Tag Archives: Hurricane Tammy

Tammy Makes Transition to Strong Extratropical Cyclone

Former Hurricane Tammy made a transition to a strong extratropical cyclone on Wednesday night. At 5:00 a.m. EDT on Thursday the center of former Hurricane Tammy was located at latitude 30.5°N and longitude 58.4°W which put it about 395 miles (640 km) east-southeast of Bermuda. Tammy was moving toward the north at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 973 mb.

Former Hurricane Tammy made a transition to a strong extratropical cyclone over the Atlantic Ocean east-southeast of Bermuda on Wednesday night. The lower part of Tammy’s circulation merged with a frontal system east of Bermuda. Tammy looked like an occluded extratropical cyclone on satellite images. An occluded front wrapped around the northern part of former Hurricane Tammy. A warm front stretched east of the occluded front. A cold front curved south to the Northern Leeward Islands. The upper part of Tammy’s circulation was captured by an upper level trough near Bermuda.

Former Hurricane Tammy was still producing winds to hurricane force. Winds to hurricane force extended out 30 miles (50 km) from the center of Tammy’s circulation. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation.

Former Hurricane Tammy is forecast to meander over the Atlantic Ocean east of Bermuda during the next few days. The upper level trough near Bermuda is between an upper level ridge over the southeastern U.S. and a second upper level ridge over the eastern Atlantic Ocean. The two ridges will keep the upper level trough from moving much. Since the upper level trough captured former Hurricane Tammy, Tammy is not likely to move much either.

There is a possibility that former Hurricane Tammy could make a transition back to a tropical cyclone during the next few days. Tammy will meander over water where the Sea Surface Temperatures are near 26°C. The vertical wind shear will decrease if the upper level trough weakens. If more thunderstorms form near the center of Tammy’s circulation and the fronts dissipate over time, then Tammy could make a transition back to a tropical cyclone.

Former Hurricane Tammy could bring gusty winds to Bermuda during the next few days. The western part of Tammy’s circulation could extend over Bermuda at times as Tammy meanders east of Bermuda.

Hurricane Tammy Spins Southeast of Bermuda

Hurricane Tammy was spinning southeast of Bermuda on Tuesday evening. At 11:00 p.m. EDT on Tuesday the center of Hurricane Tammy was located at latitude 24.9°N and longitude 60.7°W which put it about 570 miles (915 km) southeast of Bermuda. Tammy was moving toward the northeast at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 976 mb.

Hurricane Tammy started to intensify again on Tuesday evening. A small circular eye was at the center of Tammy’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Tammy. Storms near the core generated upper level divergence that pumped mass away to the northeast of the hurricane.

Winds to hurricane force extended out 25 miles (40 km) in the eastern side of Hurricane Tammy. Winds to tropical storm force extended out 170 miles (275 km) in the eastern side of Tammy’s circulation. Winds to tropical storm force extended out 90 miles (145 km) in the western half of Hurricane Tammy.

Hurricane Tammy will move through an environment favorable for intensification during the next 24 hours. Tammy will move over water where the Sea Surface Temperatures are near 27°C. It will move under the eastern side of an upper level trough that is east of the U.S. The upper level trough will produce southwesterly winds that will blow toward the top of Tammy’s circulation. Those winds will cause some vertical wind shear, but the wind shear is not likely to be strong enough to prevent intensification. Hurricane Tammy is likely to intensify on Wednesday.

The upper level trough east of the U.S. will steer Hurricane Tammy toward the northeast during the next 24 hours. On its anticipated track, Hurricane Tammy will remain southeast of Bermuda on Wednesday.

Tropical Depression Forms Near Nicaragua

Tropical Depression Twentyone formed over the southwest Caribbean Sea near Nicaragua on Monday afternoon. At 5:00 p.m. EDT on Monday the center of Tropical Depression Twentyone was located at latitude 11.6°N and longitude 83.5°W which put it about 35 miles (55 km) southeast of Bluefields, Nicaragua. The tropical depression was moving toward the west at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). The minimum surface pressure was 1007 mb.

A low pressure system over the southwest Caribbean Sea near Nicaragua strengthened on Monday afternoon and the U.S. National Hurricane Center designated the system as Tropical Depression Twentyone. More thunderstorms formed near the center of the tropical depression on Monday afternoon. Several short bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical depression.

Tropical Depression Twentyone will move around the southern side of a high pressure system over the Gulf of Mexico. The high pressure system will steer the tropical depression toward the west during the next 24 hours. On its anticipated track, Tropical Depression Twentyone will move inland over southeast Nicaragua in a few hours. The tropical depression could drop heavy rain over parts of Nicaragua. Heavy rain could cause flash floods in some locations.

Elsewhere, Hurricane Tammy moved farther north of the Leeward Islands. At 5:00 p.m. EDT on Monday the center of Hurricane Tammy was located at latitude 22.3°N and longitude 63.8°W which put it about 695 miles (1115 km) south of Bermuda. Tammy was moving toward the north-northeast at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 990 mb.

Hurricane Tammy Moves North of the Leeward Islands

Hurricane Tammy moved north of the Leeward Islands on Sunday. At 11:00 p.m. EDT on Sunday the center of Hurricane Tammy was located at latitude 20.8°N and longitude 64.0°W which put it about 190 miles (305 km) north-northwest of Anguilla. Tammy was moving toward the northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 993 mb.

Hurricane Tammy maintained its intensity on Sunday as it moved north of the Leeward Islands, but Tammy was looking a little weaker on Sunday evening. An upper level trough near the east coast of the U.S. was producing strong southwesterly winds that were blowing toward the top of Tammy’s circulation. Those winds were causing strong vertical wind shear. In addition, some drier air appeared to be entering the southwestern part of Hurricane Tammy.

