AgWeatherNet Weekly Weather Outlook Monday Update for January 25 to January 31, 2021

Chances for light precipitation through most of the week

Mark Ingalls, AgWeatherNet Intern
Craig Oswald, Field Meteorologist

Synopsis:

Most of the Pacific Northwest looks to transition to a southwesterly flow regime early in the week as a low pressure system moves offshore of the region from the northwest. This flow regime will help to draw moist air from the south/southwest and keep nearly all of Washington State under a chance of light precipitation from Tuesday night through the week, even as a weak upper ridge is expected to quickly pass through the region Friday. A return to a generally southwest flow regime is quickly reestablished as a strong circulation moves into the Gulf of Alaska. This looks to bring a return of light precipitation throughout the state through the weekend with guidance hinting at a more impactful system Saturday night/Sunday. Temperatures look to be near to slightly below normal for the week.

Discussion:

Radar imagery and surface observations from midday Monday indicate a few snow and rain showers remaining throughout the Palouse and the eastern Washington regional area. Some convective type rain showers look to be moving through western Washington thanks to colder temperatures aloft, with most of the activity concentrated along the coast. In both cases this activity is expected to continue to diminish through the day and evening. Some areas of fog and freezing fog can be expected throughout the valleys and low areas of Washington east of the Cascades Monday night. A dry day looks to be in store for Tuesday statewide aside from a high elevation light snow shower or two.

Conditions are expected to become more active as a low pressure system originating form near the Gulf of Alaska takes residence off the coast of the Pacific Northwest. Breezy to windy east/southeasterly surface winds can be expected Tuesday night into Wednesday with the Cascade gaps particularly vulnerable to strong gusts. The south/southwesterly flow aloft will help to move moisture into the region. Paired with sufficient forcing thanks to the position of the subsequent long wave trough that is expect to dig south along the west coast and another upper feature/weak surface low moving south along the coast around the Wednesday night time frame, a chance of shower activity will be maintained in the outlook throughout the week and weekend.

Snow levels are to be below pass levels through the period with lowland snow likely throughout Washington east of the Cascades, primarily during the overnight hours. Accumulations are expected to be light. A rain/snow mix can generally be expected for lowland western Washington Tuesday night, with greater snow chance to the north. No significant accumulations are anticipated on the west side. Temperatures look to warm slightly after Tuesday night with lowland western Washington expected to receive rain with any subsequent shower activity through the week. Washington east of the Cascades will maintain a regime of generally overnight snow and day time rain/snow mix with any passing showers. The exception to this will be northern Washington where colder temperatures are expected to linger, allowing for mostly lowland snow during the day. Locations along the Idaho border also have a better chance of trending toward snow. Low land accumulations are anticipated to be light with only an inch or two throughout the week while mountain locations are likely to receive several inches throughout the course of the week, including at pass levels.

A lessening in shower activity may be noticed across the state Friday as a small and weak ridge quickly traverses the region; however multiple forms of model guidance suggest that a few showers are to linger across the state with no significant change in weather being extracted by the ridge other than a slight clearing of skies. This chance for continued scattered showers will be reflected in the outlook.

By Saturday, a strong circulation reestablishes itself in the Gulf of Alaska. This feature looks to eject upper disturbances, subsequently forming modest surface cyclones that are anticipated to move into Washington. A system bringing more widespread lowland rain and mountain snow showers is expected by Saturday night with conditions remaining unsettled statewide through Sunday.


Important Points About Next Week's Weather

South Central Washington
Remainder of the Week
  • Wind: Calm to light and variable. Becoming E/SE Tue and breezy, some gusts to 25mph possible. Trending N and lighter Wed. Return to calm to light and variable by Fri.
  • Precipitation: Dry through Tue. Snow Tue night and trending dry Wed. Mostly dry with a low chance for a passing rain/snow shower beginning Wed night and remaining through the week.
  • High Temps: Upper 30s Tue, near 40 Wed, near 40 Thu, low 40s Fri.
  • Low Temps: Low 20s Mon night, upper 20s Tue night, mid 20s Wed night, upper 20s Thu night.
  • Sky Cover: Mostly cloudy. Areas of fog and freezing fog Mon night and Thu night.
Weekend
  • Wind: Becoming S and breezy/windy Sat. Remaining so for Sun.
  • Precipitation: Mostly dry with a low chance for a rain/snow shower. More widespread rain/snow Sun.
  • High Temps: Low 40s Sat, mid 40s Sun.
  • Low Temps: Upper 20s Fri night, near 30 Sat night, low 30s Sun night.
  • Sky Cover: Partly cloudy to mostly cloudy.

