A Warm July Ends With A Heatwave

9:00pm Monday…

It’s vacation season in the Pacific Northwest; the best weather of the year! So I’ll be joining many of you travelling across the region the next week and a half. Heading out for camping in parts of southern Oregon. No posts during that time, unless something really serious pops up (major fire close to us, huge earthquake, volcanic eruption, tsunami, etc…). I’ll be back at work Sunday August 8th.

The end of July is quickly approaching and it’s been a warm month! No record-breaking heat, or heatwaves, but consistently warmer than normal. It appears we’ll end up with at least the 5th warmest July on record, likely #3 or #4.

The western 1/3 of the USA has been sizzling so far this month, following the warmest June on record for some.

We’ve been “lucky” west of the Cascades, picking up just enough cooling onshore flow to keep us near/below 90 degrees most of the month. Portland has seen (12) 90 degree days so far this year

Yet, just slightly farther removed from that ocean air, both Salem and Eugene have seen over 20 days at/above 90!

Looking ahead, we have a heat wave on the way Wednesday-Saturday. This is what we’re thinking this evening for Portland:

No record highs, since they are generally 100+ this time of year. But four 90+ days to wrap up July.

Why is it turning hot again?

Strong high pressure bringing heat over the Rockies is far enough east to keep our temps reasonable again tomorrow. That “594” contour centered over Colorado is the center of the upper-high.

But you see it snuggles up a bit closer to us Friday and Saturday. Here’s midday Saturday; the ridge of high pressure has amplified, and southerly flow is in charge across the West Coast. This MAY bring thunderstorms north into the Cascades and Eastern Oregon. There are even a few GFS and ECMWF ensemble members sending a disturbance north with showers/thunderstorms WEST of the Cascades this weekend. But not enough to put it in the forecast. Just be aware that this weekend is not “guaranteed” dry. Keep an eye on the forecast.

This pattern doesn’t produce a hot easterly wind over the Portland area (ridge is too far east), which should keep us below 100 degrees…but just barely! Then Sunday and beyond the ridge weakens; we’re back to reasonably warm temperatures for the first few days of August. This is Tuesday (August 3rd)

By the way, we are at day #41 without rain in Portland. The last MEASURABLE rain was June 15th. There WAS a trace at PDX on July 1st. Assuming we don’t get rain in the next 12 days (possible), we’ll be up in the “top 5” range for dry spells. But for now we’re a long way from that 71 dry day record

A few more notes:

  1. I don’t expect high humidity during the upcoming heat wave, UNLESS we get some showers or thundershowers Saturday/Sunday.
  2. Overnight temperatures will be turning very warm, mid-upper 60s. This isn’t as extreme as the historic heatwave back in June, but it’s still worth checking in on elderly friends/relatives.
  3. Southerly flow = overhead fire smoke from California fires. Expect increasing haze and yellow/orange sun after Wednesday. Low-level smoke is UNLIKELY west of the Cascades since wind will be coming from the northwest and west.

Stay safe during summer vacation travels!

Chief Meteorologist Mark Nelsen

217 Responses to A Warm July Ends With A Heatwave

  1. Ryan Lounsbury says:

    GFS has been running cooler for a few runs vs. the run-up to this event. I’m starting to think we only come away with 1 day over 100 given this wrinkle and what seems like likely upper-level smoke.

    At least it is looking like a lock that we nose dive with a trough early next week. I just hope we are done with this ridiculous heat for the balance of Summer.

  2. tim says:

    12z euro is now following the gfs with a trough early next week so maybe this won’t be a prolong heatwave after all.

    • Anonymous says:

      We can only hope. Luckily, we lose a lot of daylight in August which limits just how hot it can get.

  3. Evan -- Cedar Mill says:

    Cliff Mass didn’t even mention the pending heat wave most likely because it doesn’t support his narrative. Very selective reporting if you ask me. Maybe if you ignore it will go away lol.

  4. runrain says:

    Weather Channel has Portland at 110° on Thursday.

    • Anonymous says:

      I’ve found TWC always runs hot. All the local stations have Thursday at 104, minus KOIN 6 with a 109. I’m waiting to see what Mark has to say.

