Clean Air Returns & Thunderstorms Tonight Eastside

9:40pm Thursday

Today has been refreshing…brief morning clouds and then cooler temps.  We hit 83 in Portland this afternoon; down from 89 yesterday and 90s on Monday and Tuesday.

High Temp Last 13 Days

Most noticeable is the cleaner airmass over us.  Everyone in the metro area is breathing GOOD air quality this evening


You probably noticed there is still high-level smoke overhead, evidenced by the yellowish sunshine.  Even that goes away Friday as upper-level winds turn westerly for a few days.

We are getting another push of marine air this evening and models show low clouds coming up mainly the Columbia River for a gray start in much of Cowlitz, Clark, and Multnomah counties Friday.  After that you can expect a very BLUE sky overhead since that smoke should be gone.

As expected, thunderstorms have fired up across central and eastern Oregon this evening.  Take a look at the 100+ cloud/ground strikes in the past half hour

KPTV 2017 Default Earth

Many of these are producing very little rain so obviously this is a huge concern for fire starts.  Hopefully new fires remain small.  I saw what appears to be a new fire producing a large smoke plume just southwest of Summer Lake earlier this afternoon on GOES-16 imagery.

What’s ahead?  Typical late August weather…a little heat, but cooler periods as well.  It’s pretty obvious we have passed the worst of summer.  That is normal for us.  Nights are getting longer; giving us cooler nights.  In fact even the middle of the metro area should drop into the mid 50s tonight and tomorrow night.  Nice.

There should be one more brief hot period Sunday-Tuesday, then cooling again later next week.  Notice the good agreement on the ECMWF ensemble chart; a peak around Monday/Tuesday, then quite a dip later next week before more warming.


Down here at ground level that translates to high temps back into the 90s early in the week and then back down around 80 (or below) a week from now.  This is what the same ECMWF model thinks Portland will look like over the next 10+ days


Rain?  Unlikely we’ll see anything other than sprinkles out of marine clouds the next 10 days.  Only 6 out of 51 ensemble members bring .10″ or more to Portland in the next 2 weeks.


Chief Meteorologist Mark Nelsen

30 Responses to Clean Air Returns & Thunderstorms Tonight Eastside

  1. K says:

    Possibility for widespread smoke through Tuesday. Cliff Mass has posted on it, calling it a “smokestorm”.

  2. Ken in Wood Village says:

    Wow, it’s really quiet on this blog. I thought there would be more talk about what could be coming up in the next couple of days…lol

  3. Roland Derksen says:

    Well, smoky skies are back today. One good thing- at least the temperatures are still pleasant, being in the low 70’s. the heat is also coming back on Sunday and Monday, however.

  4. Ken in Wood Village says:

    W7ENK, have you looked at the 18Z GFS on Monday? The CAPE is looking good and I also looked at the “LI” and the “K-Index” and they all look good too. We’ll see how things turn out 🙂

    • K says:

      Fingers crossed….

      NWS mentions it too.

      • Ken in Wood Village says:

        Yea, but just looked and the NWS took out the mention of thunderstorms in their forecast. I haven’t looked at the models yet because I was helping my sister and her husband with The Oregon Bigfoot Festival. I’ll look and see what the models are saying 😉

      • Ken in Wood Village says:

        I just looked at the models (GFS & EURO) to see what’s up for Monday. The GFS shows thunderstorms for Sunday (but it doesn’t look that great) but for Monday, the GFS is screaming thunderstorms. The “LI” and “K-index” really look great. The EURO has some CAPE (I found the “K-index” (which is good but not great) but couldn’t find the “LI” for the EURO). We’ll just need to see how things go when we get closer. The NAM and HRRR should start showing up on their models.

        If the models keep showing this, I guess the NWS should come back around and say something about it. 🙂

  5. It’s me Lee lol, had a change in youtube at any rate.
    WOW is all I can say we brought in about 3 kw-hrs already.I like the bright sun and cooler days.

    at any rate we used a generator to heat up the pressure cooker and then after pressure was built up, we coasted using the sun’s rays to made a nice delicious lunch.

    Sun 08/05/2018 -1 Kwhr 65207 Valid
    Fri 08/10/2018 5 65261 Valid

    Got to love this weather.
    Wish we could get the thunder storms

  6. Roland Derksen says:

    54.1F for a minimum this morning- that’s the lowest temperature I’ve had since July 8th. A bit of marine type cloud invading the sky late this morning.Together with the breeze it’s keeping temperatures down a little.

  7. Ken in Wood Village says:

    I walked outside and what did I feel. A nice brisk feeling in the air. Feels good 🤗😉❤

  8. SK says:

    I have a bit of a weather phenomenon question. Yesterday we met some friends at Glenhaven Skatepark on 82nd (below Rocky Butte). Our friends were saying “you just missed the rain!” Baffled, I looked around and saw nothing but dry grass and concrete and dusty dirt. They were adement that it rained enough for people to leave and the concrete to get wet. My entire trip there and while I was there, not a cloud in the sky nor a drop of rain. What’s the scoop?

    • Anonymous says:

      Felt a drizzle near Sellwood last night as well. Drips on the windshield. Found it odd and kept looking for the cloud. Covered by smoke I’m guessing

  9. Long-range outlooks don’t look very good for rain in the next month or so.

    Three-month outlook is on the dry side, too, but a) it’s far enough out that I take it with a grain of salt, b) even if it does end up on the dry side, odds are still very high we will be getting at least some rain by then.

  10. Robert Brown says:

    Forecast looks heavenly! I’d even take 100 degree weather as long as the air is clear!

  11. Brian Schmit says:

    The 5-minute observations are rounded because they are actually reported in centigrade. 32°c is actually 89 and 90°F which can cause some confusion.

  12. W7ENK says:

    Could really do with some rain over here on the West side… and I mean, real rain.

  13. Paul D says:

    If someone could explain this to me: I go to the NOAA web site and see 90 degrees recorded at 4:45pm on 8/15 for PDX, but the official high is 89. What gives?

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