Today was another fantastic day...as the most consistent/stable weather pattern of the entire warm season continues. Each of the past 8 days in Portland we've topped out between 78 and 84 degrees. Keep in mind a typical high temp this time of year is 80-81 degrees; this is about as normal as it gets folks!
Humidity has been low, skies have been mainly sunny, & nights have cooled well down into the 50s. Many would say we are having a perfect summer weather pattern. That's because hot high pressure has stayed to the south, allowing just enough onshore flow to keep us comfortable
Somehow my pool has remained in the mid-upper 70s, even with lows in 40s and highs only 75-80 out there. Must be the constant sunshine each day. We are living through another warmer-than-average August.
Does it seems like late summers have been consistently warm lately? Sure enough, Portland hasn't seen a cool August since 2010! Although 2011/2013 were only a little above average. Of course the Portland/Vancouver metro area has an increasingly warm "urban heat island" at night which leads to ever-increasing nighttime temps under clear skies. But daytime highs (a more reliable indicator of a warming climate in a city) have been steadily marching uphill too. 1940-2020 August high temps at PDX, make sure you click on it for a MUCH better view.
After a slightly warmer day tomorrow, in the 85-88 degree range, we'll cool off over the weekend with more onshore flow. Then a weak upper-level trough passes nearby Monday
Models say we could get lots of clouds and even a few light showers out of this system late Sunday night and Monday morning. I have a feeling the last day of August will feel more like September. But then things heat up again the first week of September. All models agree a flat, but strong ridge of high pressure in the upper atmosphere parks over the Pacific Northwest. You can see the very warm ridge on Tuesday's 500mb chart...this is the pretty one we use for TV.
The ECMWF ensembles say summer is coming back the first 7-10 days of September. Check out the rain outlook, little/no chance for rain through the 10th, after the showers this coming Monday
And the surface temp forecast shows 10-15 degrees above average daytime highs. The Euro, GFS, & GEM all hint there could be some sort of heat event during this period. I mean several days at/above 90 degrees. At least hot weather in September is accompanied by much cooler nights than July and early August!
- Nice summer weather continues through Sunday
- Monday is THE ONE DAY in the next 10 we may see some showers
- Sunshine and much warmer weather returns the first week of September.
- There is no sign of an early start to fall rains and/or cool/wet September weather like we saw last year.
Chief Meteorologist Mark Nelsen