AgWeatherNet Weekly Weather Outlook for Oct 23 to Oct 29, 2020

Potential record breaking cold over the weekend with temperatures recovering early next week

Mark Ingalls, AgWeatherNet Intern
Craig Oswald, AgWeatherNet Field Meteorologist
Joe Zagrodnik, AgWeatherNet Postdoctoral Research Associate

Synopsis:

Cold temperatures, possibly record breaking, continue to remain in the forecast for this weekend. As the current weather system continues to move through the state from the northwest to the southeast, a potent cold air surge will move in from the north/northeast. This will work to drop overnight low temperatures into the teens Saturday and Sunday night in many fruit growing regions east of the Cascades. With clear skies by Saturday night and winds trending light to calm by Sunday, climatologically cold spots through these regions may see overnight lows reach the low teens, and even flirt with the single digits in some cases Saturday and Sunday nights.

Temperatures look to slowly recover beginning Monday with seasonable temperatures generally expected near the end of next week. Dry conditions look to prevail through most of the week as well, outside of some mountain rain/snow and low land rain mid week throughout the northern half of western Washington.

Discussion:

Mountain snow and low land mixed precipitation will continue through this evening and overnight in eastern Washington, primarily in the northern and far eastern regions. Mountain snow will also continue throughout western Washington with primarily rain throughout lowland areas. This is thanks to a surface low that continues to track toward the southeast. As precipitation wanes through Friday night and Saturday morning, unseasonably cold air looks to move into the state from the north/northeast fast on the heels of the passing system. This early arctic blast will also be particularly dry with dew points dropping into the single digits in many areas throughout eastern Washington. This looks to create possibly record breaking cold temperatures through parts of eastern Washington. Not only do records for overnight lows stand to be broken, but records may also be set for cold day time highs as well, especially in the northeastern corner of the state. Western Washington will also feel the effects of the cold weather with widespread freeze advisories already being published by the National Weather Service. Please take extra note this outlook of the projected regional temperatures published in the below sections. Also understand that these are regionwide temperature guidances and many areas that typically trend cooler due to inversion effects and effects of the local topography will trend colder overnight than indicated below. Some of the coldest areas stand to see lows in the low teens, and even near single digits, as indicated in the synopsis. Areas with fresh snow cover are especially likely to see temperatures on the colder end of the forecast range. Please track local weather reports and forecasts for your area to stay up to date on the latest temperature trends for this weekend.

Temperatures are expected to slowly begin warming after Sunday as a modest ridge moves into the Pacific Northwest from the west. Temperatures look to return to mostly seasonable by the end of the week with dry weather expected nearly statewide through the week as well. The broader synoptic set up over the north Pacific indicates that a strong surface low will maintain residence near the Aleutian Islands with a surface high off the west coast of the United States. Washington looks to again transition to a strong northwesterly flow regime aloft early next week. This will allow relatively moist air from the tropics to funnel into the state as it rides along the strong flow aloft between the afore mentioned low pressure and high pressure systems. The effects of this will be an increase in cloud cover through the week statewide and a chance for precipitation in the northwest corner of the state by Tuesday night, lasting through Thursday. Precipitation will be mostly orographically driven with mountain rain showers and high elevation snow the greatest impacts located primarily through the Olympics and northern half of the Cascades, generally north of I-90. A few scattered rain showers are also possible throughout low land areas in the northern half of western Washington.

Current guidance is hinting at a weak surface cyclone impacting the British Columbia coast in the Thursday night timeframe. This is indicated to bring widespread rain showers to western Washington with some high mountain snow also likely. Far eastern and northern Washington are also likely to pick up some precipitation with the Columbia Basin remaining mostly dry. This will be explored more in depth in Mondays outlook.


8 to 14 Day Outlook – Oct 30, 2020 to Nov 5, 2020
  • Warmer than average temperatures and slightly below average precipitation are expected during the 8 to 14 day time frame.

