The historic July 2022 heatwave has ended

9pm Monday…

What a terrible week to be without air conditioning in western Oregon or southwest Washington. I was off on vacation (Leavenworth WA & B.C.), and I can tell you it was hot everywhere in Cascadia…except along the coastal beaches.

Summary

• The last week of July 2022 will go down in history featuring one of our greatest heatwaves
• Portland, Seattle, Eugene, & Medford saw their hottest week on record, Salem, Pendleton, & Redmond 2nd hottest
• As expected, nighttime temperatures were record-breaking warm due to high humidity
• Humidity was quite high; one of the “sweatiest” heatwaves I’ve seen in our area

All the Stats

Today’s high in Portland was 89 degrees, our first day back in the 80s since Saturday the 23rd. You just endured the warmest/hottest week on record in Portland. Take any 7 days in Portland’s history, adding the 14 highs/lows, then divide by 14. You get the average temperature for those 7 days. The 83.4 you see below is the highest on record

(kptv)

This included a record 7 consecutive days at/above 95 degrees

(kptv)

Salem was worse, enduring 7 days at/above 98 degrees! In Portland is was NOT the longest spell of 90+ days though. That record is from 2009

(kptv)

We hit 100 degrees 3 times, peaking out at 102 on 2 separate days. Note no “extreme” hot days (103 or higher) this time around west of the Cascades. As expected ahead of the heatwave, a weak onshore flow was present most of the past week (except Tuesday). Believe it or not, that means we could have been quite a bit hotter.

(kptv)

In my view, the most stunning part of this heat wave is what happened overhead. The 850mb temperatures (in Celsius around 5,000′) on the Salem weather balloon soundings were record warm/hot. It peaked at 25.4 on Tuesday and Wednesday, 28.2 on Thursday, 26.8 on Friday, 27.0 Saturday, & 26.2 on Sunday. That Thursday number is higher than anything previously seen in either July or August (27.6 deg). So it’s fair to say this was the hottest overhead atmosphere we’ve seen in these two months. IF WE HAD SEEN OFFSHORE (EASTERLY) FLOW last week, temperatures would have peaked between 105-109. I think it’s especially interesting that the atmosphere got so hot considering 500 millibar maps were not shockingly warm. Highest heights were 590-595dm during that time.

East of the Cascades the hottest air DID surface Thursday, Friday, & Saturday. Take a look at the high of 112 at The Dalles and 109 at Redmond on Friday the 29th. If not for last year’s heatwave, those would have been all-time records. What’s the chance of setting all-time records in 2 consecutive years? It’s almost as if our climate is changing and warming (it is!).

(kptv)

Of course what made this heatwave really bad was the lack of overnight cooling and high relative humidity. Dewpoint is the best measure of moisture in the air we breath. It was regularly between 60-70 degrees, especially the 2nd half of the week through Saturday. There were plenty of spots in the hills with dewpoints at or even slightly above 70 (due to vegetation). The last time Portland dropped below 69 degrees was Thursday morning! I grew up and started my career with the mantra “you don’t need A.C. in Portland”. That’s no longer the case. Anyone in the urban area should have at least a room air conditioner for sleeping.

(kptv)

Finally, July ended up the 4th warmest month on record in Portland, only eclipsed by July 1985, 2015, & 2018. Those months were generally warmer across the entire month. Notice we were near normal until the heatwave arrived. This month just barely edged out August 2017.

(kptv)

That’s it for now. August is here and warm temperatures continue through the foreseeable future. A brief heatwave is possible Saturday through Monday with highs in the 90-95 degree range. Humidity should be LOW with that heat too. I see dewpoints mainly in the 50s.

Enjoy the cooldown through Friday!