The New Normal

70 degrees is no longer normal in Seattle.

Today marks the first day since June 13 where the average high temperature is below 70—with 69 degrees the normal high for Sept. 20. Right on cue, after a week with readings in the 70s and 80s, the mercury dropped back to more seasonable levels today, with Sea-Tac topping out at 67 degrees.

Similar temperatures are in store tomorrow, with highs struggling to reach the upper 60s after another round of chilly morning fog. Late in the afternoon, we’ll warm up as sunshine takes hold, but until then, expect gray skies and temperatures only in the 50s.

Saturday will be even cooler yet, with temperatures falling into the mid- to lower-60s. Amazingly, if we don’t reach 65, we’ll end a 90-day stretch of temperatures at or above 65 degrees—Seattle’s second-longest, according to the National Weather Service. Heck, even sultry Chicago’s seen a colder day more recently.

Lightning Wildfires
Thunderstorms Saturday night could start more wildfires in hard-hit areas around Wenatchee.

With the cooler weather will also come a change in the large-scale weather pattern, as a ridge of high pressure overhead gives way to an upper-level low. The low, currently over the eastern Pacific, will move toward the Washington coast on Saturday, dragging up unstable air as it does. By Saturday night, isolated thunderstorms will be possible over Central Washington, the Cascades and outlying areas of Seattle—especially southeast of the city.

These storms are expected to generate plenty of lightning and wind—but little to no moisture—potentially making the nightmarish wildfire situation around Wenatchee and Ellensburg even worse. In response to this, the National Weather Service has issued a Fire Weather Watch for much of the state, from east of I-5 all the way to the Tri-Cities.

The upper-level low drifts into Oregon on Sunday, ending the thunderstorm threat. Skies will remain cloudy most of the day in Seattle, however, with high temperatures only in the upper 60s.

The new normal around here.

4 COMMENTS

  1. “Amazingly, if we don’t reach 65, we’ll end a 90-day stretch of temperatures at or above 65 degrees—Seattle’s second-longest, according to the National Weather Service.” You can’t type something like that and not tell us:
    A. How long the first longest streak is, and
    B. When the first longest streak occurred.
    C. Sheesh

    • Seattle’s longest stretch of temperatures at or above 65 degrees spanned 102 days, from June 10-Sept. 19, 1961. Sadly, we didn’t even get to second place—Friday’s high of 61 degrees ended the streak at 89 days, a day shorter than a 90-day run in the summer of 2006.

  2. Hmmm, KOMO had it listed as 69 on Friday night, I am pretty sure. NOAA
    has it at 61 like you say. RATS!

    Thanx Justin, I don’t know how to access the databases to get that kind of info. 3rd is OK by me I guess. 🙂

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