Once those pellets are too heavy to remain in the air, they fall - as hail. So, it was sleet ticking against your window panes Wednesday night, and not hail. A phenomenon known as cold air damming will help produce a wintry mix tonight as some snow, ice and rain spread over the region. Cold air damming develops when a cold dome of high pressure settles over the northeast. The clockwise circulation around the high banks cold air up against the slopes of the Appalacian Mountains.
Warm air begins to override the cold air at the surface.
Because this warm air aloft is lighter than the cold air, the cold air gets trapped in the valleys. The winds are really going kick up on Tuesday with the passage of a cold front. Wind chills will be in the 20's in the suburbs, but in the teens in the city. Out in the open, the wind has a certain speed as it flows freely across the countryside. If no other forces are acting on the wind, it will maintain its speed and wind chills will remain constant.