Sunday, September 12, 2021

Hurricane Nicholas (2021)

Storm Active: September 12-16

During early September, another tropical wave crossed the Atlantic, this one passing through the tropics without incident until it reached the southwestern Caribbean Sea. While the wave moved over central America on September 9, the northern portion pursued a more northwestward course toward the Bay of Campeche. There it merged with a trough, producing a large area of disturbed weather. Southwesterly wind shear made development slow, but the system managed to organize enough to be designated Tropical Storm Nicholas during the morning of September 12.

Nicholas initially moved northward, but turned a little toward the right on the 13th. Though that was the storm's general trajectory, the evolution of the interior was complex. The cyclone reformed to the north and east a few distinct times that day, and at points there were multiple vortices evident on radar, rotating one another cylonically. Despite the lack of a persistent center, Nicholas deepened significantly over the warm waters of the western Gulf of Mexico and reached hurricane strength very close to the coast of Texas that night (attaining a minimum pressure of 988 mb).

Just before landfall, Nicholas turned northeast and slowed down, postponing when it crossed the coastline into the early morning hours of September 14. At the time, it had its greatest peak winds of 75 mph. The storm quickly weakened inland as it moved east-northeast. Nevertheless, it was a prolific rain producer, with storm totals exceeding a foot of rain in parts of Texas and Louisiana. That night, it weakened to a tropical depression. Nicholas lingered near the Louisiana coast for several more days, decaying gradually, but still adding to its rain totals in the south. It became post-tropical on September 16, and finally dissipated on the 17th.



The above infrared satellite imagery shows Hurricane Nicholas just before landfall in Texas very early on September 14.



Nicholas's slow forward motion over the Gulf coast elevated rainfall amounts in Louisiana.

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