Post Mortem 2015

In general, the 2015 Atlantic basin hurricane season was correctly predicted to be below average by most organizations. Most forecast models called for a strong El Niño to develop during the summer of 2015, and this prediction verified. Eastern and central tropical Pacific sea surface temperatures were at near-record warm levels during August-October, the peak months of the Atlantic hurricane season. Associated with El Niño were very strong upper-level winds that produced extraordinarily strong vertical wind shear in the Caribbean, suppressing storm formation in this area. This strong shear extended far enough east in the tropical Atlantic that any tropical cyclones that did form tended to get sheared apart as they approached the Lesser Antilles.

The primary story of the 2015 Atlantic hurricane season was Hurricane Joaquin. Joaquin generated near half of the Accumulated Cyclone Energy that occurred in 2015. This system formed from a non-tropical area of low pressure and strengthened to a strong Category 4 hurricane. It devastated portions of the central Bahamas, but fortunately, no one on the islands died. Unfortunately, Joaquin was responsible for the sinking of the ship El Faro, killing all 33 people on board. Joaquin’s moisture combined with a mid-latitude system to produce copious amounts of flooding in South Carolina as well.

A much more thorough verification of the 2015 Atlantic hurricane season is available from Colorado State University’s website.

Hurricane Joaquin seen in the Atlantic Ocean North of Bermuda on October 5, 2015. Credit: NOAA/NASA