Summer 2016: A Scorcher or Not?

It’s that time of year! Memorial Day Weekend is just days away; the traditional “start of summer”.  We’ve had a very warm spring (until the last few days) and endured 2 of the 3 hottest summers we’ve seen in Portland.  2015 was the warmest, followed by 2014 & 2009:

BMAC Summer Wrap

Remember last summer we had 27 days at/above 90 degrees, more than double the average number…it was a scorcher.


Will it happen for a 3rd consecutive summer?  I think that’s unlikely…


  1. Summer is June-August in weather circles…the 3 warmest months fo the year for most of the northern hemisphere
  2. It’s unlikely we have a scorching hot summer again, I don’t expect a repeat of last summer
  3. Of course we will have hot days (90+), but probably closer to the typical number, maybe 12-18 hot days.
  4. There is no evidence/modeling that implies we have a COOL summer on the way
  5. Most models & organizational forecasts are pointing to a warmer than normal summer

For the record…summers have been getting warmer since I was a kid (1970s).  This chart includes all stations in NCDC’s climate zone #2 here in Oregon (Willamette Valley):


I’ve spent some time looking over LOTS of data related to ENSO (El Nino Southern Oscillation), PDO (Pacific Decadal Oscillation), and analogs (similar weather setups in the past).  This is where we are right now:

May has been warm in the Pacific Northwest; what was looking like a record warm May has now been tempered by cooler weather that continues through the upcoming weekend:


Spring has been the warmest on record here in Portland.  A few degrees warm in March, record warmest ever in April, and still running 4 degrees above normal in May.

Sea surface temperatures remain very warm along the Pacific Coast and hundreds of miles offshore.  It shows no signs of cooling; a good chunk of this is due to El Nino effects lingering.  This is not THE BLOB that we talked about during 2013-2015, but the effect is similar along the coast…warmer than normal water offshore means warmer than normal temps as the summertime northwest wind moves over the milder water.  During the cold summers around 2010-2012 the waters were normal or cooler than normal.


El Nino is fading and models say we are headed towards at least a weak La Nina (or neutral on the cool side) Winter 2016-2017


The negative side represents La Nina.

The PDO is very much related to El Nino, but not always locked in together (warm PDO is not always right with an El Nino event).  The theory is that PDO runs in twenty or so year cycles of cool & warm.  The theory is also that we entered a cool period after 1998.



Talking to Cliff Mass about this last week at the AMS meeting, he suggested there is a line of thought (surprise!) that there is much more to the PDO than just a “15-30 year cycle”.  Basically we have a relatively short period of record and it’s possible there is no such thing as a specific cycle.  Look at what has happened right in the middle of the “cool phase”.  We are now past the two-year mark of a very warm PDO.  In fact the PDO number for April was the highest on record for that month!


We may have entered into a warm phase of the PDO, or it may be just a blip, a two-year warm period during a 30 year cool PDO.  It has happened before…in the late 1950s:


although it didn’t go on for two years.

So we have an El Nino transitioning to La Nina, Warmer than normal SST offshore, and a positive PDO.

I looked back at the last 13 El Nino years, then a closer look at the 7-8 that transitioned to La Nina the following winter.  A real mixed bag…4 of those 8 had normal or above normal number of 80 degree days (56) in Portland.  But 4 did not…roll the dice.  Not real helpful when using just that index.  I even added in warm/cold PDO.  Nothing significant sticks out.  Could be that I’m using the 80 degree threshold.

Instead I moved on to the NCDC anomaly plotting tool, first for all summers in which we were in an El Nino or finishing up an El Nino:


Then the summers when we were going from El Nino into La Nina (like this year maybe)…an average summer in the Pacific Northwest but a hot one across the USA in general:


But if we take only warm PDO years with El Nino in effect or fading…


If we take out 2015, the hottest ever, and 1983, the “summer of green tomatoes”:



Here are 3 forecasts, none expect a cool summer…NOAA’s official outlook:



The Weather Company (formerly known as WSI):


And WeatherBELL:



I can’t show these images, but some model forecasts:

CANSIPS:  Normal to above normal through August, SSTs remain above normal through December offshore

CFS:  Well above normal June, above normal July-September, above normal SST through at least fall.

