Thursday, June 16, 2016

Tropical Cyclone Season Is Underway

Hurricane Alex in January 2016
The season for tropical cyclones in the Atlantic begins June 1 and ends December 1. Here we are two weeks into June and we've already had three this year. El Nino has apparently been snuffed out and La Nina has not yet reared its head. A La Nina pattern may develop as early as late summer or early Fall. In this situation, sea surface temperatures in the equatorial Pacific usually run below normal as opposed to the above-normal temperatures of an El Nino pattern that we've seen in the past couple of years. We are currently experiencing a neutral pattern that may continue over the next several months. This is often associated with a more active Atlantic hurricane season and a less active eastern Pacific cyclone season. After the devastation caused by cyclones in Vanuatu and Fiji, that will be welcome news in the Pacific.

But what does more active season mean to us in the Atlantic? Our first hurricane in 2016, Hurricane Alex, a category 1 storm, was way back in January. It roared across Bermuda and the Azores. The last time a hurricane formed in January was in 1938, so it is quite rare. Hurricane Pali developed over the Central Pacific in early January, and persisted through the formation of Alex. This marked the first known occurrence of simultaneous January tropical cyclones within the two basins. Since Alex, there have been two additional tropical cyclones in the Atlantic, Bonnie formed in May off the SE coast of the US and Colin formed in early June in the Gulf of Mexico.

Despite three named storms early in the year, NOAA has predicted a near normal hurricane season, with a 70% likelihood of 10-16 named storms in the Atlantic and 13-20 in the Pacific. As the last three years had a lower than normal season in the Atlantic, that means we should expect more cyclones than we had last year.

But it appears to be a highly unpredictable year. There is uncertainty about whether the high activity era of Atlantic hurricanes, which began in 1995, has ended. This high-activity era has been associated with a warm temperature phase of the Atlantic Multi-Decadal Oscillation or AMO. However, during the last three years weaker hurricane seasons have been accompanied by a shift toward an AMO phase marked by cooler Atlantic Ocean temperatures. If this shift proves to be more than short-lived, a new era of low-activity for Atlantic hurricanes may already have begun. High- and low-activity eras typically last 25 to 40 years.

I for one am hoping that a period of low storm frequency has arrived. Nevertheless, it pays to be prepared and to review hurricane preparedness strategies now before you need to deploy them. Here's a plan I wrote for our situation that may help you think through yours.

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