AgWeatherNet Weekly Weather Outlook for August 30 to September 5, 2021

Generally dry and seasonably mild

Mark Ingalls, AgWeatherNet Field Technician

Note: In observation of Labor Day, next week's AgWeatherNet Outlook will come out on Tuesday, September 7 instead of Monday, September 6.

Synopsis:

The first half of the week is forecast to be dominated by generally cool conditions. Some rain showers are possible in Western Washington Monday evening into Tuesday, but chances are low and precipitation values are forecast to be light. Gradual warming begins Thursday. Temperatures are forecast to peak around average for this time of year this weekend. A weak cold front may come through Sunday, bringing some rain chances to Western Washington and the mountains and providing a modest cool down for the start of next week.

Discussion:

A cold front coming through the Pacific Northwest on Monday is bringing a few isolated rain showers for Western Washington, mainly north of Seattle. Breezy conditions are being seen through the Strait of Juan de Fuca and Cascade mountain gaps, as well as in Eastern Washington lowlands. Isolated showers may linger into Tuesday, otherwise expect a dry week.

Upper level troughing should keep the region cool through Wednesday. Highs in Western Washington are forecast to be generally around 70 in the Puget Sound Region, reaching around 75 in Clark County. East of the Cascades, highs are also likely to remain in the 70s. Lows into the 30s are expected Monday and Tuesday nights in the northern highlands of Eastern Washington, with a few areas of frost possible in typical cold spots and at high elevations.

Troughing gives way to zonal flow Wednesday into Thursday, allowing temperatures to rise modestly. Weak ridging is likely to come into play for the weekend, rising temperatures to near average for early September. While there is some uncertainty in the model guidance, look for a cold front to come through on Sunday. This is expected to bring a chance of showers for Western Washington and mountainous areas with gusty winds in typical windy spots. Temperatures are forecast to cool somewhat for Monday.

Central Washington Heat Stress:
Note: This is an experimental forecast product that may undergo changes over the coming weeks. For questions or comments, please email Mark Ingalls.

As noted in the discussion, temperatures are forecast to remain near or below seasonable averages for this time of year over the coming week. Highs will start off in the mid 70s, climbing to the mid 80s by Friday. With dew points in the mid 40s and light winds, this creates a wet bulb globe temperature around 72 for the hottest days. Look for somewhat warmer temperatures during the weekend, but with dew point remaining low the wet bulb temperature should only peak around 74. Fruit skin temperatures are similarly expected to remain low. With the warmest days during the outlook period reaching to the mid to upper 80s and dew points not getting above 50, look for the warmest FST values to remain below 110.


8 to 14 Day Outlook, September 6 to September 12, 2021
  • Above average temperatures and below average precipitation are favored for the period.

Important Points About This Week's Weather

South Central Washington
Remainder of the Week
  • Wind: W with breezy areas Tue, N and light Wed_Thu, NE and light Fri.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 70s Tue, upper 70s Wed, low 80s Thu, mid 80s Fri.
  • Low Temps: Near 50 Mon night, mid 40s Tue-Wed nights, low 50s Thu night, mid 50s Fri night.
  • Sky Cover: Mostly clear. Hazy.
Weekend
  • Wind: NE and light Sat, becoming W with breezy areas Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 80s Sat & Sun.
  • Low Temps: Upper 50s Sat & Sun nights.
  • Sky Cover: Mostly clear. Hazy.

North Central Washington
Remainder of the Week
  • Wind: W with breezy areas Tue, N and light Wed_Thu, variable and light Fri.
  • Precipitation: Dry conditions expected except isolated showers in mountainous areas near the Canadian border Tue night.
  • High Temps: Mid 70s Tue, upper 70s Wed, low 80s Thu, mid 80s Fri. Cooler in higher terrain.
  • Low Temps: Mid 50s Mon night, near 50 Tue night, mid 50s Wed night, near 60 Thu night, low 60s Fri night. Cooler in higher terrain and sheltered areas.
  • Sky Cover: Mostly clear. Hazy.
Weekend
  • Wind: NE and light Sat, becoming W with breezy areas Sun.
  • Precipitation: Low chance of showers along the Canadian border, otherwise dry.
  • High Temps: Mid 80s Sat & Sun. Cooler in higher terrain.
  • Low Temps: Mid 60s Sat & Sun nights. Cooler in higher terrain and sheltered areas.
  • Sky Cover: Mostly clear. Hazy.

Eastern Washington
Remainder of the Week
  • Wind: W with breezy areas Tue, N and light Wed_Thu, NE and light Fri.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 70 Tue, low 70s Wed, mid 70s Thu, near 80 Fri. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 50 Mon night, mid 40s Tue-Wed nights, upper 40s Thu night, low 50s Fri night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly clear. Hazy.
Weekend
  • Wind: Light and variable Sat, becoming W with breezy areas Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 80s Sat, near 80 Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Mid 50s Sat night, low 50s Sun night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Mostly clear Sat, mostly cloudy Sun. Hazy.

Western Washington
Remainder of the Week
  • Wind: Generally light and variable, except W and breezy through the strait and NW and breezy along the coast.
  • Precipitation: Isolated showers tapering off Tue north of Seattle. Otherwise dry.
  • High Temps: Low 70s Tue-Wed, mid 70s Thu, upper 70s Fri. Cooler in higher terrain and along the coast.
  • Low Temps: Low 50s Mon-Wed nights, mid 50s Thu-Fri nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy Tue, mostly clear Wed-Fri.
Weekend
  • Wind: Generally light and variable, except W and breezy through the strait and NW and breezy along the coast Sat, generally light except W and breezy along the coast and strait Sun.
  • Precipitation: Low chance of showers Sat, scattered showers Sun.
  • High Temps: Mid 70s Sat, near 70 Sun. Cooler in higher terrain.
  • Low Temps: Upper 50s Sat & Sun nights. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy.

Like us on Facebook at https://www.facebook.com/AgWeatherNet
Follow us on Twitter at https://www.twitter.com/AgWeatherNet
Washington State University