Tropical Activity Peak Explained
The Atlantic tropical storm season began early in the summer at the beginning of June but the most active period occurs much later from mid-August to mid-October. This period accounts for 87 percent of the category 1 and 2 storms and 96 percent of the major hurricanes classified at or above category 3. September 10 marks the peak of Tropical storm activity in the Atlantic based on the number of storms over the past 100 years.
Why now? Think of a hurricane as a fire. A fire only starts when a small flame from a match sets it off. A hurricane needs a disturbance to start off as well. Usually these are thunderstorms off the western coast of Africa, and during the later summer period there tends to be more disturbances to light up a hurricane.
You can’t have a fire without something to burn, hurricanes need warm surface water in order to survive and grow as well-like wood. Water in the Atlantic slowly heats up throughout the summer, providing more wood for the fire.
Finally and most importantly, a new fire cannot survive if there is too much wind which tears it apart. Those disturbances off Africa cannot survive and strengthen to become fledgling hurricanes if there is too much wind shear which will pull the storms apart. Wind shear decreases throughout the summer before reaching its minimum in late August.
It just so happens that the late summer and early fall months are most conducive to tropical storm formation when all of these elements come into play together: increased disturbances, warmer sea surface temperatures, and low wind shear.
September 10 is just the statistical day in which you are most likely to see a tropical storm in the Atlantic, but at the moment there are currently none to be seen. Though the peak will pass soon, the season is not yet over.