Cooler temps, rain coming as if on schedule for start of autumn

Autumn arrives Wednesday afternoon and, as if on cue, it’s going to feel like it.

After a high in the 80s on Sunday and expected again Monday, a high of 74 is forecast for Wednesday, which is right around average, National Weather Service meteorologist Myranda Fullerton said.

Autumn will officially start at 3:21 p.m. Eastern time. The lower temperature on Wednesday is expected to be accompanied by a steady, all-day rain, Fullerton said.

Rain is forecast to arrive in the Pittsburgh area after 8 p.m. Tuesday. Tuesday’s high will be around 76.

The more seasonal weather is coming a week after area residents were taking note of unseasonably warm weather for September.

The cooler temperature and rain are coming with a “seasonal changer” cold front, Fullerton said.

“It’s kind of cool,” she said. “I appreciate it because oftentimes Mother Nature does not cooperate. Here, at least for this week, Mother Nature is doing exactly what it’s supposed to be doing.”

The sun is rising on what should be our last "summer-like" day this week. A strong cold front is on the way, proving Mother Nature to be right on que for the start of fall, which begins this Wednesday. ????➡️???? pic.twitter.com/qugSXuExnH

— NWS Pittsburgh (@NWSPittsburgh) September 20, 2021

It will be even cooler on Thursday, when the high is forecast to be 65, almost 10 degrees below average, Fullerton said. The widespread rain should be over, but scattered showers could linger in the area.

Temperatures should moderate some for the weekend, with highs slightly below or near the seasonal averages. Friday should be a cool, dry day with a high of 67, five degrees below the average of 72.

“It will really feel like fall on Friday,” Fullerton said.

The 2021 harvest moon will reach peak illumination at 7:55 p.m. Monday, and will appear full through Wednesday morning, according to NASA. But Fullerton said Pittsburgh area residents may not be able to see much of it because of cloud cover.