AgWeatherNet Weekly Weather Outlook for July 12 to July 18, 2021

Alaskan low to bring milder temperatures later this week

Mark Ingalls, AgWeatherNet Intern

Synopsis:

Temperatures are forecast to remain above average for much of Washington through Wednesday under mostly clear skies (with regional hazy and locally smoky conditions) thanks to a transient ridge. The exception will be coastal areas, which should remain under low stratus from the marine layer through the entire week. Wednesday afternoon, the Pacific Northwest begins to fall under the influence of an area of low pressure dropping southward from Alaska. This is forecast to spread some marine influence eastward with gusty winds in typical windy spots Thursday. Cooler temperatures last through the weekend under the influence of the low and associated trough, but little if any precipitation is forecast.

Discussion:

A shortwave trough is moving out of the Pacific Northwest, being replaced by a ridging pattern that is forecast to remain in place until Wednesday. Temperatures should warm a few degrees Tuesday and Wednesday, reaching above 100 for the Columbia Basin and into the 80s for much of the Western Washington interior. A persistent marine layer should remain along the coast, keeping mostly cloudy skies and even a chance of drizzle there, elsewhere look for mostly clear skies. Haze from regional wildfires should be noticeable throughout much of Washington during this period with thick smoke possible near wildfires and the Canadian border.

Wednesday afternoon, a low pressure system and associated upper level trough should begin influencing Pacific Northwest weather. This should result in the marine layer spreading through much of Washington. In Western Washington, look for mostly cloudy skies to spread inland to the Cascades with highs in the low to mid 70s. Areas of drizzle or light rain are possible along the Coast.

East of the Cascades, the marine influence is forecast to be responsible for dropping highs by as much as ten degrees leading into the weekend. Little if any cloud cover is expected there, however. A tightening pressure gradient between the low to the north and the region of high pressure over the Interior Southwest should produce breezy conditions Wednesday, Thursday, and Friday afternoons in typical windy spots. Cooler temperatures last through Saturday. Sunday, the ridge of high pressure over the Southwest builds northward, kicking the low and its trough to the west and forcing a warming trend to start the following week.


8 to 14 Day Outlook, July 19 to July 25, 2021
  • Above average temperatures and below average precipitation are favored for the period.

Important Points About Next Week's Weather

South Central Washington
Remainder of the Week
  • Wind: Generally W to SW, breezy Wed-Fri.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 100 Tue-Wed, mid 90s Thu, near 90 Fri.
  • Low Temps: Upper 60s Mon-Tue nights, mid 60s Wed night, low 60s Thu-Fri nights.
  • Sky Cover: Mostly clear with widespread haze.
Weekend
  • Wind: Generally light. W on Sat, variable on Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 90s Sat, mid 90s Sun.
  • Low Temps: Low 60s Sat night, mid 60s Sun night.
  • Sky Cover: Mostly clear, haze possible.

North Central Washington
Remainder of the Week
  • Wind: Generally W to SW, breezy Wed-Fri.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 100s Tue, upper 90s Wed, low 90s Thu, upper 80s Fri. Cooler in higher terrain.
  • Low Temps: Near 70 Mon-Tue nights, upper 60s Wed night, low 60s Thu-Fri nights. Cooler in higher terrain and sheltered areas.
  • Sky Cover: Mostly clear with widespread haze.
Weekend
  • Wind: Generally light. W on Sat, variable on Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 90 Sat, mid 90s Sun. Cooler in higher terrain.
  • Low Temps: Low 60s Sat night, mid 60s Sun night. Cooler in higher terrain and sheltered areas.
  • Sky Cover: Mostly clear, haze possible.

Eastern Washington
Remainder of the Week
  • Wind: Generally W to SW, breezy Wed-Fri.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 90s Tue-Wed, near 90 Thu, mid 80s Fri. Warmer in the Lewis & Clark Valley.
  • Low Temps: Low 60s Mon night, mid 60s Tue night, low 60s Wed night, upper 50s Thu-Fri nights. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly clear with widespread haze.
Weekend
  • Wind: Generally light. W on Sat, variable on Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 80s Sat, mid 90s Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 60 Sat night, low 60s Sun night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly clear, haze possible.

Western Washington
Remainder of the Week
  • Wind: Generally NW to W with breezy periods along the coast and through the strait.
  • Precipitation: Periodic drizzle and light rain along the coast, otherwise dry.
  • High Temps: Low 80s Tue, upper 70s Wed, low 70s Thu-Fri. Cooler in higher terrain and along the coast.
  • Low Temps: Near 60 Mon night, upper 50s Tue-Wed nights, mid 50s Thu night, upper 50s Fri night. Cooler in higher terrain.
  • Sky Cover: Mostly clear through Wed, mostly cloudy Thu-Fri. Mostly cloudy all week along the coast.
Weekend
  • Wind: Generally W with breezy periods along the coast and through the strait.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 70s Sat, upper 70s Sun. Cooler in higher terrain and along the coast.
  • Low Temps: Upper 50s Sat night, near 60 Sun night. Cooler in higher terrain.
  • Sky Cover: Mostly clear.

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