AgWeatherNet Weekly Weather Outlook for Mar 13 to Mar 19, 2020

A cold and snowy weekend followed by a clear week with serious cold hardiness concerns

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

Discussion:

The forecast of snow and unseasonably cold weather that has been advertised for this weekend remains generally on track. Precipitation looks to continue to move through the state Friday afternoon bringing snow showers and lowland rain showers throughout. Precipitation looks to continue through the overnight switching over to snow in lowland areas in conjunction with a blast of cold, dry air that will be moving into Washington state from the north (however, lowland areas in western Washington will likely remain rain with perhaps a few snow flakes mixed in during the overnight). This cold air surge appears to be a product of a robust ridge forming across the north Pacific and into Alaska. Subsequently, a deep trough downstream looks to be produced allowing cold arctic air to move south and into the Pacific Northwest. The formation of this trough is also creating enough instability in the atmosphere to produce this weekend's precipitation in the absence of a pronounced surface cyclone which is usually responsible for bringing wet weather to Washington this time of year.

Snow showers and precipitation in general are expected to linger through Saturday and begin to taper off through Saturday evening/night. Some snow showers will likely linger throughout parts of southern Washington into Sunday but are expected to clear Sunday night. Total snow accumulations look to be light, such as an inch or two in lowland areas like the Yakima Valley for example. Pass routes are expected to see a few inches, and parts of upland Washington may see up to a foot. Strong northerly winds can also be expected Friday night through Saturday night with gusts near 40 mph in some locations. Some blowing and drifting snow is likely, especially in areas where larger snow totals are anticipated.

Once precipitation comes to an end, conditions are expected to remain dry for the remainder of the outlook period. Blustery winds are also anticipated to become calmer by Sunday and remain light and variable through next week.

The greatest threat to agriculture with this weekend's event looks to be the combination of cold overnight temperatures, gusty winds, and low dewpoints. The coldest locations (upland northern Washington) will likely see temps dip as low as the single digits Friday and Saturday nights. Please see the regional temperature breakdown at the end of the outlook for expectant temperatures in your region. Dew points also look to dip into the low teens and even single digits in areas through central and northern Washington. Please closely monitor local observations and forecasts for the most up to date temperature and dew point information. Growers are encouraged to check the bud stage of their crops in order to determine the best cold damage mitigation techniques that may be applied, which may be challenging on Saturday night due to the strong winds and exceedingly low dew points expected. One slightly positive note is that the models have trended slightly less cold for Saturday night, although a significant cold event is still anticipated.

Ranchers and dairy farmers are also encouraged to prepare as best they can as cold temperatures paired with strong winds look to drop wind chill temperatures to just below zero in the worst locations (again upland northern Washington), primarily Friday and Saturday nights. Again, please monitor local observations and forecasts for the most up to date weather information.

Sunday night will be another cold night, although it will be a more typical radiative cold event with calm winds, clearing skies, and the coldest temperatures in low-lying areas. Dew points will also recover somewhat by Sunday afternoon, although cold damage is still a serious concern for Sunday night with teens to low 20s expected in south-central Washington. Temperatures will slowly begin to recover after Sunday, but overnight low temperatures are still expected to be in the 20's through at least mid-week through eastern Washington, dragging the concern for crop damage into next week.


Key Points:

  • Cold air surge and snow Friday night through Saturday.
  • A few inches of snow accumulations in lowland eastern Washington expected as well as temps below bud kill thresholds for some perennial fruit crops in the southern half of eastern Washington.
  • Slow and gradual warming next week with temps remaining chilly early in the week.

Temperatures
  • Temps MUCH cooler than usual with cold air surge expected Friday night
  • Coldest temps expected Friday and Saturday nights.
  • Temps to slowly start recovering Sunday and through mid-week but remaining cold until mid/end of the week.

Precipitation
  • Precip to continue moving across the state from the NW with upland snow and lowland rain.
  • Precip switching over to snow Friday night for all regions except lowland western Washington.
  • Slowly tapering off Saturday night and Sunday.
  • Dry statewide next week.