    • Joshua Lake Oswego says:

      The 12z Euro and GFS are both cooler than the 00z runs. I’m thinking 102-104 on Thursday. Hotter than heck no matter how you slice it. We could get “lucky” and stay under 100 if the smoke is thick enough.

      • W7ENK says:

        You folks keep referencing smoke, but none of the smoke product models show significant smoke in/over Portland metro. In fact, they show the little bit that we do have overhead tight now blowing away to our S and SE, clearing out skies with a N-NNW flow.

        Where are you guys coming up with this assertion?

      • Gene says:

        Getting enough smoke to stay under 100 degrees is not getting “lucky.”

        • Joshua Lake Oswego says:

          Depends on your perspective. Personally, I would take enough smoke to knock 10 degrees off and lower the solar radiation being imparted on our flora. Too much smoke is of course bad for many reasons. I put it in parenthesis for a reason.

  5. Evan -- Cedar Mill says:

    GFS back on the drugs. Forecasting a high of 59 on Tuesday the 17th.

  6. Joshua Lake Oswego says:

    200 hours out looks beautiful on the 00z GFS. If it was heat being forecasted, it would end up verifying with 5 degrees added on top just for fun. Since it’s cool and wet being advertised, add 25 degrees and remove 90% of the precipitation.

  7. Anonymous says:

    KPTV taking the day off it seems and their forecast is very conservative for the heatwave compared to other sources.

    I’ve always found the online forecast update times to be really bizarre. It makes more sense to me to update at 6am and 5pm than the typical 3am and 2pm.
    I wonder if Forgeron feels miserable working that early morning shift.

  8. tim says:

    I think it’s safe to say this will be the last heatwave of the year.

    • Anonymous says:

      Yup, looks like pretty pleasant temps after the heatwave is over that will take us into meteorological fall.

    • Snomanski says:

      Given that we now are forced into defining a heat wave in terms of triple digits, you may be right. By the traditional definition of multiple days in the 90s, I’m not sure we’ll be out of the woods till October. Sad but true. BTW, I guess I am one who ‘prefers’ (as in hates less) heat to smoke. Just bought 6 new furnace filters today, and I expect to use them. Yikes.

    • Zach says:

      We aren’t in the clear until late September.

  9. runrain says:

    Looks like no one is minding the store at Fox12 weather. When the cat’s away…

  10. Joshua Lake Oswego says:

    50 out of the last 56 days have been warmer than normal including the 3 hottest days of all time.

    Depending on the impact of smoke, we could have a couple of days next week approaching or exceeding the previous hottest day of all time.

    We have had 3.8’’ of rain in the past 160 days including the driest spring ever.

    This will likely be the warmest summer of all time.

    That is all.

    • Michael says:

      I have worked outside most all of my life and have to say that things are strangely different for all 4 of the seasons. Different in such a way it sends a little message that we might be in for some troubles ahead.

    • Anonymous says:

      Not sure where you are seeing us possibly exceeding 116F for this next week. At this point it appears unlikely we go above 110F (knock on wood)

  11. Andy says:

    Not strange for a heat wave in August…I’m not going to be worked up about it. Fall rains will be here before we know it…What was out of the ordinary was the heat wave in June…that was more historic.

    • Evan -- Cedar Mill says:

      Wrong. This would have been historic if it weren’t for June.

      • Andy says:

        Not true…check your weather history for August….I think there is to much hype…June is the anomaly.

        • Zach says:

          Yeah. August of ’81 would possibly still remain on top.

          99, 103, 107, 105, 107, 97

        • Zach says:

          Also July of ’41

          101, 103, 103, 102, 100, 97. Less magnitude but 5 days above 100 in a row…

        • Evan -- Cedar Mill says:

          I was talking about us hitting 108, but that seems unlikely now.

        • Anonymous says:

          Looks like pdx is due for another 81 or 41, but it doesn’t appear that’s gonna happen this year.

  12. runrain says:

    In the old days, days like today would be around 70°. In compliance with the new reality, it’s around 80°.

    • Evan -- Cedar Mill says:

      Exactly what I was discussing with some friends.

    • Hank says:

      heres a quick little thing. currently for about 5 years give or take, we have been experiencing a weather pattern, gives us hotter temperatures, and its unknown how much longer it will last, something like this is normally 10-26 years long so its a big range, if you consider 1970s 1980s old days, we have warmed up
      0.5 – 1 degres since then, so with what i listed, our warm days may be 3-6 degrees warmer on average, but for conditions like this 2 degrees max, and if you look at weather history days like this wouldnt be 70 degrees, so pretty much my point is, your comment is inaccurate.