Important Points About Next Week’s Weather

South Central Washington
Weekend
  • Wind: N wind. Breezy Sat with gusts to 30 mph.
  • Precipitation: Rain/snow mix likely Fri night, ending early Sat AM. Light accumulations, if any, expected.
  • High Temps: Near 40 Sat, near 40 Sun.
  • Low Temps: Near 30 Fri night, near 20 Sat night, upper teens Sun night.
  • Sky Cover: Cloudy with skies gradually clearing through Sat. Mostly clear by Sat night and remaining sunny/mostly clear through Sun.
Next Week
  • Wind: Generally light and variable.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 40s Mon, near 50 Tue, upper 50s Wed, near 60 Thu.
  • Low Temps: Low 20s Mon night, near 30 Tue night, low 30s Wed night, mid 30s Thu night.
  • Sky Cover: Mostly sunny to partly cloudy through the week.

North Central Washington
Weekend
  • Wind: NE wind. Breezy in the Basin Sat with gusts to 35 mph.
  • Precipitation: Precipitation likely through Sat AM. Snow level dropping from around 2,000 feet Fri PM to below 1,000 ft early Sat AM. Snow accumulations ranging from under an inch near Wenatchee and in the Basin to around 6” in the Methow Valley and near Republic. Higher amounts in the mountains.
  • High Temps: Upper 30s Sat, upper 30s Sun. Cooler in high terrain.
  • Low Temps: Mid 20s Fri night, mid teens Sat night, mid teens Sun night. Cooler in high terrain and deep valleys.
  • Sky Cover: Cloudy with skies gradually clearing through Sat. Mostly clear by Sat night and remaining mostly sunny/mostly clear through Sun.
Next Week
  • Wind: Generally light and variable.
  • Precipitation: Chance of rain, some high elevation snow showers in the Cascades Tue night-Thu, otherwise dry.
  • High Temps: Upper 30s Mon, low 40s Tue, upper 40s Wed, low 50s Thu. Cooler in high terrain.
  • Low Temps: Low 20s Mon night, low 30s Tue night, mid 30s Wed night, upper 30s Thu night. Cooler in high terrain and deep valleys.
  • Sky Cover: Mostly sunny to partly cloudy early in the week. Becoming mostly cloudy by mid week.

Eastern Washington
Weekend
  • Wind: NE wind. Breezy Sat with gusts to 30 mph.
  • Precipitation: Snow likely Fri night, ending Sat AM except in the Lewis & Clark Valley where it should be mostly rain. Accumulations ranging from 1-3” on the Palouse and around Spokane.
  • High Temps: Low 30s Sat, upper 20s Sun. Cooler through the Blues.
  • Low Temps: Mid 20s Fri night, low teens Sat night, low teens Sun night. Cooler through the Blues.
  • Sky Cover: Cloudy with skies gradually clearing through Sat. Mostly clear by Sat night and remaining mostly sunny/mostly clear through Sun.
Next Week
  • Wind: Generally light and variable.
  • Precipitation: Dry conditions expected.
  • High Temps: Low 30s Mon, low 40s Tue, mid 40s Wed, low 50s Thu. Cooler through the Blues.
  • Low Temps: Low 20s Mon night, upper 20s Tue night, mid 30s Wed night, upper 30s Thu night. Cooler through the Blues.
  • Sky Cover: Partly cloudy through the week.

Western Washington
Weekend
  • Wind: N/NE wind. Breezy Sat in the San Juans and greater Bellingham area with gusts to 35 mph.
  • Precipitation: Precipitation (rain in the lowlands, snow in the mountains) likely Fri night. Trending dry through Sat morning.
  • High Temps: Low 50s Sat, upper 40s Sun. Cooler through the Cascades and Olympics.
  • Low Temps: Upper 30s Fri night, upper 20s Sat night, mid 20s Sun night. Cooler through the Cascades and Olympics.
  • Sky Cover: Cloudy with skies gradually clearing through Sat. Mostly clear by Sat night and remaining mostly sunny/mostly clear through Sun.
Next Week
  • Wind: Light and variable Mon & Tue. S/SW Wed & Thu. Breezy in the Puget Sound Region Wed.
  • Precipitation: Chance of rain showers in the lowlands and rain showers/high elevation snow showers in the mountains north of I-90 Tue-Thu.
  • High Temps: Near 50 Mon, mid 50s Tue, upper 50s Wed, upper 50s Thu. Cooler through the Cascades and Olympics.
  • Low Temps: Mid 30s Mon night, low 40s Tue night, mid 40s Wed night, mid 40s Thu night. Cooler through the Cascades and Olympics.
  • Sky Cover: Mostly sunny to partly cloudy early in the week. Becoming mostly cloudy by mid week.

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