Tropical Storm Sebastien (1995)
Encyclopedia
Tropical Storm Sebastien was the twentieth cyclone
of the active 1995 Atlantic hurricane season
. Sebastien originated from a tropical wave that near the coast of Africa
on October 13 and moved westward toward the Caribbean Sea
. The wave increased in convection and became Tropical Depression Twenty on October 20, strengthening into a tropical storm within 12 hours of formation. Sebastien encountered a tropical low off of Puerto Rico
and entered some southwesterly wind shear, which stopped strengthening at 65 miles per hour (104.6 km/h) on October 23. The now-depression Sebastien made landfall in Anguilla
on the morning of October 24. Sebastien soon entered a low-level flow and encountered wind shear
, becoming a remnant low on October 25 near the Virgin Islands
and Puerto Rico. While over that area, it produced moderate rain, but damage was minimal, and no deaths were reported.
that formed off the west coast of Africa
on October 13 and moved westward across the Atlantic until October 19. The next day shower activity increased with the tropical wave and it was declared a depression by the afternoon of October 20. Twelve hours after forming, the depression became a tropical storm, named Sebastien. Upon doing so, the depression had become better organized and then gained a good outflow.
By that night, the National Hurricane Center
was forecasting Sebastien to intensify somewhat. Afterword, wind shear
halted further intensification, and little more was expected. Instead, it started to intensify. Sebastien started interacting with a low pressure area
near Puerto Rico
at that time the system reached its peak of 65 mph (100 km/h) and a peak pressure 1001 millibars later on October 22, based on ship reports. However, it was originally believed to be weaker.
At this time, it was located a few hundred nautical miles northeast of the northern Leeward Islands
.
Not long after, the associated steering circulation near Sebastien's center turned the storm to the north and entered southwesterly wind shear, which prevented the system from strengthening into a hurricane. It started to move with the low-level flow from the southwest at this time, thus causing that storm to move into the storm into the southwesterly wind shear and caused Sebastien to weaken. As a response, the storm weakened into a tropical depression the next day. The tropical cyclone made landfall in Anguilla
as a weak tropical depression the next day. Sebastien degenerated into a remnant low on the morning of October 25 while located due east of the U.S. Virgin Islands and the remnants continued westbound.
for the United States Virgin Islands
and the British Virgin Islands
. Other islands were on alert as the NHC stated that the watch area may need to be expanded. Still recovering from Hurricane Marilyn
less than a month ago, residents living in damaged homes reportedly evacuated their homes. However, the watch was discontinued 24 hours later after the storm weakened to a tropical depression.
The remnants of Sebastien produced moderate rainfall across parts of Puerto Rico between October 24 and 26, with most areas receiving at least 0.25 in (6.4 mm) of rain. A maximum of 3.53 in (89.7 mm) fell in Quebradillas. Offshore, satellites estimated that up to 12.6 in (320 mm) of rain fell due to Sebastien. Throughout the Leeward Islands
, there were no reports of casualties or damages; however, offshore, three ships recorded gale-force winds in relation to the storm.
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
of the active 1995 Atlantic hurricane season
1995 Atlantic hurricane season
The 1995 Atlantic hurricane season was the third most active Atlantic hurricane season on record. It officially began on June 1, 1995, and lasted until November 30, 1995. These dates conventionally delimit the period of each year when most tropical cyclones form in the north Atlantic ocean...
. Sebastien originated from a tropical wave that near the coast of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
on October 13 and moved westward toward the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
. The wave increased in convection and became Tropical Depression Twenty on October 20, strengthening into a tropical storm within 12 hours of formation. Sebastien encountered a tropical low off of Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
and entered some southwesterly wind shear, which stopped strengthening at 65 miles per hour (104.6 km/h) on October 23. The now-depression Sebastien made landfall in Anguilla
Anguilla
Anguilla is a British overseas territory and overseas territory of the European Union in the Caribbean. It is one of the most northerly of the Leeward Islands in the Lesser Antilles, lying east of Puerto Rico and the Virgin Islands and directly north of Saint Martin...
on the morning of October 24. Sebastien soon entered a low-level flow and encountered wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
, becoming a remnant low on October 25 near the Virgin Islands
Virgin Islands
The Virgin Islands are the western island group of the Leeward Islands, which are the northern part of the Lesser Antilles, which form the border between the Caribbean Sea and the Atlantic Ocean...
and Puerto Rico. While over that area, it produced moderate rain, but damage was minimal, and no deaths were reported.
