The hot weather that has baked the midwest and south for the past few days has settled over Northeast Florida and Southeast Georgia, sending Monday's heat index to 110 degrees and beyond.

The National Weather Service has issued a excessive heat warning for Duval, Nassau, Baker, Columbia, Camden and Charlton counties through 8 p.m. Monday.

With high temperatures in the upper 90s and humidity and still air making it feel 10 to 15 degrees warmer, people are encouraged to stay indoors when possible and seek shade and drink plenty of water when outdoors.

"The combination of hot temperatures and high humidity will combine to create a dangerous situation in which heat illnesses are likely," Channel 4 meteorologist Richard Nunn said. "For those more susceptible to heat illness, stay in an air-conditioned room and stay out of the sun. Do you part and check up on relatives, elderly neighbors and make sure pets have cool, clean water and plenty of shade."

Health officials echo the call for taking care to avoid ill effect of heat.

"Avoid becoming dehydrated by staying out of the direct sun, wearing light colored, loose fitting clothing, limiting physical activity, and using fans when available," said Dawn Allicock, director of the St. Johns County Health Department.

Children and pets should never be left unattended in vehicles under any circumstances, and this is especially true during hot weather when car interiors can reach lethal temperatures in a matter of minutes.

The same heat wave has plagued much of the eastern United States over the weekend, with 1,900 high temperature records either tied or broken over the past four days.

To make matters worse, strong storms across four states left electricity out for an estimated 2 million people. Utility officials said the power will likely be out for several more days.

From Atlanta to Baltimore, temperatures approached or exceeded triple digits. Atlanta set a record with a high of 105 degrees, while the temperature hit 99 at Ronald Reagan Washington National Airport just outside the nation's capital. With no air conditioning, officials urged residents to check on their elderly relatives and neighbors. It was tough to find a free pump at gas stations that did have power, and lines of cars snaked around fast-food drive-thrus.

The JEA is sending 45 linemen and workers to help restore power in Savannah, joining utility crews from as far away from Oklahoma are headed the the mid-Atlantic region to help get the electricity back on and the air conditioners running again. Even if people have generators, the gas-run devices often don't have enough power to operate an air conditioner.

Since Friday, severe weather has been blamed for at least 17 deaths, most from trees falling on homes and cars.

Nunn said there's only a 20 percent chance of rain in the Jacksonville area Monday and Tuesday, but due to excessive heat, if a thunderstorm does pop up, it could be severe.

Above-average heat is forecast for Tuesday and will begin to moderate on Wednesday.