Those people hoping for an early fall are getting a reminder that summer is far from over as the heat index could reach 111 degrees Tuesday, resulting in an excessive heat advisory.

The advisory expires at 9 p.m. Tuesday, according to the National Weather Service. All of northeast Kansas is affected, in addition to Dallas, Oklahoma City and Kansas City, Mo. The heat index, a “real-feel” temperature factoring humidity, reached 106 Monday with an actual high of 94.

A stagnant air mass combined with high humidity from weekend storms has resulted in a “heat dome” covering Manhattan and much of the central United States, said Mary Knapp, K-State climatologist.

Heat-related illnesses are possible, especially for the young and elderly and those without air conditioning, according to the NWS. It advises to limit outdoor activities during this period and check up on neighbors. While outside, drink plenty of water, wear light and loose-fitting clothing, and reduce strenuous activities.

“It’s not going to be super hot temperature-wise, but the high humidity and lack of air movement will drive up the index,” Knapp said.

A low-pressure front moves in Tuesday night with northwest winds ushering in cooler air. The high Wednesday is expected to be 88 with a low of 68 with a 60% chance of thunderstorms in the afternoon.

But that doesn’t necessarily signal the start of fall-like weather, Knapp said.

“We’re expected to be warmer than usual this fall,” Knapp said. “It’s not unheard of to hit 100 around here in September.”

The latest 100 on record for Manhattan was 106 on Sept. 28, 1956.

Manhattan has only reached 100 twice this year, on July 18 and 19, as it’s been a below-average summer. Knapp said Manhattan usually reaches 100 four or five times a summer. The average temperature this August has been 77.5 while the all-time average is 79, Knapp said.

Manhattan’s low this year was minus 2, reached on Jan. 30, Jan. 31, March 3 and March 4, considered the year’s coldest day as the high was only 7.

Weekend storms and rain helped contribute to the high humidity. Strong winds knocked down several power lines and uprooted large, healthy trees in Riley at 6:05 a.m. Friday and on Saturday another round of storms produced a possible unconfirmed tornado in northern Riley County near Riley, Knapp said.

The same Friday storm uprooted a weak tree in Clay Center and produced winds of 60 mph 2 miles north-northeast of Green and 75 mph in Randolph.

Four tornadoes were reported in Waubunsee and Geary counties Friday morning, mainly in open country near Volland with the latest reported at 2:27 a.m. 6 miles east of Alta Vista, visible during lightning flashes.

No property damage or injuries were reported.