AgWeatherNet Weekly Outlook for February 12 to February 18, 2021

Widespread snow this weekend followed by a warming trend

Mark Ingalls, AgWeatherNet Intern
Craig Oswald, AgWeatherNet Field Meteorologist

Synopsis:

Light snow is expected to continue primarily throughout the southern half of Washington during the afternoon Friday before becoming more widespread Friday night into Saturday. This upcoming disturbance is expected to have more moisture embedded within it allowing for higher snowfall totals. Sunday should be dry across most of Washington before a third system brings in more precipitation from the west starting Sunday evening. This third event will have a warm front with it that is expected to bring an end to low elevation snow across western Washington as temperatures rise precipitation transitions to rain on Monday. However, expect continued lowland snow east of the Cascades. Ridging offshore early in the week should also keep the Northwest under northwest flow and unsettled conditions with rain and high elevation snow in mountain areas and west of the Cascades for much of the week as multiple upper disturbances embedded in the flow move across the region. The ridge transits the state Wednesday into Thursday ahead of another possible winter system heading into the weekend.

Discussion:

Many parts of the state woke up to snow Friday morning, especially south of Interstate 90. Light snow showers have been observed throughout the lowlands with fairly consistent mountain snow during the daytime hours. Snow showers look to become more widespread with a new incoming low which should begin impacting Washington Friday evening and spread precipitation inward from the southwest. Snowfall accumulations are expected to be subdued north and east of a line extending from Colfax to Soap Lake to Omak. In the Puget Sound Region, easterly winds blowing dry air and warming as they descend out of the mountains may limit snow accumulations east of I-405 and SR 167. Otherwise, a significant lowland and mountain snow event is expected through Saturday.

With the exception of the Southwest Interior, Sunday morning should be precipitation free before the last of this series of winter storms moves into the region starting in Western Washington Sunday afternoon and spreading east of the Cascades. This may bring a couple inches of snow to the southern half of Western Washington before a transition to rain, but it looks like it will remain as snow in the Cascades and along the I-5 corridor north of Everett as well as on the Palouse until the precipitation ends there Tuesday morning. There is a chance that it will transition to rain in the Lower Columbia Basin as well, but if it doesn't it will be just marginally cold enough to keep snowing.

Temperatures will be at their coldest over the weekend with temperatures similar to what was seen during the day Thursday. Winds should let up somewhat compared to Thursday, but gusty conditions remain a possibility in the Cascades and around Spokane through Saturday. As noted above, easterly winds may also create gusty conditions in some eastern suburbs and exurbs of the Puget Sound Region. In all of these instances, the wind combined with cold temperatures will create low wind chill values. Following the warm front Sunday night, temperatures moderate somewhat but highs are expected to remain 5-10 degrees below average for most of the state.

During the transition away from snow, some freezing rain and sleet are possible along the coast and I-5 before switching fully to rain. Northwesterly flow aloft is expected to keep the pattern unsettled for a time with mountain snow and some light rain showers in Western Washington. The ridge responsible for this flow pattern looks to cross the state Wednesday night allowing the mountains to even have a few precipitation free hours.

Perhaps as early as before sunrise Thursday, the next disturbance makes it's way ashore and into Western Washington. Lowland snow for the I-5 corridor north of Olympia is possible with rain elsewhere west of the Cascades. As it spreads east of the Cascades, some rain and/or snow showers are possible for the Columbia Basin and Yakima Valley, with the precipitation type being mainly snow on the Palouse, in the Okanogan, and in the Blues.

As of early Friday afternoon, much of the snow across Washington had fallen south of Seattle in Western Washington and south of Othello in Eastern Washington. Outside of the mountains, the highest snowfall values appear to be in the Olympia area where some folks saw over six inches and in the Columbia River Gorge where a blizzard warning was in place for a while. White Salmon, located across the Columbia from Hood River, saw just short of a foot. A few inches were observed in the Yakima Valley and greater Tri-Cities area.

