A Wet and Windy Wednesday on Tap

I don’t know about y’all, but I’ve absolutely loved our summertime weather. Granted, it’s been extremely boring and there hasn’t been much to write about, but I’ll take anything over the apocalyptic fires and smoke we saw the past two summers. And it doesn’t hurt that our “boring” summers are pretty much “perfect” by any definition, with warm days, cool nights, lots of sunshine, and a continuous stream of fresh, clean, onshore flow from the Pacific.

But all that boring weather will be a distant memory soon, and a quick glance at the GOES-17 satellite shows why.

A front is quickly approaching the coast, and precipitation from this front is already visible on radar. It’s not much, but tons more precipitation is on the way.

The uber high-resolution 1 1/3 km UW WRF model shows widespread totals of 0.25 to 0.5 inches, with over an inch possible over the Olympics, North Cascades, and possibly even a Puget Sound Convergence Zone!

The middle of August is often when we first start to see the potential for “autumn-like” storms to hit the Pacific Northwest, though they are still generally pretty anemic at this time of the year. But with temperatures to our north beginning to cool, meridional temperature gradients increase, resulting in stronger jet streams and a more active storm track. Additionally, the tropics are plenty active at this time of the year and tropical moisture is often entrained into the westerlies, and that’s exactly what happened with this system as well. A look at the “total precipitable water” (drop that one at a cocktail party) satellite below shows a tongue of moist, subtropical air – an atmospheric river – aimed directly at the Pacific Northwest. Indeed, it will feel quite humid tomorrow morning ahead of this system, though I’m a firm believer that Pacific Northwesterners have no right to complain about the humidity, just like southerners have no right to complain about cloudy skies.

Tl;dr

I’ve got to rush to a jam session (btw, if you are in Portland, check out the Rose City Book Pub jam session every first and third Tuesday of the month from 7-10. But to quickly summarize, expect rain to arrive for the PDX metro area shortly before noon and persist through the early evening before switching to showers. Highs will have trouble reaching 70 degrees, some 10-15 degrees below average for this time of the year.

Thanks for reading, and I hope you enjoy the rain! If you miss the heat, you won’t have to wait long – Portland should rise into the 90s next week as a thermal trough develops along the West Coast.

Charlie