Portland has a 20% chance of showers and thunderstorms overnight Tuesday and into early Wednesday. The thunder chances are highest over the central Cascades and may start by Tuesday afternoon, the National Weather Service says.
“A low pressure system will move northward this evening, leading to a slight chance for isolated to scattered thunderstorms through early Wednesday morning,” the Tuesday afternoon forecast said. “Lightning and critically dry fuels may result in numerous fire starts east of the Coast Range.”
Some of that activity may move westward into the valleys. Fire danger is high as vegetation is dry after a long string of hot days. Much of western Oregon and along the Cascades are under a fire weather watch which means fire concerns are high. The watch continues until Wednesday evening.
Portland will see some clouds early Wednesday before skies gradually clear. The high temp will reach about 90 degrees as a high pressure ridge builds back into the region. Onshore flow will keep temps cooler along the coast.
The weather service released the information below on Tuesday afternoon.
Map shows where thunderstorms may occur.National Weather Service