Here are my thoughts at 11pm:
Amazing that we made it to 103 (all airports in the PDX area hit the same temp!) with essentially a flat gradient, or just slightly easterly. I rode my bike past Crown Pt. around 9am there was just a light easterly breeze. So with a slightly warmer atmosphere tomorrow, but just a flat/light easterly flow, I figure about 2 degrees warming. That’s how I ended up with the 105. As for tonight…whew! This will probably be the only time I’ll hop into the kids swimming pool when I get home. At 10pm it’s 90 degrees. I think even during the bizarre cloudy night during the 2006 heat wave we had dropped to 88 at 10pm. Looks like a low around 70 will probably be reasonable.
Wednesday and Thursday’s temp forecast is a bit problematic. It’ll be scorching hot…that much is for sure. But we get much stronger offshore flow, more like September easterly wind due to a surface high coming down into the northern Rockies. I think it may actually turn breezy through at least the eastern half of the metro area. With better mixing one would think it could turn even hotter than that 105. But the upper-level heights and 850 mb temps drop a bit at the same time. So do we turn cooler or warmer? I’m not sure, so I just left it at 105. I could see a situation where we don’t get much, or any, atmospheric cooling and then the easterly breezes pick up in the afternoon. Maybe we’ll get a surprise 107? This could be fun (and brutal). Even with an east wind blowing, Thursday’s atmosphere is slightly cooler again, so maybe right around 100 or just under. Holy cow…we’re talking 4 days at/above 100 degrees if that’s the case.
Beyond Thursday: I see the 00z GFS has backed off on the trough approaching the Coast, pretty much eliminating the thunderstorm threat and keeping us pretty warm (85 at least) through the weekend and early next week. Now to give some of you hope, I’m headed into Eastern Oregon starting Friday for a week-long vacation. So that’s probably when the low will make it’s move, giving us a severe thunderstorm outbreak west of the Cascades. Stay cool!
Chief Meteorologist – Mark Nelsen