A Nor’easter is a term used to describe storms that travel northeast, often over the United States. There are scenarios in which warm air from a hurricane might contribute to the formation of a Nor’easter or Nor’easter-like conditions. For example, 2012’s Hurricane Sandy combined with polar jet stream air to create Nor’easter conditions. That’s why Hurricane Sandy essentially caused a blizzard over the Appalachian Mountains and dropped one to three feet of snow over more than half of West Virginia.
However, most Nor’easters are not caused by hurricanes. Hurricanes form near the equator, while the majority of Nor’easters form in the latitudes between New Jersey and Georgia during the winter.
The polar jet stream sends cold air from the arctic south through central North America. As that jet stream runs into warm air closer to the Gulf of Mexico it begins moving east, and then north once it nears the warmer air over the Atlantic. The Gulf Stream keeps the Atlantic warmer even during winter. The cold arctic air combined with the warm Gulf Stream air is what powers Nor’easters.
Yes – they’re technically called “synoptic-scale extratropical cyclones.” This is different from a hurricane, which is a “tropical cyclone.” Both are cyclones but they develop in different parts of the Earth due to different weather factors.
Both often develop over the Atlantic, except Nor’easters develop much further north than hurricanes. They are also their most intense around New England or the East Coast of Canada instead of in the Caribbean or Gulf of Mexico, where you’ll never find a Nor’easter.
When eastward moving jet stream air reaches the east coast, it creates an area of low pressure. This area of lower pressure can form inland or over the water, where it’s pushed north or northeastward.
Although Nor’easters typically form near the coast these can be massive storms with big rotations that drop heavy snows all along the Appalachian regions of the United States and New England.
Although Florida is highly susceptible to hurricanes, we generally aren’t heavily impacted by Nor’easters. The polar jet stream swings northeast by the time it reaches near the Gulf of Mexico, which means it mostly passes Florida by. Nor’easters also develop either parallel with or most often to the north of Georgia.
No – Nor’easters can be windy, but they aren’t windy on the same level as hurricanes. They’re instead measured with the Northeast Snowfall Impact Scale (NESIS), which is based on square miles affected, snowfall and population effected.
There are still five categories on NESIS:
A category one storm would only affect a relatively small area while a category five can affect large swathes of North America. There have only been two Category 5, or “Extreme,” Nor’easters since the NESIS system was implemented – one in March 1993 and another in January 1996.
The 1993 storm actually did drop between one to four inches of snow on parts of Florida’s panhandle, but the heaviest snows of that storm were over the Appalachian Mountains in West Virginia, Pennsylvania and New York. The path was similar for the 1996 storm, except it was more concentrated between the Virginias, Maryland, Southeastern Pennsylvania and New Jersey.
Very common. For much of the winter there are Nor’easters of various strength dropping snow in New England and Appalachian states. As of October 27, 2021, there’s an active Nor’easter that’s knocked out power for nearly 300,000 residents of Massachusetts, Rhode Island and New Hampshire. The storm brought wind gusts measuring up to 85 mph and sparked a state of emergency in New York and New Jersey.