Get ready to endure a week-long heatwave as July wraps up
Temperatures around 100 on tap for multiple days in Portland
It’s midsummer; best weather of the year in the Pacific Northwest and vacation time. Forecasting is typically quite easy this time of year so I’ll be on vacation next week as well. Luckily the forecast IS quite straightforward.
1) It’ll be sunny EVERY DAY Sunday through late next week.
2) BUT...it’ll be HOT starting Sunday afternoon and that continues through the end of next week.
See, that’s an easy forecast. A few highlights...
Our 7 Day Forecast looks like this right now
That’s an especially long heatwave isn’t it? For comparison, the longest stretch we’ve seen at/above 95 degrees in Portland is 6 days...we may be close. Up until 2015 & 2021, that heatwave in 1981 was the all-time hot weather event in our area. The 1941 event was amazingly hot in early July. And of course 2015 (until last year) was one of our greatest/longest heatwaves
How about 90+ day hot streaks? Back in 2009 we had a 10 day stretch starting in late July. That was the heatwave that gave us back to back 106 degree days. I sure don’t see that happening next week. Notice 2015 pops up again.
The ECMWF model’s ensemble average has been very consistent the past 4-5 days. It looks like this right now; a bit hotter than our 7 day forecast since typically these run a bit cool (ECMWF #s) compared to reality in the summer. For example we should be in the lower 80s tomorrow, not 78. This would imply at least 8 days at/above 90 degrees...a scorcher!
This is a great chart that looks very confusing at first glance, but stay with me...
It shows the last 5 days of ECMWF (European model) runs; technically this is the average of all 51 members of each run. You are looking at maximum temperature forecast each 6 hours at PDX. The most recent run (today’s) is the last horizontal line (highlighted in yellow). I’ve put in S-M-T-W-TH-F-S-S to point out Sunday, Monday, Tuesday, etc... through next weekend. The beauty of this chart is that a forecaster can quickly look at any one day in the future and see what the model has been forecasting FOR THAT DAY over the past 10 runs. For example a few days ago (circled) this model was going extremely hot (102+) for Tuesday. But it backed off in later runs. The most important message here is that for day after day models have been forecasting the heat to begin Sunday, and continue through the end of next week.
There is a sliver of good news about next week. This will be a heatwave that features a shutdown of cooling onshore breezes, but no sign of a hot east wind coming down through the Gorge or off the Cascades. That’s good for fire weather. Much of next week will feature calm or just light wind conditions. With models generally forecasting 850mb temperatures at/below +25 (Celsius) and no easterly wind, it’ll be tough to get above 102 west of the Cascades. That’s good as well.
Without a dry east wind, the ocean beaches should be pretty comfortable during this upcoming week. I doubt 80s or 90s make it TO the beaches, but it’ll be hot just a few miles inland
And you can escape the heat (just barely) up around 4,000′ and above in the Cascades. These forecast numbers for Government Camp also work for all those mountain lakes (Lost, Timothy, Clear, Trillium, Laurance, etc...)
We’ve enhanced and added content to our FOX12 WEATHER APP recently. Make sure you download it.
Plus we’ve got a fresh podcast out discussing the upcoming heat. You can find that on your regular Apple Podcasts feed or here: https://www.kptv.com/podcasts/weather/
That’s it for now, I probably won’t be posting again until the last day of July or August 1st. Enjoy your weekend! At least until it gets hot later Sunday afternoon.
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