Temperatures reaching the mid-90s and high humidity are forecast to make it feel like triple digits in Baltimore on Wednesday.
Temperatures dropped to 70 degrees overnight at Baltimore/Washington International Thurgood Marshall Airport early Wednesday morning, and surged to 88 degrees by noon.
Humidity was reported at uncomfortable level, with dew points in the lower 70s. The humidity was expected to make it feel about 6 degrees hotter than the air temperatures by early afternoon.
The heat prompted utility Baltimore Gas and Electric Co. to declare its first "Energy Savings Day" of the summer, offering bill credits for cutting back on electricity usage.
The heat and humidity could fuel storms, with a 50 percent chance in the afternoon and evening hours.
Storms could continue into Thursday morning, with cooler and drier air moving in after that. Highs Thursday are forecast in the mid-80s.
Mostly sunny skies and low humidity are expected Friday, with highs in the mid-80s.
Some clouds and slight storm chances could return Saturday and Sunday, with highs in the mid-80s.