Then there's the temperature of the ocean.
As for the great storm that hit Britain in 1987, the one BBC weatherman Michael Fish told viewers the night before that there wouldn't be, that wasn't strictly a hurricane.
Lack of wind shear in the atmosphere?
Hurricane Florence's eye wall has grown since yesterday, now measuring approximately 35 to 40 miles (48 to 56 kilometers) in diameter, according to a report issued this morning (Sept. 11) by the National Hurricane Center (NHC). Rain will continue through Sunday, dumping feet of water over a wide area. "As the air far above the sea rushes upward, even more warm moist air spirals in from along the surface to replace it".
If these projections hold, University of Miami hurricane researcher Brian McNoldy says "it's exceptionally bad news, as it smears a landfall out over hundreds of miles of coastline, most notably the storm surge".
Look to the northeast of that storm, and you'll find two more systems.
"It wants to get stronger", he said of the storm. This year's season had been relatively quiet in the Atlantic Basin up to recently, but there has been an increase in activity in the last while, with a number of tropical disturbances live at present. "The models indicate it will travel up the west side of the United Kingdom, before crossing Scotland and going out the north of Scotland, but that could change as the storm degrades and changes its habits". The government of France has discontinued the Tropical Storm Watch for St. Martin, and the government of St. Maarten has discontinued the Tropical Storm Watch for St. Maarten.
Elsewhere on the planet, the patterns are different.
It's called a typhoon if it occurs in the Northwest Pacific.
"Life-threatening flash flooding is possible with Isaac".
What qualifies as a tropical cyclone?
Chris Landsea, chief of the analysis and forecast branch, told the Associated Press that such waves are entirely possible within the storm, but there's also a chance "radar misinterpreted rain as an 83-foot wave".
Current paths show Florence making landfall near Wilmington, N.C., before tracking inland.