A bicycle rider uses a poncho to shield himself from the rain Monday in Ann Arbor on Liberty Street. Tuesday's weather will be much different than Monday's, with the high eclipsing 90 degrees, but a cold front expected by the end of the week may bring thunderstorms and cooler temperatures.

Brianne Bowen | AnnArbor.com

The Ann Arbor area should prepare for a scorcher Tuesday, the National Weather Service warns, as temperatures are expected to rise into the 90s.

Tuesday's forecast calls for mostly sunny skies and a high around 93 or 94 degrees. Much cooler weather will then move in by the end of the week.

With the heat index, it will feel as if it's about 97 degrees outside during the hottest hours of the day, said meteorologist Rachel Kulik.

"It's going to be quite hot tomorrow," she said.

That's a far cry from the conditions the area was experiencing Monday afternoon. The thermometer stood at 62 at 1 p.m. Monday as light rain fell. The weather service was forecasting a high of about 83 degrees and said the chance for rain and thundershowers would continue, mainly before 2 p.m.

University of Michigan weather observer Dennis Kahlbaum said the Sept. 10 record high, set in 1987, is 95 degrees. Kahlbaum said it's unlikely the record will be broken tomorrow.

Kahlbaum said the most recent occurrence of 90 degree weather was July 19, when the high reached 94 degrees.

Meteorologists are advising people who have to be outdoors Tuesday to stay hydrated and dress appropriately for the weather.

"It's going to be mostly clear tomorrow so if you can, stay out of the sun," Kulik said. "If you don't have air conditioning, try to find a place that has some."

With highs around 88 or 89 degrees, Wednesday won't be as steamy as Tuesday, Kulik said. However, storms may come through the area on Wednesday.

"We might see a few rain showers today, but the next major rain storms are going to occur Wednesday afternoon," she said.

The National Weather Service, there's a 30 to 40 percent chance for thunderstorms on Wednesday.

Kulik said the heat will trigger the storms, bringing in a cold front.

"Highs on Thursday will only be 75 degrees," she said.

Friday, temperatures will be slightly cooler and around 61 degrees.

Kulik said the high temperatures are part of the usual fluctuations seen this time of the year, but by the end of September, highs are usually around the mid-70s.

"September is a transitional month, so we're transitioning from summer temperatures to fall and wintry type weather," she said. "We definitely get those fluctuations this time of year."

Katrease Stafford covers Ypsilanti for AnnArbor.com.Reach her at katreasestafford@annarbor.com or 734-623-2548 and follow her on twitter.