  13. tim says:

    Weather.com is showing 108 for pdx but the smoke says no that’s not gonna happen which we should be grateful for.

  14. tim says:

    12z euro is crazy hot, didn’t Mark say to add 3-8 degrees to the highs on the euro since its cool bias?.

  15. Evan -- Cedar Mill says:

    Funny because this upcoming heat would have had a chance to set the all time record if it weren’t for June’s jaw-dropping heat wave.

  16. tim says:

    I’ll be going to the hardware store this weekend to buy new air filters for my heat and AC furnace for the thick smoke that will be coming in from BC and Eastern WA late next week, yuck.

  17. Weatherdan says:

    84 at 3:00PM. Not a drop of rain today, so this is number 52 of our dry spell. Next 16 days look hot and dry. Just like the last 8 weeks. One good thing though, we are all used to the heat now. Also the rainy season may be here in just two months. I’m hoping for a cold and snowy Winter. But what we get may be another thing altogether. Stay cool. Peace.

  18. tim says:

    I’m assuming Mark will post about the possible pending heatwave, the nws seattle has growing confidence this pattern could happen and the cpc is on board as well.

  19. Zach says:

    It is of no surprise that this event is such an under performer. That has more or less been the rule rather than the exception over the past couple years.

  20. Roland Derksen says:

    Disappointng, to say the least. Just mainly cloudy skies here this morning. Felt a few raindrops last night before 9pm, but that was it!

    • Roland Derksen says:

      Light rain reported now at YVR , so this time it looks like rain is coming at last. No downpour like last year, though. Actually that’s good- too much rain too quickly can cause problems.

      • Roland Derksen says:

        Wow- i picked up 1.02 inches here this morning. Looks like more showers are possible, or thundershowers. This won’t end the drought, but it certainly will put a dent in it.

  21. Garron near the Hillsboro airport says:

    This system reminds me of those marginal snow events, where the showers get gobbled up by the coast range. We are gonna struggle to get a measurable amount of rain in in the PDX area.

  22. Evan -- Cedar Mill says:

    Lots of showers lol. Desert northwest.

  23. Hank says:

    The weather.com radar is terrible, if you compare it to a good radar, weather.com doesn’t show the storm over spokane and north idaho, while a working one shows a decently big storm, weather.com doesn’t show the one above the dalles, but a functioning radar shows very heavy rain, same thing with many other storms,

  24. Weatherdan says:

    82 at 1:00PM so relatively cool. Friday system looks weak, so I expect little if any precipitation. Eugene .00 to .02. Salem .T to .04. Portland .02 to .06. The Saturday system looks still weaker yet. Salem and Eugene .00 and Portland .T to .02. Then The heat begins. Soak your trees this weekend before the heatwave, shrubs too. This heatwave won’t be as hot as June but some could see 106. Might hit over 100 from Wednesday through Saturday. 90,s may go from Tuesday the 10th until Saturday the 21st. Peace.

  25. tim says:

    The good news is If this coming heatwave materializes the thick smoke coming from east of the cascades should keep temps from reaching there full potential, I think most of us rather have smoke and cooler temps then no smoke and hotter temps.

    • Anonymous says:

      If that happens, it’ll remind me a lot of last September. The smoke was absolutely horrendous, but the one plus was that it kept our temps reasonable. I think we stayed in the 60s and 70s for highs because of it.

      • tim says:

        If 60s and 70s is the case then bring on the thick smoke, of course not good for ppl with lung issues.

      • W7ENK says:

        Not good for people with gardens, either. Last year, the smoke was so thick over my neighborhood it blocked out virtually all insolation, and after just 4 days I lost everything but my squash. 100% of my corn terminated about a week before it would have grown mature. My beans terminated, and they usually keep producing until a week or so before Thanksgiving. All 6 of my tomato plants terminated, all still full with green tomatoes on the vines, they just shriveled and turned to rot.

        I’d really rather not repeat that again. Like, ever!

    • Evan -- Cedar Mill says:

      Not at all lmao. Bring on 120 degree heat. Please no smoke.

