The temperature in Medford could hit 100 today, for only the second time this summer.

The temperature in Medford could hit 100 today, for only the second time this summer.

Today's forecast calls for plenty of sun and a high of 100, said Chuck Glaser at the National Weather Service office in Medford

It should be the hottest day of the week, as high pressure building over the region will begin to weaken, lowering temperatures to around 90 by Friday and through the long weekend.

"We'll be back to near normal," said Glaser, who is the weather service's data acquisition program manager.

He noted that this summer hasn't had much hot weather. The only other day so far to clear the triple-digit mark was July 10, when the high hit 105.

A string of unseasonably hot weather in late May and early June pushed temperatures into the mid 90s. Temperatures on July 4 and 5 hovered around 98 and 99, and August opened with a 98-degree day.

This hot spell could cause scattered thunderstorms to develop east of the Cascades today and especially Thursday as it begins to break.

A fire weather watch has been issued for Thursday afternoon and evening for the Southern Oregon Cascades. Across the Fremont-Winema National Forest and points east, lightning with little precipitation could develop as upper level moisture moves northward but doesn't deliver rain, the watch said.

— Anita Burke