Friday’s cloudy, cool day masks next week’s big heat up when temps near 100

Large round outdoor thermometer showing temp of 98 degrees.

More forecast models are agreeing temperatures will near 100 degrees by mid-week next week. Oregonian file photo. Rosemarie Stein/Staff


Friday’s cool and cloudy day, which may struggle to reach 80 degrees, gives no hints about heat wave coming next week to Portland.

The National Weather Service points out that Portland is 95% likely to not see temps this cool for at least the next 10 days. High pressure dominating the weather pattern through the end of July is likely to bring a long stretch of days with temperatures reaching the high 90s and even into 100-degree territory.

Some forecast models are suggesting a shorter stretch of hot weather with about three days of high temperatures topping out in the mid-90s in the Willamette Valley and Columbia River Gorge. But most models are showing at least three days, and some as many as five, with temperatures near 100 degrees across much of inland western Oregon.

Forecasters are expecting Portland’s hottest days to be Wednesday or Thursday next week, with temps that could reach 105 degrees.

If you want to escape the heat, the coast may be a good bet. Forecasters are showing onshore flow during this period will keep the coast much cooler than inland locations for most, if not all of next week. The onshore flow will also keep low level moisture across the region allowing for muggy conditions inland during the heat spell.

If you got instantly hot from reading all that, remember there are still a couple of days to go before the heat sets in. Forecasters say there’s a 60% chance of metro area temperatures not even reaching 80 degrees Friday under mostly cloudy skies. The high at the Portland International Airport will likely reach about 77.

Saturday will start off cloudy as well, but the clouds should be thinner and burn away quicker. Expect a mostly sunny afternoon with highs near 81.

Sunday could kick off the heat wave, as high pressure builds in northwestward bringing hot air into the region. Skies will be mostly clear, and the daytime high temp should reach near 90 degrees.