Warmer weather will arrive this weekend, and perhaps help break up ice jams that are clogging parts of the Connecticut and Housatonic rivers.
But some riverside spots will see flooding, the National Weather Service warns.
Saturday’s temperatures will reach into the lower 50s in the Hartford area, and may dip below freezing and into the 20s at night, the weather service said.
Sunday’s high temperature will be in the mid to upper 40s, and the overnight low will sink to the upper 20s. There’s a chance for rain — and snow — Monday after 4 p.m.
The weather service said that as river ice begins to melt, some places will see flooding, and evacuations of low-lying areas along the Connecticut River in Cromwell and Portland may be necessary.
Flooding already has closed part of Route 17A in Portland, the state Department of Transportation said.
The Harbor Park area of Middletown, right next to the Connecticut River, also is expected to flood, the service said.
The Middle Haddam area of East Hampton, also on the Connecticut River, already has surpassed flood stage, the weather service said. And in Kent, where unprecedented ice jams on the Housatonic River and flooding made national news this week, Route 7, Schaghticoke Road and River Road are still closed.
The ice jams formed because of the extreme shifts in temperature. First, the recent unseasonably warm temperatures and rain melted snow, which swelled rivers. Meanwhile, river ice that had formed during the preceding arctic blast began to break up — but quickly refroze as temperatures again plummeted.
U.S. Coast Guard ice cutters have been dispatched to break up the ice on the Connecticut River and get the water flowing again.
And Haddam’s first selectwoman on Thursday asked the governor to declare a state of emergency in her riverside town.
Courant Staff Writer David Owens contributed to this story.