The National Weather Service has posted a flood watch for Berkshire County, southern Vermont and northwest Connecticut extending through Saturday morning.
Forecasters in the NWS Albany office predicted heavy rainfall from Friday afternoon until dawn on Saturday, with a minimal risk of thunderstorms.
Total rainfall could range from 1.5 to 2.5 inches, enough to cause minor flooding along the Hoosic River in Northern Berkshire, specifically in Williamstown. The forecasters also warned of potential ponding of water on roadways, and flooding of poor-drainage and low-lying areas. Flash floods cannot be ruled out, they added.
The widespread soaking rainfall will be followed by a weekend cooldown with less humidity but a chance of occasional showers, especially on Sunday.
On Friday afternoon and evening, winds of 30 to 40 miles per hour are likely, with possible higher gusts. The heaviest rain in Western Massachusetts and southern Vermont is expected Friday night, according to forecaster Neil Stuart's early-afternoon outlook.