A flood watch is in effect across much of the Baltimore region starting at 6 p.m., with two inches of rain possible overnight into Thursday morning.
The National Weather Service issued the watch through late Wednesday night, cautioning that heavy rain could cause flooding in low-lying and urban areas. It is in effect for Baltimore City and Baltimore, Howard, Anne Arundel and Harford counties.
An inch or two of rain is forecast, with higher amounts possible in some areas, depending on where the bands of heaviest precipitation set up. A high pressure system is moving off of northern New England as a low pressure system moves in from the Atlantic and up the coast.
Forecasters said the watch could be extended into early Thursday morning.