Cold air surging down the Fraser River from Central British Columbia created a strong wind event in Whatcom County Thursday. AgWeatherNet stations there observed gusts to 65 mph and the National Weather Service noted a gust to 70 mph in the area. Elsewhere, Quillayute set a new record low Tuesday at 23 and Walla Walla tied its' record low for Thursday by reaching 18.


8 to 14 Day Outlook, February 19 to February 25, 2021
  • Below average temperatures and above average precipitation are favored for the period.

Important Points About Next Week’s Weather

South Central Washington
Weekend
  • Wind: Generally N and light.
  • Precipitation: Snow tapering off Sat PM, possibly resuming again Sun PM.
  • High Temps: Upper 20s Sat & Sun.
  • Low Temps: Low 20s Fri night, mid teens Sat night, near 20 Sun night.
  • Sky Cover: Mostly cloudy to overcast.
Next Week
  • Wind: Switching from N to S Mon, breezy Tue & Thu.
  • Precipitation: Chance of snow Mon, chance of rain/snow Thu.
  • High Temps: Mid 30s Mon, near 40 Tue-Wed, low 40s Thu.
  • Low Temps: Mid 20s Mon & Tue nights, near 30 Wed & Thu nights.
  • Sky Cover: Mostly cloudy Mon-Tue, partly cloudy Wed, mostly cloudy Thu.

North Central Washington
Weekend
  • Wind: Generally N/NE, breezy in the basin with gusts to 20 mph through Sat.
  • Precipitation: Lowland snow Fri night-Sat and again Sun night. Mountain snow possible through the period.
  • High Temps: Low 20s Sat, upper 20s Sun. Cooler in higher terrain.
  • Low Temps: Mid teens Fri & Sat nights, near 20 Sun night. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.
Next Week
  • Wind: Light and variable Mon, W Tue-Thu. Breezy in the basin Tue & Thu.
  • Precipitation: Snow Mon, low of lowland chance of rain/snow Tue & Thu. Mountain snow possible through the weekend.
  • High Temps: Low 30s Mon, low 40s Tue-Thu. Cooler in higher terrain.
  • Low Temps: Mid 20s Mon night, upper 20s Tue night, near 30 Wed & Thu nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.

Eastern Washington
Weekend
  • Wind: NE and breezy through Sat, gusts to 25 mph.
  • Precipitation: Snow south of Spokane Fri night-Sat, snow Sun night.
  • High Temps: Mid 20s Sat, upper 20s Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 10 Fri night, low teens Sat night, near 20 Sun night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Increasing clouds Fri night, mostly cloudy to overcast Sat-Sun.
Next Week
  • Wind: Switching from N to S Mon, breezy Tue & Thu.
  • Precipitation: Snow likely Mon, tapering off Tue. Chance of rain/snow Thu.
  • High Temps: Upper 20s Mon, low 30s Tue, mid 30s Wed, upper 30s Thu. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 20 Mon night, low 20s Tue night, mid 20s Wed & Thu night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly cloudy to overcast.

Western Washington
Weekend
  • Wind: Generally E, locally breezy.
  • Precipitation: Snow Fri night-Sat, rain/snow Sun-Sun night.
  • High Temps: Mid 30s Sat, upper 30s Sun. Cooler in higher terrain.
  • Low Temps: Mid 20s Fri night, near 30 Sat night, low 30s Sun night. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.
Next Week
  • Wind: W Mon-Tue and breezy along the coast, strait, and South Sound. S and breezy in the NE interior Wed & Thu.
  • Precipitation: Rain and mountain snow Mon, chance of rain and mountain snow Tue-Thu, rain and mountain snow Thu. May also have lowland snow north of Everett Mon.
  • High Temps: Low 40s Mon, mid 40s Tue-Thu. Cooler in higher terrain and north of Everett.
  • Low Temps: Upper 30s Mon-Thu nights. Cooler in higher terrain and north of Everett.
  • Sky Cover: Mostly cloudy to overcast.

Like us on Facebook at https://www.facebook.com/AgWeatherNet
Follow us on Twitter at https://www.twitter.com/AgWeatherNet
Washington State University