Wind
  • Blustery Friday night through Saturday night statewide with winds from the N/NE and gusts into the 40 mph range, especially through the Basin/Palouse, Puget Sound, and coastal areas.
  • Winds subsiding through the day Sunday.
  • Light and variable winds through next week.

8 to 14 Day Outlook - Mar 20, 2020 to Mar 26, 2020
  • Below average temperatures and below average precipitation are expected during the 8 to 14 day time frame.

Important Points about Next Week's Weather

South Central Washington
Weekend
  • Snow and lowland rain beginning Friday afternoon and switching to snow Friday night. Precip becoming more scattered in nature Saturday with some lingering snow showers into Sunday. Becoming dry Sunday night. A few inches of accumulation expected with more in upland areas. Blustery N/NE winds Friday night through Saturday night, calming through Sunday. Partly sunny to overcast.
  • Highs in the upper 40s Friday, upper 30s Saturday, and upper 30s Sunday.
  • Lows in the low 20s Friday night, near 20 Saturday night, and low 20s Sunday night.
Next Week
  • Dry conditions expected for the week. Light and variable wind with a slight increase in wind speed possible Friday. Sunny to mostly cloudy
  • Highs in the low 40s Monday, upper 40s Tuesday, low 50s Wednesday, and mid 50s Thursday.
  • Lows in the low 20s Monday night, upper 20s Tuesday night, and near 30 Wednesday night.

North Central Washington
Weekend
  • Continued upland snow showers and lowland rain/snow transitioning to snow Friday evening. Precip becoming more scattered and tapering down through Saturday with a few lingering upland snow showers through Sunday. Trending dry Sunday night. Blustery N/NE winds Friday night through Saturday night, calming through Sunday. Mostly sunny to overcast.
  • Highs in the upper 30s Friday, low 30s Saturday, and near 40 Sunday. Cooler through higher terrain.
  • Lows in the upper teens Friday night, mid teens Saturday night, and low 20s Sunday night. Cooler through higher terrain.
Next Week
  • Dry conditions expected for the week. Light and variable wind with a slight increase in wind speed possible Friday. Sunny to mostly cloudy
  • Highs in the mid 40s Monday, low 50s Tuesday, and mid 50s Wednesday and Thursday. Cooler through higher terrain.
  • Lows in the mid 20s Monday night, upper 20s Tuesday night, and near 30 Wednesday night. Cooler through higher terrain.

Eastern Washington
Weekend
  • Snow and lowland rain Friday late afternoon transitioning to snow Friday night. Precip becoming more scattered and tapering down through Saturday with a few light snow showers lingering into Sunday. Trending dry Sunday night. Blustery NE winds Friday night through Saturday night, calming through Sunday. Partly sunny to overcast.
  • Highs in the mid 40s Friday, mid 30s Saturday, and upper 30s Sunday.
  • Lows in the low 20s Friday night, upper teens Saturday night, and low 20s Sunday night.
Next Week
  • Dry conditions expected for the week. Light and variable wind with a slight increase in wind speed possible Friday. Sunny to mostly cloudy.
  • Highs in the low 40s Monday, mid 40s Tuesday, near 50 Wednesday, and upper 40s Thursday.
  • Lows in the mid 20s Monday night, upper 20s Tuesday night, and near 30 Wednesday night.

Western Washington
Weekend
  • Snow and lowland rain to continue, becoming more scattered in nature Friday night. Precip to continue to taper down through Saturday night. Mostly dry Sunday and Sunday night. Blustery N/NE winds Friday night through Saturday night, especially near Puget sound and the coast. Calming through Sunday. Mostly sunny to overcast.
  • Highs in the mid 40s Friday and Saturday, upper 40s Sunday. Much cooler throughout the mountains.
  • Lows in the low 30s Friday night, mid 20s Saturday night, and mid 20s Sunday night,. Much cooler throughout the mountains.
Next Week
  • Dry conditions expected for the week. Light and variable wind. Sunny to mostly cloudy.
  • Highs in the low 50s Monday, upper 50s Tuesday, Wednesday, and Thursday. Much cooler throughout the Cascades.
  • Lows near 30 Monday night, low 30s Tuesday night, and mid 30s Wednesday night. Much cooler throughout the Cascades.

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