What's a nor'easter?

Dateline article| David Murphy|

by David Murphy

A Nor'easter is a winter storm that passes by the Delaware and Lehigh Valleys, just off the coast of the Jersey and Delaware shoreline. The storm often forms to our south in the vicinity of the Carolinas and charges up the coast, intensifying as it nears our region. The counter-clockwise circulation around the center of the storm generates strong winds out of the northeast, thus the name nor'easter. These winds force relatively warm and moist air into our area from over the ocean, which clashes with cold Canadian air sweeping down from the northwest. It can be a volatile combination. Nor'easters are usually the sources of our worst winter snowstorms, capable of immersing us in more than a foot of snow, sometimes more than two feet! Most blizzards in our area are caused by nor'easters.

At the shore, we generally see less snow, but plenty of flooding and pounding surf that leads to beach erosion and occasional property damage. Again, this is all because of the intense onshore winds generated by the passing storm.

Wind gusts from nor'easters can sometimes reach tropical storm force (74 mph), although 50 to 60 mph gusts are more common. As the storm lifts away to the northeast, a drier but rather bitter and windy day usually follows, as Canadian air rushes-in from the northwest behind the departing storm. We often see sun on this day after, but nobody wants to be outside for long because of bitter wind chills.

By the way... similar storms occur outside of the winter season on occasion, either in the spring or fall. For lack of a better term, we sometimes refer to these as out-of-season nor'easter's or spring nor'easters. Personally, I like the term coastal storm instead. True weather fans know that the actual definition of a nor'easter includes the wordswinter storm and that the threat of snow is part of what a nor'easter is all about.

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