Hottest of the Summer On the Way

It’s been a very mild summer.  As mentioned in previous posts areas most exposed to the onshore flow of Pacific air have been the coolest, but even areas well inland have only been average at best.  What’s been missing is a real absence of hot spells.  We’ve only had one period, July 7th-9th, where temps jumped into the mid  90s here in the Portland/Vancouver Metro area.  We seen 4 days at/above 90 degrees this summer.  In an “average” year we see about 13 @ PDX. 

In a normal year during the period from early June through early September we go through periods of hot weather followed by cooling onshore flow…some years more heat than others.  One thing that tends to change after mid-August is the longer nights start to catch up with us.  Overnight temperatures start to drop off a bit and it’s also a bit harder to heat up the land surface each day as the sun angle drops as well.  As a result when you look back at Portland records you generally don’t see long periods of 90+ weather the 2nd half of the month.  I did find two years where that happened.  Notice that both in 1967 and 1977 (both in the top 5 warmest Augusts) there were long periods of heat around mid-month.  8 days of 90+ in August 1967, and check out 1977!  In the first 17 days of the month, there were only two days at 85 degrees; the other 15 were 88 or higher!  But then the following two weeks?  Never got above 80 the rest of the month…summer just “stopped” after mid-month in August 1977.  This coming Monday and Tuesday’s record highs are from that period…102 & 105 degrees.  Those will be tough to beat, but we might get really close!

For the real weather geeks out there, I checked out the 1977 heat wave.  Easterly wind never made it to PDX, so apparently that is not required with a hot enough airmass; similar to last year’s 106 degree day in early August.  Even more geekery…at 11pm that night wind went SW 21 mph at PDX with a drop to 75 degrees; a major southwesterly marine push kept highs the next day below 80 degrees.

So what’s changed in the last 24 hours?  It appears that instead of just a few days at/above 90 degrees, we’re going to see a major “late summer” heat wave.  I say late summer because of the reasons mentioned above.  Yes, I know summer doesn’t end until September.  Anyway, models have made a change, keeping a large area of low heights in the upper-atmosphere much farther to the west (offshore) through the middle of next week.  The result is the 4-Corners High pokes right up into the Pacific Northwest Monday through Wednesday.  Heights go up to around 590dm. at 500mb (or even higher on the ECMWF).   That combined with offshore flow REALLY heats us up.  Both GFS and ECMWF have 850mb temps between +22 and +26 from Sunday afternoon through Wednesday.  For some perspective, I see only 2 August days in the last 10 years have seen offshore flow AND 850mb temps at/above +23.  Both days were 100+.  Due to that we put 100 degree temps in for Monday and Tuesday.

It’s now safe to say that we probably have a 5-6 day stretch of 90+ weather on the way, at least 4 of those probably 95+.  That’s warmer than anything we’ve seen this summer.  The good news is that we very likely won’t see anything like it again as we head towards the end of August.

Chief Meteorologist Mark Nelsen

132 Responses to Hottest of the Summer On the Way

  1. Tja, das Leben kann so einfach sein, mann muss nur gluck haben.

  2. Kyle says:

    I’ve noticed everytime I try to make a joke it always happens right when Mark makes a new topic.


    *kicks the model ride machine in the foot*

  3. Derek Hodges says:

    I would have to say the consistency of the models trying to bring in some kind of cool showery weather in the long range is interesting. The exact details of how and when aren’t known, but it may be a pattern change from what we have had since early july.

  4. Kyle says:

    How much can these model rides handle before they break themselves down? 😮 😕

    83.1F and sunny.

  5. Tyler in Hazel Dell says:

    Watch the wind barbs off of the north coast the last ten frames you can see the heat low wandering around…

  6. muxpux says:

    think the low clouds will hold off tonight here in longview?

    were having a bonfire on the beach at a buddies private beach for some beers, friends, and watch the meteor shower, hate to get a bunch of people out there only to have it cloud up. also, i hope the wind doesnt pick up. usually on warm days, west winds get rifled up the river into longview as we cool down. im really hoping its calm tonight.

    • Tyler in Hazel Dell says:

      Last night it started getting cloudy around 9 PM in Kelso, and it never really cleared out around Long Beach. I think there may be a patch or two, but only right around sunrise. GFS continues to show a slight offshore flow developing around 1 AM. Should be just fine.

  7. Washington Observer says:

    I live on the southeast side of Mt. Adams.
    There is not a cloud, and I mean not a single white speck in the sky.
    The breeze has shifted from southwest to south.

    Some of the fires in central British Columbia have started back up with the hot dry winds. Those who had the evacuation order lifted yesterday afternoon were able to return home, only to be evacuated again this morning.
    Lots of people praying for rain with NO thunder and lightening.

    • W7ENK says:

      You just got me thinking:

      It’s amazing, the lack of fires in Oregon and Washington this summer, especially considering how wet our spring was which grew a TON of fuel that is now tinder dry, or at least will be by this time next week. Throw in some thunderstorms, and we could have a really dangerous situation lining up here.

      Hmmm… 😕

    • Washington Observer says:

      Unlike us, certain areas of British Columbia had a very dry spring. Add that to the abundance of dead pine trees from the beetle kill and they were a tinder box waiting to happen.
      Some of the more desert areas of B.C. had the same wet spring we experienced. In fact, the humorous comments were made that the sage brush was dying from too much water.

  8. WEATHERDAN says:

    I am beginning to believe that this hot spell might be our last big burst of heat for this year. We will probably have one or two days in the low 90’s in September or late August but they will be singular in nature. most warm spells (80+) will probably be no longer than 5 days consecutive. But as far as this heat wave goes we in Salem could see 100+ for four consecutive days, Saturday through Tuesday. And 90+ for 6 consecutive days, Friday through Wednesday. Next Thursday might still be just above 90. After all is said and done Salem will probably have a near normal summer. 100+ days 4, currently 0. 90+ days 15, currently 6. 80+ days 60, currently 35. My feeling is that we will have an early start to our fall wet season, probably starting in mid to late September. Meaning that we still have about 6 weeks of decent summer weather left. So enjoy it. Autumn will be here before you know it.

    • chris s says:

      Dan i dont know about 4 straight 100s as i dont see any model except gfs that hs spitting out 100s and mmt sure if you know or not but gfs 2mt temps are reading high as most of us thought on here. I think at this point we are looking at mid to upper 90s and i think the models are starting to come to a sort of agreement we cool down either tuesday or wednesday. I totally agree that this is it for the heat this year save an except for a 90 here or there in september so bring on fall as far as i am concerned.:-)

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