AgWeatherNet Weekly Weather Outlook for September 17 to September 23, 2016

Becoming Active This Weekend; Possibly Calmer Later Next Week

Nic Loyd, Meteorologist, 509-786-9357

Starting tonight, a fairly active Pacific jet stream coupled with deep subtropical moisture will begin to impact Washington for the first time this autumn. As a result of this pattern shift, the weather should be rather different than it has been in recent days. Wetter and cloudier conditions are expected at times for especially western Washington, while most of the state is likely to be periodically windy due to the passage of a couple of storm systems. Temperatures should become cooler again overall, but the main change initially will be a decrease in the diurnal range, as unsettled conditions lead to (relatively) warmer nights and cooler days. Given the anticipated westerly storm trajectory, south central Washington should remain rather dry due to the downslope flow.

Although Saturday morning should be somewhat mild, an approaching system will cause western rain to develop. As a windy front sweeps across the region on Saturday, cooler air should move into Washington. Another storm is possible around next Tuesday, as a cool low pressure area drops in toward our region. The low center is forecast to remain north of the state, such that showers with the system may be largely limited to northern Washington. However, it will usher in even cooler and breezy conditions. A calmer regime may try to become established later next week; but in light of the changeable transition season patterns and the active tropical weather, confidence in the extended outlook is rather low.

Temperatures
  • Mild early on Saturday, and then cooler.
  • Possibly becoming warmer later next week.

Precipitation
  • Rain developing on Saturday morning in the west, and then a chance of rain in eastern Washington by mid day.
  • A chance of rain at times thereafter, especially in the northwest, and decreasing later in the period.
  • Mostly dry through the period in south central Washington.

Wind
  • Breezy to windy on Saturday. Breezy at times thereafter, with decreasing wind potential later in the period.

8 to 14 Day Outlook - September 24, 2016 to September 30, 2016
  • Overall, near to above average temperatures and near to below average precipitation are expected during the 8 to 14 day time frame.

Important Points about Next Weeks Weather

South Central Washington
  • Normal conditions for this time of the year would be highs in the upper 70s and lows in the mid 40s to low 50s.
Weekend
  • Mostly dry. A slight chance of rain.
  • Highs in the mid 70s to around 80 on Saturday, and mid to upper 70s on Sunday.
  • Lows in the mid 50s to low 60s on Saturday morning, and upper 40s to 50s on Sunday morning.
Next Week
  • Mostly dry.
  • Highs in the mid to upper 70s on Monday, and then cooler.
  • Lows in the mid 40s to low 50s on Monday morning, and then cooler.

North Central Washington
  • Normal conditions for this time of the year would be highs in the 70s and lows in the upper 40s.
Weekend
  • A slight chance of rain.
  • Highs in the 70s on Saturday, and low to mid 70s on Sunday.
  • Lows in the mid 50s to low 60s on Saturday morning, and upper 40s to 50s on Sunday morning.
Next Week
  • A slight chance of rain at times, especially early in the week.
  • Highs in the low to mid 70s on Monday, and then cooler.
  • Lows in the mid 40s to low 50s on Monday morning, and then cooler.

Eastern Washington
  • Normal conditions for this time of the year would be highs in the 70s and lows in the 40s.
Weekend
  • A chance of rain.
  • Highs in the upper 60s to mid 70s on Saturday, and mid 60s to low 70s on Sunday.
  • Lows in the 50s on Saturday morning, and upper 40s to mid 50s on Sunday morning.
Next Week
  • A slight chance of rain at times, especially early in the week.
  • Highs in the mid 60s to mid 70s on Monday, and then cooler.
  • Lows in the 40s to low 50s on Monday morning, and then cooler.

Western Washington
  • Normal conditions for this time of the year would be highs in the upper 60s to low 70s and lows in the mid 40s to low 50s.
Weekend
  • Rain spreading from north to south on Saturday. A chance of showers on Sunday.
  • Highs in the mid 60s to low 70s on Saturday, and 60s to low 70s on Sunday.
  • Lows in the 50s to low 60s on Saturday morning, and 50s on Sunday morning.
Next Week
  • A slight chance of showers at times, especially early in the week and in the north.
  • Highs in the 60s to low 70s.
  • Lows in the upper 40s to mid 50s on Monday morning, and then cooler.
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