AgWeatherNet Weekly Outlook for May 14 to May 20, 2021

Warm weekend, becoming cooler next week

Mark Ingalls, AgWeatherNet Intern

Synopsis:

Ridging continues to dominate the weather pattern in the Pacific Northwest through the weekend. Temperatures warming to near 80 for parts of the I-5 Corridor and into the 90s for parts of the Columbia Basin are expected. The coast is likely to stay cooler thanks to semi-persistent low level cloud cover. Temperatures moderate somewhat Monday with a cold front moving in Tuesday to push the ridge out and bring in unsettled weather for the remainder of the forecast period.

Discussion:

During the day Friday, a weak upper level trough punched through the ridge sitting over the Pacific Northwest, becoming a closed low pressure system in California. This shifted upper level flow to out of the southwest which may provide enough stability for isolated thunderstorms in the Blue Mountains and on the Palouse Friday afternoon. Otherwise mostly clear and dry conditions are forecast to last through the weekend.

The ridge rebounds Saturday and Sunday to give the region the highest temperatures of this warm spell. The Southwest Interior may reach 80 degrees with some areas in the Columbia Basin and adjacent valleys forecast to reach into the 90s Sunday afternoon. Winds are forecast to remain light except some breezy conditions during the afternoon hours through mountain gap areas.

Cooler temperatures are forecast statewide Monday with a more pronounced onshore marine push. The cooldown is likely to be more apparent west of the Cascades where stubborn low level stratus may be widespread. Tuesday the real cool down starts with a cold front pushing the ridge out and ushering in a period of upper level troughing over Washington State. Breezy conditions are expected in typical windy spots as the cold front moves through.

Increased cloudiness is forecast statewide with some shower activity possible Tuesday through Thursday. As is usually the case, the best chances of rain are in Western Washington and mountainous areas with lower chances on the Palouse and around Spokane. Current indications are that much of Central Washington will remain dry. Snow levels may be as low as 3000 feet along the Canadian border, raising to near 4500 feet along the Oregon state line.

Drought conditions continue to plague parts of the state. No major changes in Eastern Washington were noted by the National Drought Mitigation Center in this week's update. West of the Cascades, severe drought (D2/4) is being observed in Clark County with moderate drought (D1/4) elsewhere generally south of US 12. This comes after a particularly dry couple of months. Vancouver had its driest April on record with only 0.33 inches of rain which is well below the monthly average of 2.93 inches.


8 to 14 Day Outlook, May 14 to May 20, 2021
  • Below average temperatures and below average precipitation are favored for the period.

Important Points About Next Week's Weather

South Central Washington
Weekend
  • Wind: Generally W/SW, breezy periods through mountain gaps.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 80s Sat, low 90s Sun.
  • Low Temps: Near 50 Fri night, mid 50s Sat-Sun nights.
  • Sky Cover: Mostly clear.
Next Week
  • Wind: Generally W and breezy.
  • Precipitation: Low chance of showers Wed.
  • High Temps: Mid 80s Mon, near 80 Tue, Upper 70s Wed, near 70 Thu.
  • Low Temps: Near 50 Mon-Tue night, mid 40s Wed night, low 40s Thu night.
  • Sky Cover: Mostly clear Mon-Tue, mostly cloudy Wed, partly cloudy Thu.

North Central Washington
Weekend
  • Wind: Generally W, breezy periods through mountain gaps.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 80s Sat, mid 80s Sun. Cooler in higher terrain.
  • Low Temps: Near 50 Fri-Sat nights, mid 50s Sun night. Cooler in higher terrain.
  • Sky Cover: Mostly clear.
Next Week
  • Wind: Generally W and breezy.
  • Precipitation: Chance of rain showers Wed, upslope showers also possible Tue & Thu.
  • High Temps: Mid 80s Mon, near 80 Tue, upper 60s Wed, mid 60s Thu. Cooler in higher terrain.
  • Low Temps: Upper 40s Mon night, mid 40s Tue-Thu nights. Cooler in higher terrain.
  • Sky Cover: Partly cloudy Mon-Tue, mostly cloudy Wed, partly cloudy Thu.

Eastern Washington
Weekend
  • Wind: W/SW and light.
  • Precipitation: Low chance of rain Fri PM, otherwise dry.
  • High Temps: Near 80 Sat, low 80s Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Mid 40s Fri night, upper 40s Sat-Sun nights. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly clear.
Next Week
  • Wind: Generally W and breezy.
  • Precipitation: Chance of rain Wed & Thu.
  • High Temps: Mid 80s Mon, upper 70s Tue, mid 60s Wed, low 60s Thu. Warmer in the Lewis & Clark Valley.
  • Low Temps: Upper 40s Mon-Tue nights, low 40s Wed-Thu nights. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Partly cloudy Mon-Tue, mostly cloudy Wed-Thu.

Western Washington
Weekend
  • Wind: Generally W/NW, breezy periods through the Strait and along the Coast.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 70s Sat, mid 70s to near 80 Sun. Cooler in higher terrain and along the coast.
  • Low Temps: Near 50 Fri-Sun nights. Cooler in higher terrain.
  • Sky Cover: Ranging from mostly cloudy along the coast to mostly clear along I-5.
Next Week
  • Wind: W and mainly light Mon, S with breezy areas Tue, W with breezy areas Wed, W and breezy Thu.
  • Precipitation: Chance of rain and mountain snow Tue-Thu.
  • High Temps: Upper 60s Mon, mid 60s Tue, low 60s Wed-Thu. Cooler in higher terrain.
  • Low Temps: Upper 40s Mon-Thu nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.

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Washington State University