In November, most people up north are bundled up in warm clothes, beginning to scrape ice off their cars and turning on their fireplaces. Not a thought about destructive hurricanes enters the mind — and for good reason.
While down here in Mérida we are around 80°F outside right now, enjoying fantastic warm weather and saying good bye to another hurricane season. Most Meridanos remember Gilberto (1988) and Isidoro (2003) as two of the strongest ones to hit the state capital in recent history.
According to Dan Kottlowski, AccuWeather’s chief hurricane expert: “November is not known for its tropical activity,” . Hurricane season in the Atlantic basin officially starts on June 1 and doesn’t end until Nov. 30.
“By November, the westerlies are well entrenched across the southern U.S. and into the northern Gulf of Mexico,” he explained, referring to the prevailing winds from the west toward the east in the middle latitudes. “The only opportunity for tropical development is in the southern Gulf of Mexico and over the Caribbean. Even there, strong vertical wind shear can make it rather difficult for tropical formation.”
November hurricanes have been rare historically because the warm ocean waters begin to cool at the same time the atmosphere experiences changes in wind shear in the Northern Hemisphere. The result: Conditions become less favorable for tropical development.
“Since 1995, sea surface temperatures have averaged above normal across the Atlantic Basin through November, and the central Atlantic has been no exception,” Kottlowski said. “Since we now have much better satellite data over the Atlantic, it’s easier to catch late-season and short-lived tropical cyclones in the central and far eastern Atlantic. Rina of 2017 was a good example of this.”
But hurricanes in November, rare as they may be, are certainly a real possibility. Just this year, forecasters kept a close eye on Tropical Storm Sebastien, which flirted with becoming a November hurricane as it swirled over the open Atlantic before it fizzled.
According to data from NOAA’s Atlantic Oceanographic and Meteorological Laboratory, for the years from 1851 to 2018, 47 total hurricanes have formed in November and only five of those made landfall in the United States. The data sets show September has been the month with the most hurricanes out of any other month in the Atlantic basin, with a total of 406 hurricanes from 1851 to 2018 — 44 of which made landfall on U.S. shores since 1950.