AgWeatherNet Weekly Outlook for April 30 to May 06, 2021

Off and on wet weather west of the Cascades, mainly dry in the east

Mark Ingalls, AgWeatherNet Intern
Craig Oswald, AgWeatherNet Field Meteorologist

Synopsis:

A cold front working its way across the state is bringing an end to this week's early season heat wave. Rain showers are expected in Western Washington and mountainous areas through the weekend while lowland Eastern Washington should remain dry with breezy areas. The whole state sees a break from the rain Sunday before another cold front moves in. Again, Western Washington and mountainous areas can expect some rain showers with arid regions staying dry. A ridge briefly builds over the region for a mainly dry Tuesday and Wednesday before a trough pushes it out Thursday in favor of more unsettled conditions beyond the end of the forecast period.

Discussion:

Rain showers are forecast to taper off slowly overnight Friday night and into Saturday in and west of the Cascades. As the cold front moving across the Pacific Northwest sweeps across the Cascades, winds will pick up in Eastern Washington. The highest winds are expected to be along Cascade mountain gaps such as the Kittitas Valley and Columbia River Gorge, but breezy conditions should extend throughout most of the Columbia Basin as well.

Sunday will be dry across Washington, but on Monday another cold front is expected to move through the region. This will result in conditions similar to the front moving through when this forecast was written – rain showers in the mountains and Western Washington, dry conditions with breezy to windy areas for Eastern Washington. A weak ridge builds over the West Coast beginning Tuesday with dry conditions forecast statewide through Wednesday.

On Thursday, a third cold front is expected to begin moving from west to east across the region with rain showers in and west of the Cascades. It is possible that some rain showers may occur in arid portions of the state on Friday, but it is too far out to tell with any certainty. The upper level low that is expected to produce the cold front may move over the Pacific Northwest during the weekend to keep unsettled weather in place.

Drought conditions continue to slowly worsen in Eastern Washington. The National Drought Mitigation Center noted this week that severe drought conditions (D2/5) have expanded to include Yakima, the Tri-Cities, and Othello, with moderate drought conditions (D1/5) encompassing most areas east of a line from The Dalles to Wenatchee to Republic, including Spokane and the Palouse. Elsewhere, abnormally dry conditions (D0/5) were noted for most of Washington outside the Cascades and Olympics.

Using the Tri-Cities as an example and assuming today's forecast verifies, only a trace of rain was observed during the month of April. This ties a couple other years as being the driest April on record (most recently 1973), and is the first month to only have a trace of rain since September 2018. Since the beginning of 2021, the Tri-Cities have only seen 1.28 inches of rain, the lowest value since 2013 and 7th lowest on record. This scene is playing out in many other Central Washington cities, including Yakima (only 0.04 inches in April) and Ephrata (only 0.07 inches in April).


8 to 14 Day Outlook, May 07 to May 13, 2021
  • Below average temperatures and near average precipitation are favored for the period.

Important Points About Next Week's Weather

South Central Washington
Weekend
  • Wind: W & breezy Sat, W with breezy areas Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 70s Sat & Sun.
  • Low Temps: Mid 40s Fri night, near 40 Sat night, low 40s Sun night.
  • Sky Cover: Partly cloudy Sat & Sun.
Next Week
  • Wind: Generally W. Breezy Mon & Thu.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 70 Mon-Tue, mid 70s Wed, low 80s Thu.
  • Low Temps: Mid 40s Mon-Thu nights.
  • Sky Cover: Partly cloudy.

North Central Washington
Weekend
  • Wind: W & breezy Sat, W with breezy areas Sun.
  • Precipitation: Upslope showers possible Fri night.
  • High Temps: Near 70 Sat & Sun. Cooler in higher terrain.
  • Low Temps: Upper 40s Fri night, low 40s Sat & Sun nights. Cooler in higher terrain.
  • Sky Cover: Partly cloudy.
Next Week
  • Wind: Generally W. Breezy Mon & Thu.
  • Precipitation: Low chance of upslope showers Mon & Thu.
  • High Temps: Near 70 Mon-Tue, mid 70s Wed, upper 70s Thu. Cooler in higher terrain.
  • Low Temps: Mid 40s Mon-Tue nights, near 50 Wed-Thu nights. Cooler in higher terrain.
  • Sky Cover: Partly cloudy Mon-Wed, mostly cloudy Thu.

Eastern Washington
Weekend
  • Wind: W & breezy Sat, W with breezy areas Sun.
  • Precipitation: Upslope showers possible Fri night.
  • High Temps: Near 70 Sat, upper 60s Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Mid 40s Fri night, near 40 Sat-Sun nights. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Partly cloudy.
Next Week
  • Wind: Generally W. Breezy Mon & Thu.
  • Precipitation: Chance of rain Tue.
  • High Temps: Mid 60s Mon-Tue, near 70 Wed, mid 70s Thu. Warmer in the Lewis & Clark Valley.
  • Low Temps: Mid 40s Mon night, near 40 Tue night, mid 40s Wed-Thu nights. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Partly cloudy Mon-Wed, mostly cloudy Thu.

Western Washington
Weekend
  • Wind: W and breezy Sat, W and breezy along the Strait Sun.
  • Precipitation: Rain showers through Sat.
  • High Temps: Near 60 Sat & Sun. Cooler in higher terrain.
  • Low Temps: Upper 40s Fri night, mid 60s Sat-Sun nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy Sat, partly cloudy Sun.
Next Week
  • Wind: W & breezy Mon, light and variable Tue-Wed, W and breezy Thu.
  • Precipitation: Rain showers Mon & Thu.
  • High Temps: Upper 50s Mon, near 60 Tue, upper 60s Wed, mid 60s Thu. Cooler in higher terrain.
  • Low Temps: Upper 40s Mon night, mid 40s Tue night, near 50 Wed-Thu nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy.

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