AgWeatherNet Weekly Weather Outlook for December 9 to December 15, 2017

High Pressure Continues to Dominate the Weather Pattern

Nic Loyd, Meteorologist, 509-786-9357

The stubbornly persistent ridge of high pressure that assumed residence over the Northwest on Monday will continue to be the main driver of our weather during the coming week. As a result, dry, calm, and stable conditions are likely to persist for much of the period. Air stagnation and areas of low clouds or fog should be the main issues for the lowlands in the coming days, as chilly temperatures look to linger for a while underneath the inversion. As we have observed recently, a lack of storms and precipitation does not always translate to a lack of slick roads. Freezing fog can cause travel problems, especially in the morning on untreated surfaces.

Meanwhile, the mountains and the coast are expected to experience very mild, mostly sunny, and pleasant weather. Although the pattern is forecast to remain rather consistent, there may be day to day variability in the coverage of the fog/low clouds, which would also impact the temperatures. By the end of next week, there is a chance that this benign regime will begin to change, although the nature of the potential transition is not clear. In other words, the end of the ridge is in sight, but what comes next is an open question.


Temperatures
  • Generally near normal in the lowlands, except mild at the coast.
  • Possible lowland warming and mountain/coastal daytime cooling later next week.

Precipitation
  • Mostly dry.
  • A slight chance of western rain by next Friday.

Wind
  • Generally light, expect possibly breezy by next Friday.

8 to 14 Day Outlook - December 16, 2017 to December 22, 2017
  • Overall, above average temperatures and below average precipitation are expected during the 8 to 14 day time frame.

Frost Risk Summary
  • This Weekend: Moderate to high risk.
  • Next Week: Moderate to high risk.

Important Points about Next Week's Weather

South Central Washington
  • Normal conditions for this time of the year would be highs in the upper 30s to mid 40s and lows in the 20s to low 30s.
Weekend
  • Mostly dry, with low clouds and fog.
  • Highs in the 30s to low 40s.
  • Lows in the 20s to mid 30s.
Next Week
  • Mostly dry, with possible fog and low clouds, especially early in the week.
  • Highs in the 30s to mid 40s early, and possibly warmer later in the week.
  • Lows in the 20s to mid 30s early, and possibly warmer later in the week.

North Central Washington
  • Normal conditions for this time of the year would be highs in the 30s and lows in the 20s.
Weekend
  • Mostly dry, with possible low clouds and fog.
  • Highs in the 30s to low 40s.
  • Lows in the 20s to mid 30s.
Next Week
  • Mostly dry, with possible fog and low clouds, especially early in the week.
  • Highs in the 30s to mid 40s early, and possibly warmer later in the week.
  • Lows in the 20s to mid 30s early, and possibly warmer later in the week.

Eastern Washington
  • Normal conditions for this time of the year would be highs in the mid 30s to low 40s and lows in the mid to upper 20s.
Weekend
  • Mostly dry, with possible low clouds and fog.
  • Highs in the 30s to low 40s.
  • Lows in the 20s to mid 30s.
Next Week
  • Mostly dry. Possible areas of fog and low clouds, especially early in the week.
  • Highs in the 30s to mid 40s early, and possibly warmer later in the week.
  • Lows in the 20s to mid 30s early, and possibly warmer later in the week.

Western Washington
  • Normal conditions for this time of the year would be highs in the mid to upper 40s and lows in the 30s to around 40.
Weekend
  • Mostly dry. Areas of fog and low clouds in the interior.
  • Highs in the 40s to 50s, except low 60s possible at the coast.
  • Lows in the mid 20s to 30s on Saturday morning, and upper 20s to 30s on Sunday morning.
Next Week
  • Mostly dry, with areas of fog/low clouds in the interior early in the week.
  • Highs in the 40s to 50s.
  • Lows in the 30s early, and possibly warmer later in the week.

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