Last round of summer heat felt in Portland on Thursday?

PORTLAND, Ore. (KOIN) -- Summer heat, haze and high humidity remain over western Oregon and southwest Washington on Thursday.

Temperatures are expected to warm into the upper 80s again on Thursday as humidity values keep the heat going. Haze from wildfire smoke is expected to remain over much of the Pacific Northwest. Air quality could be impacted for some throughout the end of the week.

A gradual cooling trend will start taking shape across the Pacific Northwest after Thursday. High pressure will start to fade as an isolated thunderstorm or two develops on Thursday afternoon and evening. One or two of those isolated storms could move into the Willamette Valley by Friday morning.

Lightning will keep the wildfire threat elevated through the end of the week. This comes from the dry landsc