AgWeatherNet Weekly Weather Outlook Monday Update for Mar 16 to Mar 22, 2020

A cool and dry week ahead with likely inversion concern

Craig Oswald, Field Meteorologist, 509-786-9256
Joe Zagrodnik, Postdoctoral Research Associate

Discussion:

The dry forecast for this week looks to remain on track for much of the state. However there is a low chance for a few scattered rain and upland snow showers throughout different parts of the state in conjunction with two separate, weak disturbances that are moving by the region.

The first low chance for precipitation is expected to be for far southeast Washington Tuesday night and into Wednesday morning with low land rain/snow and upland snow to be expected with any such activity. Any showers look to move into the area from the southeast in conjunction with a cut off low type disturbance that is expected to move from the California coast, across Nevada, and into Idaho from the southwest. This feature is a product of the strong trough that remains situated over the western U.S. and brought the cold weather that many have been doing battle with the past few days.

The second low chance for precipitation looks to come for western Washington Thursday night as a few scattered rain showers have the opportunity to move into the area from the west in conjunction with a modest low pressure system that is expected to make its way south along the coast of British Columbia and the Pacific Northwest without actually moving inland before dissipating.

Temperatures look to remain cool for the week but slowly warm as the week progresses with close to average temperatures likely by weeks end. There exists however, ideal conditions for radiative inversion formation through the week (clear skies and calm winds). South central Washington looks to face the biggest impacts with cooler air likely to pool in low lying areas. This may nudge the temperature slightly cooler than anticipated with some lows in the low 20s possible in low lying areas Monday night and mid 20s Tuesday night, producing more unneeded concerns for cold hardiness for the already budding trees in this part of the state. Areas of fog look to also develop during the overnights as surface temps cool, especially for western Washington.

Dry weather is expected to continue for the first part of the weekend statewide. Sunday will likely see some scattered rain and upland snow showers move into northern Washington from the north associated with some cooler air that looks to move south from Canada. As of now, this is not anticipated to be a significant cold air intrusion. Low temperatures for northern Washington look to be in the mid 30s during the weekend.


Key Points:

Temperatures
  • Remaining cool with temps slowly warming through the week
  • Slightly cooler in low lying areas due to radiative inversion
  • Slight cool down during the weekend, low temps expected to remain in the mid 30s through eastern Washington

Precipitation
  • Low chance for a stray rain/snow and upland snow shower in far southeast Washington Tuesday night into Wednesday morning.
  • Low chance for a stray rain shower in western Washington Thursday night
  • Scattered rain and upland snow showers for northern Washington Sunday
  • Dry expected elsewhere

Wind
  • Light, generally northeast, yet variable winds to continue into the weekend

South Central Washington
Remainder of the Week
  • Dry conditions expected. Sunny to partly cloudy.
  • Highs in the upper 40s Monday, low 50s Tuesday, mid 50s Wednesday, and upper 50s Thursday and Friday.
  • Lows in the mid 20s Monday night, near 30 Tuesday night, low 30s Wednesday and Thursday nights, and mid 30s Friday night .

North Central Washington
Remainder of the Week
  • Dry conditions expected. Sunny to partly cloudy.
  • Highs in the upper 40s Monday, near 50 Tuesday, and low 50s Wednesday, Thursday, and Friday. Cooler through higher terrain.
  • Lows in the mid 20s Monday night, upper 20s Tuesday and Wednesday nights, and low 30s Thursday and Friday nights. Cooler through higher terrain.

Eastern Washington
Remainder of the Week
  • Low chance for a stray rain/snow and upland snow shower Tuesday night and into Wednesday morning for southern fringes of the region. Otherwise dry conditions expected through the week. Mostly sunny to mostly cloudy.
  • Highs in the mid 40s Monday, Tuesday, and Wednesday, near 50 Thursday, and low 50s Friday.
  • Lows in the mid 20s Monday night, upper 20s Tuesday, Wednesday, and Thursday nights, and near 30 Friday night.

Western Washington
Remainder of the Week
  • Low chance for a stray rain shower Thursday night. Otherwise dry conditions expected through the week. Areas of fog. Sunny to mostly cloudy.
  • Highs in the upper 50s Monday, mid 50s Tuesday, upper 50s Wednesday, Thursday, and Friday. Much cooler throughout the Cascades/Olympics.
  • Lows in the upper 20s Monday night, near 30 Tuesday night, low 30s Wednesday night, and mid 30s Thursday and Friday nights. Much cooler throughout the Cascades/Olympics.

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Washington State University