Heat Subsides; Cooler Weather Returns Monday

A respectable, but pedestrian 80 degrees the day before.

A middle-of-the road 78 the day after.

Was Wednesday’s 93-degree reading a one-hit wonder or what?

Just like on Tuesday, Seattle was unable to overcome thick fog this morning, resulting in a high temperature far shy of the predicted mid 80s. This leaves yesterday as the sole standout of the past three—the only one able to dodge the morning clouds and hit the ground running, ultimately catapulting into the record books as Seattle’s third-warmest September day on record.

The chances for another flash in the pan are all but history the remainder of the week, as the thermal trough that boosted yesterday’s temperatures into record territory has shifted east of the Cascades. As a result, thick morning fog will become even more common the next few days, especially south and west of the city.

More nice weather is expected in Seattle through Saturday, after the city fights off fog in the morning. Rain returns starting Sunday night.
More nice weather is expected in Seattle through Saturday, after the city fights off fog in the mornings. Rain returns starting Sunday night.

Tomorrow starts off on a gray note for almost all of the Sound, with the sun reappearing shortly before noon. With high pressure still nearby overhead, temperatures will rebound into the upper 70s—similar to today’s highs.

Fog fills back in overnight Friday into Saturday, although it shouldn’t be as dense as tomorrow’s. With high pressure nudging closer to us, we’ll warm things up a little more, climbing into the low 80s by late afternoon. While that’s no 93, it’s still pretty balmy for mid-September—by now, the average high is just 72 degrees.

The pleasant weather holds over through early Sunday afternoon as an upper level low approaches the West Coast, supplying the region with an additional tap of warm, albeit slightly muggy, air. By late in the afternoon, scattered thunderstorms will start firing over the Cascades in advance of the low—with some possibly drifting into the Seattle area as evening gets underway. A cold front with light rain will quickly follow, dropping temperatures back into the low 70s.

Behind the front, much cooler air settles in to kick off next week, with highs struggling to climb out of the 60s amid plenty of clouds and showers. Rain then looks to continue at times through at least next Wednesday as we draw ever closer to fall.

The season when a dry day becomes a one-hit wonder.