90+ Today, Much Cooler Tomorrow

June 24, 2018

7pm Sunday…

We’re in the slowest season of the year weather-wise; under a relatively stable summertime weather regime.  So the frequency of blog posts slows down too.

Today was another example showing what just a little bit of offshore flow can do.  Models have advertised for several days that 850mb temps would rise up above +15 and we’d get a light easterly drift through the Gorge in the morning.  Combine that with the highest sun angle of the year and temps skyrocketed.  We hit at least 91 in Portland with solid 90s up/down the Willamette Valley

Todays Observed Highs OrWa 2017

That means we’ve already seen 5 days at/above 90 degrees and we haven’t made it to July yet!

90 Degree Days In June

I’m confident we don’t have any 90 degree weather in the next week or so, in fact we should linger near normal temperature-wise over the next week.

90 Degree Days Summer Heat

By the way, there was just a little bit of fire smoke (nothing like last year!) that drifted in on light east/southeast flow the first half of today.  I noticed it on the east side of the metro area.  GOES16 imagery showed the smoke movement from the fires in north-central Oregon, I’ve highlighted the smoky area in yellow.



A sharp upper-level trough quickly swings through tomorrow morning, dropping a few light showers or drizzle in spots.  But then I expect some decent clearing in the afternoon.  So we might at .01″ or so to the PDX rain gauge for June.  It’s been our 2nd dry month; interesting that most measurable rain has fallen around weekends.  Of course the thunderstorms on Friday missed east & north metro, and part of south too, including PDX.

Mark Monthly Climate Rain Calendar

We are more or less tied for driest “late spring/early summer” in Portland.  Just taking the mid-April to late June rainfall, only 2015 is similarly dry.  Do you realize we’ve had only 1.27″ since the middle of April???  Amazing.  No wonder it looks like late July with everything browning up quickly now.  And it’s too late to get a cool/wet spring pattern now, so fire season and drought development is totally dependent on what happens over the next 3 months.  If we remain warmer than normal with no significant cool spells things are going to get rough by the time we get into August!

There does appear to be some sort of upper-level troughing attempting to come into the Western USA around this Thursday/Friday.  Note the 500mb height anomaly from the ECMWF ensembles


That ridge offshore tries to move in over us those first few days of July, but then it’s interesting that all 3 models I generally look at through the 10 day period show another trough right overhead on the 4th of July.

This slideshow requires JavaScript.

That said, it’s 10 days away.  It’s also interesting that my 17/16 year old kids haven’t seen it rain on the 4th of July in their lifetime.  We are overdue for a showery 4th, but that doesn’t mean it’s going to happen this time.  I think the main message here is that we have pretty typical late June/early July weather coming up in the next week or so.  No extremely warm or chilly weather, and just a threat of drizzle or a shower over a few different days.

Keep watering your lawns and gardens…it’s going to be a long summer!

Chief Meteorologist Mark Nelsen