Warmest Stretch Of Summer Ahead

August 10, 2016

6pm Wednesday…

This summer has sure been different.  A perception I keep hearing is that it’s been a “cool and cloudy summer”.  The cloudy part might be partly right, but it definitely has not been cool here in Western Oregon and Washington.  June was above normal and July was near or 1-2 degrees below normal:

I think what sticks out this year is a lack of very hot days; and I don’t think any of us are complaining!  That said, it IS a bit strange to go from early June to early August and only see 2 days above 90 degrees.  Note the 5 warmest days so far:

MarkHeatWave_HottestDaysSoFar

How does this summer compare to the well-known “green tomato” summers?  Not even close.

July average high temperatures at PDX and rain:

1954   72.6  1.24″
1955   72.2    .89″
1983   75.2  2.68″
1993   72.8  2.41″
2011   76.9    .96″  <– Not really a green tomato year but close
2016   79.1    .66″  <– Rainfall exactly normal

Yeah, this past July was definitely not “wet” or “cool” west of the Cascades…just NORMAL.  And it’s obvious why 1983 and 1993 stick in our minds…cool and very wet!  I wasn’t around for 1954-55 but those must have felt about the same.

Where do we go from here?  Models say we’re headed for the longest/warmest period of the summer between now and the third week of August.

Check out the 850mb ensemble chart from the ECMWF.  The thick line is the average temperature this time of year over Salem (in celsius).  Note that just about all of the next two weeks the forecast temps are ABOVE that line:

tseries_850t_000-360_Portland

There is a huge amount of spread after about day #8, but most of those 51 ensemble members are above average.  The actual forecast highs for Portland look like this:

ECMWF_ensemble_16daytemps

That’s the most consistent warm to hot weather we’ve seen so far this summer.  And considering we’re moving through mid-August, that’s likely to end up the warmest as well.  Once we get to late August temperatures typically are cooling off a bit.

The GEFS ensembles are similar:

GFS_ensemble_16days

so confidence is high that a prolonged spell of warm to hot weather is on the way.  No rain in sight either of course.

By the way, the all-time high temperature at PDX was set on this date 35 years ago.  During the big 1981 heatwave we hit 107 not once but twice!  That was a huge scorcher.  As I recall I was 12 years old and watching a Planet of the Apes marathon right here on Portland TV from the cool family room in the basement.  It may have been on KPTV as well!  Full circle right?

MarkHeatwaveStudio_1981

We’ve actually hit that 107 mark THREE times…one day in July 1965 as well.

Chief Meteorologist Mark Nelsen