  26. Hank says:

    Wow the rain isn’t being a total bust, just a couple hours ago I thought a few light showers max, but this is looking good, but probably would be better without the lightning, since fires, but there’s a decent amount of rain coming with it so that might put out the sparks.

  27. Ken in Wood Village says:

    Can someone confirm that there are thunderstorms next to The Dallas. I just got a lightning tracker notification, saying 50 miles away

    • W7ENK says:

      Yes, there have been several lightning strikes from a cell that popped up between Hood River and The Dalles in just the last 15 minutes.

      • Ken in Wood Village says:

        Makes me wonder if we could see a thunderstorm here if they are popping up everywhere 🤔

        • W7ENK says:

          Seems like a distinct possibility. There’s a whole line of them developing right now along the Cascade Crest between Hood and Jefferson, poised to scoot toward the N and W over the next couple hours.

          We’ll see…

        • Ken in Wood Village says:

          I looked at the Visible Satellite picture and the last couple of frames, you can see some forming and moving NW. Hopefully we will see thunderstorms tonight 🤗⛈

        • Hank says:

          Those thunderstorms went from nothing to red in an hour

    • Hank says:


  28. tim says:

    12z euro is cooler then the 00z but still hot, maybe this cooler trend will continue hopefully.

    • Joshua Lake Oswego says:

      Sad that 4 straight days above 100 at PDX is cooler. The good news is that our expectations are so low now that it’s impossible to be surprised or disappointed.

      • tim says:

        Weather.com just bump the temperature up a couple more notches from early this morning, yuck.

  29. W7ENK says:

    Huge thunderstorms just blew up in the Coast Range between Eugene/Springfield and Roseburg.

    Not really moving anywhere yet, just kind of meandering about. But the are spitting some dry lightning into the Cascades on the other side of I-5.

    Not good!!

    • Ken in Wood Village says:

      I saw that earlier but the radar showing a lot of moisture with the thunderstorms. At least that’s what my radar was showing. I posted around 10:45am or so.

      • W7ENK says:

        As you can see in the first image, all of the moisture (at least what’s being picked up by the radar) is to the West of I-5. Lightning strikes on the East side of I-5 are not (presumably, based on the radar) accompanied by any rainfall, and therein lies the danger.

  30. Ken in Wood Village says:

    Anyone noticed the line for thunderstorms between Eugene and Roseburg? It looks like they are just drifting and not really moving much. There is over 100+ lightning strikes with these storms 🤔⛈

  31. Well, I hope this wrinkle on the 06Z GFS plays out. But, unlike the 00Z EURO, it wants to send another low south out of Alaska and the hot weather shifts back to the midwest.

    I have no interest in another multi-day 100+ degree run.

  32. tim says:

    00z euro has 4 days at or above 100 for pdx but 00z gfs is cooler, isn’t the euro model supposed to be more accurate? tonight’s 00z euro must be a outlier.

    • Mr T says:

      Lots of free Tri Max days coming up and reduced speeds! 🤣🤣🤮🤮

      (When it’s around 100F they operate at speeds no greater then 35mph and offer free rides to cooling centers)

    • Zach says:

      Honestly I think with the smoke cover over us we won’t be seeing the temps currently projected by the Euro.

  33. W7ENK says:


    Tomorrow is going to be super smoky.



  34. runrain says:

    Greenville, CA near Lake Almanor has been hit pretty bad by the Dixie Fire.

  35. Garron near Hillsboro airport says:

    I guess we better enjoy these showers, gonna be hot after. 100’s possible by next Wednesday.

    • Garron near Hillsboro airport says:

      It seems like this stagnant high pressure system has pretty much been parked near or directly over us since April. Wondering if we’ve got the infamous “warm blob” off the west coast? That will play into our upcoming winter.

  36. tim says:

    I wonder if cliff mass will back off on his Sunday forecast since models are now backing way off on the rainfall amounts, here comes the august heat.

    • tim says:

      However the cascades and BC will get between 1 and 1.5″ which is good for the wildfire situation.

  37. Evan -- Cedar Mill says:

    KPTV 7 day has 100 back in the forecast. Here we go again…

  38. tim says:

    The 12z euro did throw a 107 at the end of the run for pdx, on to the 00z.

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