AgWeatherNet Weekly Weather Outlook for November 15 to November 21, 2021

Cooler temperatures on the way with more activity before the weekend

Mark Ingalls, AgWeatherNet Field Technician

Synopsis:

A cold front will cross Washington Monday, shifting rain back over the region, increasing wind speeds, and dropping snow levels. Some showers are expected to continue west of the Cascades into Tuesday but otherwise a drying trend is forecast into Wednesday. Thursday a new disturbance transits the region to bring a chance of rain and mountain snow statewide. A chance of rain continues through the weekend in Western Washington, but a building ridge makes dry weather appear more likely east of the Cascades.

Discussion:

The Pineapple Express event sitting along a nearly stationary boundary and bringing widespread flooding and landslides to southern British Columbia is expected to begin sliding southeastward as a cold front during the day Monday. This will cross the state from northwest to southeast. Many parts of the state were already seeing strong winds during the morning hours, but winds are forecast to be the strongest right as the cold front passes. Rain, heavy in and west of the Cascades, can also be expected in association with the cold front.

Some rain showers are likely in the postfrontal environment in Western Washington thanks to cooler air aloft on Tuesday, but generally speaking a drying trend is forecast to start. This will allow flooding rivers to crest Monday or Tuesday and fall below flood stage later this week, though some rivers may break records. For more detailed flood information, see the National Weather Service and alerts from local authorities.

A weak ridge is forecast to cross the Pacific Northwest midweek for dry conditions throughout Washington, but look for the next disturbance to begin bringing rain showers to the coast by the evening hours. This will spread inland through Thursday with precipitation tapering off Friday along the Idaho state line. With cold air from the cold front in place, there is a low chance of snow or wintry mix in Eastern Washington lowlands Thursday morning, but accumulations, if any, should be minimal. Snow levels will rapidly rise to near-to-above pass level during the day.

Northwesterly flow aloft ahead of a building ridge of high pressure should keep cool rain showers moving through Western Washington into the weekend, but current indications are that this activity won't be enough to bring much to Eastern Washington beyond Friday.

Drought conditions in Eastern Washington continue to improve, but in last week's Drought Monitor update exceptional drought (D4/4) was still noted in the southeastern corner of the state, from Goldendale through the Tri-Cities and to the Idaho state line south of Pullman. This information predates the rainfall seen over the weekend, but while that was beneficial the southern end of the Columbia Basin and Palouse still have a long ways to go to make up the existing moisture deficit.


Network Updates

Last week, AgWeatherNet staff decommissioned the Wenatchee.S and Connell.N stations. AgWeatherNet thanks the landowners that hosted these sites for their generous support and thanks all users for their patience as we undergo a multi-year project to modernize the network.


8 to 14 Day Outlook, November 22 to November 28, 2021
  • Above average temperatures and near average precipitation are favored for the period.

Important Points About This Week's Weather

South Central Washington
Remainder of the Week
  • Wind: W and breezy Tue, NE with breezy areas Wed, light and variable Thu-Fri.
  • Precipitation: Low chance of wintry mix Thu AM, chance of rain Thu-Fri AM.
  • High Temps: Low 50s Tue, upper 40s Wed, mid 40s Thu, upper 40s Fri.
  • Low Temps: Upper 30s Mon night, upper 20s Tue night, low 30s Wed-Thu nights, mid 30s Fri night. Cooler in sheltered areas.
  • Sky Cover: Partly cloudy Tue-Wed, mostly cloudy Thu-Fri.
Weekend
  • Wind: Light and variable Sat & Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 40s Sat & Sun.
  • Low Temps: Mid 30s Sat & Sun nights.
  • Sky Cover: Mostly cloudy.

North Central Washington
Remainder of the Week
  • Wind: W and breezy Tue, NE with breezy areas Wed, light and variable Thu-Fri.
  • Precipitation: Rain tapering off Mon night. Chance of rain/snow Thu, chance of rain and mountain snow Fri.
  • High Temps: Upper 40s Tue, low 40s Wed-Thu, mid 40s Fri. Cooler in higher terrain.
  • Low Temps: Upper 30s Mon night, upper 20s Tue night, near 30 Wed night, low 30s Thu-Fri nights. Cooler in higher terrain.
  • Sky Cover: Partly cloudy Tue & Wed, mostly cloudy Thu & Fri.
Weekend
  • Wind: Light and variable Sat & Sun.
  • Precipitation: Low chance of mountain rain/snow.
  • High Temps: Mid 40s Sat & Sun. Cooler in higher terrain.
  • Low Temps: Low 30s Sat & Sun nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy.

Eastern Washington
Remainder of the Week
  • Wind: W and breezy Tue, NE with breezy areas Wed, light and variable Thu-Fri.
  • Precipitation: Chance of rain/snow Thu night & Fri.
  • High Temps: Mid 40s Tue, near 40 Wed, low 40s Thu, mid 40s Fri. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 30 Mon night, low 20s Tue night, upper 20s Wed night, low 30s Thu night, near 30 Fri night.
  • Sky Cover: Partly cloudy Tue-Wed, mostly cloudy Thu-Fri.
Weekend
  • Wind: Light and variable Sat & Sun.
  • Precipitation: Mountain rain/snow possible.
  • High Temps: Low 40s Sat & Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Upper 20s Sat & Sun nights. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly cloudy.

Western Washington
Remainder of the Week
  • Wind: Becoming light and variable Tue, E with breezy areas Wed-Thu, N with breezy areas Fri.
  • Precipitation: Rain showers tapering off Tue. Rain and mountain snow Thu-Fri.
  • High Temps: Upper 40s Tue-Fri. Cooler in higher terrain.
  • Low Temps: Lower 40s Mon night, mid 30s Tue night, near 40 Wed night, low 40s Thu-Fri nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.
Weekend
  • Wind: Light and variable Sat & Sun.
  • Precipitation: Chance of rain and mountain snow Sat & Sun.
  • High Temps: Upper 40s Sat & Sun. Cooler in higher terrain.
  • Low Temps: Low 40s Sat & Sun nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.

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Washington State University