JAMSTEC: Above normal temps, above normal SST continues through winter offshore

One last thought…since all models appear to be headed to at least a weak La Nina this coming winter/spring, you can get used to this cool/wet spring weather.  I have a feeling next February-April will be far different from what we have seen the past few years.  Lower snow levels and cool/wet late winter and spring are likely…

Chief Meteorologist Mark Nelsen




44 Responses to Summer 2016: A Scorcher or Not?

  1. Dopper Dave PDX says:

    Great write-up Mark!!! Only one correction, summer 2015 had 29 days reach 90+ at PDX if you include the 2 in September. 🙂 I’m sure you were speaking to June, July and August only.

  2. Paul D says:

    Who’s playing a cruel joke with that 7-day forecast!?! 90+?? Sigh…

  3. Dizzyland says:

    We never even got much rain out of it more like light showers. Welcome to Global Warming and it’s going to get worse before it gets better.

  4. Marc (Brush Prairie, WA) says:

    How high can we go!

  5. MasterNate says:

    GFS showing a scorcher out in lala land around June 5th, 6th time frame. Never the less, looks like full blown summer weather rears its ugly head again.

    • Joshua Downtown PDX says:

      Yep. Rain is fizzling out, and warm/hot weather is imminent indefinitely after this weekend. No shocker there.

    • It looks like there’s one more chance I’ll see some measurable precipitation here before the heat returns next week. That chance will be tomorrow and Friday.

    • Paul D says:

      Ugly is right. 87 next week!? Groan…..

  6. Anonymous says:

    I enjoy a hot summer- but I’m excited to have a colder, wetter winter bring on the snow-we really haven’t gotten since 2008 – loved that winter.

    • 2014 wasn’t bad in Portland and 2012 wasn’t bad in Seattle (and was downright epic in Olympia and Centralia). But neither could hold a candle to 2008. 2008 is tied with 1990 for the coldest and snowiest winter since I moved to this region in 1989.

    • 2008-09 winter was indeed a classic, but I wonder if it’s the last one I’ll see. One intresting memory from that winter that I recall is, seeing patches of snow mold on my front lawn as the last of the snow melted later on in January. I hadn’t seen that since the 70’s.

    • High Desert Mat says:

      Oh yes, Dan’s nemesis.

      And thanks for the great info Mark, you’re one of a kind.

    • Jason Hougak says:


    • My alter ego says:

      In the 2013-2014 Winter we had 21 inches of snow. 18 in Feb and 3 in Dec. We seem to have a very snowy Winter about once every 5 years or so. This pattern has existed over the last 50 years. I doubt we get an epic snowstorm this Winter. However I expect more snow this Winter than the last two. Maybe 3-5 inches total from 2 storms. Not great but better than it has been. Peace.

    • My alter ego says:

      You might get a colder but probably not a wetter Winter than last. After all we had a record amount of rain last Winter. And Winters that have a lot of cold air tend to be drier. Cold air can’t hold as much moisture as warm air. Not to say it won’t be wet, just not as wet. Peace.

    • Since we seems to be discussing about a colder winter more than a hot summer lately, I just want to add one more point: I won’t be satisfied about having a colder, snowier winter until I see most of that snow fall in January. I don’t know what stats the rest of you guys have, but for me, the month of January used to be the coldest/snowiest month. Not anymore. In the last 31 years(1986-2016) I’ve had no snow at all 10 times in that month, with only 5 that had more than 10 inches.(10 in. is the norm historically)

    • “Cold air can’t hold as much moisture as warm air.”

      Also, our coldest air comes from northern Canada via the BC interior (and, for Portland, the Columbia basin of eastern Washington). A completely inland source, which starts out super-cold (like forty or fifty below zero Fahrenheit). Therefore super-dry.

      Cold and dry is hard enough for us to get in the winter, but cold and wet is a very hard one for us to achieve. It’s why we simply don’t get much snow on average.

