Upper-level disturbances can produce clouds and precipitation. Upper air disturbances can also make the atmosphere unstable by dragging cold air into the higher altitudes. How winter storms create different forms of precipitation . Cold air damming can cause severe ice storms east of the Appalachian Mountains. Overrunning causes much winter precipitation .
Northeasters are extratropical cyclones along the USA's East Coast.
Alberta clippers are a kind of winter storm November Witches often wreak havoc across the Great Lakes. Bomb cyclones are intense storms, often hybrid storms. Graphic explains center-jumping storms . Graphic shows conditions favoring development of MCCs Complex fronts, gravity waves Research is finding that cold fronts can be extremely complex. The following Web sites offer details, some highly technical, about cold fronts above the ground that often trigger heavy rain and thunderstorms well ahead of surface cold fronts.