Snow Sunday for Parts of Middle Atlantic States

Friday 10:10 a.m.

Any time you see a storm system that gives nothing in one place and an inch of water 150 miles away, you know there is a forecast challenge. If the storm track or size of the storm changes, forecasts have to be adjusted in a big way. There's always the question of whether to react to each new model or be more methodical about it by changing things incrementally. We also study the models versus real time weather maps, satellite pictures and radar observations. This video show the way the GFS portrayed things with its 1 a.m. EST Friday run.

This preliminary snowfall map will be reviewed continuously as the storm takes shape: