Tropical Storm Sebastien was the eighteenth named storm of the 1995 Atlantic hurricane season. Sebastien formed on October 20 to the east of the Lesser Antilles. Sebastien moved to the northwest, quickly gaining tropical storm status. The cyclone then took a sharp turn to the southwest, dissipating to the east of Puerto Rico on October 25.
Sebastien caused no damage and no deaths.
|Formation||October 20, 1995|
|Dissipation||October 25, 1995|
|Highest winds||65 mph|
|Lowest pressure||1001 mbar|
|Areas affected||Leeward Islands|
|Part of the||1995 Atlantic hurricane season|
Sebastien's origins can be traced back to a tropical wave that left the coast of Africa on October 13. The wave moved westward across the Atlantic Ocean through October 19, and associated convective activity remained disorganized and mostly south of 15°N latitude during that period. On October 20, deep convection became more organized about 350 miles east of the island of Barbados. That day, Dvorak classifications were taken on the wave, and within 24 hours, T numbers had increased to 2.5. Based on this, it is estimated that the wave developed into Tropical Depression Twenty at 1200 UTC October 20 while located east of the Lesser Antilles. At 0000 UTC October 21, it is estimated that the depression strenthened into Tropical Storm Sebastien. From October 20 to October 22, Sebastien was embedded within the outer part of the circulation associated with a large, deep low-pressure area located just northeast of Puerto Rico. The associated steering currents moved the cyclone to the northwest at about 15 knots during this period. Strong upper-level southwesterly vertical wind shear inhibited any significant development of the cyclone, and based on a ship observation at 1800 UTC October 22, Sebastien is estimated to have reached its peak intensity of 65 mph. At this time, the cyclone's exposed low-level circulation center was located about 350 miles northeast of the northernmost Leeward Islands. On October 23, Sebastien took an abrupt turn to the southwest as it began to move with the low-level flow. This pushed Sebastien directly into the southwesterly wind shear, which displaced the coldest cloud tops about 100 miles to the east and northeast of the low-level circulation center.
On the evening of October 23, Sebastien weakened to a tropical depression as it moved under the upper-level cyclonic circulation. Sebastien's dissipating swirl of low clouds was near the U.S. Virgin Islands about 24 hours later, while some remnant deep convection peristed well to the east of the low-level circulation center. Sebastien dissipated on October 25.
Lack of Retirement
Because there was no damage, the name Sebastien was not retired in the Spring of 1996 by the World Meteorological Organization. It was not used during the 2001 Atlantic hurricane season or the 2007 Atlantic hurricane season, and is thus on the list of names to be used for the 2013 Atlantic hurricane season.