AgWeatherNet Weekly Weather Outlook Monday Update for January 11 to January 17, 2021

Wet Weather to Continue for the Week

Mark Ingalls, AgWeatherNet Intern
Craig Oswald, Field Meteorologist

Synopsis:

A potent jet stream screaming across the North Pacific from as far as mainland Asia will remain in place for the period. Thanks to this, weather conditions look to remain active and very similar to those of last week. As a series of strong surface cyclones look to form and move into the Gulf of Alaska, their associated warm and cold fronts are to move across the state through the week. This is expected to bring multiple rounds of precipitation. Paired with a tropical plume that looks to also remain in place through midweek, plenty of moisture should be available for opportunity for precipitation statewide early in the week. Conditions look to trend less active after midweek, but chances for precipitation are to remain in the forecast.

Discussion:

The majority of the precipitation this period looks to come within the Monday night through Wednesday time period. Temperatures look to remain quite mild with snow levels generally residing above 5000 ft to 6000 ft in most places until late Tuesday night, where snow levels look to drop to around 3000 ft in the Cascades and 4000 ft east of the Cascade Range. Please see the regional breakouts below for a little more detail in the timing and anticipated heights of snow levels through Wednesday. Please see the region breakouts for timing of precipitation events through the period as well.

From now until noon Wednesday, liquid water equivalent precipitation totals across the state look to be in these general ranges; 0.10 inches to 0.75 inches for south central Washington, with greater accumulation to the north. Locations along the east slope of the Cascades may receive around 1.5 inches. However, do expect a sharp precipitation gradient here from west to east, as is usually the case.

North central Washington looks to receive around 0.75 inches of rain across the Basin with the northern lowlands anticipated to receive around an inch. Mountain regions may approach the 2 inch mark in some locales, especially near the Idaho border. Again, a strong west to east gradient in precipitation totals can be expected along the east slope of the Cascades, but these areas should receive around 1.5 inches as stated earlier.

The eastern Washington region looks to see around 0.75 inches with totals along the Idaho border nearing 1 inch. The Blue Mountains and areas east stand a good chance to see between 1 and 1.50 inches.

Western Washington is to see nearly continuous precipitation, heavy at times, from Monday night into Wednesday. Lowland locations are expected to receive between 2 and 3 inches of rain, with some locales possibly receiving more. Areas along the coast may near 4 inches and high mountain locations in excess of 5 inches. Please be aware of local flooding and landslide potential in these circumstances.

In association with the passage of the frontal boundaries that are working to initiate widespread precipitation across the state, expect windy conditions early in the week as well. Tuesday night and Wednesday will be the windiest periods with many gusts likely to exceed 50mph, and with the potential to exceed 60mph in some locales, primarily coastal regions and throughout the Columbia Basin.

A transient ridge is anticipated to move into the Pacific Northwest by Thursday, displacing the tropical plume and trending weather conditions to a drier regime. This will provide a dry day statewide Thursday. Beyond Thursday, a weak disturbance looks to move through the state Friday night, producing some areas of precipitation. This event will be much weaker than those expected for Monday night through Wednesday. More detail on this can be found in the regional breakouts below.


Important Points About Next Week's Weather

South Central Washington
Remainder of the Week
  • Wind: Calm to light and variable becoming S/SE and breezy Mon night. S/SW and windy by Tue night, and W/SW by Wed with gusts 50+ mph possible. Trending back calm to light and variable Wed night and generally remaining so for the week.
  • Precipitation: Rain showers Mon night into Tue. Activity lessening Tue yet remaining in the area. Resurgence of widespread rain showers Tue night. Becoming dry Wed and remaining so Thu. Low chance for a stray rain shower Fri afternoon, greater chance near the east slope of the Cascades.
  • High Temps: Near 50 Tue, low 50s Wed, mid 40s Thu, mid 40s Fri.
  • Low Temps: Upper 30s Mon night, low 40s Tue night, low 30s Wed night, low 30s Thu night.
  • Sky Cover: Cloudy early in the week, trending to partly cloudy Wed and remaining so through weeks end. Patchy fog Wed & Thu night.
Weekend
  • Wind: Light and variable. SW and light to breezy Sun.
  • Precipitation: Dry conditions expected.
  • High Temps: Mid 40s Sat, mid 40s Sun.
  • Low Temps: Low 30s Fri night, near 30 Sat night, low 30s Sun night.
  • Sky Cover: Partly cloudy to mostly cloudy.

