Warmest Memorial Day Weekend in Decades

Here it is, the Thursday evening before Memorial Day Weekend and it looks like summer on the weather maps.   Now each year I like to point out that the traditional “start of summer” weekend is generally nothing like summer in our area.  Our AVERAGE high this time of year is 70 in Portland; that’s the same as early October!  And the chance of getting showers on at least one of those 3 days is relatively high.

Oh, but this year is TOTALLY different.  We’ve seen an unusual late May warm & dry spell.  8 days dry so far with 6 more to go (through Wednesday).

Who would have thought we’d see 14 consecutive dry days!  By the way, the longest dry spell WITHIN the month of May WAS that 23 day period in 1940 on the graphic.

After a cool upper-level trough passed through yesterday, an upper-level ridge has now begun to rebuild over the West Coast.  Upper-level heights rise and the atmosphere warms through Monday.  That means warmer temps each day.  You can see the maximum strength of the ridge on Memorial Day from the ECMWF model:

Then beyond that time the ridge breaks down and we finally get a showery pattern (maybe for just a few days…unsure) beginning next Thursday.


It means we’ll see a historic weekend, most likely one of the warmest or THE warmest on record.  I have only checked records back to 1987 (ran out of time), but this will be the warmest/driest in those 30 years.  In fact we haven’t even hit 80 degrees in 22 years during this holiday weekend!  With 850mb temps up around +16 to +20 Saturday through Monday, weak onshore to weak offshore flow should allow temperatures to rise up to around 90 degrees.  Warmest days appear to be Sunday and Monday.

We were close in 1995, with highs 78-87-86.  That was the weekend the Grateful Dead was in town.  I remember heat exhaustion issues (likely fueled by something else?) at Delta Park with that concert.  3 years previous in 1992 we reached 87-93-78.

I do see cooling next week with our 1st chance for showers in 2 weeks coming up next Thursday.   The verdict is still out on whether this will be a brief downturn followed by more ridging the following weekend or a return to a longer period of cool showers.   There is a huge amount of “noise” in the ensemble forecasts beyond that point

Note the big dropoff in temps the middle of next week, but more important is the big spread in solutions from next Thursday through the following week.  One thing we can glean from this is that IN GENERAL it appears that temperatures remain near or above normal…there isn’t much support for a long cold spell.   The 10 day ECMWF operational run for rainfall is still pretty weak through the first weekend of Rose Festival:

So enjoy the summer-like weather this weekend and try to stay cool if you are indoors.  At least relative humidity will be low through the weekend.

Chief Meteorologist Mark Nelsen


23 Responses to Warmest Memorial Day Weekend in Decades

  1. Kaboom! Thunderstorm time!

  2. Wow…WRF-GFS map is giving us a major westerly windstorm in the eastern Gorge tomorrow. Like 60+ mph gusts in the most favored locations…

  3. Paul D says:

    Now that Monday didn’t get anywhere near the 90 that was forecasted previously, I wonder if this weekend will go down in the record books.

    • Jason Hougak says:

      NOT!!! Missed forecast by epic proportions. Everybody I was with today was talking about how bad the forecast was. 70F was the warmest it got and it was 63 most of the day. Very nice comfortable Memorial Day. 👍🏼👍🏼

  4. Roland Derksen says:

    A touch cooler here today, but still sunny. My maximum yesterday was 86.5F- which happens to be exactly the maximum temperature for last May. However, starting tomorrow it’s back to a more unsettled pattern with near average temperatures.

  5. Jason Hougak says:

    Mist and light drizzle in the foothills this morning

  6. Jason Hougak says:

    Mark said 90 Sunday and Monday… was in Happy Valley and never saw it warmer than 81F, tomorrow looks even cooler with T-Storms possible later in the afternoon/ evening.

  7. Paul D says:

    Now it’s 82 on Monday and 64 on Tuesday. Much better!!

  8. davidbarts says:

    Reached 78 here yesterday, forecast to hit 77 today, then 69, 61, 59 (cue game show losing sound music). Quite a bit warmer down your way in Portland, of course (as is typical in the warmer months), but it looks like clouds and showers are in your forecast, too.

    Oh well, it’s not even summer yet, nobody really expected it to last indefinitely, did they? Enjoy it while it lasts!

  9. Ken in Sheridan says:

    I’m surprised at you,Mark,for forgetting the Memorial Day weekend of 1983! The all-time high temp for May was recorded on Saturday May 28 of that weekend … Portland hit 103 degrees at the airport. I remember cooling off at my girlfriend’s house that day, soaking our feet in cold pans of water! All this following my asking her to marry me the “hot” evening before ….!

  10. Love it! Bring it!

  11. Roland Derksen says:

    A cool wet June isn’t out of the question. I do recall sunny stretches in late May in past years being followed by cloudy unsettled weather in June. But I don’t expect it to be a record in that category.

    • JERAT416 says:

      I doubt we get anything like that but I’m sure we will waffle between warm and cool with showers on and off like a typical June.

    • Roland Derksen says:

      Some of the really wet Junes I can recall are; 1971,1980,1981,1983,1990,1997,1999,2007,2012. There may be a difference compared to Portland in some of these years, but I think most of these listed years would be the same as in my area.

    • davidbarts says:

      It was 2010 or 2011, I was living in Portland at the time, and I remember one of those years had an exceptionally dreary and cool June. I remember firing up the wood stove in mid-June.

  12. JERAT416 says:

    Just wait until we have a record cold and wet June…..

    • Paul D says:

      HAHAHAHA!! Wouldn’t that be something. You never know what’s going to happen.

  13. Paul D says:

    I wish August would wait it’s turn. It would be nice to have some 70 degree days, not 90.

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