A foot of snow is expected on Boston, 12 to 18 inches is forecasted to fall in MetroWest and the Merrimack Valley, with the Cape and islands due for a smaller dose of between 4 and 6 inches. The National Weather Service estimated wind could reach 50 miles per hour inland and 65 miles per hour along the coast amid the heavy snow. Thundersnow and coastal flooding could also accompany the storm. National Weather Service officials said there also is a winter storm watch for a larger area that includes much of New Jersey, Pennsylvania, upstate New York and New England. “It’s a noticeable difference. It’s going to be a cold week,” said Brian Hurley, a meteorologist. New York Gov. Andrew Cuomo announced Sunday that the New York State Emergency Operations Center will be activated Monday evening, with stockpiles of sandbags, generators and pumps at the ready.