Flash flooding is possible throughout the entire D.C. area Friday and a tornado watch is in effect in Maryland as the first named storm of hurricane season soaks the East Coast.
The tornado watch for St. Mary's County expires at 8 p.m.
Tropical Storm Andrea will deliver rainfall -- sometimes heavy -- throughout the day, Storm Team4 Chief Meteorologist Doug Kammerer said. A flash flood watch is in effect for the entire D.C. area through Friday evening.
The storm is expected to reach southeastern Virginia and the mouth of the Chesapeake Bay by about 6 p.m.
The storm is expected to maintain tropical-storm-force winds when it makes its way out over the Atlantic Ocean again off the coast of Ocean City, Md., Friday evening.
Up to an inch of rain fell in the D.C. area overnight. With moderate-to-heavy rain continuing through the evening, another 1-3 inches is expected in D.C., the suburbs and Maryland's Eastern Shore.
Flash flooding can be dangerous, particularly to drivers who think they can drive through standing water, said Storm Team4 Meteorologist Tom Kierein.
"Every time we get high water, people get stranded driving," he said. "People are driving a big SUV and they think, 'I have ground clearance, I will be fine,' but they don't know how deep that water is."
Even shallow water can separate a car's tires from the roads -- and lead to the car floating away.
Another safety concern: streams and creeks that are attractive to kids and thrill-seekers, who can be swept away by fast-moving water, Kierein said.
Evening commuters will face hazardous driving conditions, AAA Mid-Atlantic warned.
“Commuters heading home this evening are reminded that they will be faced with the same treacherous weather conditions as this morning’s drive to work,” AAA Mid-Atlantic's John B. Townsend said. “The most important steps to take when driving in wet weather are to buckle up, slow down, and keep a safe distance from the car in front of you.”
- Slow down and increase following distances. Safe following distance on slippery roads should be increased to eight seconds.
- Do not attempt to drive through standing water. Try to avoid bridges and roads known to flood. On pothole-filled roads, hold the steering wheel firmly to avoid losing control.
- Watch out for hydroplaning, even with four-wheel drive vehicles.
- Alert drivers behind you that you’re slowing with your brake lights. Without anti-lock brakes, squeeze the brakes until they are about to lock up and then release. With anti-lock brakes, use the same move – but don’t pump the brakes, which would work against the operation of the ABS system. Slow down as you approach a pothole. However, do not brake when your vehicle is directly over a pothole.
- Use the central lanes. Avoid outside lanes where the water collects at curbside.
- Use low-beam headlights to help other drivers see your car and increase visibility.
- Use your defroster with your air conditioning to keep the air dry and prevent windows from fogging.
- Do not drive around barricades.
- Turn off the cruise control in wet weather driving. The use of cruise control on wet roads can cause hydroplaning.
- If conditions worsen to the point where there is any doubt about your safety, take the nearest exit and find a safe location. Don’t just stop on the shoulder or under a bridge where you may feel less anxiety.
Saturday and Sunday will be mostly dry, but there will be a chance of rain both days.
Andrea became the first named storm of the Atlantic Hurricane Season Wednesday.
The National Oceanic and Atmospheric Administration believes we'll see 13 to 20 named Atlantic storms this season, with seven to 11 that strengthen into hurricanes and three to six that become major hurricanes.
MORE ON NBCWASHINGTON:
- "Be Ready": NOAA Warns of Busy Hurricane Season
- Tropical Storm Andrea Gains Strength
- Tropical Storm Andrea Forms in the Gulf, Tropical Storm Warning Issued
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Photo Credit: NOAA