North Central Washington
Remainder of the Week
  • Wind: Calm to light and variable becoming S/SE and breezy Mon night. S/SW and windy by Tue night, and W/SW by Wed with gusts 60+ mph possible in the Basin. Trending back calm to light and variable Wed night and generally remaining so for the week.
  • Precipitation: Rain showers across the Basin and snow showers north Mon night into Tue. Showers lingering through Tue with all northern lowland areas trending toward mixed/rain. Only elevations 6000 ft+ likely to hang onto snow showers. Resurgence Tue night with snow levels lowering to near 4000 ft late. Becoming dry Wed and remaining so Thu. Low chance for a stray lowland rain/upland mixed shower Fri afternoon, primarily west of the Okanogan valley. Snow along the Cascade crest expected.
  • High Temps: Upper 30s Tue, mid 40s Wed, upper 30s Thu, upper 30s Fri. Cooler in high terrain.
  • Low Temps: Low 30s Mon night, mid 30s Tue night, mid 20s Wed night, upper 20s Thu night. Cooler in high terrain. Cooler in deep valleys Wed & Thu nights as well.
  • Sky Cover: Cloudy early in the week, trending to partly cloudy Wed and remaining so through weeks end. Patchy fog Wed & Thu night.
Weekend
  • Wind: Light and variable. W/SW and light to breezy Sun.
  • Precipitation: Trending dry early Fri night. Dry expected Sat. A few lowland rain and mtn snow showers along the Cascade crest/east slope and Idaho border Sat night. Dry expected Sun.
  • High Temps: Upper 30s Sat, mid 30s Sun. Cooler in high terrain.
  • Low Temps: Mid 20s Fri night, mid 20s Sat night, mid 20s Sun night. Cooler in high terrain.
  • Sky Cover: Partly cloudy to mostly cloudy.

Eastern Washington
Remainder of the Week
  • Wind: Calm to light and variable becoming S/SE and breezy Mon night. S/SW and windy by Tue night, and W/SW by Wed with gusts 60+ mph possible. Trending back calm to light and variable Wed night and generally remaining so for the week.
  • Precipitation: Lowland rain and mtn mixed/snow showers Mon night into Tue. Showers lingering through Tue with mtn mixed/snow trending toward mixed/rain. Resurgence Tue night with snow levels lowering to near 5000 ft late. Becoming dry Wed and remaining so Thu. Low chance for a stray shower Fri afternoon, primarily south of Hwy 26/272.
  • High Temps: Low 40s Tue, upper 40s Wed, low 40s Thu, low 40s Fri. Cooler through the Blue Mtns.
  • Low Temps: Mid 30s Mon night, near 40 Tue night, near 30 Wed night, low 30s Thu night. Cooler through the Blue Mtns.
  • Sky Cover: Cloudy early in the week, trending to partly cloudy Wed and remaining so through weeks end. Patchy fog Wed & Thu night.
Weekend
  • Wind: Light and variable. SW and light to breezy Sun.
  • Precipitation: Chance for a few rain showers and mtn snow showers early Fri night, primarily south of Hwy 26/272. Dry expected Sat. Chance for a few rain showers along the Idaho border Sat night. Dry expected Sun.
  • High Temps: Near 40 Sat, upper 30s Sun. Cooler through the Blue Mtns.
  • Low Temps: Low 30s Fri night, upper 20s Sat night, upper 20s Sun night. Cooler through the Blue Mtns.
  • Sky Cover: Partly cloudy to mostly cloudy.

Western Washington
Remainder of the Week
  • Wind: Calm to light and variable becoming E/SE and breezy Mon night. S/SE and windy by Tue night, and W/SW by Wed with gusts 60+ mph possible, especially near the coast and sound. Trending back calm to light with offshore breeze yet variable Wed night and generally remaining so for the week.
  • Precipitation: Lowland rain and mtn mixed/snow showers Mon night into Tue with snow levels near 4000 ft. Showers remaining Tue with snow levels rising above 6000 ft. Resurgence of widespread rain and mtn snow showers Tue night with snow levels lowering to near 3000’ late. Lowlands trending dry Wed with mtn snow showers lingering through the day (snow levels below pass level). Dry everywhere Thu. Light rain showers and high mountain snow to begin moving in from the west late Thu night. Trending dry Fri with a few showers lingering over the mtns.
  • High Temps: Mid 50s Tue, low 50s Wed, near 50 Thu, low 50s Fri. Cooler through the Cascade and Olympic Mtns.
  • Low Temps: Upper 40s Mon night, mid 40s Tue night, upper 30s Wed night, low 40s Thu night. Cooler through the Cascade and Olympic Mtns.
  • Sky Cover: Mostly cloudy to cloudy.
Weekend
  • Wind: Light and variable. Slightly breezier Sun.
  • Precipitation: Dry expected Sat. Light rain and mtn snow showers Sat night, primarily along the coast and northern half of the region. Some showers lingering Sun, otherwise dry expected.
  • High Temps: Upper 40s Sat, upper 40s Sun. Cooler through the Cascade and Olympic Mtns.
  • Low Temps: Near 40 Fri night, upper 30s Sat night, upper 30s Sun night. Cooler through the Cascade and Olympic Mtns.
  • Sky Cover: Mostly cloudy.

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