Well…The Dalles and Eastern Oregon just endured their second hot spell / heatwave of the 2017 summer season. The LATE SPRING HEATWAVE over Memorial Day Weekend doesn’t count in this case. Here in town, or at least at the airport, our high temp yesterday was 98 and today was 99. That’s not quite as hot as we got a couple weeks ago. HOWEVER…and this is the critical part… our nighttime temps this time around are at least 10-15 degrees warmer than they were during the June heatwave. Dewpoints are also significantly higher.

Last night was obnoxiously sultry, with a temperature of 85 degrees at the airport at 11pm! That’s the kind of smothering heat that makes sleeping so uncomfortable, unless your A/C is working overtime. For me it brought back horrid memories of the 2014 and 2015 seasons…hopefully we don’t see too much of that this summer. (See the long-range discussion below!)

Tonight is nearly as warm, but tomorrow we should cool off a bit. We will see a bit more of the “marine influence” in NW Oregon / SW Washington, but NOT a big flood of ocean air. Just enough for a few brief AM clouds west side, and about 8-10 degrees cooler for both Portland and The Dalles. Sunday and Monday look like they could be slightly cooler yet, with temps only in the mid 80s for a day or two.

Looking ahead…see that temperature map above? The extended 6-10 day outlook (next Wednesday through the following weekend) shows a big hot ridge over the Rockies and Northern Plains, with Eastern Oregon and Washington right on the edge of the hot air. There will likely just enough onshore flow in the Pacific Northwest, to keep both the westside and the Gorge out of the real heat. Seasonably warm and sunny almost every day. For The Dalles, that means a majority of days in the 85-95 range, not 100-plus. The GFS ensembles are very supportive of the “average to slightly above” scenario:

One or two of the last 8 GFS runs tried to show another minor hot spell out around days 8-10 (late next week), but most looked pretty seasonable. This is almost the exact same pattern that developed for much of July 2013: just slightly on the warm side for Portland and The Dalles, relative to their respective norms. But much hotter, not too far to the east or south. As I recall that year, there were a lot of days when Eugene was a good 5-7 degrees hotter than Portland – and The Dalles only a degree or two above Eugene. Who knows if we see a similar temperature geography this year or not?