A flash flood watch has been issued through Thursday night for the possibility of flooding along with any strong rain showers that could move through the area overnight.

The National Weather Service said the flood watch – which means conditions are favorable for flood conditions – started at 4 p.m. on Thursday and runs through Friday morning.

It covers Middlesex County, including Reading and North Reading, plus most other counties in central and eastern Massachusetts and a portion of Rhode Island.

Sudden heavy downpours will occur with any thunderstorms late (Thursday) afternoon and tonight,” the weather service said in issuing its watch. “Rainfall of 2 to 4 inches are possible within a short period of time.”

The heavy rain “may result in significant urban and poor drainage flooding,” and small streams may also rise out of their banks, the weather service said.