Maryland weather: Wednesday temperatures hit high 90s; nighttime storms possible, followed by potential flooding

Temperatures throughout the Baltimore region neared 100 degrees Wednesday afternoon, as heat advisories for counties near the Chesapeake Bay remained in effect and the area braced for a flash flood watch for Thursday and Friday.


Wednesday reached a high of 98 degrees at BWI Thurgood Marshall Airport with a heat index of 105 degrees, according to the National Weather Service.

The temperature is expected to fall as a cold front is forecast to slowly move in Wednesday night from the Northwest, according to the weather service.


Scattered showers and thunderstorms are expected throughout Wednesday night, with storms gaining momentum into Thursday and Friday.

Special marine warnings were issued until 8:45 p.m. Wednesday for the Chesapeake Bay from Pooles Island to Sandy Point; for the bay north of Pooles Island; for the Patapsco River, including Baltimore Harbor; for the tidal Potomac from Indian Head to Cobb Island; and for the tidal tidal Potomac from Key Bridge to Indian Head.

Oldtown in Allegany County was under a severe thunderstorm warning through 5:15 p.m. Wednesday. Little Orleans in Allegany County was under the same warning until 5:45 p.m. Wednesday.

Counties east of Blue Ridge Mountains are under a flash flood watch from 2 p.m. Thursday to 8 a.m. Friday.

Forecasts estimate the front will cross the water going into Friday, but could stall and lead to a high-pressure system Thursday that may require an advisory for boats on the water, according to the service.


The heat prompted Baltimore City officials to announce the first “Code Red” heat advisory of the season for Tuesday and Wednesday. Across the region, officials have opened cooling areas in senior centers, libraries and rec centers.


Baltimore Health Commissioner Dr. Letitia Dzirasa urged residents to limit outdoor activity in the middle of the day and never leave children or pets in closed vehicles.

“Excessive heat is the leading weather-related killer in the United States,” Dzirasa said in a news release. “The effects of extreme heat are exacerbated in urban areas, especially when combined with high humidity and poor air quality.”

Benjamin Zaitchik, a Johns Hopkins professor of earth science, said residents should check in on loved ones who may be susceptible to heat-related illnesses.

“[Heat stress] doesn’t feel scary, like a hurricane, so we underestimate it, but it also kills a lot of people,” Zaitchik said. “It’s also really easy to treat, like giving someone a bottle of water, turn on their air conditioners or a fan, open a window, get them to a cooler place. … It’s not rocket science, but you need to know the people who need help and recharge them at the right time.”

Cooling centers at senior centers across the city will be open both days of the heat advisory for residents. Those seeking relief from the heat in the centers are required to wear masks and practice social distancing. Public pools are also open to all residents who register in advance online or by phone.

In Baltimore County, emergency officials directed residents toward public libraries, except the Reisterstown branch. In Carroll County, all public libraries will function as cooling centers, plus four senior centers in Mount Airy, North Carroll, South Carroll and Taneytown. In Anne Arundel, libraries, certain police stations and certain senior centers will be open for cooling.


By Thursday, temperatures are expected to cool down, with highs in the low 80s, according to the weather service. The chance for storms rises from 40% Wednesday afternoon to 80% Thursday evening. Scattered thunderstorms are also likely throughout the weekend.

The Maryland Department of Health also issued a release Monday afternoon warning Marylanders of extreme heat this week and provided safety tips to avoid heat-related illness.

Health department officials suggested wearing lightweight clothing, avoiding alcohol and sweetened beverages, and scheduling physical activity in the mornings rather than later in the day to cope with the hot weather.

According to Maryland health officials, there’s been one heat-related death reported in Maryland in 2021. During last year’s extreme heat season, there were 16 reported deaths.

A historic heat wave is setting record-breaking temperatures on the West Coast, with excessive heat warnings issued for nearly all of Washington and Oregon as well as Idaho and Northern California.

Baltimore Sun reporters Christine Condon, McKenna Oxenden and Rose Wagner contributed to this article.