  7. Lee Wilson says:

    All I can say is it looks like we are goig to have an Early Harvest season this year.

    I have a larger Question, How are the storms in the “Food Belt” going to effect farmers this year?

    Has any one else save for e noticed the increase in grain products?

  8. Jason Hougak says:

    What about 97-98 super El Niño swinging hard to a strong La Niña 98-99. History repeats itself, I’m saying strong La Niña.

  9. I’m not looking very far ahead for the moment. Right now, I’m getting used to cloudy skies again. If it wasn’t for the calendar and the temperatures, I’d say we’re having a fine January! 🙂

  10. Garron 1/3 of a mile from Hillsboro Airport says:

    Ok, so to summarize, this spring good for making wine, next spring good for making whine! Good thing I like beer. Great post again BTW!

  11. Boydo3 N. Albany says:

    A lot of shuffling of the deck, me thinks. And the wild cards will turn up when least expected..

  12. The bees have been released!!

  13. JohnD says:

    Thank you Mark! As always, cool and compelling stuff to ponder!

  14. W7ENK says:

    I’m still sticking with my forecast for a cooler and wetter than normal Summer through August, then a more normal pattern come Fall. That’s based on absolutely nothing necessarily historical or scientific, it’s just my personal line of thinking. If that offends, too freakin’ bad.

    Suck it up, buttercup!

  15. “I have a feeling next February-April will be different…”

    Any particular reason for this three-month period Mark??? o.O

    • Mark Nelsen says:

      I am thinking 2nd half of winter and the first part of spring. I just know the February/March period seems most favored for whining and/or late low elevation snows (like in 2011/2012)

    • JohnD says:

      …and 2014!…

    • I think we should cherish this upcoming Nina/cool cycle, especially if it becomes really strong for a couple years. It may be one of the last chances we ever get to see lowland snow in March, before that opportunity vanishes like a dying glacier…

  16. Dizzyland says:

    The big question is can places further south of Portland ever see a string of sub 50F nights in the heart of summer again?

    It used to not be hard where Portland always had warmer minimums but cooler highs.

  17. Joshua Downtown PDX says:

    Thanks for all the information and analysis, Mark. No doubt this took you a bit of time to put together for us nerds.

  18. JERAT416 says:

    Good information! Who knows what will happen! I just hope Summer is average, not hot again.

  19. My alter ego says:

    We had a record 103 days over 80 last Summer. If we knock that down by 20% we get 87 days. We had 30 days over 90 last Summer. Knock that down by 20% you get 24. We had 160 days over 70. Knock that down by 15% you get 148. That is what I expect this Summer. Very war but the coolest since 2013. However we had 35 nights above 60. I expect that number to rise to around 38. Peace.

    • Dizzyland says:

      When it comes to Salem you know it pretty well.

      These blogs live far (enough) away and don’t quite get that Salem can be quite different then Portland even under similar weather patterns due to influence of the big river known as The Columbia Gorge acting as a natural air conditioner.

      The big question is can Salem ever see sub 50F at night in the summer time again?

    • Dizzyland says:

      My bad. I meant bloggers.

    • WEATHERDAN says:

      We used to average 1 night over 60 in the Summer. Now we average 1 night in July and August under 50. As warm as our nights have been this Spring we might not even see that. Peace.

  20. Gene says:

    Lots of great information — thanks for taking the time to put it all together and share with us. Looking forward to another nice summer, though maybe not as hot as last year

  21. As I’ve posted several times already, the past two summers have been so super-warm that there’s plenty of room for the coming summer to be both (a) above average in temperature yet (b) significantly cooler than the past two summers. And that’s what I’m forecasting.

  22. Aleta-West Gresham says:

    Thank you Mark! Warmth through August will be perfect and anything beyond a bonus! Not looking forward to next Spring, I have a feeling that’s exactly what will happen.

  23. Tyler Mode in Battle Ground says:

    WHOA! Lots of detail I love it! And best of all, it’s the closest to a long term forecast I’ve ever seen from Mark!

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