From accuweather NOT 80's:

http://www.accuweather.com/en/weather-news/new-york-philadelphia-mild-and/2544393

New York, Philadelphia Mild and Wet, Then Colder

December 10, 2012; 6:25 AM

Temperatures will climb to October-like levels over the mid-Atlantic and southern New England on Monday as a rainy cold front rolls across the Appalachians.

A few thunderstorms will erupt as far north as central New Jersey, but rain will fall most steadily along the central Appalachians to central and northern New England. Near the coast, the mid-Atlantic may have no more than a shower during the day.

Readings will rival record highs in reaching about 61 degrees in Boston, 63 degrees in New York, 67 degrees in Philadelphia and 69 degrees in Washington, D.C.

In Washington, D.C., the standing record high of 67 degrees, set in 1966, will face strong challenge. The record maximum of 64 degrees in Boston, last reached in 1907, may also be in play. Less likely to fall are the official highs of 70 degrees in New York and of 71 degrees in Philadelphia.

 

Behind the cold front, temperatures will tumble first along the Great Lakes and Ohio Valley. The leading edge of the cold will leap-frog the Appalachians in the wake of the front Sunday night and Monday, shaving about 15 degrees off big city high temperatures versus Sunday.

By Wednesday, temperatures will end up within the normal range for the second week of December.