Record Lows This Morning, 80s Next Weekend?

Spring used to be my least-favorite season. Back in elementary and middle school, I grieved the transition to boring weather, the seasonal closing of ski resorts in the Cascades, and the departure of the windy, rainy weather that captured my imagination on many a winter day. I’d much rather stay up all night waiting for snow than look at a few tulips. Because the last time I checked, school was never cancelled due to tulips!

As I grew older, I gained a far greater appreciation for spring. Instead of being sad that our snow and storms were over, I learned to love the blossoming of trees and plants and the return of robins and dragonflies. And summer vacation was the best because I would go fishing on my neighbor’s dock and catch perch and bass out of Lake Washington every morning with the worms from our backyard compost. Nowadays, I try not to have a least favorite season, because even if the weather is so-so at the moment, better weather is likely on the horizon, and there’s always something special going on in the atmosphere.

And something very special indeed happened Saturday morning! My family shares some property with some other families in Teanaway, WA, which is approximately 8 miles east of Cle Elum and 100 miles ESE of Seattle. One of the families staying there woke up to a surprise snowfall Saturday morning as a cold springtime system pushed through the area.

By the afternoon, the snow had melted under the strong April sun, but with a cold airmass overhead, temperatures plummeted Saturday night and many locations registered record lows Sunday morning. Portland Airport hit freezing this morning, breaking the previous record of 33 set back in 1991. And Hillsboro, which is away from the “urban heat island” in the city, dropped all the way down to 26!

A number of locations in northwest Oregon & southwest Washington tied or broke record April 11th low temperatures earlier this morning. #pdxtst #orwx #wawx pic.twitter.com/YIzZpzNwLS

— NWS Portland (@NWSPortland) April 11, 2021

Despite the frigid temperatures this morning, temperatures rose to the upper 50s/lower 60s across NW Oregon and SW Washington this afternoon under beautiful blue skies, which is right around average for this time of the year. Springtime can have some of the largest diurnal swings in temperatures since the atmosphere is still relatively cool but we are getting more and more sunshine during the day, and today’s pleasant afternoon after the record lows this morning was a perfect example.

Forecast

We will see a warming trend this week as a ridge of high pressure builds off the coast, with highs rising from the mid/upper 60s on Monday to the low/mid 70s on Thursday with sunny skies each and every day. But while temperatures will be mild and skies will be clear over Western Washington and Western Oregon, a deep trough will move south through the Inland Pacific NW Monday and into the Intermountain West Tuesday and Wednesday.

This trough will bring chilly weather to areas east of the Cascades and substantial late-elevation snow to SE Idaho and much of Wyoming. If the below model is right, the Wyoming Rockies could see over two feet of snow during this time!

The entire week will feel increasingly warm here in the Pacific NW, but things will really start to heat up on Friday when this ridge strengthens further and a “thermal trough” builds over the I-5 corridor. These thermal troughs are our classic heatwave setup because they draw hot, continental air through the Columbia River Gorge into the Willamette Valley and prevent any cooler, onshore flow from moving inland. You can see the thermal trough extending from the Central Valley of California through the Willamette Valley and into Western Washington in the image below, which shows the predicted temperature/pressure/winds at 5pm Saturday.

This is a pretty wimpy thermal trough as far as thermal troughs go, but it is strong enough to keep any onshore flow at bay. By Friday, I think Portland could hit the upper 70s, and at this point, I think there’s a pretty good chance that at least one day next weekend will hit 80 degrees!

And after the subfreezing lows this morning, you can bet that anything above 80 will feel like an absolute scorcher!

Have a wonderful week and enjoy the sunshine. 🙂
Charlie