Final taste of summer, Portland hit with 20-degree temp swing

PORTLAND, Ore. (KOIN) -- Summer heat finds its way back to the Pacific Northwest Tuesday as highs return to the low 90s around Portland.

A sun-cloud mix won't stop temperatures from soaring into the low 90s Tuesday afternoon and evening. This early autumn heat up isn't expected to break records for Portland, but it is unseasonably late.

The best time to water heat stricken lawns and gardens will be early in the morning and closer to sunset. Watering during the peak of the heat will be wasteful due to high evaporation rates.

The high heat is short-lived. A nearly 20-degree temperature drop is expected from Tuesday afternoon to Wednesday. A cold front will increase Oregon and Washington's cloud coverage Wednesday. Rain comes into the picture Wednesday afternoon thanks to a dying atmospheric river. Rain accumulation will only sit around a tenth to a quarter-inch along the Willamette Valley.

The fast moving weather systems this week will stabilize by Thursday. Near average highs of the low- to mid-70s return late in the week and last through the weekend.

A few spotty shower are possible late Thursday night to Friday morning with no real accumulation expected. Temperatures will remain mild and skies will stay dry through the start of next week.