There has been little change in the weather in Baltimore -- a heat advisory is in effect again Thursday, and storm forecasters are again predicting a slight chance of severe weather in the region. A break to the heat may be in sight, though.

In southern Baltimore County and Baltimore City, the heat advisory was upgraded to an excessive heat warning at 1:43 p.m. through 8 p.m. Heat index values are expected around 110 degrees.

Central Maryland has escaped nearby severe weather since Friday's derecho storm and another band of rough weather that came overnight Sunday into Monday. Severe storms passed through Northern Virginia for the Fourth of July, but others that were on a path toward the Baltimore area fizzled.

The Storm Prediction Center is calling for 5-15 percent chances of strong winds and a "slight" chance of severe storms over the Appalachians and mid-Atlantic. The Baltimore region is on the edge of that zone.

The area faced similar storm chances Wednesday, but fireworks shows went off without a hitch, as far as the weather was concerned.

The heat advisory, for northern Baltimore, Harford, Howard and Anne Arundel counties, calls for high temperatures in the upper 90s and lower 100s, with heat index values around 105 degrees. The heat is expected to extend through Sunday, and Baltimore health officials have extended a "code red" accordingly and plan to open cooling centers through then.

Saturday could bring the worst of the heat. Local meteorologist Eric the Red cites a model predicting highs up to 106 degrees in the Baltimore area, which would smash the record of 101 set in 2010.

The current streak of 90- to 100-degree temperatures -- nine days and counting -- could come to an end Monday. National Weather Service forecasts call for highs in the upper- and mid-80s Monday and Tuesday.

Four people have died of heat-related illnesses, two of them elderly Baltimore men July 1. Weather and health officials warn residents to be wary of heatstroke and heat exhaustion and to stay indoors, drink lots of water and wear light-colored, loose-fitting clothing.

Of course, staying indoors isn't the best idea for the about 50,000Baltimore Gas and Electric Co.customers still without power as of 10 a.m. The Maryland Public Service Commission has scheduled a press conference for 11 a.m. Thursday to address the investigation into utilities' storm response, a standard practice after major widespread outages.

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