Western WA weather: Hottest temperatures of the year so far

Let’s cut to the chase.

It’s been 236 days since the last 80-degree day in Seattle, according to the National Weather Service, and the wait may soon be over.

A high-pressure system — which causes air to descend rapidly, warming and drying along the way — began to build over Western Washington on Wednesday, strengthening at the end of the workweek.

Translation?

Forget about rain — we’re entering a sun-soaked spell with temperatures nearly tripping over themselves to reach 80 degrees.

It will be “a pretty dramatic warmup over the next couple of days,” said Dustin Guy, a meteorologist with the weather service in Seattle.

If you recall, Sunday’s high in Seattle was 51 degrees, the normal high for late February and the third coldest May 5 in 80 years, according to the weather service. By Friday, the mercury will catapult up the thermometer to what is typically recorded in early August.

But Mother Nature, with all her grace, will kindly ease us into this rapid warmup. Temperatures Wednesday were right around normal for this time of year, “in the mid-60s or so,” Guy said.

The mercury Thursday will continue to crawl up the thermometer, rising several degrees into the 70s across the Puget Sound interior. The coast, however, is expected to pick up a few more degrees as offshore flow nudges highs near 80 degrees, the weather service said.

Take out a pen and circle Friday on the calendar, as that is expected to be the warmest day of the year so far — and perhaps the start of a three-day weekend for those who can’t resist the sun’s siren song.

Seattle’s forecast high Friday is 80 degrees, according to the weather service. Cities south of Seattle, like Olympia, are expected to surpass even that, while highs in areas north of the city will settle on the other side, in the upper 70s.

Seattle’s average first 80-degree day is May 20. The earliest 80-degree day of a year recorded in the city was April 1, 1987, and the latest was July 21, 1980, according to the weather service.

The weather service is urging caution this weekend as people likely take to the water, which will remain cold despite warmer air temperatures in the coming days.

“It doesn’t matter what water you’re talking about, whether it’s the lakes, streams, or even Puget Sound, which is always cold,” Guy said.

A cooling breeze from the Pacific Ocean will cool coastal areas as much as 20 degrees on Saturday, but (don’t panic!) the interior will cling onto 80 degrees for another day.

By Sunday, though, a couple of passing systems to the north will flatten the aforementioned ridge of high pressure, lowering temperatures back to slightly above seasonal levels, in the 60s and 70s, the weather service said.

With the exception of a few possible showers in the North Cascades, the remainder of the region looks to stay dry on Mother’s Day.

The region will cool off heading into next week, “but it’s not going to be like rain and temperatures in the 50s,” Guy said.

Instead, expect morning clouds, afternoon sun and temperatures in the 60s as dry and warm spring weather lingers.