As much as 6 inches of rain could bring floods

As much as 6 inches of rain, and more in isolated areas, could cause widespread flooding across Central Maryland through Friday — including in Ellicott City, still recovering from the July downpour that triggered a deadly flash flood.

A slow-moving low-pressure system coming from the Great Lakes is forecast to pull in tropical moisture as it spreads over the region, likely soaking Maryland. Thunderstorms and pockets of intense rainfall could inundate some areas, National Weather Service meteorologist Chris Strong said, but it’s impossible to predict where.

“It’s like predicting where bubbles are going to be in your boiling pot of water,” he said. “There’s potential for spotty areas to see exceptional rain and extreme flash flooding.”

Those predictions had Baltimore officials urging residents to clear storm drains, and meteorologists reminding them of the dangers of fast-rising, swift-moving waters.

Six inches of rainfall in a two-hour span July 30 sent a river down Main Street in Ellicott City that drowned two people and swept away dozens of vehicles. Officials were preparing for the possibility of another flood.

Howard County officials have been in “constant communication” with the weather service and relaying meteorologists’ warnings to business owners and residents in Ellicott City, spokesman Mark Miller said. Crews put up sandbags along a stream bank that has not been restored since the flood, he said, and building inspectors have been checking on some of the properties still repairing flooding damage.

Miller said officials aren’t expecting any flooding as severe as Ellicott City saw in July, because the rain is expected to fall over a longer period of time.

“We are just making sure we’re taking every preventative measure we can,” he said.

The heaviest rain was forecast to begin falling Wednesday night and continue through today, Strong said. The system has the potential to drop as much as a foot of rain in isolated areas, he said.

Showers could then linger through Friday and into early Saturday, he said.