Hottest Weather of Summer Ahead

8pm Tuesday

Today was a fantastic day in my opinion…clouds to sunshine and temperatures right near seasonal averages.  The Willamette Valley ended up right around 80 degrees.

If you don’t like our mid-summer hot weather, find a cool place; it’s about to get hot west of the Cascades.  A sprawling upper-level ridge is already building this evening over the Pacific Northwest and more or less remains over us the next 7-10 days.


A long period of very warm to occasionally hot weather is likely Wednesday through the middle to end of NEXT week.

  1. Every day is likely to exceed 85 degrees, with temps as high as 95 either Thursday or Sunday/Monday.
  2. I think temps up to 100 or higher are unlikely at this point
  3. Overnight lows will be moving into the low-mid 60s at times…getting uncomfortable in the urban areas if you don’t have air conditioning
  4. Record highs are unlikely…all records through the 21st are at/above 101 degrees.

This one is interesting because it’s not a sharp ridge which gives us extremely hot weather and/or easterly downslope wind.  Instead it’s quite flat, indicating a large area of much warmer than normal temps.  Here’s the 500mb forecast from the ECMWF model ensembles (actual heights are the lines, anomaly is the color) for Thursday, Sunday, next Wednesday, and Saturday the 22nd.  No big, hot ridge, but abnormally high heights…seems like a lot of red across a good chunk of North America.

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850mb temps peak out around +22 Thursday and 19-21 on ECMWF ensembles Sunday-Monday.  Without decent offshore flow it’ll be very tough to get above 95 degrees (good!).

Note the surface temp forecast for Portland from this model


These numbers are a good 8-15 degrees above average for our area.  If you are into water sports this is excellent news.  If you work for a paving company…well…October will eventually get here.  We can forget about precipitation because in this pattern even thunderstorms are hard to come by as high heights squash the convective stuff.  Not a single GEFS ensemble member produces even .10″ rain in the next two weeks.  The ECMWF is similar.


Of course if we’re going to get an extended very warm to hot stretch this IS the time to do it.  Notice that here in Portland the hottest time of the year is typically the 3rd week of July to the middle of August.


How about the coastline?  Can you escape the heat there?  Yes!  In this pattern we shouldn’t see easterly flow make it to the beaches so 65-80 is a good guess for the next week, depending on location and day

7 Day Coast Plus Cascades Summer

And the Cascade lakes will be an excellent place to be as well as anywhere else at/above 4,000′

7 Day Coast Plus Cascades Summer2

I would suggest Ape Cave or any other lava tube near Trout Lake or Bend…it’s in the 40s year-round in most of those cave since they follow the ground, not air, temperature.

On a “big-picture” note…unless something changes drastically in August, this is going to be our FIFTH warm/hot summer in Western Oregon and SW Washington.  I can’t find any other period in at least the last 100 years where we’ve seen such a stretch of abnormally warm weather.  2015 was the hottest summer on record here in Portland.


As mentioned in the past, this is one season in which we are seeing dramatic warming in our area…not so much in winter but in summer.  That doesn’t mean we can’t have a round of cool summers right around the corner, but the trend is definitely up.  That cool summer of 2011 seems a long way back now doesn’t it?

MarkSummer RecentYears

Chief Meteorologist Mark Nelsen


25 Responses to Hottest Weather of Summer Ahead

  1. Roland Derksen says:

    Happy St.Swithin’s Day tomorrow, everybody! The way the weather is going, I can believe the next 40 days will remain dry! 🙂

  2. alohabb says:

    Keep the heat coming. This is great!

  3. W7ENK says:

    Overnight low of 66F at my place last night. First night in probably well over a year that I slept with my window shut. Bedroom door wide open, A/C in the living room on full blast, and a fan drawing the cool air through.

    This next stretch of days is definitely going to be reflected in my energy bill.

  4. JohnD says:

    Hi 97′ Lo 65′ with full sunshine (+ breezes to boot!) yesterday @ PDX = a pretty impressive summer day!

