AgWeatherNet Weekly Weather Outlook Monday Update for November 30 to December 6, 2020

Dry conditions and mostly seasonable temperatures for the week

Mark Ingalls, AgWeatherNet Intern
Joe Zagrodnik, AgWeatherNet Postdoctoral Research Associate

Synopsis:

As showers associated with a passing cold front continue to move out of the region to the east, a ridge of high pressure looks to be the main weather influence for the week. This will bring a stretch of dry weather and near seasonable temperatures. Strong inversions and overnight fog/freezing fog are expected to be the main considerations this week, especially east of the Cascades.

Discussion:

Scattered rain showers and mountain snow are to continue to diminish through the day (Monday), and trend dry overnight, as they move through the state from west to east in association with a quickly moving cold front. Post frontal windy conditions also look to trend light through Monday night.

A change in the upper wave pattern will allow for a ridge to build over the west coast Tuesday and effectively begin to guide incoming Pacific storms north toward far northern British Columbia. This change will produce dry conditions statewide through the week and for most of the weekend. Calm to light winds and generally partly cloudy skies can also be expected along with near seasonable temperatures. The main concern for the period will be inversions and fog, primarily east of the Cascades. Temperature inversions this time of year aren’t as detrimental as during the growing season from an agriculture perspective, and more attention should be paid to the formation of fog and freezing fog, especially in low lying areas. Fog will greatly reduce visibility and prolonged freezing fog can cause icing on various objects. The greatest threat for these conditions are within valleys and throughout the Columbia Basin where light winds and a capped boundary layer (thanks to inversion formation) will make it difficult to mix down to the surface, especially with the low sun angle this time of year. Don’t be surprised if conditions become slightly hazy by weeks end/the weekend in these areas as well.

Parts of western Washington look to have a return to action Sunday as a few light scattered lowland rain and mountain snow showers move in from the southwest. Areas affected look to primarily be along the coast, the northern third of the region, and to a greater degree the Olympic Peninsula. Other than this, conditions are to remain dry through the weekend statewide with similar weather conditions as projected through the week.


Important Points About Next Week's Weather

South Central Washington
Remainder of the Week
  • Wind: Windy conditions trending light through Mon night and remaining so Tue. Switching to E/NE yet variable Tue night and remaining mostly light to calm.
  • Precipitation: Low chance for a scattered rain shower or two coming to an end Mon night. Dry conditions expected Tue and the remainder of the week.
  • High Temps: Low 40s Tue, mid 30s Wed, upper 30s Thu, upper 30s Fri.
  • Low Temps: Mid 20s Mon night, mid 20s Tue night, low 20s Wed night, low 20s Thu night.
  • Sky Cover: Mostly sunny to partly cloudy. Overnight/early morning areas of fog/freezing fog.
Weekend
  • Wind: E/NE yet variable and light to calm.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 30s Sat, upper 30s Sun.
  • Low Temps: Near 20 Fri night, near 20 Sat night, low 20s Sun night.
  • Sky Cover: Partly cloudy to mostly cloudy. Overnight/early morning areas of fog/freezing fog.

North Central Washington
Remainder of the Week
  • Wind: Breezy and windy conditions trending light through Mon night and remaining so Tue. Switching to N/NE yet variable Tue night and remaining mostly light to calm.
  • Precipitation: Scattered rain showers and mountain snow trending dry through Mon night. Dry conditions expected Tue and the remainder of the week.
  • High Temps: Upper 30s Tue, low 30s Wed, mid 30s Thu, mid 30s Fri. Cooler in high terrain.
  • Low Temps: Low 20s Mon night, low 20s Tue night, low 20s Wed night, low 20s Thu night. Cooler in high terrain and deep valleys.
  • Sky Cover: Mostly sunny Tue and becoming partly cloudy by Wed. Cloudier throughout high terrain. Overnight/early morning areas of fog/freezing fog, especially within deep valleys.
Weekend
  • Wind: N/NE yet variable and light to calm.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 30s Sat, mid 30s Sun. Cooler in high terrain.
  • Low Temps: Near 20 Fri night, near 20 Sat night, low 20s Sun night. Cooler in high terrain and deep valleys.
  • Sky Cover: Partly cloudy to mostly cloudy. Overnight/early morning areas of fog/freezing fog, especially within deep valleys.

Eastern Washington
Remainder of the Week
  • Wind: Windy conditions trending light through Mon night and remaining so Tue. Switching to E/NE yet variable Tue night and remaining mostly light to calm.
  • Precipitation: Scattered rain showers and mountain snow trending dry through Mon night. Dry conditions expected Tue and the remainder of the week.
  • High Temps: Upper 30s Tue, mid 30s Wed, near 40 Thu, near 40 Fri. Cooler through the Blues.
  • Low Temps: Mid 20s Mon night, mid 20s Tue night, mid 20s Wed night, mid 20s Thu night. Cooler through the Blues.
  • Sky Cover: Mostly sunny to partly cloudy. Overnight/early morning areas of fog/freezing fog.
Weekend
  • Wind: E/NE yet variable and light to calm.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 30s Sat, upper 30s Sun. Cooler through the Blues.
  • Low Temps: Mid 20s Fri night, mid 20s Sat night, mid 20s Sun night. Cooler through the Blues.
  • Sky Cover: Partly cloudy to mostly cloudy. Overnight/early morning areas of fog/freezing fog.

Western Washington
Remainder of the Week
  • Wind: Breezy and windy conditions trending light through Mon night and remaining so Tue. Switching to E/NE yet variable Tue and remaining mostly light to calm. Breezier near the coast and straight.
  • Precipitation: Scattered rain showers and mountain snow trending dry through Mon night. Dry conditions expected Tue and the remainder of the week.
  • High Temps: Mid 40s Tue, upper 40s Wed, mid 40s Thu, upper 40s Fri. Cooler through the Cascades and Olympics.
  • Low Temps: Low 30s Mon night, upper 20s Tue night, upper 20s Wed night, upper 20s Thu night. Cooler through the Cascades and Olympics.
  • Sky Cover: Mostly sunny to partly cloudy. Overnight/early morning patchy fog/freezing fog.
Weekend
  • Wind: E/NE yet variable and light to calm. Breezier near the coast and straight.
  • Precipitation: Dry conditions Sat with a few light scattered lowland rain/mountain snow showers along the coast, northern third of the region, and mostly the Olympic Peninsula Sun.
  • High Temps: Upper 40s Sat, upper 40s Sun.
  • Low Temps: Upper 20s Fri night, low 30s Sat night, low 30s Sun night. Cooler through the Cascades and Olympics.
  • Sky Cover: Mostly sunny to partly cloudy. Overnight/early morning areas of fog/freezing fog.

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