AgWeatherNet Weekly Weather Outlook for Jan 3 to Jan 9, 2020

A week's worth of unsettled weather expected, likely followed by arctic air in mid-January

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

Discussion:

A one-two punch of modest surface cyclones associated with a series of passing short wave troughs aloft are expected to impact the west coast this weekend and mid-week, leaving Washington state with rather unsettled weather for the outlook period. The period is expected to be defined by periods of rain in the west and mostly scattered and showery rain/snow in the east (south central Washington looks to remain mostly dry however). While impacts are not anticipated to be on the order of record-breaking rain fall, such as we recently experienced in the Seattle area, this coming outlook period will prove to have its own unique impacts.

The first storm arriving tonight (Friday night) is a potent, fast moving cold front that will bring an abrupt end to the recent stretch of mild temperatures. The front will bring a brief burst of moderate rain and gusty winds in the late evening to areas west of the Cascades. Travel conditions will deteriorate rapidly in the mountain passes with snow levels falling to 2,000 ft and 6-12 inches of snow possible overnight. East of the Cascades expect an abrupt increase in westerly winds overnight with precipitation confined to the mountains. Cold, moist flow from the Pacific will continue to bring snow to the Cascades through the weekend with a secondary wave on Sunday further enhancing snowfall amounts. Total snow accumulations of 1-2 feet are expected above 2,000 ft by Sunday night. Northern/northeastern portions of the Columbia basin could receive a few inches of snow on Sunday with slightly higher amounts in the Okanogan highlands.

Windy conditions are also anticipated to continue through the weekend, particularly within the Basin and Palouse, with gusts in the 40-50 mph range leaving these regions vulnerable to another tumbleweed 'tumblegeddon' as coined by our friends at WSDOT. Fortunately, winds in these areas look to ease by Sunday but will likely remain breezy for the coming week. Temperatures will remain cool through the weekend before leveling off for the week. Even though a slight cooling is expected, day time highs look to remain above freezing.

The second major round of active weather is expected Monday night - Wednesday morning with more rain and snow possible across the majority of the state. At this time it appears snow levels will rise on Tuesday followed by another cold front on Tuesday night with snow levels dropping again and precipitation falling across the majority of the state. Windy conditions are likely as well with this system.

Active weather will continue into next weekend with another significant storm possible at the end of next week. Attention then turns to the potential for an arctic air blast for the week of January 10-16. At this time there is high likelihood of unseasonably cold air across the state with all of the major mid-range weather forecast models predicting a deep trough over the western US. Details on the timing, strength, and extent of the cold air remain uncertain at this time. In the meantime, follow @AgWeatherNet on Twitter for the latest updates.


Key Points:

  • On/off light to moderate precip for the entire outlook period west of the Cascades.
  • Generally occasional precip east of the Cascades.
  • A windy weekend.

Temperatures
  • Slight cooling trend through the weekend.
  • Temps then holding fairly stable for the week.

Precipitation
  • Wet for western Washington.
  • Mostly scattered precip east of the Cascades with the exception of south-central Washington which will likely remain dry.

Wind
  • Windy conditions for the weekend with gusts into the 40-50 mph range, particularly through the Basin/Palouse. Winds to ease by Sunday but remain breezy at times through the week.

8 to 14 Day Outlook - Jan 10, 2020 to Jan 16, 2020
  • Below average temperatures and slightly above average precipitation are expected during the 8 to 14 day time frame.

Important Points about Next Week's Weather

South Central Washington
Weekend
  • Dry conditions expected. Partly sunny to overcast.
  • Highs in the mid 50s Friday, near 50 Saturday, and upper 40s Sunday.
  • Lows near 40 Saturday morning, and upper 30s Sunday morning.
Next Week
  • Dry conditions expected. Partly sunny to overcast.
  • Highs in the upper 40s Monday and slightly cooling to mid 40s by Thursday.
  • Lows in the upper 30s.

North Central Washington
Weekend
  • Chance for light rain and high terrain snow, particularly Friday night and Sunday evening. Partly sunny to overcast.
  • Highs in the low 40s Friday and Saturday, and upper 30s Sunday. Cooler throughout higher terrain.
  • Lows in the mid 30s Saturday morning, and upper 20s Sunday morning. Cooler throughout higher terrain.
Next Week
  • Chance for high terrain snow showers, trending dry by mid week. Partly sunny to overcast.
  • Highs in the upper 30s Monday and slightly cooling to mid 30s by Thursday. Cooler throughout higher terrain.
  • Lows rebounding to near 30 for the week. Cooler throughout higher terrain.

Eastern Washington
Weekend
  • Periods of light rain and snow showers, particularly Friday night and Sunday evening. Partly sunny to overcast.
  • Highs in the upper 40s Friday, low 40s Saturday, and upper 30s Sunday.
  • Lows in the mid 30s Saturday morning, and near 30 Sunday morning.
Next Week
  • Chance for light snow showers through the week. Partly sunny to overcast.
  • Highs in the upper 30s Monday, cooling to mid 30s by Thursday.
  • Lows near 30 Monday morning, cooling to upper 20s by Friday morning.

Western Washington
Weekend
  • On/off light to moderate rain and more consistent high terrain snow. Mostly cloudy to overcast.
  • Highs in the low 50s Friday, and mid 40s Saturday and Sunday. Much cooler throughout the Cascades.
  • Lows near 40 Saturday morning, and upper 30s Sunday morning. Much cooler throughout the Cascades.
Next Week
  • Continued on/off light to moderate rain and more consistent high terrain snow. Partly sunny to overcast.
  • Highs in the upper 40s Monday, cooling again to mid 40s by Thursday. Much cooler throughout the Cascades.
  • Lows in the upper 30s. Much cooler throughout the Cascades.

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