How Rare Are November Hurricanes?

November weather in most of North America is synonymous with chilly breezes rustling through red, yellow and orange leaves. It is usually not a time when people associate tropical storms with the U.S., but that is what is happening with Tropical Storm Nicole, which is expected to make a direct hit on Florida.

The official Atlantic Hurricane season lasts through November 30 and is less frequent at this time of year. During the blockbuster 2005 season, there was a storm that formed on December 20 and lasted until January 6.

When atmospheric and ocean conditions are most suitable for storm formation is when the season begins. When ocean warmth coincides with wind conditions that are more favorable to storm formation, the season peaks at the end of August through October. Once November 1 hits, storm activity begins to decline, according to a researcher. Ryan Truchelut, a co-founder of WeatherTiger, a private weather-forecasting group, says November is the quietest month of the year. He says that there have been only 10 tropical storms and three hurricanes in the U.S. over the last 150 years.

Some years are not normal. There were three November storms in 2005. November was crazy in 2020 due to the warm waters in the Caribbean. Two weeks later, another category 4 storm, Iota, hit the country.

The storms that form in November tend to be less powerful than the ones that don't. The solar energy in the Northern Hemisphere goes to the Southern Hemisphere as fall progresses. The warmth farther south causes the polar jet stream to strengthen and send cold air southward. These incursions increase a feature called wind shear, when winds vary in speed and direction at different levels of the atmosphere, and that in turn disrupt the convection at the core of tropical systems that powers them

Nicole's winds cover a large area and are expected to bring storm surge to the east coast of Florida. Surge amounts will be amplified by higher-than-normal high tides.

In the past, any November storms that hit the U.S. tend to hit Florida because they form in the western Caribbean. Kate was a category 2 storm when it hit the Florida Panhandle in 1985. Nicole will set a new record for the most storms in a single season. The previous record was held by the Yankee Hurricane, which hit Miami Beach in 1935.

As climate change brings warmer ocean waters, the question of whether late-season storms will become more frequent will be raised. He co-authored a study that looked for evidence that the season might be growing longer. Evidence was weak for the end of the season despite the fact that the season is starting earlier. He notes that it is hard to get a trend for rare events.

People living in areas prone to hurricanes need to be prepared to act on forecasts even after the peak of the season has passed. It's important to drive to that point.