It was Maine's first hurricane watch in 17 years, the National Weather Service said. Elsewhere in New England, a hurricane warning was posted for Nantucket Island off the coast of Massachusetts in September 1996, according to the weather service office in Taunton, Mass.
Two to 4 inches of rain had already fallen along some coastal areas by midday Saturday, and the storm was expected to deliver an additional 2 to 4 inches, said Eric Schwibs of the weather service in Gray.
At 5 p.m. EDT, Kyle was centered about 315 miles west-northwest of Bermuda and 485 miles south of Nantucket, Mass., the National Hurricane Center said in Miami.
The storm had top sustained wind near 75 mph and became a Category 1 hurricane Saturday afternoon. It was moving north over the open Atlantic at 23 mph.
Kyle's center was forecast to be near eastern New England or the Canadian Maritime provinces late Sunday, the hurricane center said.
The hurricane center posted a hurricane watch from Stonington, at roughly the center of the Maine coast, to Eastport, on the border with New Brunswick, Canada. A tropical storm warning extended from Port Clyde, about 50 miles northeast of Portland, to Eastport.
A hurricane watch means hurricane conditions, with winds of at least 74 mph, are possible within 36 hours. A tropical storm warning means conditions for that type of storm, with winds of 39 to 73 mph, are expected within the next 24 hours.
Kyle could make landfall near Eastport, possibly late Sunday, the hurricane center said.
That would put the storm's strongest wind in New Brunswick, rather than in Maine, which would get conditions more akin to "a garden variety nor'easter," Schwibs said.
The government of Canada issued a hurricane watch and a tropical storm warning for southwestern Nova Scotia, and a tropical storm watch remained in effect for the rest of Nova Scotia and southwestern New Brunswick.
The weather service also issued flood watches for the southern two-thirds of New Hampshire and southern Maine through Sunday evening.
McAleer said the storm's biggest threat in Maine would be the potential for high waves and small stream flooding.
"We urge everyone to pay close attention to weather warnings, and stay away from any flooded roadways, or fast-running streams," McAleer said.
The Coast Guard prepared crews and equipment for the storm and urged boat owners to secure their vessels in anticipation of high wind and seas that could run 10 to 20 feet high off shore.
Eastern Maine's power company, Bangor Hydro-Electric, said it prepared for potential outages and planned to have additional crews on duty.