Wednesday, October 4, 2017

Hurricane Nate (2017)

Storm Active: October 4-9

During the last week of September, a tropical wave tracked across the Atlantic Ocean. As the season was progressing to its later stages, conditions were less favorable over the open Atlantic, but the wave continued across into the Caribbean. On October 3, its southern end began interacting with a vorticity called a monsoonal gyre in the southwestern Caribbean, just north of Panama. This interaction led to increased spin, and a combination of low wind shear and warm waters supported further development. During the morning of October 4, Tropical Depression Sixteen formed east of Nicaragua. Over the next day, it moved slowly northwest. Lacking an inner core, the system was not able to develop quickly, but it did become Tropical Storm Nate early on October 5.

Shortly after, the center made landfall in Nicaragua, bringing heavy rainfall to the country as well as neighboring Honduras. Late that night, it reentered the Caribbean, prompting some intensification as convection increased. Meanwhile, Nate was accelerating toward the north-northwest. Its rapid speed hampered strengthening somewhat, but parts of an eyewall appeared on the 6th in the southern and western quadrants, and the system became a strong tropical storm. That evening, it passed just east of the Yucatan Peninsula. Fortunately, the part of the circulation over land was the weaker western side, minimizing damage. However, the lack of significant land interaction allowed Nate to continue to intensify steadily and become a hurricane around midnight. Conditions were still favorable in the Gulf of Mexico, but the fast-moving system had difficulty assembling a complete eyewall. Winds still were increasing to the north and east of the center, though, and the central pressure continued to fall. At midmorning, Nate reached its peak intensity of 90 mph winds and a pressure of 981 mb.

Slight weakening occurred over the next few hours, but the system still made landfall as a hurricane that evening near the Mississippi river delta. Once inland, it moved quickly north-northeast and weakened. Nate was tropical depression strength by midday on the 8th and became post-tropical early the next morning as it sped toward the mid-Atlantic states. The system brought precipitation to a large swath of the eastern U.S., but its rapid motion mitigated flooding. The remnants of Nate dissipated soon after.

The above image shows Hurricane Nate near peak intensity shortly before its Gulf coast landfall. The system's rapid motion prevented further organization.

Though Nate reached hurricane strength only in the Gulf of Mexico, its worst impacts occurred in central America, where prolonged heavy rains caused extensive flooding.

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