AgWeatherNet Weekly Weather Outlook for September 27 to October 3, 2021

Active weather to lead to a calm and dry weekend

Mark Ingalls, AgWeatherNet Field Technician

Synopsis:

The week will start off wet and cool as a cold front exits the region. Showers should taper off for much of Eastern Washington by Tuesday morning, but last through the day west of the Cascades. With the exception of the coast, northwest interior, and Cascades, look for dry conditions statewide to start the day Wednesday. The next disturbance reaches the I-5 Corridor late Wednesday afternoon, crossing the Cascades into Eastern Washington on Thursday. Precipitation values from this system are likely to be lower than the Monday-Tuesday frontal passage. Friday, the weather pattern dries out and warms up as the jet stream aims precipitation at Southeast Alaska and the northern British Columbia coast for the remainder of the week.

Discussion:

A cold front is crossing Washington on Monday, bringing with it rain showers and cooler temperatures. Behind the cold front, a strong upper level low sweeps through the region, bringing cooler temperatures. Rain showers taper off for most of Eastern Washington by Tuesday morning but with cold temperatures aloft and ample moisture, shower activity is expected to remain in place for the west side of the state.

A short lived ridge of high pressure transits the Pacific Northwest on Wednesday. Thanks to clearing skies the night before, Wednesday morning may bring near to below freezing temperatures to Eastern Washington generally north of a line from Yakima to Colfax. While showers remain along the coast and Northwest Interior, the rest of the state is forecast to start the day dry. The next disturbance reaches the I-5 Corridor that afternoon, bringing in more rain showers that should spread into Eastern Washington on Thursday.

The moisture content in this system is likely to be less than that of the Monday-Tuesday cold front and low, leading to lighter rainfall values. Still, modest improvement to the drought is possible for Western Washington, the Palouse, and Okanogan Highlands. Snow levels are likely to remain above pass level. Friday through the weekend, moderate ridging over the region will push the jet stream north to aim Pacific moisture at Southeast Alaska and the northern British Columbia coast. In the Pacific Northwest, look for mostly clear skies through the weekend with temperatures near average.


8 to 14 Day Outlook, October 4 to October 10, 2021
  • Near 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: SW & breezy Tue, S & light Wed, SW with breezy areas Thu, N and light Fri.
  • Precipitation: Rain showers tapering off Tue AM. Rain showers Thu.
  • High Temps: Mid 60s Tue-Wed, low 70s Thu, near 70 Fri.
  • Low Temps: Near 50 Mon night, low 40s Tue night, mid 40s Wed night, near 50 Thu night, mid 40s Fri night. Cooler in sheltered areas.
  • Sky Cover: Mostly cloudy Tue, partly cloudy Wed, increasing clouds Thu, partly cloudy Fri.
Weekend
  • Wind: Generally NE and light.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 70s Sat, mid 70s Sun.
  • Low Temps: Mid 40s Sat & Sun nights. Cooler in sheltered areas.
  • Sky Cover: Mostly clear.

North Central Washington
Remainder of the Week
  • Wind: SW & breezy Tue, S & light Wed, SW with breezy areas Thu, N with breezy areas Fri.
  • Precipitation: Lowland rain showers tapering off Tue AM, mountain showers tapering off Tue PM. Rain showers Thu.
  • High Temps: Low 60s Tue, mid 60s Wed, near 70 Thu-Fri. Cooler in higher terrain.
  • Low Temps: Upper 40s Mon night, low 40s Tue night, low 50s Wed-Thu nights, mid 40s Fri night. Cooler in higher terrain and sheltered areas.
  • Sky Cover: Decreasing clouds Tue, partly cloudy Wed, mostly cloudy Thu, decreasing clouds Fri.
Weekend
  • Wind: Generally NE and light.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 70s Sat, mid 70s Sun. Cooler in higher terrain.
  • Low Temps: Upper 40s Sat & Sun nights. Cooler in higher terrain and sheltered areas.
  • Sky Cover: Mostly clear.

Eastern Washington
Remainder of the Week
  • Wind: SW & breezy Tue, S & light Wed, SW with breezy areas Thu, N and light Fri.
  • Precipitation: Rain showers Tue & Thu.
  • High Temps: Near 60 Tue & Wed, near 70 Thu, mid 60s Fri. Warmer in the Lewis & Clark Valley.
  • Low Temps: Mid 40s Mon night, upper 30s Tue night, near 40 Wed night, low 40s Thu night, near 40 Fri night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly cloudy Tue, partly cloudy Wed, mostly cloudy Thu, partly cloudy Fri.
Weekend
  • Wind: Generally NE and light.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 70 Sat, low 70s Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Low 40s Sat & Sun nights. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly clear.

Western Washington
Remainder of the Week
  • Wind: Generally S with breezy areas Tue-Wed, light and variable Thu, N with breezy areas along the coast and I-5 Fri.
  • Precipitation: Rain showers Mon-Thu.
  • High Temps: Near 60 Tue & Wed, low 60s Thu & Fri. Cooler in higher terrain.
  • Low Temps: Low 50s Mon night, near 50 Thu night, mid 50s Wed night, near 50 Thu & Fri nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.
Weekend
  • Wind: Light and variable.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 60s Sat & Sun. Cooler in higher terrain.
  • Low Temps: Near 50 Sat & Sun nights. Cooler in higher terrain.
  • Sky Cover: Partly cloudy.

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