Heat Wave Continues One More Day

8pm Wednesday…

One week ago I posted that our hottest weather of the year was on tap, evening mentioning a 100 degree temp was possible. It happened, and now we are in the middle of a heat wave across Oregon and the southern part of Washington. We actually do very well (as do models) with heat waves; I can’t think of a heat wave we have “missed” in at least 15 years. They are so easy to forecast compared to wintertime events with inversions, temps near freezing, and mixed precipitation types. PDX hit 93 today and the entire Willamette Valley reached into the mid 90s

A scorching mid-summer heat wave continues in central/eastern Oregon. Expect over 105 along the Columbia River from John Day Dam to the Tri-Cities. Hermiston has gone from 101 > 104 > 106 the past three days

Tomorrow the NWS is forecasting 109 at Hermiston, among the top 5 hottest values there. Just about everyone east of the Cascades, even up around 3,000′, will hit 100 degrees.

Hermiston hit 111 during the June 2015 heat wave so this won’t be an all-time record, but close. Why so hot? A typical summertime hot ridge of high pressure in the upper atmosphere; centered just about over the Grand Canyon region. Hottest air is east of the Cascades = less than 100 degrees for Portland. Plus with the upper-level ridge east of us we don’t get easterly surface wind like we saw Sunday.

Tired of hot weather? Good news is that marine air will surge inland tomorrow night and cool us back into the 80s. By Saturday the ridge is a bit weaker overhead too, but “heights” are still high enough for a very summery weekend in the Pacific Northwest.

Then an upper-level trough moves by just north of us late Sunday/Monday. That’s a big push of marine air, maybe a day only in the 70s Monday if we get lucky

In general this ridging seems to want to stick around for another 10-14 days. The result should be little/no rain through early August and temperatures near/above average. Check out the ECMWF ensemble forecast for rain. Each line in the top half of the image is one individual ensemble member’s rain forecast. The bottom half shows the average of all ensemble members. Yep, less than .10″ rainfall at Salem in the next two weeks!

How warm? After one more hot day tomorrow in Portland, we cool into the low-mid 80s and then around 80 next Monday/Tuesday. Expect at least some warming the mid-latter part of NEXT week.

To summarize…


Chief Meteorologist Mark Nelsen

34 Responses to Heat Wave Continues One More Day

  1. tim says:

    To runrain,
    we are not done with the 90,s for the summer not even close not sure why u whould even say that cfs model has a big warmup
    second week of August and beyond.

  2. runrain says:

    I wonder if we’ve seen our last 90 of the summer.

    • Paul D says:

      That would be WONDERFUL!


      I am going to predict a harsh winter this year with cold temps starting in mid October, We won’t have snow and I mean a real snow until early to mid November, I think we will even get to see a blizzard occur at the valley floor. This fall, we will have your average storms with winds ranging from 60 to 80 mph, and early mountain snow. People will be caught off guard by a freak storm that will hit in the Cascades in early November. I think we will see temps this winter in to the lower digits of 15 F. prepare now for higher power rates, and be sure to have a generator on stand by.

      • W7ENK says:


        Did you move to interior Alaska or something? That’s obviously not within the realm of standard deviations from climatologal norms for the Western Valleys of the PNW. So you’re either talking about someplace else, or you’re having a really weird dream right now, Lee.

        • Kyle says:

          I smell a paid troll here.

        • Kyle says:

          The reason I said paid is that’s how paid ones generally operate trying to sound ‘smart’ where as non paid trolls don’t even try to look good as nothing is in it for them.

          Paid trolls are a very real thing and a dangerous threat for political crap. Got going after 2015ish when world governments woke up to the ‘digital age’ and started to panic for control.

        • W7ENK says:

          Paid? Who’s paying, and where’s my money??

          And since when did pointing out climatological (or any) facts become trolling?

          It’s time to go take your pills again, Kyle.

  3. Paul D says:

    PDX hit 90 today, so that title needs to be “heat wave continues two more days”. Six 90+ in a row 😦

  4. Roland Derksen says:

    Some light sprinkles coming through here today- no thunder heard yet.

  5. W7ENK says:

    Marina push fail? 80 degrees at 9:30am, were on track to have another 95 degree day…

  6. W7ENK says:

    The sky is starting to look a little dramatic…

    I know, I know… helplessly hopefully

  7. W7ENK says:

    Building nicely.

  8. Roland Derksen says:

    Looks like tomorrow could bring some intresting weather my way: Clouds with a chance of showers or thundershowers in the forecast. I think I spotted some already on the distant eastern horizon.

  9. W7ENK says:

    More ACCAS sliding up from the South, mostly moving along to my West. Just sitting here watching it develop and thicken up. Can’t really see what’s behind it. Hoping it’s something exciting, but probably nothing.

  10. Kyle says:

    I was right we ended up another scorcher! I saw the beginnings of this crap. Mother nature suddenly remembered we are in the 21st century warming age!

    I wonder if this may be further exaggerated by the reopening of tyhe industry creating further localized warming?

  11. …thanks for the 3000 foot forecast! ..NWS sez 100 today, 101 tomorrow….the great t-storm we had last night helped us cool down to 59 overnight so at least we got a chance to cool the house down before the raging inferno today and tomorrow 😉

  12. Lynn says:

    Let’s start taking about fall/Winter!

    • Paul D says:

      Fall & Winter will be warmer and drier than normal. No snow in the Portland metro area and we’ll have a few record warm temperatures.

    • Gene says:

      Let’s not talk about fall and winter just yet — enjoy our sunny summer days while they’re here

  13. W7ENK says:

    It’s nice to finally have some real Summertime weather! Now, if we could just convince the thunderstorm faeries to bless us…

  14. Paul D says:

    I see 7 hot days in the 7 day forecast.

    • W7ENK says:

      You must be looking at somewhere other than Portland then… 🤔

      • Paul D says:

        It’s all relative – to me 80+ is hot.

        • W7ENK says:

          Alright, I guess we’re just ignoring the forecast highs of 79 & 78 on Sunday/Monday then, huh?

        • Kyle says:

          Don’t count on it Paul. I hope we do but knowing what the ocean conditions are in I have scientific doubts. Here is the latest SST’s

          Look downstream at Baja California. It’s much warmer then normal and that’s where the high pressure ridge is being pumped from like a heat pump switching over to ’emergency heat’ mode.

        • Kyle says:

          Here’s an overall view of North America.

          The ‘hot’ weather we are having is coming from that direction. The warmer SST’s make it easier for airmasses to come in that direction as the SST’s are more warm then they are cold.

          The SST’s from the north of us the departure from average is not that great compared to the warmer departures or + departures to our south and south east!!!

          As long as all that ‘brownish red’ remains it will help bring optimal conditions for more ridgy weather in that direction to be ‘locked’ in place unless something very big displaces it all.

          The SST’s down there are like a heat pump switched over to ‘Emergency Heat’ mode in which the bills will quickly add up.

          I wonder if this means a lot of fog in winter if that keeps happening?

        • Kyle says:

          In other words I bet those ‘highs of 79 and 78 as you put it will likely have some major ‘surgery’ much like today’s forecast.

          I think right now the doctor has ordered an MRI for the ‘ocean layer’.

  15. JERAT416 says:

    Thanks for the update Mark! As usual, many of us worried for nothing the beginning of July.

%d bloggers like this: