Heat wave this weekend, plus shower/thunder chance west of Cascades

11pm Friday

It’s been a nice week with comfortable temperatures; much better than last week’s heatwave!


The heatwave this weekend will be shorter AND far drier. We won’t be seeing any of that humid weather, at least through Monday. This is what we’re thinking right now for temperatures


Notice we probably won’t break any record high temperatures. That’s because we’ve seen big heatwaves in early August (some very high records!) and we should just barely touch 100 on Sunday only. Skies remain totally sunny tomorrow and Sunday, then a few clouds show up Monday. There are also hints that a strong marine push of cooler air comes inland Monday morning. If that happens, it’ll cool the southern Willamette Valley first, with most cooling waiting until Monday evening in the Portland metro area. So it’s possible Albany and Eugene don’t make it to 90 on Monday. We will see. If we hit 100 on Sunday (again!), it’ll be the 3rd time this summer. Remember we hit that century mark FIVE TIMES last summer. It is unusual, even in our warming climate, to see so much 100 degree action. Just for fun, I looked at 100 degree days each decade in Portland. I used PDX airport records back to 1970, then downtown observations back into the late 1800s. The downtown records have lots of gaps the past 40 years. It’s obvious we have LOTS more 100 degree days than 120 years ago. A 100 degree day was extremely rare in Portland around 1900. But also notice not as many in the 1990s. It’s also interesting we’ve had (at least) 8 in just these past two years!


Cooling onshore flow begins later Monday as an upper-level low approaches the coastline.


This low will move north through the outer waters of the Pacific Northwest from Monday through Thursday. As that low passes by, we get quite a surge of moisture overhead, nice lifting, and southeasterly upper-level flow. This CAN be a perfect setup for thunderstorms west of the Cascades. We haven’t seen a good thunderstorm outbreak yet this summer along the I-5 corridor. This COULD be our chance. Of course each model is a bit different, but they all imply something interesting could happen at some point between Monday night and early Wednesday.

I’ll be down in southern Oregon next week on a final camping trip. Diamond Lake is calling! So no blog updates until at least the 15th.

100 Responses to Heat wave this weekend, plus shower/thunder chance west of Cascades

  1. Patrick says:

    91 degrees with 38% humidity has all the markings of a uncomfortable night.

  2. runrain says:

    Looks and feels very thunderstormy out there!

  3. Bethany250ft says:

    Does anyone know what happened to the December 2008 blog posts? They seem to have disappeared, and it seems like Mark would have blogged about the snowstorms. Does anyone have links to old archived posts?

  4. Bethany250ft says:

    12z GFS is showing a major heatwave for late August, three days in the 100s and one over 105. Probably won’t verify that extreme but looks like the warmth will continue

    • tim says:

      We are gonna have another heatwave at the end of the month all models and cpc are showing this the cpc also has a slight risk for excessive heat on there hazard outlook also.

    • runrain says:

      We’ve hit 100° before in early September so not out of the question. Especially in this new world.

  5. tim says:

    The saga continues the 00z gfs brings the ridge and heat back for the end of August unlike the 18z.

  6. tim says:

    If weather.com is right Seattle will break the record for most 80+ days in August which is 16 80’s is forecasted the rest of the month.

    • tim says:

      Of course that’s laughable to you guys in Oregon but it just shows our climate is rapidly warming.

  7. tim says:

    06z gfs has 100+ for Portland multiple days at the end of the month most likely won’t happen but none the less we stay hot going into September.

    • Zach says:

      12z is totally different. I think the last week of August is still pretty up in the air as far as temps are concerned.

      • tim says:

        18z is wetter and cooler the last couple days of August but it’s the 18 z and 00z will probably bring the ridge back, September can be a bone dry and hot month.

  8. Weatherdan says:

    81 and very pleasant at 4:30PM. Not a cloud to be seen. But now the heat cometh. The next 16 days all look hot. And that takes us out till the end of the month. So what in mid June looked like a cool and wet Summer will instead turn out to be another hot and dry Summer. Do we get any other kind anymore. Autumn is only 6 weeks away. Peace.

  9. Roland Derksen says:

    Some very light showers here this morning- it all added up to a grand total of 0.03 inches. Perhaps that’s it til September.

  10. tim says:

    Today’s Cpc week 3 and 4 outlook has us above normal temps so get use to the heat it’s here to stay.

    • Joshua Lake Oswego says:

      I think we’re all used to it by now. 37 out of the last 48 days have had an above average daily temp. We’re almost batting .800.

  11. Joshua Lake Oswego says:

    We could hit 90 10+ days starting on Monday.

    • tim says:

      Well if Portland wants to break the record for most 90’s in a year then better get on it, make 2015 & 2018 look cold.

  12. Weatherdan says:

    Latest 16 day GFS meteogram eye popping to say the very least. In the 10-16 day time period it has heights of 590 with surface temps of 112 for Portland. Very nearly what we saw in June of 2021. I would not be surprised to see it verify. Climate change seems to be accelerating at an amazing pace. Right now 80 on our way to about 88. Peace.

