Hurricane Sarah

**Hurricane Sarah** was the eighteenth named tropical storm, twelfth hurricane, and record-tying eighth major hurricane, and second Category 5 hurricane of the 2018 Atlantic hurricane season. Sarah was the second strongest hurricane to ever have existed the Gulf of Mexico behind Hurricane Rita in 2005, and at the time of its occurrence, was the tenth most intense hurricane ever in the Atlantic Basin. After peaking in strength with 175 mph (280 km/h) sustained winds, it made landfall southwest of Morgan City, Louisiana on October 5, 2018 as a Category 3 hurricane, with wind speeds of 120 mph (190 km/h) and a storm surge of 10 feet (3 m).

The storm first struck the Bahamas and made an approach between Cuba and Florida before moving south in the Gulf of Mexico around the periphery of a anticyclone. It subsequently struck the Scorpion Reef at peak intensity, making the storm the second of the season to make landfall at Category 5 strength; a feat previously observed only in the 2007 season. Sarah later weakened as it re-curved north before its final landfall in Louisiana. The resultant storm surge also reopened some of the levee breaches caused by Hurricane Hailey nearly two months earlier, and reflooded the affected areas as a result. Post-landfall damage was extensive in the coastal areas from extreme southeastern Texas to southwestern Mississippi.

Because the Gulf of Mexico is a major center for crude oil production and refineries, as well as home to some of the busiest ports in the world, Sarah initially presented the potential to do damage beyond the localized wind and wave surge. These concerns were not realized, as no reports emerged of long-term damage to the major U.S. refining and shipping capacities in Texas, which was spared from a direct hit by the storm.

## **Meteorological history**

On September 20, a tropical wave exited the western coast of Africa and traversed the MDR of the Atlantic. Hostile conditions, through interaction with a cold front (the same one that previously absorbed the remnants of Hurricanes Michaela and Olivia) and upwelling in the wake of Tropical Depression Seventeen, limited development as the system tracked westward; and as such was not monitored for tropical cyclogenesis. Nearly a week later on September 26, the JMC began to note the potential for the system to develop as it neared the Bahamas. Under improving conditions north of the Lesser Antilles, signs of the wave's organization were evident, but no circulation was immediately identifiable. On September 28, while situated just east of the Turks and Caicos islands, the wave exhibited well-defined curved bands and an improving circulation at the surface; this prompted the JMC to designate the system as Tropical Depression Twenty at 2000 UTC.

The depression gradually gained organization throughout the evening, with strong convection wrapping around the north side of the low-level circulation center. It became a tropical storm by 1100 UTC the following morning about 19 mi northeast of Crooked Island in the southeastern Bahamas. However, moderate southerly vertical shear, to the east of a middle- to upper-level low over the northwestern Caribbean Sea, continued to affect the system by confining upper-level outflow and deep convection to the north of the center. The storm made landfall at Long Island in the Bahamas nine hours after being named. Once the upper-level low to the west weakened on September 30 and the shear over Sarah relaxed, the convection became more symmetric about the center and the storm strengthened. Sarah reached an intensity of 70 mph (110 km/h) sustained surface winds by 1700 UTC that day while centered south of the island of Andros. At this time, the storm then turned more northwestward along the northern periphery of the upper-level low. For several hours Sarah struggled to maintain an inner core, and it remained a tropical storm with maximum winds of 70 mph into the morning of October 1 as it approached the Florida Straits. Once there, Sarah began to strengthen, and it became a hurricane with an intensity of 80 mph (130 km/h) by 0900 UTC that morning about 92 mi east-southeast of Key West, Florida. Sarah then attained Category 2 strength as it reached sustained winds of 100 mph (160 km/h by 0300 UTC on October 2 as it proceeded westward into the Gulf of Mexico.

A deep-layer ridge positioned over the central Gulf caused Sarah to steeply move southwestward around its periphery. Throughout most of the remainder of that day and into the morning of October 3, Sarah quickly intensified over the very warm waters of the Loop Current and within an environment of very weak vertical wind shear, reaching an intensity of 165 mph (265 km/h) by 1000 UTC October 3. It reached its peak intensity of 175 mph (280 km/h) and a minimum central pressure of 908 mbar (inHg) six hours later, while located about 450 mi (724 km) south of the mouth of the Mississippi River. Sarah remained at Category 5 strength for about the next 18 hours. During that time, it made its second landfall at the uninhabited Scorpion Reef. Sarah turned toward the west-northwest as it rounded the western periphery of the deep-layer ridge in the Gulf and began to travel along the western extent of the middle- to upper-tropospheric ridge centered over the southeastern United States.

The inner eyewall deteriorated later on October 3 and Sarah abruptly weakened to Category 4 strength with 155 mph (245 km/h) maximum winds by 0500 UTC October 4. A new, outer eyewall had consolidated and the hurricane had grown in size. However, Sarah did not re-intensify following the structural changes. Due to increasing southwesterly wind shear and slightly cooler waters, steady weakening continued. Sarah rounded the western periphery of the upper-level tropospheric ridge and turned toward the northeast that day, with a slight increase in forward speed from about 8 to about 10 kt. It weakened to a Category 3 hurricane with 125 mph (200 km/h) winds by 0100 UTC October 5 about 160 mi southeast of Centerville, Louisiana. Sarah maintained Category 3 strength up to the time of landfall, which occurred at 1540 UTC October 5 with an estimated intensity of 100 kt, in extreme south-central Louisiana just south of Centerville.

Sarah weakened after making landfall, remaining a hurricane until only about 0100 UTC
October 6 when it was centered about 35 mi (56 km) west-southwest of of Columbia, Mississippi. As a steadily weakening tropical storm, Sarah proceeded northeast over the Southern United States. It weakened to a tropical depression by 1500 UTC October 6 while over north-central Mississippi and then turned northeastward ahead of an approaching frontal system. The depression lost its organized convection and degenerated to a remnant low on October 7 over eastern Illinois. The low was absorbed into a frontal zone later that evening over the southern Great Lakes region.