North Central Washington
Remainder of the Week
  • Wind: Calm to light and variable. Becoming E/SE Tue and breezy, some gusts to 30mph possible in the Basin. Becoming N/NE and lighter Wed, Basin to remain breezy. Return to calm to light and variable by Fri.
  • Precipitation: Dry through Tue. Snow Tue night and Wed. On/off rain/snow showers remaining through the week with more consistent snow shower activity through the mtns.
  • High Temps: Near 30 Tue, low 30s Wed, mid 30s Thu, mid 30s Fri. Cooler in high terrain.
  • Low Temps: Mid 20s Mon night, mid 20s Tue night, upper 20s Wed night, mid 20s Thu night. Cooler in high terrain.
  • Sky Cover: Mostly cloudy to cloudy. Areas of fog and freezing fog Mon night and Thu night.
Weekend
  • Wind: Becoming S and breezy Sat, windier through the Basin. Gusty through N to S oriented valleys. Remaining so for Sun.
  • Precipitation: On/off rain/snow showers to continue. More widespread snow starting Sat night into Sun.
  • High Temps: Mid 30s Sat, upper 30s Sun. Cooler in high terrain.
  • Low Temps: Mid 20s Fri night, upper 20s Sat night, upper 20s Sun night. Cooler in high terrain.
  • Sky Cover: Mostly cloudy.

Eastern Washington
Remainder of the Week
  • Wind: Calm to light and variable. Becoming E/SE Tue and windy, some gusts to 30mph possible. Generally E and breezy through Thu. Return to calm to light and variable by Fri.
  • Precipitation: Dry through Tue. Snow Tue night and trending dry Wed. Mostly dry with a low chance for a passing rain/snow shower beginning Wed night and remaining through the week.
  • High Temps: Low 30s Tue, upper 30s Wed, low 40s Thu, upper 30s Fri. Cooler through the Blue Mtns.
  • Low Temps: Mid 20s Mon night, upper 20s Tue night, low 30s Wed night, low 30s Thu night. Cooler through the Blue Mtns.
  • Sky Cover: Mostly cloudy to cloudy. Areas of fog and freezing fog Mon night and Thu night.
Weekend
  • Wind: Becoming S/SE and breezy/windy Sat. Remaining so for Sun.
  • Precipitation: Mostly dry with a low chance for a rain/snow shower. More widespread rain/snow Sun.
  • High Temps: Upper 30s Sat, near 40 Sun. Cooler through the Blue Mtns.
  • Low Temps: Upper 20s Fri night, low 30s Sat night, low 30s Sun night. Cooler through the Blue Mtns.
  • Sky Cover: Mostly cloudy.

Western Washington
Remainder of the Week
  • Wind: S and light. Becoming S/SE Tue and windy, some gusts to 30mph possible, stronger near the coast/sound. Trending lighter Wed. Return to calm to light and variable by Fri.
  • Precipitation: Trending dry through Tue. Lowland rain/snow and mtn snow Tue night. Showers remaining very on/off through the week as they continually pass through the region. Lowland rain and mountain snow expected.
  • High Temps: Mid 40s Tue, mid 40s Wed, mid 40s Thu, mid 40s Fri. Cooler through the Cascade and Olympic Mtns.
  • Low Temps: Upper 20s Mon night, near 30 Tue night, low 30s Wed night, low 30s Thu night. Cooler through the Cascade and Olympic Mtns.
  • Sky Cover: Mostly cloudy.
Weekend
  • Wind: Becoming S/SE and windy Sat. Remaining so for Sun. Strong gusts likely.
  • Precipitation: On/off lowland rain and mtn snow showers to continue. Becoming more widespread and heavier Sat and Sat night into Sun.
  • High Temps: Mid 40s Sat, mid 40s Sun. Cooler through the Cascade and Olympic Mtns.
  • Low Temps: Mid 30s Fri night, mid 30s Sat night, mid 30s Sun night. Cooler through the Cascade and Olympic Mtns.
  • Sky Cover: Mostly cloudy to cloudy.

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