    • West Linn 200 says:

      Yeah I just saw that too. I remember Mark saying “once in a lifetime” last year and my (half-joking) response at the time was something along the lines of “famous last words”…

      The trend for extreme weather events across the globe clearly shows these types of things happening more frequently in the future, so to an extent this isn’t surprising, but it certainly turns the stomach when we do see it 😦

      • X says:

        There’s a lot of causes and theories to what’s going on but we cannot say them on here so as Michael said I’m out!

    • Joshua Lake Oswego says:

      The good news is that operational GFS is the single warmest ensemble member by a long-shot. No Euro support either.

      What is apparent is that we are going to be warm to hot indefinitely. No end in sight. Somehow our horrible summers keep getting worse.

      • Michael says:

        I think I know why we are seeing almost world wide heat storms and drought. It’s not pollution and cannot say why because I get deleted. Practice faith, needed more than ever.

        • X says:

          Same. Only one narrative is allowed so don’t bother trying to ‘educate’ or you’ll quickly be on the bad social score list when it rolls in the US. Meaning you won’t be allowed to do basic things without permission. Done with that.

          Good luck Matthew and may God bless you.

        • X says:

          I meant Michael. I saw your name wrong. I’m getting new glasses next week! I got the wrong glasses I didn’t order because of the stupid pandemic they didn’t have enough supply. Hopefully this time I don’t go thru the same hell.

    • Joshua Lake Oswego says:

      Look at the 18z. 30 degrees cooler. That’s why the operational is worthless that far out.

  13. Roland Derksen says:

    Not much to talk about yesterday’s weather here: We had a few light/sprinkly showers(the heaviest managed to wet the sidewalks for a few minutes), and that was it. We may get some showers next on Saturday morning.

  14. Weatherdan says:

    Well as Jerry Reed once sang When you’re hot you’re hot. And we are going to be hot-again. In the meantime 77 rising to about 80. Peace.

  15. runrain says:

    Sounds like next week’s heatwave could be a prolonged one too. 5-7 days?

  16. ViRGE says:

    And the KRTX radar has just failed. So there’s no way to see the cells between about Roseburg and Woodburn…

    “000 NOUS66 KPQR 100632 FTMRTX
    Message Date: Aug 10 2022 06:32:47

  17. Tanis Leach says:

    Great show tonight in Corvallis and Philomath. No hail but lightning galore.

  18. tim says:

    00z gfs is showing another heatwave on the 23rd after nextweek heatwave and why not we deserve it.

  19. Bethany250ft says:

    Some massive hail reported near Eugene, over 1″

  20. Bethany250ft says:

    Just saw lightning to my southwest

  21. Tori from Keizer says:

    Keizer just had a cool storm pass by with thunder, some purple colored lightning and a few cloud to ground strikes and cloud to cloud strikes with heavy rain.

  22. Ken in Wood Village says:

    It’s starting to get dark. Even if they don’t make it to Portland, we could see the lightning from here. I’m hoping they do make it tho 🤗🌩⛈️

  23. runrain says:

    Storms are now in the valley but not sure they can survive the trip to Portland.

  24. Ken in Wood Village says:

    Severe Thunderstorm in Central Oregon

    Hopefully we can see some thunderstorms tonight 🌩⛈️

  25. Paul D says:

    Potential forecast bust today? It’s 70 @ 11:15am at PDX, and it was 77 yesterday.

  26. happymedium says:

    Thunder in Tualatin! This midwestern girl would love a good thunderstorm – just no lightning strikes, amen.

  27. Roland Derksen says:

    Some Ac castellanus clouds have shown up here in the past hour- so the possibility of thundershowers is there, even though the official forecast for our area doesn’t mention it- yet.

  28. Ken in Wood Village says:

    It’s getting very active this early morning

    Keep your eyes on the skies 🌩⛈️

  29. tim says:

    Seattle could beat the record for most 90’s in a year which was 12 in 2015 after thls coming heatwave, so far we had 10 this year.

  30. Joshua Lake Oswego says:

    Both the 00z Euro operational and 6z GFS operational show 850mb temps in the 27c-28c range next week over PDX. Maybe we can beat the July/August record we just set last month. Of course, that is second only to the all-time record we set last June. Lucky us.

    • Zach says:

      I think the euro is overdoing the temps just like it did with the previous heatwave. 3rd week of August the days are getting a lot shorter and I’m not sure 107F is even possible then.

      • tim says:

        Weather.con has 102 now for Portland it’s still a week away plenty of time to go even higher.

      • Bethany250ft says:

        With offshore flow I think we can get close to that hot. In September 1988 Portland hit 105 with 850mb temps of 28.3.

      • Evan -- Cedar Mill says:

        107F is definitely possible with offshore flow

        • Zach says:

          Yeah looking back I see we did hit 105F on Sept 2nd 1988, which is just insane. So definitely is possible if the conditions are perfect.

      • Evan -- Cedar Mill says:

        It’s better to look at ensembles that far out. I think 107 is basically the hottest member.

