Weather Facts



What is a Noreaster?

Noríeasters are low pressure areas (extra-tropical storms) that develop along the southeast coast and move northeastward along the coast bringing copious amounts of rain and/or snow to the eastern seaboard. (Some folks call them "Northeasters") They normally occur from October through April, but they can occur outside of that period. The reason that these storms are sometimes so severe is that they draw their energy from several sources. First, the difference in temperature from northwest to southeast during the colder months of the year is quite extreme along the east coast. Second is the Gulf Stream, which is the ocean current off the east coast that brings warm water northward. The Gulf Stream enhances the east coast storms, as it provides the energy and moisture needed for the storm to grow into a monster and it causes a large temperature gradient near the east coast. Large areas of precipitation develop to the northwest, north, and northeast of the low center. Noríeasters are responsible for producing the blizzards from the Mid-Atlantic States through New England. Winds can gust to hurricane strength during intense Noríeasters. Coastal flooding and beach erosion usually occur which can cause property damage. The exact track of a noríeaster determines the precipitation type and how bad the storm will be in a given area. However, to be a true noríeaster, the storm has to move along a northward or northeastward track just east of your location. If the storm moves to the west of your location, the winds may be out of the northeast initially, but your winds will turn to the southeast and eventually the southwest as the storm gets closer. There are several different scenarios on the weather map that cause these storms to develop. I wonít go into the technical details, but they can be from lows that start developing in the Gulf of Mexico and then move to a position off of the southeast coast. Some noríeasters develop as energy is transferred from a weakening storm moving through the Ohio Valley. The energy transfers to the coast and then the storm ìbombsî, which means it intensifies rapidly when it ìfeelsî the effects of the Atlantic Ocean. Upper level winds must be favorable for a nor'easter to form and to grow into a major storm. In 1998, the Hampton Roads area was impacted by two noríeasters causing very high tides, coastal flooding, and severe beach erosion. Winds were very strong during those storms. The March 1962 noríeaster is probably the worst storm of its type to hit the Mid-Atlantic area in recorded history.

Dave