There’s a 67 percent chance that Maine’s summer lobster harvest will begin later than usual, according to the forecast issued Thursday by the Gulf of Maine Research Institute. The forecast has ramifications for both harvesters and the supply chain for Maine’s most lucrative seafood.

A week ago, the Gulf of Maine Research Institute said there was a 69 percent chance that the harvest will begin later than usual. The institute plans to issue its forecast every Wednesday through April.

This winter’s below-normal temperatures and stormy weather have cooled the waters in the Gulf of Maine. That means lobsters, which spend their winters in deeper waters offshore, will likely get a late start migrating to the coast and shedding their shells, according to scientists at the nonprofit research institute.

The forecast is based on 13 years of data on lobster landings and water temperatures measured at 50 meters – about 164 feet – below the surface at four buoys off the Maine coast, from southern Maine to Down East.