Two Hot Days Ahead, Plus Some 90s on North Coast Tuesday

7pm Monday…

In early June we had two very hot days, 97 & 98 degrees in Portland, the hottest of summer so far.

Hottest Days This Year

We have a repeat coming up tomorrow & Wednesday.   I get the feeling these two hot spells will be the “book ends” of Summer 2019.

The weather pattern is the same; a strong upper-level ridge overhead brings us a hot airmass.  But the “icing on the cake” is the switch to an offshore wind flow.  Today we lost all cooling coming in from the Pacific Ocean; light easterly flow has developed overhead.

Tonight a much stronger easterly flow develops with gusts to 40 mph in the western Gorge and exposed ridges along the west slopes of the Cascades.  Expect a that breezy easterly wind to push across most of the metro area by noon, and all the way to the coastline too.  Historically this is our hottest weather pattern.  Take a look at the surface weather map tomorrow at 5pm from the UW-WRFGFS model.  I’ve drawn in the “thermal low” which is the area of lowest pressure.  Wind moves toward that low


This is a classic hot weather setup west of the Cascades.  By Wednesday at 5pm the thermal trough is shifting over/east of the Cascades.  Weak onshore maybe arriving in the central/southern Willamette Valley at that time.  That said, often models are a few hours too fast moving that trough east so we’ve kept the high temperature forecast the same for both days.


A big push of ocean air pours inland Wednesday evening and that ends our mini-heatwave.  We’ll be somewhere down in the 80s on Thursday and that continues through at least the first part of Labor Day Weekend.

Data Driven Forecast Highs Next 7 Day Meteogram

Do you want to experience hot weather at the coastal beaches? That thermal trough position through mid-afternoon Tuesday is perfect for one hot day out there.  If easterly flow makes it all the way to the beaches, then it can be just as hot as inland spots. But I suspect the northeast morning wind turns north-northwest mid to late afternoon which should cap off the central coastline around 80 degrees and keep temps below 95 on the north coastline.

Mark Astoria Coast Record High

Let’s talk clouds and showers.  Our typical onshore flow returns Thursday and beyond and we’ll get clouds at times out of that.  But what about rain showers?  Models are hinting a weak disturbance could bring a few showers overhead during the daytime Thursday.  We now have access to the hourly runs of the ECMWF model 4 times a day which is helpful.  The 18z run, just like the 12z, showed a few light showers popping up Thursday.  So just keep in mind we might see sprinkles here/there on that day.

Chief Meteorologist Mark Nelsen


16 Responses to Two Hot Days Ahead, Plus Some 90s on North Coast Tuesday

  1. Actually reached 80˚F in my new city of residence today. That doesn’t happen often; typically the wind coming in from the strait keeps temperatures in the low/mid 70’s. Tomorrow should be a notch warmer yet.

  2. Mike says:

    I cannot remember ever seeing 82 degrees at 9pm in my rural area of Beavercreek. Of course I could be wrong, but it seems NW Oregon used to cool off very rapidly in the evenings back in the 80’s 90’s.

  3. Tanis Leach says:

    3pm in Sherwood: 101

  4. Mike says:

    Your write ups are great Mark. Thank you.

  5. Larry says:

    98 already where I live! 100 is likely at this rate

  6. runrain says:

    Already 93 deg at 12:20 at PDX. 100 deg is doable at this rate.

  7. W7ENK says:

    WRF-GFS is showing a pretty decent blob of CAPE pushing over the N. Willamette Valley overnight Wednesday night / early Thursday morning, lasting until early afternoon. Couple that with Mark’s “…light showers popping up Thursday” and a handful of other thunderstorm ingredients looking favorable, we might just see something…

    Fingers crossed!

  8. Joshua Lake Oswego says:

    In non-weather related news… Mark, did you know you are getting some internet fame for your drawing while talking about the fire in NE Portland yesterday evening? I will say that you must have worked LONG and HARD on that segment. Haha.

  9. MasterNate says:

    IMO this has been a great summer. Nice to have a majority of high temps near or slightly below or above average. Still to many 60+ degree nights for my liking. Looking forward to fall weather with some rain and cool crisp sunny mornings.

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