September 22, 2020

Forecast: September 22nd, 2020

By Calen Randall

Good Morning Huskies,

If you were missing the rain and wind last week, you are in luck. The smoke may be gone (thankfully), but rain and wind are still on the way. An atmospheric river will bring gusty conditions and downpours to western Washington starting on Wednesday. Some Puget Sound regions should see over an inch of precipitation on Wednesday and several inches of rain are expected in the mountains. Quite the transition from the dry weather earlier this month!

Check out the 48 hour cumulative precipitation from the UW WRF model. Unsurprisingly, the mountains will receive the most rain (red, black, and pink). Note the high totals around the Olympics, Mt. Rainier, and Mt. Baker. You might notice that the familiar rain shadow around Admiralty Inlet is forecast to return. Thanks to the Olympic Mountains, residents of Sequim, Port Townsend, and Whidbey Island should see less rain than other Puget Sound residents.

Precipitation totals garner most of the attention, but winds will be quite gusty during this event. Wind speeds in the 20-30 mph range are expected tomorrow, with gusts above 30 mph through much of western Washington. The graphic below shows the expected wind gust speeds for 8:00 A.M. tomorrow. Unsurprisingly the coast, where a Wind Advisory is in place through Wednesday night, should receive the brunt of the strong winds, with gusts likely reaching 40 mph.

Expect pleasant temperatures in the upper 60s and low 70s this afternoon, with overnight temperatures in the upper 50s. As the atmospheric river arrives, cooler highs in the mid 60s and lows in the mid 50s are likely, quite a small diurnal range.

We are early enough in the season that this atmospheric river is unlikely to cause any river floods. However, flooding in urban environments is common during these large precipitation events. You can help keep your neighborhood streets from flooding by clearing any debris that is nearby or blocking the entrance to storm drains.

Enjoy the last week before Fall Quarter, Huskies!

Reach forecaster Calen Randall at theuwdawgcast@uw.edu. Twitter: @Wx19Calen.

48 HOUR PRECIPITATION FORECAST	WIND GUSTS TOMORROW MORNING