Record heat first…then the rain finally comes back to Seattle?

Several sailboats head out on Lake Union during a 90-degree day on Sept. 3, 2017 (KOMO  Photo)

SEATTLE -- As toasty as Saturday and Sunday have been -- both days reaching 90 degrees in Seattle -- it's set to get even a little hotter as we wade into Labor Day and the work week.

But to those who have really missed Seattle's rain -- and who can blame them? It's only rained a couple times in the region in the past 11 weeks (77 out of 78 days' dry at Sea-Tac) -- there is finally a light at the end of the tunnel, and it's not sunlight.

First up, let's talk about the heat as a Heat Advisory is in effect from Monday morning through Tuesday late evening for much of the Western Washington interior from Everett south to Oregon. You'd think 90 is hot enough for September but the air mass will actually get even warmer on Monday and Tuesday. In addition, the winds will switch to more of a due east wind. That air is tapping into a hot Eastern Washington that will get even hotter as it sinks down the western slopes of the Cascades.

All together, raw forecast model outputs are predicting highs as warm as the mid -- maybe even upper 90s in Seattle. But! With the east winds means all that smoke from the wildfires burning in Central Washington will be blown into Western Washington. Some smoke already arrived from Oregon today but has been at higher altitudes. This could be closer to the ground. On the other hand, the smoke does blot out the sun a bit and that will keep temperatures a little cooler than the models may be thinking.

Still, we have decent odds getting into the low 90s, which would not only break the record highs for Sept. 4th and 5th (87 and 88, respectively) but become Seattle's 9th and 10th days this year at or above 90 degrees.

The all-time record for 90s in a year WAS 9 until two years ago when we had 12 during the hottest summer on record. It seemed unfathomable we'd hit double digits anytime soon, but here we are again just two years later. And don't forget during our last heat wave a few weeks ago that also featured smoke, highs "only" hit 88 in the smoke despite computer projections in the low-mid 90s. So had the fires not been there, we could have been challenging the all time 90s record again just two years after shattering the previous all time record.


The good news for those done with heat and smoke is a large scale weather pattern change appears to be taking place around the end of this week. Wednesday will be a transition day with still warm temperatures into the 80s, but by Thursday we should be much cooler and cloudier. Forecasts show a trough of low pressure to swing through on Thursday, bringing a chance of showers to the region with highs in the low-mid 70s.

Beyond Thursday, our models have not been consistent to bring much of a confident forecast -- my guess is that they've totally forgotten how to predict rain in the Northwest -- but some forecasts are suggesting perhaps a chance of showers continuing Friday and into next weekend. Rain fans, don't get your hopes up too high on a multiple-day-of-showers event just yet, but it does look like we should at least be done with the heat for a while. And each day we go down the calendar without it getting hot is another day off the clock to getting to true autumn weather.

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