The Atlantic gradually begins to slow down in activity in October in a majority of years, but the month has seen its fair share of strong hurricanes. The month of October, on average, sees two named storms form in the Atlantic, with one becoming a hurricane and a major hurricane forming about once every two years. Although October is generally less active than September, six of the last seven Atlantic hurricanes have had their strongest storm peak in intensity in October. The month of October has featured several Category 4 or stronger hurricanes forming in or lasting into the month in recent years: Ophelia (2011), Gonzalo (2014), Joaquin (2015), Matthew (2016) and Nicole (2016). In fact, the strongest Atlantic hurricane on record in terms of minimum central pressure – Hurricane Wilma in 2005 – reached its peak intensity on October 19, with maximum sustained winds of 185 mph and a minimum central pressure of 882 mb.

The typical hotspots for October tropical cyclogenesis in the Atlantic basin are the western Caribbean Sea and the subtropical western Atlantic. Tropical cyclogenesis also occurs in the Gulf of Mexico, especially the Eastern Gulf of Mexico, on occasion during October. Usually during the month of October and beyond, increasing wind shear and a southward retreating Intertropical Convergence Zone (ITCZ) limits activity in the deep tropics east of the Lesser Antilles. The primary hotspot for major hurricanes in the Atlantic basin in October is the Western Caribbean. However, somewhat unusually, there has not been a hurricane in the western Caribbean Sea in October since Sandy in 2012. The “classic” October hurricane track results in a tropical depression forming in the southwestern Caribbean Sea, before getting turned northeastward by a trough and passing near or over Cuba and South Florida. Florida is at, by far, the greatest hurricane risk for the month of October, especially South and West Florida. Since 1950, there has been a total of 14 United States hurricane landfalls in the month of October, eight of which were in Florida. The most recent U.S. hurricane to make landfall in October in the United States was Hurricane Matthew on October 8, 2016, which made landfall in South Carolina. There is a secondary peak of Atlantic hurricane activity around October 20 – and most of this activity is largely clustered to the Western Caribbean Sea. Hurricane season is not over yet, and residents in hurricane prone areas should remained prepared. This season has been brutal, and it still has nearly two months to go.

October is generally more active in ENSO-neutral and La Niña years – in El Niño years, wind shear usually increases quicker and sooner, often shutting down the basin by the end of October, though this is not always the case. 2017 is shaping up to be a cool-neutral to Weak La Niña winter, so chances of an active October in the Atlantic basin are higher than average this season.

The last Atlantic storm does not dissipate, on average, until November 5, according to The Weather Channel. Although the peak of the season has likely passed, I expect to see an additional two to four named storms form in the Atlantic this season, with the possibility of one to two hurricanes and one major hurricane.

I will be back with another post tomorrow on the possibility of a tropical disturbance forming in the Northwestern Caribbean Sea later this week.