Hurricane Matthew

**Hurricane Matthew** was the strongest hurricane of the active 2016 Atlantic hurricane season which ended the record nine-year lull in which a Category 5 hurricane was not active in the basin. It was the southernmost Category 5 ever recorded in the North Atlantic, beating Hurricane Ivan of the 2004 season. Matthew formed near the Windward Islands, before traveling westward trough the Caribbean Sea and later emerging into the western Atlantic. Matthew made landfall in South Carolina October 8 and was one of two hurricanes to make landfall in the U.S. in the season, Hurricane Hermine being the other.

## Meteorological History

On September 22, the National Hurricane Center (NHC) noted the probability of a tropical cyclone developing near the Lesser Antilles in the next five days. The tropical wave was designated Invest 97L and had a high chance of development by September 26. On the afternoon of September 27, a reconnaissance aircraft visited 97L and found winds near tropical storm force, but no well-defined closed circulation was present. The tropical wave got better organized overnight, and by early on September 28 it had acquired winds of tropical storm force. That morning, another Hurricane Hunter reconnaissance aircraft visited 97L, finding winds of up to 60 mph. A developing circulation center was found, and this was the basis for the National Hurricane Center initiating advisories on Tropical Storm Matthew at 15:00 UTC on September 28, already possessing winds of 60 mph despite a high minimum pressure of 1008 millibars.

Matthew's circulation center continued to become better defined as it passed through the Lesser Antilles. A strong convective burst occurred as Matthew emerged into the Eastern Caribbean Sea, but only slight intensification occurred that afternoon, due to the storm's fast movement and lack of an inner core. Around 12:00 UTC on September 29, winds of Matthew increased to just under hurricane force, but the circulation nearly became exposed. Shortly after Matthew's circulation became exposed, a new burst of deep convection began right over the center, and at 18:00 UTC that same day, Matthew strengthened into a category 1 hurricane. Later that evening, Matthew began to develop an eye feature, signaling the onset of intensification.

Explosive intensification began early on September 30 as the hurricane was moving westward in the typically unfavorable Eastern Caribbean Sea, despite an estimated 20 knots of vertical shear. At around 05:20 UTC that day, reconnaissance aircraft confirmed Matthew had strengthened into a category 2 hurricane, with winds of 100 mph and a pressure estimated at 979 mbar. Matthew developed an elliptical-shaped, but not very visible, eye around this time. Also, it began to develop a "blob" of deep convection to the east of its main eyewall. At 15:00 UTC that day, with a warming eye now becoming visible and dropsondes reporting winds near 100 kt, Matthew strengthened into a category 3 major hurricane, the second of the season. Several reconnaissance aircraft monitored Matthew's rapid intensification that afternoon. Based on reconnaissance data supporting an upgrade, Matthew reached category 4 status at 21:00 UTC on September 30. Around this time, the eye of the hurricane became very visible and cleared out. At 03:00 UTC, based on a Dvorak Raw T-number of over 7.0 and SFMR wind estimates of 143 and 138 kt, Matthew was upgraded to a category 5 hurricane with maximum sustained winds of 160 mph, the first since 2007. Despite being a category 5, Matthew had an unusually high pressure for this intensity at 941 mbar, which is more commonly seen in category 4 hurricanes. Matthew became the lowest latitude category 5 hurricane (reaching the intensity at 13.3 degrees latitude) in the Atlantic basin's history, surpassing Hurricane Ivan of the 2004 season. Matthew's intensification marked a 70-knot increase in a 24-hour period (from a category 1 to category 5 hurricane).

After reaching its peak intensity in wind speed, Matthew began to fluctuate in intensity. Matthew's eye contracted and became less visible on satellite imagery early on October 1, and Matthew was promptly downgraded to a category 4 hurricane at 09:00 UTC that day. Matthew's intensity fluctuations continued as the hurricane slowed down its movement in the central Caribbean Sea, eventually wobbling around before later beginning a northward movement.

## Retirement

In March 2017, the World Meteorological Organization (WMO) retired the name Matthew and replaced it with the name *Martin* for the 2022 Atlantic hurricane season.