A major winter storm from the Gulf States will be picked up by an energetic upper-air feature (a short wave with cold air aloft (a long wave is the kind that can cover much of a continent, but it often has a number of shorter waves traveling through it)) to develop a storm that strengthens on its way up the East coast. There is still some model wobble on the location of the snow/rain line at the height of the storm. This is a very big deal in a storm like this because in places where snow changes to rain, it can be snowing 1-2 inches an hour before the changeover. If a forecaster misses the timing by 3 hours, that can mean a 3- to 6-inch forecast error on accumulations. This video shows two of the model ideas from last night. The GFS (U.S. model) had taken the storm out to sea 24 hours earlier but has since trended toward the European model idea, which has changed little from run to run.
This is a draft of our accumulation forecast from this morning. Note how a shift in the storm path by 50-100 miles will have major consequences in the accumulation department. From a big picture standpoint, any storm that can affect places from Atlanta to Atlantic Canada with snow and ice will cause major disruptions.
(2) is an area of showers and thunderstorms with no defined circulation. This disturbance may follow the same general path as (1).
If correct, cooler, drier and more comfortable weather will take over in the Northeast as we go into the holiday weekend, then warmth and humidity would increase as we go through next week. This map matches that scenario.
that short wave is what the models latch onto in bringing a cold front through the Northeast Wednesday night and Thursday. This would bring noticeable cooling to the Northeast late in the week.
Labor Day is a week from Monday. The computer model used here, the GFS ensemble mean, suggests the weather will favor outdoor late summer activities across the Great Lakes and Northeast:
In response to heating at ground level and a weak cold front approaching from the west, showers and locally strong thunderstorms should develop across northern Ohio this afternoon.
... much greater interest is being generated on threats and rumors about tropical storms. It is worthwhile to read Dan Kottlowski's authoritative reports on this. Here is a copy of his map from this morning: