By Alex Sosnowski, Expert Senior Meteorologist
Break out the fans and air conditioners and get the pools ready as Mother Nature has a stretch of hot, humid weather just in time for the Memorial Day weekend for portions of the Midwest and East.
As cool air with gust winds sweep over the Southwest and snow falls over the high country in the Rockies, building heat over the southern Plains is forecast to surge northeastward later this week.
While the pattern is only likely to last several days, it will feature the highest actual temperatures and AccuWeather.com RealFeel® temperatures of the season so far. (The RealFeel temperature incorporates a number of atmospheric conditions to show how it feels on the human body).
Early-season warmth will evolve into a several-day stretch of 90-degree temperatures and high humidity with the core over the Ohio Valley states Friday into the Memorial Day weekend.
RealFeel temperatures will top 100 degrees and could reach 105 degrees for a few hours each day from St. Louis, Mo., to Cincinnati, Memphis and Nashville.
Ninety-degree temperatures and near 100-degree RealFeel temperatures will also nose eastward into Pittsburgh, Philadelphia, Washington, D.C., Baltimore and Richmond.
Thunderstorms on Rim of Heat
North of this zone, cloudy intervals and a couple of rounds of thunderstorms are forecast to mitigate the heat. As a result, areas from Chicago to Detroit, New York City and Boston will have less extreme warmth on a daily basis or only a brief spike in heat.
Chicago is likely to have one nasty hot day Sunday with temperatures making a run into the 90s. Temperatures around Detroit will peak in the 80s to near 90 most days of the weekend.
Late in the weekend, the heat is likely to collapse from northwest to southeast from thunderstorms. As a result, folks enduring several days of heat will want to keep an eye on the sky during the holiday itself.
Interestingly, folks along the southern Atlantic Seaboard could have a visit from a tropical system later in the weekend with downpours and locally gusty thunderstorms.
Be Ready for Summer Heat
While many folks may welcome the heat on the first unofficial weekend of summer for seasonal activities, many people will be sweltering away at memorial services, graduations and sports venues ranging from baseball to auto racing.
The heat and humidity will catch some folks off guard who are not yet accustomed to the conditions.
Be sure to drink plenty of fluids if you will be exposed to the heat this weekend. Avoid prolonged strenuous activity from late morning through the afternoon. Try to take breaks from the sun, if possible.
Heat could also raise mechanical issues for highway travelers and weekend automobile race activities.
Highway travelers are reminded to make sure their vehicle is ready to handle hot weather conditions. It is best to check tire pressure levels after the vehicle has been parked overnight. Only add radiator fluid to the reserve reservoir. Never take the radiator cap off of a hot engine.
Driving at excessive speed with or without properly inflated tires during hot weather can exceed the threshold of what the tire is designed to handle and could lead to a dangerous blowout.
According to AccuWeather.com Forensic Department Manager Edward Adams, "While the RealFeel temperature has no bearing on mechanical objects, given a high in the mid-90s, the actual temperature on paved surfaces exposed to sunshine much of the day will top 120 degrees."
This year's Indianapolis 500 on Sunday is forecast to take place with blazing afternoon sunshine, a high temperature challenging the highest May temperature on record and very humid conditions. The RealFeel temperature is forecast to be between 100 and 105 degrees for the Indy 500.
Meanwhile, NASCAR's Coca-Cola 600, scheduled to start early Sunday evening at Charlotte Motor Speedway will begin with temperatures near 90 degrees.
Some summer weather enthusiasts will have swimming on their minds this weekend. Even though stream, lake and ocean water temperatures are averaging about five degrees above normal for this point in the year, the water is still at its chilliest point of the summer season.
The chilly water can lead to muscle cramps and raise the risk of drowning. Swim only when and where a lifeguard is on duty and take frequent warm-up breaks.
This story was originally published on Tuesday, May 22, 2012 and has been updated.