Warmest Day Of Summer So Far, Plus More Summer Heat Ahead

8pm Monday…

We hit 97 degrees in Portland today, the hottest day so far this summer.

Recall that we hit 95 back on June 1st. Today was our 4th 90 degree day of the year.

Weak (and hot) easterly (offshore) flow continued through this morning, but now onshore flow (westerly wind) has arrived west of the Cascades. Temps are cooling nicely compared to yesterday, especially near the Coast Range where the cooler marine air is pouring through the low elevation gaps. This means our “mini-heatwave” has ended; tomorrow will be much more comfortable. In fact the next three days should be nice, just a little on the warm side

Keep in mind our typical high temperature this time of year is in the 70s, so we’re only “cooling” down to 8-12 degrees above normal this week. That’s because the hot ridge is weakening only temporarily…Here’s the Thursday map

Already a new ridge is popping up just to our west. But watch what happens by Saturday

A massive hot dome of air directly over the Pacific Northwest. For the geeks, 500mb heights are forecast to 594dm or higher. The 18z Euro ensemble average even paints a 597dm just north of us.

This is major heatwave territory

The big meteorological questions with 5-6 days to go:

  • How strong will the ridge be and where exactly will it be centered?
  • How high will 850mb temps go? Operational model runs are forecasting hottest ever recorded over Salem on Sunday (+30 to +31 on both GFS/ECMWF). Could that really happen? It’s never been above 28.3 there.
  • Will there be offshore flow…or weak onshore flow? That the difference between 102 and 108 (just an example)
  • How long will the hot ridge stick around?

For now, our 7 Day Forecast looks like this. Those numbers Saturday-Monday are a bit on the low side considering what we’re seeing on models:

I’ll get into more detail tomorrow as hopefully things become a bit more clear. For now…

  1. We have a heatwave coming next weekend. It’s TBD whether it’s a “typical” heatwave or something historic.
  2. Make your plans based on that information. If you don’t have AC…maybe head to the coast or Cascades?
  3. IF power goes out next weekend at your home, and you have a medical condition, what would you do? Start thinking about that.
  4. The all-time June temperature record (102) is in jeopardy at PDX
  5. This entire 2nd half of June is going to go into the history books as a scorcher, like 2015. Keep in mind today was the 6th day with a high temperature at/above 80 in Portland. There will be at least 7-8 more.

Chief Meteorologist Mark Nelsen

65 Responses to Warmest Day Of Summer So Far, Plus More Summer Heat Ahead

  1. Hank says:

    Sunday temperatures in Salem/Keizer, from all sites and models.
    Weather.com 112
    Accuweather.com 104
    18z gfs 113
    18z Ecmwf 114
    Timeanddate.com 108
    Norway 113
    Serbia-mos 114
    Access-g 107
    Icon 115
    Weather.bug 107
    Weather.gov 107
    This is just crazy, I remember some point in July 2018 it was supposed to be 111, but it got denied by the smoke, this time that won’t happen, Looks like history is going to be set since our original record was 108 i think in the 30s and 1981. Stay cool out there folks.

  2. runrain says:

    Freddy’s is selling out of bottled water. Limited popsicle supply too. Bet A/C units at Home Depot are gone.

  3. Garron near Hillsboro airport says:

    Man, I can’t wait for the next blog update! This is one for the all time history books! 110, maybe more????

  4. […] and jam session tonight to attend to.  You can read excellent blogs by Charlie Phillips  and Mark Nelsen on the […]

  5. tim says:

    This historic heatwave might be a bust if that upper level low moves in sooner then currently then expected.

    • Evan -- Cedar Mill says:

      That would suck.

    • Anonymous says:

      Let’s hope it joins the long list of busts this region has had over the past few years!

      • Garron near Hillsboro airport says:

        Man, I can’t wait for the next blog update! This is one for the all time history books! 110, maybe more????

  6. Evan -- Cedar Mill says:

    New 7 day on kptv is shocking. Buckle up folks.

    • Paul D says:

      Just saw it. Records will be smashed.

      I will be inside praying my A/C doesn’t melt into a puddle of goo.

  7. tim says:

    Cliff mass new post today, historic heatwave this weekend.

  8. Evan -- Cedar Mill says:

    Wow we may actually break the 107F record.

  9. W7ENK says:

    It’s gonna get HOT!! 🔥🥵💀


    248 AM PDT WED JUN 23 2021

    Dangerously hot temperatures of 98 to 103 likely, with temperatures locally 103 to 108 are possible.


  10. Joshua Lake Oswego says:

    The 12z GFS is upping the ante yet again. 121 on Monday. There is no longer a doubt that we will break our all-time temp record. The questions are: how much do we break it by and how many days consecutively do we break it?

    Back down to run-of-the-mill 90s and lower 100s indefinitely after Monday.

    Petition to change the Willamette Valley’s name to Upper Death Valley?

    • W7ENK says:

      Of course, there’s never any doubt when you worst-case-scenario. (Yes, I deliberately used that phrase as a verb, because it’s accurate.)

      • Joshua Lake Oswego says:

        I think my use of the phrase has been appropriate. When historic records are handily beaten, it stands to reason that a rational worst-case scenario (or best-case depending on perspective) would not account for that.

        Statistically speaking, the weather we are about to have is so unlikely that it is almost not possible. Yet, here we are.

        • Zach says:

          Liking the new 18z run for Monday. Dropped like 15F.

          If the Euro follows tonight I will be very pleased.

  11. runrain says:

    Fox12 weather guy this morning says Portland’s all time high of 107° was reached 79 years ago. Wrong!