  5. Jack says:

    Decent steady north wind blowing, straight as an arrow coming out of the north and headed to Mt. Hood. – Camas, WA, 600 ft. elev.

  6. Roland Derksen says:

    My last recorded cool summer was in 2011 as well. And the last average one was 2012.

    • Roland Derksen says:

      I wanted to add on a few stats to my previous message: Prior to 2000, I only recorded 3 warmer than normal summers: 1990,1992 and 1998. Quite remarkably all my summers in the 1980’s and most in the 1970’s were cooler than average. Since the new millenium began, most of my summers have been warmer than normal. Including, most likely , this one.

    • Paul D says:

      We need another 2011!

  7. SK says:

    Thought it was supposed to be sunny? Woke up to marine layer again. Another bust.

  8. alohabb says:

    I work in hvac and service is a week out and new installs are 4-5 weeks out , and that’s typical of every company in town. It’s gonna be a hot one for sure.

  9. Paul D says:

    Heading north tomorrow where it will be 70 or less! Woot!

  10. W7ENK says:

    It’s Summer, bring it on!!

  11. I guess its about to be hermit cave time.

  12. Ashley Watson says:

    As they say “the proof is in the pudding”. It doesn’t matter what your political opinion or any other personal persuasion is the weather is definitely warming. As to why, that really doesn’t matter either. It’s happening. I think people get to involved in politics. They either think it’s all man’s fault and we need to do some about it or it’s just the natural order of things and there is nothing we can do about it so whatever. People’s personal opinions and political persuasions mean nothing. As humans we are often persuaded to believe things based on our own personal agendas or emotion. Can we really know what’s going on and why our climay is warming. Mabey, mabey not. What is absolutely true and makes alot of sense is that man is ruining the planet. Cutting down vast forests, polluting the atmosphere and land with crap. Whay effect these things have on climate change, well mabey a huge effect or maybe not. The answer seems to be lost In political Tom foolery.

  13. Joshua Downtown PDX says:

    At what point does this become average? What is average? Rolling 30 year? All-time historical average? I make fun of the people who plant banana and palm trees (because they look asinine in the NW), but maybe they will have the last laugh.

    • Muxpux (Castle Rock) says:

      That’s part of the problem I think. Our “norms” were established in the last 100 years. Most places the last 75 or so. There’s a lot to be said about accuracy in the 1800’s, along with location of readings. Urban sprawl, urban heat islands, misplaced sensors, and general NATURAL climate oscillations (ice ages, and that whole cycle), it’s difficult to tell where exactly we are on the chart.

      30 years ago (when I was growing up) our averages were even shorter sighted. In those 30 years, record highs, and lows have fallen. As they do everyday. The climate is always changing, it’s dynamic. People tend to look at the issue from a “this is how it’s supposed to be” perspective, when in reality, all those numbers are, are what we have observed.

      All that being said, I can’t really deny that all the crap we pollute into the air, and as Ashley mentioned, destruction of earths natural resources to regulate climate… hadn’t speeded up the process or anything…

      It’s like smoking. The trees are earths lungs, and human caused pollution is the cigarette smoke. Would all this have happened without? Possibly. But we definitely aren’t helping to mitigate it.

      • The most useful locations for seeing the effects of global warming show up in observed records are the rural ones that have stayed rural since observations began, because it helps eliminate the effects of urban heat islands that have developed as cities have grown. (Though not perfectly; if a rural station goes from being in a green field to being at the edge of the parking lot for a new gas station/country store, you’ll see localized warming affect it, too.)

    • Pete says:

      “The average value of a meteorological element over 30 years is defined as a climatological normal. The normal climate helps in describing the climate and is used as a base to which current conditions can be compared. Every ten years, NCDC computes new thirty-year climate normals for selected temperature and precipitation elements for a large number of U.S. climate and weather stations. These normals are summarized in daily, monthly, divisional, and supplementary normals products.”

  14. Lynn G. Hocker says:

    Yuck, yuck, yuck! I hate hot weather. I’m doomed. It gets very hot in my apt. Yuck. 😦 t
    Thanks, though, for the warning.

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