Meteorological history
Sebastien originated from a tropical waveTropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
that formed off the west coast of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
on October 13 and moved westward across the Atlantic until October 19. The next day shower activity increased with the tropical wave and it was declared a depression by the afternoon of October 20. Twelve hours after forming, the depression became a tropical storm, named Sebastien. Upon doing so, the depression had become better organized and then gained a good outflow.
By that night, the National Hurricane Center
National Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
was forecasting Sebastien to intensify somewhat. Afterword, wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
halted further intensification, and little more was expected. Instead, it started to intensify. Sebastien started interacting with a low pressure area
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
near Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
at that time the system reached its peak of 65 mph (100 km/h) and a peak pressure 1001 millibars later on October 22, based on ship reports. However, it was originally believed to be weaker.
At this time, it was located a few hundred nautical miles northeast of the northern Leeward Islands
Leeward Islands
The Leeward Islands are a group of islands in the West Indies. They are the northern islands of the Lesser Antilles chain. As a group they start east of Puerto Rico and reach southward to Dominica. They are situated where the northeastern Caribbean Sea meets the western Atlantic Ocean...
.
Not long after, the associated steering circulation near Sebastien's center turned the storm to the north and entered southwesterly wind shear, which prevented the system from strengthening into a hurricane. It started to move with the low-level flow from the southwest at this time, thus causing that storm to move into the storm into the southwesterly wind shear and caused Sebastien to weaken. As a response, the storm weakened into a tropical depression the next day. The tropical cyclone made landfall in Anguilla
Anguilla
Anguilla is a British overseas territory and overseas territory of the European Union in the Caribbean. It is one of the most northerly of the Leeward Islands in the Lesser Antilles, lying east of Puerto Rico and the Virgin Islands and directly north of Saint Martin...
as a weak tropical depression the next day. Sebastien degenerated into a remnant low on the morning of October 25 while located due east of the U.S. Virgin Islands and the remnants continued westbound.
Preparations and impact
As Tropical Storm Sebastien turned towards the Caribbean Sea on October 23, the National Hurricane Center issued a tropical storm watchTropical cyclone warnings and watches
Warnings and watches are two levels of alert issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local population and civil authorities to make appropriate...
for the United States Virgin Islands
United States Virgin Islands
The Virgin Islands of the United States are a group of islands in the Caribbean that are an insular area of the United States. The islands are geographically part of the Virgin Islands archipelago and are located in the Leeward Islands of the Lesser Antilles.The U.S...
and the British Virgin Islands
British Virgin Islands
The Virgin Islands, often called the British Virgin Islands , is a British overseas territory and overseas territory of the European Union, located in the Caribbean to the east of Puerto Rico. The islands make up part of the Virgin Islands archipelago, the remaining islands constituting the U.S...
. Other islands were on alert as the NHC stated that the watch area may need to be expanded. Still recovering from Hurricane Marilyn
Hurricane Marilyn
Hurricane Marilyn was the fifteenth tropical depression and thirteenth named storm of the unusually busy 1995 Atlantic hurricane season, following closely on the heels of Hurricane Luis. Hurricane Marilyn was the most powerful storm to hit the Virgin Islands since Hurricane Hugo of 1989.Marilyn...
less than a month ago, residents living in damaged homes reportedly evacuated their homes. However, the watch was discontinued 24 hours later after the storm weakened to a tropical depression.
The remnants of Sebastien produced moderate rainfall across parts of Puerto Rico between October 24 and 26, with most areas receiving at least 0.25 in (6.4 mm) of rain. A maximum of 3.53 in (89.7 mm) fell in Quebradillas. Offshore, satellites estimated that up to 12.6 in (320 mm) of rain fell due to Sebastien. Throughout the Leeward Islands
Leeward Islands
The Leeward Islands are a group of islands in the West Indies. They are the northern islands of the Lesser Antilles chain. As a group they start east of Puerto Rico and reach southward to Dominica. They are situated where the northeastern Caribbean Sea meets the western Atlantic Ocean...
, there were no reports of casualties or damages; however, offshore, three ships recorded gale-force winds in relation to the storm.
See also
- List of Atlantic hurricanes
- List of tropical cyclones