10th Consecutive Warm/Hot August Wraps Up Soon

10pm Thursday…

Today was another fantastic day…as the most consistent/stable weather pattern of the entire warm season continues. Each of the past 8 days in Portland we’ve topped out between 78 and 84 degrees. Keep in mind a typical high temp this time of year is 80-81 degrees; this is about as normal as it gets folks!

Humidity has been low, skies have been mainly sunny, & nights have cooled well down into the 50s. Many would say we are having a perfect summer weather pattern. That’s because hot high pressure has stayed to the south, allowing just enough onshore flow to keep us comfortable

Somehow my pool has remained in the mid-upper 70s, even with lows in 40s and highs only 75-80 out there. Must be the constant sunshine each day. We are living through another warmer-than-average August.

Does it seems like late summers have been consistently warm lately? Sure enough, Portland hasn’t seen a cool August since 2010! Although 2011/2013 were only a little above average. Of course the Portland/Vancouver metro area has an increasingly warm “urban heat island” at night which leads to ever-increasing nighttime temps under clear skies. But daytime highs (a more reliable indicator of a warming climate in a city) have been steadily marching uphill too. 1940-2020 August high temps at PDX, make sure you click on it for a MUCH better view.

After a slightly warmer day tomorrow, in the 85-88 degree range, we’ll cool off over the weekend with more onshore flow. Then a weak upper-level trough passes nearby Monday

Models say we could get lots of clouds and even a few light showers out of this system late Sunday night and Monday morning. I have a feeling the last day of August will feel more like September. But then things heat up again the first week of September. All models agree a flat, but strong ridge of high pressure in the upper atmosphere parks over the Pacific Northwest. You can see the very warm ridge on Tuesday’s 500mb chart…this is the pretty one we use for TV.

The ECMWF ensembles say summer is coming back the first 7-10 days of September. Check out the rain outlook, little/no chance for rain through the 10th, after the showers this coming Monday

And the surface temp forecast shows 10-15 degrees above average daytime highs. The Euro, GFS, & GEM all hint there could be some sort of heat event during this period. I mean several days at/above 90 degrees. At least hot weather in September is accompanied by much cooler nights than July and early August!

To summarize

  1. Nice summer weather continues through Sunday
  2. Monday is THE ONE DAY in the next 10 we may see some showers
  3. Sunshine and much warmer weather returns the first week of September.
  4. There is no sign of an early start to fall rains and/or cool/wet September weather like we saw last year.

Chief Meteorologist Mark Nelsen

19 Responses to 10th Consecutive Warm/Hot August Wraps Up Soon

  1. Roland Derksen says:

    Yesterday’s rainfall came quickly, but also ended quickly. About 2 hours of light precipitation in late afternoon/early evening, with a total amount of 0.04 inches. That’s it for August- now onto what appears to be a very dry warm start to September!

  2. Ziggy says:

    This upcoming warm spell is just a preview of our impending dry warm winter🔥🔥🔥🔥

    • jim says:

      Actually a very warm to hot summer often leads to cold winters. Lived here over 60 years. Seen that happen a bunch of times

  3. W7ENK says:

    OMG, the GFS is on drugs…

    I don’t even think that’s physically possible in our climate with only 12 hours of sunlight…

    • Joshua Lake Oswego says:

      Regardless, we are in for a ridiculous stretch of heat. Heck, it would be ridiculous in late July or early August.

      I knew we couldn’t just coast comfortably into fall. Impossible without one last poignant middle finger from Mother Nature.

      Who wants to go in on a summer house in northern Scotland with me?

      • Joshua Lake Oswego says:

        Oh, and as always, the heat spell will be longer and hotter than originally forecasted. A few days where we might touch 90s is now endless 90s with some potential for 100s.

      • Paul D says:

        I’d say that’s two middle fingers from Mother Nature 😦

  4. runrain says:

    100 deg on Sep 9? If that comes to pass, would that be Portland’s latest 100 deg on record?

  5. runrain says:

    90 deg is easier to handle this time of year. Shorter days, longer nights, lower sun angle.

  6. MasterNate says:

    This next hot spell looks like it could last 2 weeks. Ugh!

  7. Roland Derksen says:

    The last really cool August for me was in 1995. The ones after that were either around normal or above. This morning we got the breezy winds that were forecasted, and it’s keeping the temperature noticeably cooler.

  8. runrain says:

    Per the phone weather app (yeah, I know), the first 10 days of September are all 87 deg or higher. 7 of those 10 days are in the 90’s.

  9. Roland Derksen says:

    While I haven’t been counting yet, I know this August has been warmer than normal. As far as precipitation goes, it’s been a bit more than usual here, but that was mainly due to that downpour we had on the 6th. We could get some more rainfall here before the month is over, however.

  10. JERAT416 says:

    I’m gonna spend most of next week at the coast, looks like good timing. If I remember right, September is actually the sunniest month down there.

  11. Paul says:

    90’s in September? No!! It’s time to cool off.

  12. Ken in Wood Village says:

    Thanks for the update Mark! I hope for nice weather on September 6th. That’s my birthday 🎂 🤪

    First!!!

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