Is It the Warmest Summer Ever in Portland?

August 26, 2014

11pm Tuesday…

The short answer is a “no“.  But it’s one of our warmest ever recorded here, and that’s without any real heatwaves!  Let me explain how that has come to be…First, here are the official numbers from this afternoon…

PLOT_Highs_Metro

And the number of 90 degree days so far this season…

BMAC July 90 degree recap

 

Notice Salem has seen 9 more 90 degree days than Portland, yet nowhere near a record as you can see in this graphic from the NWS.

nws_image

Not sure why it says Portland averages 12 since the 1981-2010 30 year NCDC average is 13.6 days.  I’ll have to check the numbers again.

So let’s talk about this summer…I did some number crunching, finishing off the August numbers with our 7 Day forecast. Assuming that forecast is within a few degrees (one hopes), here is how the summer should rank….

MarkSummerWrap1

Generally meteorologists consider summer in the northern hemisphere as the 3 warmest months June-August.  Of course in some places (along parts of the west coast) September is the same or warmer than June.  But for most areas it’s June-August.  Anyway, it appears August will end up the 2nd warmest in Portland.  That’s where the official records are kept at PDX back to around 1940.  It’ll also end up the 4th warmest month (of any month) in our history.  That’s after July 1985, July 2009, and August 1967.

What about Summer 2014?  We know it is the warmest since 2009.  Remember those 9-10 days above 90 and two days at 106?  That was definitely “Africa Hot”!  This summer should end up 3rd warmest behind 2009 and 2004.  That’s a hot summer…

Several things I’ve noticed about this summer…

MarkSummerWrap2

Much of the summer we’ve seen an upper-level ridge just to our west, out in the eastern Pacific.  It’s quite similar to the pattern we’ve seen off/on for about 18 months, most likely related to the huge pool of above average ocean temps in the eastern Paciifc Ocean.  With the ridge frequently in this position the past 2 months or so, we got weak onshore flow, but rarely get a hot thermal trough west of the Cascades.  In fact only once between mid June and late August did we get gusty easterly wind in the Gorge, that was during the 99 degree event the 1st of July.

Another effect of this pattern?  It’s been consistently warm, with no prolonged periods of cooler than average temps, yet no heat waves.  We did see 5 days at the end of July and early August with high temps between 89 and 92, but that barely qualifies as a heat wave here in Portland.  Yes, I know it was hotter to our south and east, but I’m specifically talking about the Portland metro area. 

Did you notice we didn’t hit 100 this year?  A little weird since it’ll be the 3rd warmest summer.  That’s related to the lack of strong offshore flow at any point during the summer.

And did you notice what was missing much of the summer?  Morning low clouds.  I noticed how many more days started sunny this July and August compared to the past few summers (I really liked that).  The marine layer was often present, but very thin in the metro area.  Just enough to keep us out of the “real hot” range and more in the “a little hot” range.  I don’t really know what that means, but hopefully it makes sense.

It’s pretty obvious looking at 7-10day maps/models that we’re headed into a cooler than average weather pattern as we start September.  For the next week or so we’re done with the continously warmer than average weather.  Take a look at the 12z ECMWF ensemble chart

tseries_850t_000-360_Portland

 

So what are YOUR thoughts about this summer?  Discuss and (nicely) argue below please…

Chief Meteorologist Mark Nelsen


3pm Tuesday…Turning into a Scorcher Today

August 26, 2014

Wow, already up to 91 at PDX at 3pm. PLOT_Temps_Metro  I have a feeling we’ll end up around 94 degrees.  If you’re tired of hot weather, hang on, after tomorrow’s high in the upper 80s temperatures plummet and the 7-10 day period looks more like September.