Heavy rains ended overnight, but the National Weather Service warned at 4 a.m. Friday that flooded roads, streams and rivers persist throughout much of Maryland.
At 2 a.m., the weather service issued a flood warning for southeastern Carroll County, Baltimore City, northern Anne Arundel County, eastern Howard County, Harford County, Baltimore County and northeastern Prince George’s County until 8 a.m.
Up to 1 inch of rain had already fallen at that point, with additional heavier rain expected to produce an additional 1 to 2 inches of rain.
Light showers began moving into the region Thursday afternoon, as a cold front that moved through overnight stalls southeast of the region. In the evening and overnight hours, a wave of low pressure moved in along the front and brought heavier rain.
The watch continued for portions of Central Maryland and Northern Maryland, including Anne Arundel, Prince George’s, northern and southern Baltimore, and northwest and southeast Harford counties.
Weather service meteorologists said even relatively light but steady rain could cause flooding given saturated ground and elevated streams and rivers.
“Although it seems a little unusual to be writing about the prospect of an inch of relatively slow rain to cause flooding issues, that’s the nature of this year when it comes to our flood potential,” they wrote in a forecast discussion Thursday afternoon.
A flood watch means there is a potential for flooding based on current forecasts. Residents should monitor later forecasts and be alert for possible flood warnings. Those living in areas prone to flooding should be prepared to take action should flooding develop.
Thursday’s rain brought the region’s rainfall streak to six days straight, and the 18th day so far this month. There has been more than 8 inches of rainfall at Baltimore-Washington International Thurgood Marshall Airport this month, almost enough to rank this September among the region’s top 10 wettest on record.
Baltimore is on pace for its wettest year on record, with more than 53 inches of precipitation so far this year.
And as of Wednesday, 2018 already ranks as Baltimore’s 10th-wettest year on record.
The weather service said rain is expected to stop Friday before 11 a.m. The forecast calls for partly sunny skies with a high near 72 degrees and northwest wind of 6 to 9 mph.
Friday night will be mostly clear with a low around 57. Saturday will be mostly sunny with a high near 72.