State health officials have added anelderly Baltimore County man to the heat wave death toll, bringing to 12 the number of weather-related fatalities in Maryland from a massive storm that struck July 29 and extreme heat that has lingered since.

The man brings to nine the number of heat-related deaths in the state. Another three people died in the storm. No additional details on the heat deaths were available.

Dangerous weather is expected to last for the next three days, including potentially deadly heat and more severe storms.

The National Weather Service issued an excessive heat warning about 2 p.m. Friday, cautioning of heat indices around 110 degrees in Central Maryland on Saturday from 11 a.m. to 10 p.m.

The National Weather Service is forecasting a high of 104 degrees Saturday in Baltimore, and heat indices could reach 110 degrees to 115 degrees, so it's not the day for normal weekend yard work and other outdoor activities.

A heat advisory is in effect for Friday in Central Maryland, with heat indices up to 105 degrees. 

Meanwhile Baltimore city officials voted Friday to extend the state of emergency for another seven days.

Cooling centers are open in Baltimore and across the region, with county governments encouraging residents to visit community centers and public libraries to cool off.

Four heat-related deaths were confirmed on the Fourth of July, according to a state health department report released Thursday.

Given the heat, more afternoon storms could crop up each afternoon and evening. So far this week, any such storms haven't developed into anything severe. Saturday and Sunday afternoons carry slightly elevated severe weather risks, according to the Storm Prediction Center in Norman, Okla.

Sunday could bring the best chance for severe weather on the edge of a cold front passing into the humid, stagnant air over the region. Damaging winds are the main risk, as well as some chance for hail. The storm center estimates a 30 percent chance of severe weather developing in Maryland on Sunday.

The bright side of that cold front is that highs are forecast in the upper 80s Monday through at least Wednesday of next week.

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