      • Tanis Leach says:

        We’d be looking at a day similar to the 3rd-4th week of April in terms of daylight. Just looking at the highest departure from averages, April 27th 1926 hit 93 degrees for the high (would be 95 if it happened today, assuming +.22 degrees per decade, rounding down), 30°F above average. This day is equivalent to the 15th day of August in terms of sun angle and daylight. A little earlier than the heatwave predicted by the models, however, due to the maximum heat provided is in early to mid-July (latent heat keeps going up even though the sun angle has peaked, since it takes time to absorb the extra heat), I will use it as an assumption and for simplicity with this. 5 days isn’t going to make a big difference, and it would be 1 degree at most. The average is 82 during this heat wave. This means given optimal conditions (probably 30°C 850s or higher, and a decent offshore component), a high of up to 112°F is possible.

        Full disclaimer: I do think the dynamic models are being slightly aggressive here, but like the ensembles averaging around 100 right now.

        • Bethany250ft says:

          The 12z Euro showed 95, 104, 99. In the July heatwave the Euro was extremely aggressive with heat at first and backed down slightly so I’m hoping that’s the case with this one as well

  31. tim says:

    Who’s ready for another heatwave?, both euro and gfs are showing near 100 for Portland around the 17th this is payback for a cool/wet spring.

    • Evan -- Cedar Mill says:

      Seeing that…

      Get ready guys…

    • Joshua Lake Oswego says:

      I think I see a pattern this summer. Warmer than normal for 15 days and then cooler for one day. Rinse and repeat.

      I think we’re going to take a good run at the hottest August ever. Why not?

      I have no idea how a single native plant, shrub or tree is still alive.

  32. Ken in Wood Village says:

    It’s been awhile since I posted an image so if this doesn’t work, forgive me…lol.

    The SPC has upgraded for the possibility of severe thunderstorms. I haven’t been able to see the models today but what I saw yesterday, the flow was coming off the Cascades and Portland was almost a bullseye for them to flow into our area. We’ll see if that is still the case when I get home to look at the models.

    Here is the updated thunderstorm chance.

  33. tim says:

    Weather.com is showing 95 on the 16th thru the 20th for Portland so maybe another shot of a 100+.

  34. Bethany250ft says:

    Portland actually had 5 days above 100 last year, in August they had another two.

  35. Ken in Wood Village says:

    Things look like they are lining up for a chance of thunderstorms Tuesday night into Wednesday morning. All the models are showing thunderstorms. How strong and how many, not sure yet. We’ll know more tomorrow. I’ll won’t be able to look at the models until I get home around 4pm.

    I’m hoping we can see some decent thunderstorms to clean out the air and make it feel more refreshed 🙂

  36. West Linn 200 says:

    This week is looking nice after Monday! Will be nice to have temps under 90 for a while.

    I wonder when the first real rain (>.25in) will hit. I’m thinking earlier than usual this year… maybe right after labor day weekend. What do you folks think?

  37. Weatherdan says:

    92 currently, headed for 101. Maybe a one day cool down to the 80,s then more heat. Only 140 more shopping days till Christmas. Now don’t you feel cooler already. Peace.

  38. Bethany250ft says:

    Almost every model is showing thunderstorms coming off of the Cascades into the Portland metro area Tuesday night into Wednesday. Someone with more knowledge could probably give more info though.

    • Ken in Wood Village says:

      I’m seeing that too, but I like to wait for a day and see how things play out.

      I haven’t been posting anything lately because I have been working a lot and had to move to a new place. Plus, it’s been really quiet in the weather department lately….lol.

      • Bethany250ft says:

        The latest NAM 3km was very good for thunderstorms as well, it showed PWAT values 2″+ in some areas near Corvallis! I’m hoping for some thunderstorms!

        • Ken in Wood Village says:

          Me too, I think we need some rain and wind to clean the air. Plus, we haven’t really seen anything for a long time. We are due for a good thunderstorm 🙂

      • JohnD says:

        I neglected to post this prior; but last Mon. 8/1 I did the “St Johns loop” bike ride from downtown—up to/around/back. There was actually a small shower in NOPO in mid day then. Couldn’t believe it! Although it definitely was humid that day!
        I also neglected to check the NWS for corroboration; but pretty certain nothing fell @ PDX.

  39. tim says:

    After another brief cool down this week we get hot again for the foreseeable future going into late August according to the latest models.

  40. tim says:

    This thunderstorm event is marginal at best for west of the crest then back to the heat for the rest of August and September.

  41. Vikki Bair says:

    Have fun and be safe!

  42. ViRGE says:

    “I’ll be down in southern Oregon next week on a final camping trip. Diamond Lake is calling! So no blog updates until at least the 15th.”

    So tornadoes, then? It seems like the weather around here kicks into overdrive whenever Mark goes on vacation!

    • JERAT416 says:

      Fire Sharon sharknado thundersnow-iccane!

    • Bethany250ft says:

      06/04/09 repeat now that he’s on vacation!

    • ViRGE says:

      “Back from week long camping trip at Diamond Lake. Got lucky with lakefront site for 6 days, sunshine, and only one thunderstorm nearby. No FB or Twitter for a week, yet I survived! Unfortunately I DID miss a damaging T’storm & [b]possible tornado in Wallowa County while on vacation[/b]”

      Called it!

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