AgWeatherNet Weekly Outlook Monday Outlook for February 15 to February 21, 2021

Melting in the lowlands but consistent new snow in the mountains

Mark Ingalls, AgWeatherNet Intern
Craig Oswald, AgWeatherNet Field Meteorologist

Synopsis:

The pattern that pulled three lowland snow events into the Pacific Northwest over the weekend is coming to an end. Temperatures are expected to moderate this week, with many low elevation locations reaching into the 40s by midweek. Generally northwesterly flow in place thanks to a ridge offshore will continue to bring mountain snow through Tuesday and perhaps some rain showers in western lowlands. Wednesday, the ridge crosses the state to provide dry conditions before a new series of systems start Thursday. Some snow will be possible east of the Cascades, but with highs still above freezing, accumulations should be light. West of the Cascades, rain is expected for most locations into and through the weekend.

Discussion:

High temperatures will be on the rise this week, with most lowland regions of the state reaching into the 40s by Wednesday. A weak cold front associated with a modest low pressure system will move across the state Monday night and bring rain west of the Cascades, snow possibly mixed with rain east of the Cascades, and mountain snow. Some showers are expected to linger into the day Tuesday. The cold front will decrease pressure gradients in Whatcom County and the foothills on the west side of the Cascades, significantly calming or perhaps even removing easterly winds that are responsible for keeping those areas colder as compared to Everett and Bellevue.

Wednesday should be dry across Washington thanks to a ridge of high pressure moving across the region. Some areas may even see mostly sunny skies during the day, which should help to accelerate lowland snow melt. Dry weather is only expected to last for about a day, and by Thursday the first in another series of disturbances makes its way onshore and are expected to persist into the weekend.

Temperatures are also expected to moderate this week in Alberta, with Calgary possibly reaching into the 40s this weekend. This is important for the Pacific Northwest because there will not be a flow of extremely cold air coming from the northeast, making this upcoming weekend much warmer than what the region saw over the last couple days.

Precipitation type is expected to be rain for Western Washington lowlands from Thursday and into the weekend. East of the Cascades, snow may occur, but highs are expected to remain above freezing for most which should limit accumulations. Snow levels are expected to be below pass level for this stormy stretch which will likely make cross-state travel difficult. While Western Washington should be rainy through the weekend, the driest parts of the state (Columbia Basin and Yakima Valley) may only receive precipitation on Thursday and Sunday.


Important Points About Next Week’s Weather

South Central Washington
Remainder of the week
  • Wind: Generally S, breezy areas Tue & Thu-Fri.
  • Precipitation: Rain showers ending Mon night, chance of snow Thu.
  • High Temps: Near 40 Tue, low 40s Wed, mid 30s Thu, mid 40s Fri.
  • Low Temps: Mid 20s Mon night, upper 20s Tue night, mid 20s Wed night, near 30 Thu night, low 30s Fri night.
  • Sky Cover: Mostly cloudy Tue, partly cloudy Wed, mostly cloudy to overcast Thu-Fri.
Weekend
  • Wind: Generally SW, breezy Sun.
  • Precipitation: Low chance of rain/snow Sun.
  • High Temps: Mid 40s Sat, near 50 Sun.
  • Low Temps: Mid 30s Sat night, upper 30s Sun night.
  • Sky Cover: Mostly cloudy.

North Central Washington
Remainder of the week
  • Wind: Generally S, breezy areas Tue & Thu-Fri.
  • Precipitation: Lowland rain/snow ending Mon night. Beginning Wed night with chances lasting through Fri. Mountain snow every day except Wed.
  • High Temps: Upper 30s Tue, near 40 Wed, mid 30s Thu, low 40s Fri. Cooler in higher terrain.
  • Low Temps: Mid 20s Mon night-Thu night, near 30 Fri night. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy Tue, partly cloudy Wed, mostly cloudy to overcast Thu-Fri.
Weekend
  • Wind: Generally SW, breezy Sun.
  • Precipitation: Mountain snow. Lowland rain/snow possible Sun.
  • High Temps: Low 40s Sat, upper 40s Sun. Cooler in higher terrain.
  • Low Temps: Low 30s Sat night, mid 30s Sun night. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.

Eastern Washington
Remainder of the week
  • Wind: Generally S, breezy areas Tue & Thu-Fri.
  • Precipitation: Snow tapering off Mon night & Tue. Chance of rain/snow Thu-Fri.
  • High Temps: Low 30s Tue, mid 30s Wed & Thu, upper 30s Fri. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 20 Mon-Wed nights, near 30 Thu night, upper 30s Wed night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly cloudy Tue. Partly cloudy with patchy fog Wed. Mostly cloudy to overcast Thu-Fri.
Weekend
  • Wind: Generally SW, breezy Sun.
  • Precipitation: Chance of rain/snow Sun.
  • High Temps: Upper 30s Sat, low 40s Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Low 30s Sat night, mid 30s Sun night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly cloudy to overcast.

Western Washington
Remainder of the week
  • Wind: W & breezy in areas Tue. W & mainly light Wed. Becoming S Thu, breezy areas Fri.
  • Precipitation: Rain and mountain snow showers through Tue, again Thu-Fri.
  • High Temps: Mid 40s Tue-Fri. Cooler in higher terrain.
  • Low Temps: Near 40 Mon night, upper 30s Tue-Wed nights, near 40 Thu-Fri nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast. Patchy fog Wed.
Weekend
  • Wind: Generally SW, breezy Sun.
  • Precipitation: Rain and mountain snow.
  • High Temps: Mid 40s Sat, near 50 Sun. Cooler in higher terrain.
  • Low Temps: Low 40s Sat and Sun nights. Cooler in higher terrain.
  • Sky Cover: Overcast.

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Washington State University