Severe Thunderstorm Watch Issued, MD Braces For 'Intense Rain'

Updated at 3:25 p.m.

MARYLAND — Maryland is under a severe thunderstorm watch Wednesday until 10 p.m. The alert covers the entire state except Allegany, Garrett and Washington counties in western Maryland. The alert warned that "intense rain" could cause flash flooding.

The rain could quench the 100-degree heat and drop highs to the low-90s through the weekend.

The real-feel heat index could hit 108 degrees Wednesday, drawing a heat advisory that's in effect from 11 a.m. to 8 p.m. It covers portions of central, northern and southern Maryland.

Thunderstorms may roll in during the afternoon and evening. Rain may fall at a rate of 2 inches per hour.

"Excessive runoff may result in flooding of poor drainage and urban areas and a few small streams," the National Weather Service said in a flood watch.

"If locally repetitive or prolonged thunderstorms develop, flash flooding could occur in flood prone urban and suburban areas," the flood watch said. "Please visit www.weather.gov/safety/flood for flood safety and preparedness information."

The current flood watch means dangerous conditions may develop. If upgraded to a flood warning, the danger would be eminent and shelter would be required.

"You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued," the National Weather Service said.

The flood watch lasts from 2 p.m. through Wednesday evening. It covers Anne Arundel, central and southeast Howard, central and southeast Montgomery, Prince George's and southern Baltimore.

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

Wednesday: Showers and thunderstorms likely, mainly after 4pm. Some of the storms could be severe and produce heavy rainfall. Partly sunny and hot, with a high near 98. Heat index values as high as 104. Southwest wind 8 to 11 mph, with gusts as high as 20 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.

Wednesday Night: Showers and thunderstorms before 2am, then scattered showers. Some of the storms could be severe and produce heavy rainfall. Low around 73. Southwest wind 5 to 9 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

Thursday: Mostly sunny, with a high near 92. Northwest wind around 7 mph.

Thursday Night: Partly cloudy, with a low around 69. North wind 3 to 6 mph.

Friday: Sunny, with a high near 91. North wind 3 to 7 mph.

Friday Night: Partly cloudy, with a low around 71.

Saturday: Partly sunny, with a high near 91.

Saturday Night: Mostly cloudy, with a low around 72.

Sunday: Mostly sunny, with a high near 93.

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

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

Monday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 73. Chance of precipitation is 40%.

Tuesday: A chance of showers and thunderstorms. Partly sunny, with a high near 92. Chance of precipitation is 50%.