ASK TOM: Can you please explain what a nor'easter brings in terms of weather?

Dear Tom,

Can you please explain what a nor’easter brings in terms of weather?

— Marge Copson


Dear Marge,

A nor’easter is the colloquial name given to a strong low pressure system that moves up the East Coast from Georgia or the Carolinas to New England and the Canadian Maritimes. The name originates from the strong northeast winds that batter the coast with high waves, causing beach erosion and flooding. These storms intensify rapidly as they pass over the warm Gulf Stream waters with their central pressure often dropping more than 1 inch of mercury in 24 hours in a process forecasters refer to as “bombogenesis.” They usually occur in late fall and winter. The nor’easter also is responsible for most of the major snowstorms that affect the Eastern Seaboard.