    • Paul D says:

      How about this:

      Portland has topped out at 107 degrees three times. The first time was on July 30, 1965. It happened twice again in 1981, on August 8 and 10

      Saw it on KGW

    • W7ENK says:

      Jeezus, I’m old…

    • Tanis Leach says:

      Downtown that is correct. I know it was 1942, but I don’t know which July day. I think it was the 2nd. That being said, it is still inaccurate as downtown is not Portland’s official observing station.

  12. tim says:

    The strongest ridge in history possibley this weekend and seattle will not tie or break the all time record high of 103 set july 2009 the reason becaus there’s no strong offshore flow with this event.

  13. Joshua Lake Oswego says:

    Sad to think that our coolest day in the next two weeks is still 8 degrees above normal. When it’s all said an done, we will likely have at least 20 straight days above normal. Many 15 to 30 degrees above.

    As I said regarding the dry spring, it’s worse than a worst-case scenario.

  14. Tanis Leach says:

    For comparison, here’s what each TV station plus the same websites from yesterday are saying for temperatures only from Friday to Tuesday.
    NWS: 94, 103, 103, 102, 93
    KATU: 96, 102, 103, 100, 88
    KOIN: 94, 103, 102, 100, 92
    KGW: 96, 103, 105, 103, 95
    KPTV: 97, 102, 106, 106, 96
    Rod Hill (portlandweather.com): 96, 100, 102, 98, 90
    TWC: 97, 107, 107, 104, 96
    Accuweather: 96, 104, 100, 86, 91

    The non-Portland websites are in to compare to how conservative/aggressive they are.

  15. Evan -- Cedar Mill says:

    If we could just get some offshore flow we could easily hit 110F.

    • Anonymous says:

      Why would anyone want that?

      • Evan -- Cedar Mill says:

        People who want to witness history.

        • Paul D says:

          I want to witness history when the high is 30 below normal, but that never happens in the summer. It’s always the hot records. 😦

        • JERAT416 says:

          I want to witness history where there is record snow in the mountains and there is still 10 feet on the ground at skibowl by labor day …..my kind if history

        • Gene says:

          Why on Earth would you want to “witness history when the high is 30 below normal”? You’d want a high of 45 in the summer? Besides being impossible, that’s just crazy talk. People like to go outside in the summer and do a variety of fun activities in the nice weather, which would not be possible in 45-degree temps

      • runrain says:

        It’s a weather geek thing. 110 would be miserable. But I want to see it!

  16. JERAT416 says:

    It seems like yesterday that we were in a cool, damp pattern around this time of year and people were whining because they wanted sunny, warm, and hot. Better be careful what you wish for!

  17. Jake says:

    Weather Underground has officially jumped into la la’ land with the weather models.

    It is calling for:

    Sat: 108
    Sun: 108
    Mon: 104

    Crying and laughing has commenced.

  18. tim says:

    What’s gonna happen in july and august?, do things level off to the typical 80s and 90s or only get even hotter since those are the hottest months of the summer.

    • Zach says:

      Its impossible to say. I don’t really trust the seasonal modeling much. I doubt the rest of summer is “cool” but hopefully at least more average mid July – August.

  19. Evan -- Cedar Mill says:

    Too bad there is not much offshore flow. Otherwise we would have easily broken the 107 record.

    • Zach says:

      We definitely might break it. Granted I agree, the offshore flow looks weak and could end up being more NW depending on where the ridge sits.

      I am hoping the pacific saves the day and keeps us lower in the 100s.

  20. Lurkyloo says:

    “This is so nuts I can’t believe it.

    The origin of this potential heatwave is a huge, high amplitude ridge of high pressure aloft (see the forecast for 11 AM Sunday. It would represent the strongest ridge in history for our region.”

    Copied from Cliff Mass’ blog.

    Again, F this.

  21. Lurkyloo says:

    F this.

  22. Anonymous says:

    Anyone else already looking forward to “fall”?

    • Joshua Lake Oswego says:

      Very much. Although, I wouldn’t be surprised if fall doesn’t show itself until around Halloween. Our summers seem to be getting longer on both ends. It started at the end of February this year.

      • Anonymous says:

        Yup, I have similar thoughts about the arrival of our usual fall weather as well. I’d be okay with warmer (not hot) September and October temps as long as we get a good amount of rain. Probably not a popular opinion but I’d love an October 2016 redux.

    • Paul D says:

      I’m looking forward to retiring in a few years and moving somewhere that has weather like we used to.

  23. Winter Enthusiast says:

    The END is near!

  24. Jake says:

    This previous heatwave was clearly a taste for what Summer is going to bring. I really hope I am wrong. Last Summer was apocalyptic.

    Covid-19, forest fires, heatwaves and such a dry season even the trees showed signs of drought which can reach way down.

    If that occurs again I will be writing local gov. on measures to create new artificial water reservoirs in harping back to this:


  25. runrain says:

    Seattle is only 34% air conditioned – lowest in the nation. Portland is #3 at 70%. This according to The Weather Channel.

  26. W7ENK says:

    Definitely gonna be HOT!! 🔥🥵

  27. Joshua Lake Oswego says:

    00z GFS upping the ante…

    Saturday – 110
    Sunday – 116
    Monday – 118
    Tuesday – 108
    Wednesday – 104

  28. runrain says:

    The not-to-be-mentioned weather apps showing 106° for Sat and Sun.

  29. geo says:

    Had a historic ice/snow storm in feb. now this could be historic!

  30. tim says:

    I see mark keeps referencing to 2015, enough said.

  31. JERAT416 says:

    As we ride this heatwave, remember to keep your hands, arms, feet, and legs inside at all times, and please, no flash photography. Stay cool everyone!

  32. Gene says:

    Thanks as always for keeping us informed, Mark, especially with this potentially record-breaking pattern coming up!

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