Heat Wave Day #5: More Humid & Warmer Nights Ahead, Then It Gets Better

July 26, 2018

5:30pm Thursday…

It’s ANOTHER scorcher out there folks.  I see it’s 95 on the roof of the FOX-12 broadcasting fortress (business park building).  Officially here in Portland we hit 96 degrees this afternoon, that’s our 5th day into the mid 90s.

Let me throw a whole bunch of hot numbers at you…

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10 of the last 14 days have stayed above 90 here in Portland

High Temp Last 13 Days

This is our 16th day at/above 90 degrees this summer, we’re headed for 20-21 by the time this heat wave ends!

90 Degree Days Summer Heat

Of course you may be wondering if we’re breaking any sort of “consecutive 90 degree days” record?  IF the last 90 degree day is Monday, we’ll be at #9.  If we still reach 90 on Tuesday, we’ll tie the all-time record of 10 days at/above 90 set during the 2009 heat wave.  Remember those back to back 106 degree days?  95 doesn’t seem so bad now does it?

90 degree streak history


  1. A slight cool-down Friday/Saturday due to a very weak seepage of marine air into the western valleys of NW Oregon and SW Washington…high temps drop closer to 90.
  2. Hotter again Sunday/Monday as weak onshore flow ends.  We could hit 100 on Sunday…for sure it’ll be between 98 and 102 that day.  That’s assuming we don’t get a bunch of thick fire smoke.  Speaking of…
  3. On Sunday, and possibly Monday, all that fire smoke plaguing SW Oregon may move north on southerly upper-level winds.  Could be a very smoky/hazy day or two.  Westerly flow returns later Monday/Tuesday and that would clear us out again
  4. Higher relative humidity.  Models are all showing rising dewpoints (measure of moisture in the air) both Sunday and Monday.  Most likely due to the slight influx of marine air plus southwesterly flow developing overhead as the strong ridge rebounds just to our east.  This means not only hotter weather Sunday & Monday but more humid…yuck!
  5. Warmer nights.  A hotter airmass plus more humidity means our current low-mid 60s low temps will warm another 3-5 degrees.  The result will be lows closer to 70 in the Portland urban areas Sunday and/or Monday mornings.  2nd yuck!

Try to stay cool the next 4-5 days…getting into water is an excellent idea…check out those river temps!


Speaking of water, two years ago I picked up a smokin’ hot Craigslist deal.  A nearly new pool someone wanted to unload quickly at less than 1/4 the original price.  Those are the best few hundred dollars I’ve spent!  This is my new mid-summer “pre-work” exercise routine…


Chief Meteorologist Mark Nelsen