1821 Norfolk and Long Island Hurricane - Meteorological History

Meteorological History

A tropical cyclone was first observed on September 1 off the southeast coast of the United States. Initially, it was believed to be the same storm that struck Guadeloupe on the same day, though subsequent research indicated there were two separate storms. The hurricane tracked by the Bahamas while tracking generally northward, and it attained major hurricane status over the western Atlantic Ocean. As it approached the United States coastline, the hurricane was very intense, with winds estimated at over 135 mph (215 km/h) and potentially as strong as 160 mph (260 km/h), or a Category 5 hurricane on the Saffir–Simpson Hurricane Scale. Late on September 2, the hurricane made landfall near Wilmington, North Carolina and later turned to the northeast to cross the Pamlico Sound.

The hurricane accelerated northeastward, and passed over the Hampton Roads area early on September 3. After crossing the Chesapeake Bay, the cyclone traversed the Delmarva Peninsula near the Atlantic coastline, and at around 1500 UTC the eye passed directly over Cape Henlopen, Delaware; a thirty minute period of calm was reported. It continued across the Delaware Bay and later passed over Cape May, New Jersey, where a fifteen minute calm was reported. Modern researchers estimate it was a Category 3 or Category 4 hurricane upon striking New Jersey, one of the few hurricanes to hit the state. Moving ashore at very low tide, it paralleled the state's coastline just inland, and after exiting into Lower New York Bay the hurricane made landfall on New York City at around 1930 UTC on September 3; this makes it the only major hurricane to directly hit the city. A minimal hurricane in 1893 also made landfall on New York City. One modern researcher estimates the hurricane was moving at a forward speed of 35 mph (55 km/h), and upon moving ashore had a pressure of 965 mbar. The hurricane continued northeastward through New England, and after entering Massachusetts on September 4 its exact path was unknown; one researcher estimated the cyclone tracked northeastward until losing its identity over southeastern Maine, while another assessed the storm as passing far to the west of Maine.

Based on the arrangement of effects in New England, meteorologist William C. Redfield deduced that the wind field and center of tropical cyclones are circular; previously the winds were believed to be in a straight line.