AgWeatherNet Weekly Outlook for November 13 to November 19, 2020

Active weather to continue for the week

Mark Ingalls, AgWeatherNet Intern
Craig Oswald, AgWeatherNet Field Meteorologist

Synopsis:

The strong low impacting the Pacific Northwest Friday will continue to bring gusty winds and precipitation to the state as it moves from Vancouver Island to southwest Alberta. Winds ease somewhat Saturday morning before increasing again with another system Saturday afternoon, lasting into Sunday. This is expected to raise snow levels to be near pass level, bringing mostly rain to lowland areas in Washington. Monday, a warm front moves across the state from the south to bring more precipitation, higher snow levels, and more wind. Another frontal passage is expected to impact the region Tuesday into Wednesday. Finally, a trough off the west coast may start moving across the area Thursday to keep active weather conditions in place.

Discussion:

Rain showers in Western Washington and mountain snow will continue through the day Friday and into the overnight hours with the low pressure system impacting the region. East of the Cascades, gusty winds are expected to last until early Saturday with gusts having the potential to exceed 50 mph in some areas. Light rain showers in Western Washington along with upslope snow in the Cascades should last into Saturday morning with significantly lower precipitation rates.

By the afternoon on Saturday, the next system works its way onshore with another blast of widespread lowland rain and mountain snow for all of Washington. Snow levels may be low enough for snow to mix with rain in Spokane and on the Palouse early Sunday morning. Winds pick up in association with this system, though they aren't expected to be quite as strong as those on Friday and Friday night. The highest gusts look to be around 45 mph on the Palouse and in the Strait of Juan de Fuca, with gusts around 35-40 mph for the Columbia Basin and Puget Sound region.

Winds ease for most Sunday night as the atmosphere stabilizes, but a warm front advances from south to north on Monday to bring widespread precipitation. Rising snow levels to around 4,000 feet and even higher as the front passes, should make this mostly a rain event for Washington lowlands. Rain should be light in Eastern Washington and may be heavy at times west of the Cascades. The front is expected to bring windy conditions on the Coast, with gusts possibly exceeding 60 mph in more exposed locations.

Tuesday, the low that produced Monday's warm front is expected to move north paralleling the coast, draping its' cold front across the state. Snow levels will remain high keeping rain as the dominant precipitation type, but lower back to around 2000-2500 feet by Wednesday. Heavy rain is possible Tuesday into Wednesday. With liquid precipitation expected in mid-elevation locations that are currently snow covered on Tuesday, some waterways draining the Cascades, Blues, and Okanogan Highlands may experience higher flows. This system may also produce a strong wind event, though more details on that will be provided in the Monday outlook.

An upper level trough located off the west coast on Thursday may provide some shower activity to mountain locations as well as Western Washington. Models are not signaling a major surface system with this event, so right now the expectation is that precipitation will be light and precipitation will be mainly limited to western Washington and upland areas. There is however a bit of divergence in the exact solution of the upper pattern among the models for the Thursday/Friday time frame. But whatever the outcome may be, the overall general pattern being exhibited will certainly be conducive for unsettled conditions as mentioned.

Overnight lows are expected to remain around five degrees above average statewide for the forecast period, with active conditions inhibiting development of strong nighttime inversions. Highs will be a little more varied, starting between average and five degrees below average Saturday, becoming above average in the Columbia Basin Sunday, and leveling off near to a little above average for most folks through Thursday.


8 to 14 Day Outlook, November 20 to November 26, 2020
  • Below average temperatures and near average precipitation values are favored for the period.

Important Points About Next Week's Weather

South Central Washington
Weekend
  • Wind: S-SW wind. Breezy Fri & Fri night with gusts to 50 mph, breezy Sun with gusts to 35 mph.
  • Precipitation: Chance of rain Sat night & Sun night.
  • High Temps: Near 50 Sat, mid 50s Sun.
  • Low Temps: Mid 30s Fri & Sat night, low 40s Sun night.
  • Sky Cover: Partly to mostly cloudy.
Next Week
  • Wind: E-NE Mon becoming S Tue-Thu. Breezy conditions possible Tue & Wed.
  • Precipitation: Chance of rain Mon & Wed.
  • High Temps: Low 50s Mon, mid 50s Tue, low 50s Wed & Thu.
  • Low Temps: Low 40s Mon & Tue night, near 40 Wed & Thu night.
  • Sky Cover: Partly to mostly cloudy.

North Central Washington
Weekend
  • Wind: W wind, breezy Fri & Fri night with gusts to 50 mph, breezy Sun with gusts to 30 mph.
  • Precipitation: Rain & snow showers likely in the mountains through the weekend. Lowland rain/snow mix likely Sat night, chance of rain Sun, rain likely Sun night.
  • High Temps: Upper 40s Sat, near 50 Sun. Cooler in higher terrain.
  • Low Temps: Low 30s Fri & Sat nights, upper 30s Sun night. Cooler in higher terrain.
  • Sky Cover: Partly to mostly cloudy.
Next Week
  • Wind: E-NE Mon becoming S Tue-Thu. Breezy conditions possible Tue & Wed.
  • Precipitation: Rain likely Mon, chance of rain Tue-Thu. Mountain snow possible Mon & Thu.
  • High Temps: Upper 40s Mon, near 50 Tue & Wed, upper 40s Thu. Cooler in higher terrain.
  • Low Temps: Near 40 Mon night, upper 30s Tue night, mid 30s Wed night, low 30s Thu night.
  • Sky Cover: Mostly cloudy to overcast.

Eastern Washington
Weekend
  • Wind: S-SW wind. Breezy Fri & Fri night with gusts to 50 mph, breezy Sun with gusts to 35 mph.
  • Precipitation: Chance of rain early Fri night. Rain/snow mix likely Sat night, chance of rain Sun.
  • High Temps: Near 40 Sat, mid 40s Sun. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 30 Fri night, low 30s Sat night, mid 30s Sun night. Warmer in the Lewis & Clark Valley.
  • Sky Cover: Partly cloudy to overcast.
Next Week
  • Wind: E-NE Mon becoming S Tue-Thu. Breezy conditions possible Tue & Wed.W/SW wind. Breezy conditions possible Mon & Wed.
  • Precipitation: Rain likely Mon, chance of rain Tue-Thu.
  • High Temps: Mid 40s Mon, near 50 Tue, upper 40s Wed, mid 40s Thu. Warmer in the Lewis & Clark Valley.
  • Low Temps: Near 40 Mon night, mid 30s Tue & Wed night, low 30s Thu night.
  • Sky Cover: Mostly cloudy to overcast.

Western Washington
Weekend
  • Wind: SW-W wind. Breezy Fri with gusts to 25 mph. Higher on the coast and in San Juan/Whatcom Counties.
  • Precipitation: Chance of rain Fri night, rain likely Sat-Sun.
  • High Temps: Near 50 Sat & Sun. Cooler in higher terrain.
  • Low Temps: Near 40 Fri night, low 40s Sat night, mid 40s Sun night. Cooler in higher terrain.
  • Sky Cover: Mostly cloudy to overcast.
Next Week
  • Wind: E becoming S-SW Mon. S Tue-Thu. Windy on the coast Mon, widespread wind possible Tue.
  • Precipitation: Rain likely Mon & Tue, chance of rain Wed & Thu.
  • High Temps: Low 50s Mon, mid 50s Tue, near 50 Wed & Thu.
  • Low Temps: Upper 40s Mon night, mid 40s Tue & Wed night, low 40s Thu night.
  • Sky Cover: Mostly cloudy to overcast.

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