nor'easter, northeaster, Nor'easter, Northeaster
The word northeaster is sometimes capitalized as "Northeaster" and very often is spelled nor'easter to imitate the pronunciation of a wizened New England mariner.
Reference works define a northeaster as "a storm or strong wind from the northeast" (Webster's New World Dictionary, Third College Edition, which marks this word as an Americanism and gives a second "nautical" pronunciation of this word as "nor'easter") or as "a cyclonic storm occurring off the east coast of North America" (found by Google via "define:nor'easter").
The book The Complete Weather Resource, Volume 1 by Phillis Engelbert says (p. 137):
A northeaster, or "nor'easter" is a strong, northeasterly wind that brings cold air to the coastal areas of New England and the mid-Atlantic states, occasionally as far south as Florida. Nor'easters are generated by storm systems in the Atlantic. These storms develop or intensify off the eastern seaboard of North America and move to the northeast along the coast. The gale-force wind that spins off the storm is often accompanied by heavy rain, snow, or sleet.But this is not the meaning of nor'easter as the term is used in news and weather reporting today. Judging from how the word is used, a nor'easter (newsreaders are fond of the faux-nautical pronunciation) seems to mean any widespread snowstorm in the northeastern part of the United States, as far from the Atlantic as Ohio. The TV weather animation of the progress of a recent weather system described as a "nor'easter" showed it moving, like most weather in North America, from west to east, with a counterclockwise whirling pattern that produces winds from every direction, which makes it just as justifiable to call the storm a "sou'wester" or a "sou'-by-sou'easter" as a "nor'easter".
(December 8 & 10, 2003)