NEW YORK, United States (AFP) — Millions of Americans will spend the weekend hot under the collar as soaring East Coast temperatures and stifling humidity slapped excessive weather warnings on New York and Philadelphia.

Both cities issued excessive heat warnings, warning the combination of mercury and humidity would make it feel as hot as 110 degrees Fahrenheit (43 degrees Celsius) in New York and Philadelphia over the weekend.

Temperatures would stay in the mid 90s from Friday through Sunday, meaning it was the humidity that would push the heat index values higher in New York and Philadelphia, home to around 10 million people combined, meteorologists warned.

Authorities warned of heat-related health problems, especially for the elderly and those with chronic health problems, and those working outdoors.

Americans were advised to stay inside and use air conditioning where possible, check on vulnerable friends and neighbors, drink plenty of fluids to stay hydrated, and not leave children or pets unattended in vehicles.

Overall the heatwave stretches from southwest Ohio to west Virginia, Washington DC, Boston, New York and Philadelphia, said David Roth, a meteorologist with the National Weather Service.

Dallas, Washington DC, parts of New Jersey and Long Island might see records on Friday, but only because local databases are shorter, Roth told AFP.

Five other spots stretching from Ocean City in Maryland to Connecticut might set similar records on Saturday, before the heat fades Sunday and Monday, he added.

In the south, heavy rainfall pummelled parts of Louisiana and Mississippi as an area of low pressure moved west along the Gulf Coast.

Ten to 15 inches (25.4 to 38.1 cm) of rain fell across parts southern Mississippi and southeastern and south central Louisiana, Roth said. Another 10 inches were expected in parts of Louisiana over the next two days.

“Even for them its very unusual,” he told AFP.

US media reported that heavy rain caused flooding and closed schools in some areas on Friday.