GFS of 06z,Monday valid till 24hrs showing both the systems.
Low pressure is seen North East USA and High pressure over the North Central USA.
Severe Weather Forecaster
North East USA is going to experience the blast of cool air as High pressure-Low pressure system brings this effect. A high pressure North Central states which previously was in CANADA will center over North Central USA laying over Iowa.A low pressure which at present is in Atlantic will move inland in next 24hrs at the extreme North East of USA. As these two pressure systems begin to interact, very cold arctic air will be pulled towards the low pressure area resulting in a Blast of cool air over Mid Atlantic states.
Minimum temperatures will drop more as the high pressure skips to Canada and bringing a direct wind from North in these states. Temperatures will be near 20F or -6C in areas like District of Colombia,Maryland,Northern and Eastern Virginia,New Jersey.
So 06,07,08,09th Dec will be very cold.