An excessive heat warning is in effect for central and southern Maryland and part of the Eastern Shore from 11 a.m. to 10 p.m. Saturday.

High temperatures could reach a record-breaking 104 degrees, according to the National Weather Service, with heat index values up to 110 degrees. A high of 101 degrees from a heat wave in 2010 is the record for BWI Marshall Airport on July 7.

That means a high risk of heat exhaustion or other heat-related illnesses, the weather service warns. That is particularly true for the several thousand Baltimore Gas and Electric Co. customers still without electricity.

There is also a risk of severe weather. The Storm Prediction Center in Norman, Okla., is calling for a 15 percent chance of severe storms forming in central and western Maryland.

The heat could be a crescendo for Mother Nature, after what has so far been a 10-day stretch with highs in the 90s and 100s and also included the powerful derecho storm July 29. A stretch with highs in the upper 80s is forecast to begin Monday.

Officials with the Maryland Emergency Management Agency encourage anybody in Maryland who needs transportation to a government-run cooling center to dial 211.

Have a weather question? E-mail me at sdance@baltsun.com or tweet to @MdWeather.