AgWeatherNet Weekly Weather Outlook Monday Update for September 28 to October 4, 2020

Warm and dry conditions statewide

Craig Oswald, AgWeatherNet Field Meteorologist

Synopsis:

As a stark contrast to last weeks active weather, this outlook period is expected to be warm and dry statewide thanks to a robust ridge in place over the Pacific Northwest. Light winds and mostly sunny and mostly clear skies will also prevail through the week, promoting exceptional night time radiational cooling with strong inversions and cool overnight temperatures in locations that generally trend cooler during such conditions, particularly east of the Cascades.

Discussion:

The unusually warm temperatures expected for this outlook period can be chalked up to a high amplitude wave pattern aloft with strong low pressure churning near the Aleutian islands, a robust ridge over the western U.S., and a significant trough and cool temperatures situated east of the Rockies. This general pattern looks to remain in place through the outlook period. High temperatures look to be above normal state wide and are even expected to be 10 to 15 degrees above normal for most of eastern Washington. Generally sunny and clear skies and calm to light winds will help to promote large diurnal temperature cycles and night time surface inversions with low temperatures expected to continue to dip into the 30s in the particularly cool spots throughout eastern Washington for the first part of the week. Lows throughout western Washington will generally remain as they have with a slight warming trend. By mid week, low temperatures look to settle to around seasonable. Areas of fog will also continue to be prevalent during the overnights and early morning hours throughout western Washington and some deep valleys of eastern Washington.

In closing, the below table lists last weeks rain fall totals as observed from different locations throughout the state. The table is for the period of September 21 through 27. For the majority of the locations listed, most of the rain accumulation came on Thursday in conjunction with the passage of the strong cold front. These totals are for point locations throughout the state and as rainfall can be highly variable geographically, may not be completely representative of totals observed at other regional locations.


Important Points About This Week's Weather

South Central Washington
Remainder of the week
  • Wind: Light and variable during the day, becoming slightly breezy at times by late afternoon. Trending much calmer during the overnights.
  • Precipitation: Dry conditions expected.
  • High Temps: Near 80 Tue, low 80s Wed, low 80s Thu, mid 80s Fri.
  • Low Temps: Low 40s Mon night, mid 40s Tue night, upper 40s Wed night, near 50 Thu night.
  • Sky Cover: Sunny and clear.

Weekend
  • Wind: Light and variable during the day, becoming slightly breezy at times by late afternoon. Trending much calmer during the overnights.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 80s Sat, low 80s Sun.
  • Low Temps: Near 50 Fri night, near 50 Sat night, low 50s Sun night.
  • Sky Cover: Sunny and mostly clear with a few overnight high clouds by Sun.

North Central Washington
Remainder of the week
  • Wind: Light and variable during the day, becoming slightly breezy at times by late afternoon. Trending much calmer during the overnights.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 70s Tue, low 80s Wed, low 80s Thu, low 80s Fri. Cooler in high terrain.
  • Low Temps: Mid 40s Mon night, upper 40s Tue night, near 50 Wed night, low 50s Thu night. Cooler in high terrain and deep valleys.
  • Sky Cover: Sunny and clear early in the week with a few clouds building in after mid week but remaining mostly sunny and mostly clear.

Weekend
  • Wind: Light and variable during the day, becoming slightly breezy at times by late afternoon. Trending much calmer during the overnights.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 80s Sat, near 80 Sun. Cooler in high terrain.
  • Low Temps: low 50s Fri night, low 50s Sat night, low 50s Sun night. Cooler in high terrain and deep valleys.
  • Sky Cover: Mostly sunny and mostly clear.

Eastern Washington
Remainder of the week
  • Wind: Light and variable during the day, becoming slightly breezy at times by late afternoon. Trending much calmer during the overnights.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 70s Tue, near 80 Wed, upper 70s Thu, upper 70s Fri. Cooler through the Blues.
  • Low Temps: Low 40s Mon night, mid 40s Tue night, low 40s Wed night, mid 40s Thu night. Cooler through the Blues.
  • Sky Cover: Sunny and clear early in the week with a few clouds building in after mid week but remaining mostly sunny and mostly clear.

Weekend
  • Wind: Light and variable during the day, becoming slightly breezy at times by late afternoon. Trending much calmer during the overnights.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 70s Sat, upper 70s Sun. Cooler through the Blues.
  • Low Temps: Mid 40s Fri night, mid 40s Sat night, mid 40s Sun night. Cooler through the Blues.
  • Sky Cover: Mostly sunny and mostly clear.

Western Washington
Remainder of the week
  • Wind: Light and variable during the day, and trending calmer during the overnights. Sea breeze expected near the coast.
  • Precipitation: Dry conditions expected.
  • High Temps: Upper 70s Tue, low 80s Wed, upper 70s Thu, upper 70s Fri. Cooler through the Cascades and Olympics.
  • Low Temps: Near 50 Mon night, low 50s Tue night, low 50s Wed night, low 50s Thu night. Cooler through the Cascades and Olympics.
  • Sky Cover: Mostly sunny and mostly clear. Areas of fog expected.

Weekend
  • Wind: Light and variable during the day, and trending calmer during the overnights. Sea breeze expected near the coast.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 70s Sat, low 70s Sun.
  • Low Temps: Low 50s Fri night, low 50s Sat night, low 50s Sun night. Cooler through the Cascades and Olympics.
  • Sky Cover: Mostly sunny and mostly clear. Areas of fog expected.

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