What does an Active Hurricane Season Mean for Antigua?

9 05 2022

Dale C. S. Destin |

The early forecast is for the 2022 Atlantic hurricane season to be an active one or above normal. What could this mean for you? Will Antigua be affected by a named storm (tropical storm or hurricane)?

What is an active or above normal hurricane season? This is a season with the accumulated cyclone energy (ACE) index in the top third of the 1991-2020 dataset, or an ACE of 152 or higher. The ACE is a metric that takes into consideration not only the number of named tropical cyclones (subtropical storms, tropical storms or hurricanes) but also their strength and duration.

Given the forecast for an active hurricane season, there is a 43 percent chance/probability of a named storm passing within 105 nautical miles of Antigua or affecting (hitting of brushing) us. This translates into a named storm return period of 2 to 3 active years or a named storm affecting us every 2 to 3 active years, on average. Our last named storm during an active year was Tropical Storm Laura of 2020. This means statistically we are not due one this year, if the season turns out to be active, as forecast.

With an active season forecast, a named storm has a 28 percent probability of affecting us as a hurricane and an 18 percent probability of affecting us as a major hurricane (Category 3 or higher). On average, we get a hurricane passing within 105 nautical miles of Antigua every 3 to 4 active seasons and a major hurricane every 5 to 6 active seasons.

Our last hurricane during an active season, which was also a major hurricane, was Maria of 2017. It did not cause us hurricane winds, but it passed within 105 nautical miles to our southwest, affecting us with storm-force winds. Given we average a hurricane every 3 to 4 active years, and there has been only one active season since then, 2020; statistically, this means we are NOT due for a hurricane this year. Additionally, we are also NOT due a major hurricane this year.

What if a season is not active? For a near normal season, the chance of us being affected by a named storm drops to 23 percent and the chance of that named storm being a hurricane plummets to just 3 percent. If by some miracle, the season is below normal, the chance of a named storm passing within 105 nautical miles from Antigua is 21 percent with a 6 percent chance of it being a hurricane. For non-active seasons, near or below normal, we stand a zero percent chance of getting a major hurricane.

A tropical storm or hurricane not being due does not guarantee one will not occur. The fact that the probability of a named storm in any given year is not zero means that one could occur in any year, despite not being statistically due. An event with a given return period is said to be not due when the average return period has not yet elapsed. Because this is an average return period, the event can happen at any time before or after the return period.

Annually, based on the standard climate period of 1991 to 2020, taking all seasons into consideration, there is a 66 percent chance of a named storm affecting Antigua. Further, there is a 35 percent chance of the named storm being a hurricane and an 18 percent chance of it being a major hurricane.

Tracks of all 31 named storms to have passed within 105 nautical miles of Antigua, 1991 to 2020

Active hurricane seasons are generally not good for us, which may not come as a surprise to you. What may be new here are the relatively high chance of us being affected during such a season, which the forecast is calling for this year.

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