbia Basin and Yakima Valley where conditions will remain dry. A ridge is expected to bring a brief period of dry weather to most of the state by Wednesday before a couple disturbances raise precipitation chances once again Thursday and Friday. For the weekend, ridging looks to be the primary influence on the region with dryer conditions possible.

Discussion:

Snow levels in the Cascades were around 4000-5000 feet to start the day Monday, but a cold front coming into the state from west to east is expected to lower them to 2000-3000 feet. This will change rain to snow on the Cascade passes this evening, with heavy snow possibly causing continued cross-state travel issues late Monday into Tuesday. Rain will decrease in coverage Monday night in Western Washington before picking up again Tuesday. Showery precipitation is likely west of the Cascades on Tuesday with the potential for a convergence zone to bring locally heavy rain to Snohomish County on Tuesday afternoon. One to two feet of snow will pile up in the Cascades by Tuesday evening. Avalanche danger will remain high on Tuesday as well.

East of the Cascades, the Columbia Basin should remain dry with some light rain showers possible around Spokane, on the Palouse, and mountain snow in the Okanogan highlands. Winds in the Columbia Basin remain strong thanks to the jet stream being right over that area with its wind periodically mixing down to the surface. This wind should ease Tuesday morning. Temperatures overnight on the Palouse may be cool enough to produce lowland snow around cities like Pullman.

As the shortwave exits the Pacific Northwest, a transient upper-level ridge is forecasted to pass over Washington on Wednesday. This will allow most areas to see drier conditions with mostly sunny skies for parts of Eastern Washington. Partly to mostly cloudy skies can be expected in the mountains and Western Washington.

This drier period will not last long, though, with another upper-level disturbance expected to make its way into Washington by Thursday morning. Most of the state will see rain or mountain snow, though current indications are that the Columbia Basin and Yakima Valley will be the exception with dry conditions. Snow levels will be below pass level in the Cascades with more travel impacts expected. This storm lasts into Friday with the typical windy spots (Columbia Basin, Strait of Juan de Fuca, etc.) possibly seeing gusty winds both days. Into the weekend, a second ridge is expected for the state, allowing for another drying period Saturday and Sunday.


Important Points About Next Week’s Weather

South Central Washington
Remainder of the week
  • Wind: Generally S/SW Mon-Wed, breezy Mon-Tue. Generally W Thu-Fri, breezy to windy.
  • Precipitation: Possible showers Tue & Fri, mainly near the mountains.
  • High Temps: Near 50 Tue, mid 40s Wed, near 50 Thu & Fri.
  • Low Temps: Upper 30s Mon night, mid 20s Tue night, near 30 Wed night, mid 30s Thu night, low 30s Fri night.
  • Sky Cover: Decreasing clouds Tue, mostly sunny Wed, mostly cloudy Thu-Fri.
Weekend
  • Wind: Generally S, breezy Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 50 Sat & Sun.
  • Low Temps: Near 30 Sat night & Sun night.
  • Sky Cover: Partly cloudy with areas of fog.

North Central Washington
Remainder of the week
  • Wind: Generally S/SW Mon-Wed, breezy Mon-Tue. Generally W Thu-Fri, breezy to windy.
  • Precipitation: Rain and mountain snow showers ending Tue. Resuming Wed night-Fri.
  • High Temps: Upper 40s Tue, mid 40s Wed-Fri. Cooler in higher terrain.
  • Low Temps: Low 30s Mon night, mid 20s Tue night, near 30 Wed night, low 30s Thu night, near 30 Fri night. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy Tue, partly cloudy Wed, mostly cloudy Thu-Fri.
Weekend
  • Wind: Generally S, breezy in the Basin Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 40s Sat & Sun. Cooler in higher terrain.
  • Low Temps: Upper 20s Sat night & Sun night. Cooler in higher terrain.
  • Sky Cover: Partly cloudy with areas of fog.

Eastern Washington
Remainder of the week
  • Wind: Generally S/SW Mon-Wed, breezy Mon-Tue. Generally W Thu-Fri, breezy to windy.
  • Precipitation: Rain and overnight snow showers ending Tue, resuming Thu-Fri.
  • High Temps: Mid 40s Tue, near 40 Wed, low 40s Thu-Fri. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 30 Mon night, mid 20s Tue night, upper 20s Wed night, low 30s Thu night, mid 20s Fri night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly cloudy Tue, partly cloudy with areas of fog Wed, mostly cloudy to overcast Thu-Fri.
Weekend
  • Wind: Generally S, breezy Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 40 Sat & Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Mid 20s Sat night & Sun night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Partly cloudy Sat, mostly cloudy Sun. Areas of fog.

Western Washington
Remainder of the week
  • Wind: Generally W through Wed, breezy through Tue. Thu starts S becoming W and breezy, W and breezy Fri.
  • Precipitation: Rain and mountain snow tapering off Tue night, resuming Wed night-Fri.
  • High Temps: Upper 40s Tue-Fri. Cooler in higher terrain.
  • Low Temps: Near 40 Mon night, mid 30s Tue night, near 40 Wed & Thu nights, upper 30s Fri night. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.
Weekend
  • Wind: Light & variable Sat, S with breezy areas along the water Sun.
  • Precipitation: Possible isolated upslope showers Sat & Sun.
  • High Temps: Upper 40s Sat-Sun. Cooler in higher terrain.
  • Low Temps: Upper 30s Sat & Sun nights. Cooler in higher terrain.
  • Sky Cover: Partly to mostly cloudy.

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Washington State University