AgWeatherNet Weekly Weather Outlook for February 1 to 7, 2014

Cool and Dry This Weekend; Arctic Outbreak Possible Next Week

Nic Loyd, Meteorologist, 509-786-9357
Gerrit Hoogenboom, Director, 509-786-9371

Although Phil has yet to make his annual proclamation, AgWeatherNet declares that Washington can expect at least one more week of winter. It is becoming increasingly probable that polar air will enter Washington beginning on Monday or Tuesday, although just how low temperatures will fall remains uncertain. Whether or not a true arctic outbreak occurs, colder temperatures are coming. For much of next week, a cold and dry northeast wind will cause potentially biting wind chill values. Looking farther ahead, the weather may become more active by next weekend, although there is a broad spectrum of possibilities in how the pattern will unfold.

In the mean time, cool and mainly dry conditions are expected this weekend, as a benign split flow regime dominates the Northwest weather picture. The main exception will occur around Sunday night and Monday morning, when a weak and moisture-starved disturbance will bring a chance of west-side rain / snow showers or eastside flurries to Washington. While the passage of any notable storm systems is not expected through most of next week, nor is a return to the recent stagnant low cloud pattern anticipated.

The evolution of next week's weather will hinge upon a critical battle between the northern and southern branches of the jet stream. Often, when a portion of the jet stream is near Washington, it is consolidated in one general region. However, a large ridge of high pressure over western Alaska will split the jet into two pieces next week. The southern branch will undercut the 'blocking' ridge, while the northern branch will travel over the top of the blocking ridge, and then drop into the United States by way of the arctic. The winner of the battle will determine whether relatively milder air (southern branch) or bitter cold air (northern branch) takes up residence in Washington. Currently, the latter outcome is favored, but not yet certain.

If the coldest model solutions verify, typically chilly and snow-covered areas may drop to near zero on clear, calm nights during the middle of next week. For reference, the coldest solutions currently show an air mass similar to the early December arctic outbreak, although the current forecast is more conservative. In any event, there is a good chance that a stormier and milder flow regime will take over next weekend, and persist into week two. Warmer temperatures and wetter conditions would be likely. The 64,000$ question will be how the transition from cold and dry to milder and wet occurs. Sometimes mountain and even lowland snow events happen during such transition periods.

Temperatures
  • Cool through early next week. Cold in the mountains.
  • Possibly much colder by the middle of next week.

Precipitation
  • Light showers (west) or flurries (statewide) possible on Sunday night and Monday morning.
  • Mainly dry overall through at least the middle of next week.
  • Rain or snow possible, especially in the west, by next weekend.

Wind
  • Generally light to moderate this weekend.
  • Increasing north or east winds next week, especially around Vancouver, Bellingham, and Omak.

Frost Risk Summary
  • This weekend and next week: High east of the Cascades and moderate to high in the west.

8 to 14 Day Outlook - February 8 to 14
  • Overall, near to above average temperatures and near to above average precipitation are expected during the 8 to 14 day time frame.

Important Points about Next Week's Weather

South Central Washington
  • Normal conditions for this time of the year would be highs in the mid 40s and lows in the mid to upper 20s.
Weekend
  • Partly sunny.
  • Highs in the 30s to low 40s.
  • Lows in the 20s.
Next Week
  • Mostly dry. A slight chance of snow on Monday morning.
  • Highs in the 30s on Monday, and mid 20s to low 30s later in the week.
  • Lows in the upper teens to mid 20s early, and upper single digits to teens later in the week.

North Central Washington
  • Normal conditions for this time of the year would be highs in the upper 30s and lows in the low to mid 20s.
Weekend
  • Partly sunny.
  • Highs in the 30s.
  • Lows in the upper teens to 20s.
Next Week
  • Mostly dry. A slight chance of snow on Monday morning.
  • Cold north winds by mid week.
  • Highs in the upper 20s to 30s on Monday, and 20s to around 30 later in the week.
  • Lows in the mid teens to mid 20s early, and mid single digits to teens later in the week.

Eastern Washington
  • Normal conditions for this time of the year would be highs around 40 and lows in the upper 20s to around 30.
Weekend
  • Partly sunny.
  • Highs in the 30s.
  • Lows in the 20s.
Next Week
  • Mostly dry. A slight chance of snow on Monday morning.
  • Highs in the upper 20s to mid 30s on Monday, and 20s later in the week.
  • Lows in the mid teens to mid 20s early, and mid single digits to teens later in the week.

Western Washington
  • Normal conditions for this time of the year would be highs in the upper 40s to around 50 and lows in the mid to upper 30s.
Weekend
  • A chance of showers, especially on Sunday night.
  • Highs in the 40s.
  • Lows in the upper 20s to 30s.
Next Week
  • A chance of rain or snow showers on Monday morning, and then drier.
  • A slight chance of rain or snow late in the week.
  • Highs in the low to mid 40s early, and 30s to low 40s by mid week.
  • Lows in the mid 20s to 30s on Monday morning, and upper teens to 20s by mid week.

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