MD Air Quality Alert As Scorching Heat Returns, Stormy Weekend Ahead

MARYLAND — Scorching summer temperatures return to Maryland Thursday after a short reprieve from last month's heat wave. A new heat wave could be on the way, as highs exceed 90 degrees until at least Wednesday.

The real-feel heat index could hit 108 degrees Thursday and Friday in the Old Line State. That drew a heat advisory and a code orange air quality alert.

Storms are also possible daily through Sunday.

AccuWeather said the jet stream will dip Friday and mix with a storm and tropical moisture. This will bring thunderstorms to the Mid-Atlantic through the weekend.

"There is the likelihood of slow-moving and repeating thunderstorms along the busy Interstate 95 corridor and other major highways in the region, which may lead to areas of flash flooding and even some road detours in low-lying exposed areas," AccuWeather Senior Meteorologist Brett Anderson said.

Anderson also warned of travel delays at major airports and noted that the storms would likely brew in the evening.

"Often during the summer, thunderstorms tend to wait until the end of the day or at night before reaching the beaches," Anderson said. "With this setup, storms could occur anytime, especially Saturday into Sunday, which will keep many off the beach."

The National Weather Service's heat advisory covers portions of central, northeast, northern and southern Maryland. It lasts from noon to 8 p.m. Thursday.

The Maryland Department of the Environment's code orange air quality alert warns that air pollution concentrations may become unhealthy for sensitive groups in the Baltimore and Annapolis regions. Children, people suffering from asthma, heart disease or other lung diseases and the elderly should avoid strenuous activity and outdoor exercise.

Here is the National Weather Service's seven-day forecast at Baltimore/Washington International Thurgood Marshall Airport:

Thursday: Isolated showers between 11am and 2pm, then scattered showers and thunderstorms after 2pm. Sunny and hot, with a high near 98. Heat index values as high as 105. Calm wind becoming west around 6 mph in the afternoon. Chance of precipitation is 30%.

Thursday Night: Scattered showers and thunderstorms, mainly before 11pm. Partly cloudy, with a low around 76. Southwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 30%.

Friday: Showers likely and possibly a thunderstorm after 2pm. Mostly sunny, with a high near 96. Heat index values as high as 108. Calm wind becoming south 5 to 8 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Friday Night: Showers likely and possibly a thunderstorm before 2am, then a chance of showers and thunderstorms after 2am. Mostly cloudy, with a low around 75. South wind around 6 mph becoming calm in the evening. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

Saturday: A chance of showers before 11am, then a slight chance of showers and thunderstorms between 11am and 2pm, then showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 93. Light southwest wind becoming south 5 to 9 mph in the morning. Chance of precipitation is 70%.

Saturday Night: Showers likely and possibly a thunderstorm before 2am, then a slight chance of showers and thunderstorms after 2am. Mostly cloudy, with a low around 74. Chance of precipitation is 60%.

Sunday: A chance of showers between 8am and 11am, then a chance of showers and thunderstorms after 11am. Partly sunny, with a high near 91. Chance of precipitation is 50%.

Sunday Night: Mostly clear, with a low around 72.

Monday: Sunny, with a high near 96.

Monday Night: Partly cloudy, with a low around 72.

Tuesday: Mostly sunny, with a high near 92.

Tuesday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 72. Chance of precipitation is 30%.

Wednesday: A chance of showers and thunderstorms. Mostly sunny, with a high near 91. Chance of precipitation is 40%.