The effects of the strong wind shear and the drier air caused the distribution of thunderstorms in Hurricane Tammy to become asymmetrical again. Many of the thunderstorms were occurring in bands in the northern and eastern parts of Tammy’s circulation. Bands in the western and southern parts of the circulation consisted primarily of showers and lower clouds. Winds to hurricane force extended out 25 miles (40 km) from the center of Hurricane Tammy. Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation.

Hurricane Tammy will move through an environment that will be unfavorable for intensification during the next 24 hours. Tammy will move over water where the Sea Surface Temperatures are near 29°C. However, the upper level trough near the east coast of the U.S. will continue to cause strong vertical wind shear. The strong wind shear will inhibit intensification and Hurricane Tammy could weaken on Monday.

Hurricane Tammy will move around the western end of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Tammy toward the north during the next 24 hours. On its anticipated track, Hurricane Tammy will move farther north of the Leeward Islands on Monday.

Hurricane Tammy Passes Over Barbuda

Hurricane Tammy passed over Barbuda on Saturday night. At 11:00 p.m. EDT on Saturday the center of Hurricane Tammy was located at latitude 17.8°N and longitude 61.9°W which put it about 15 miles (25 km) north-northwest of Barbuda. Tammy was moving toward the north-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 992 mb.

Hurricane Warnings were in effect for Anguilla, Barbuda, St. Maarten, St, Martin, and St. Barthelemy. Tropical Storm Warnings were in effect for Saba and St. Eustatius.

The center of Hurricane Tammy passed directly over Barbuda on Saturday evening. Tammy produced strong gusty winds and heavy rain in Barbuda. Heavy rain was likely to cause flash floods in some locations.

Hurricane Tammy showed signs of weakening a little on Saturday night. Breaks appeared in the ring of thunderstorms around the center Tammy’s circulation. The distribution of thunderstorms became more asymmetrical. Many of the thunderstorms were occurring in bands in the eastern and northern parts of Hurricane Tammy. Bands in the southern and western parts of Tammy’s circulation consisted primarily of showers and lower clouds. Storms near the center of Tammy’s circulation generated upper level divergence that pumped mass away from the hurricane.

Winds to hurricane force extended out 25 miles (40 km) from the center of Hurricane Tammy. Winds to tropical storm force extended out 125 miles (200 km) from the center of circulation. The Hurricane Intensity Index (HII) was 12.7. The Hurricane Size Index (HSI) was 8.3 and the Hurricane Wind Intensity Size Index (HWISI) was 21.0. Hurricane Tammy was capable of causing localized minor damage.

Hurricane Tammy will move through an environment somewhat favorable for intensification during the next 24 hours. Tammy will move over water where the Sea Surface Temperatures are near 29°C. It will move under the northeastern part of an upper level low over the Eastern Caribbean Sea. The upper level low will produce southwesterly winds that will blow toward the top of Tammy’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification. The wind shear could be strong enough to cause Hurricane Tammy to weaken during the next 24 hours.

Hurricane Tammy will move around the western end of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Tammy toward the north during the next 24 hours. On its anticipated track, the center of Hurricane Tammy will move north of the Leeward Islands on Sunday.

Hurricane Tammy will continue to produce strong winds and heavy rain in Barbuda during the next few hours. The weather conditions will start to improve in Barbuda when Tammy moves north of the Leeward Islands on Sunday. Hurricane Tammy could also bring gusty winds to Anguilla, St. Maarten, St. Martin and St. Barthelemy on Sunday.

Tammy Strengthens to a Hurricane East of the Lesser Antilles

Former Tropical Storm Tammy strengthened to a hurricane east of the Lesser Antilles on Friday morning. At 11:00 a.m. EDT on Friday the center of Hurricane Tammy was located at latitude 14.1°N and longitude 58.6°W which put it about 165 miles (265 km) east-southeast of Martinique. Tammy was moving toward the west-northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 992 mb.

Hurricane Warnings were in effect for Guadeloupe, Antigua, Barbuda, Montserrat, St. Kitts, and Nevis. Hurricane Watches were in effect for Anguilla, St. Maarten, St. Martin, and St. Baarthelemy. Tropical Storm Warnings were in effect for Dominica, Anguilla, St. Maarten, St. Martin, St. Barthelemy, Saba and St. Eustatius. Tropical Storm Watches were in effect for Martinique and Barbados.

U.S. Air Force Reserve and NOAA planes flying in former Tropical Storm Tammy found that Tammy had intensified to a hurricane on Friday morning. A circular eye with a diameter of 14 miles (22 km) formed at the center of Hurricane Tammy. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Tammy. Storms near the core generated upper level divergence that pumped mass away from the hurricane. The removal of mass caused the surface pressure to decrease on Friday morning.

Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Hurricane Tammy. Winds to tropical storm force extended out 140 miles (220 km) in the eastern side of Tammy’s circulation. Winds to tropical storm force extended out 90 miles (145 km) in the western side of the circulation.

Hurricane Tammy will move through an environment somewhat favorable for intensification during the next 24 hours. Tammy will move over water where the Sea Surface Temperatures are near 30°C. It will move under the far eastern part of an upper level low over the Eastern Caribbean Sea. The upper level low will produce southwesterly winds that will blow toward the top of Tammy’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but it will not be strong enough to prevent intensification. Hurricane Tammy is likely to intensify during the next 24 hours.

Hurricane Tammy will move south of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Tammy toward the northwest during the next 24 hours. On its anticipated track, the center of Hurricane Tammy could be near Guadeloupe on Saturday morning.

Hurricane Tammy is likely to bring strong winds and locally heavy rain to the central and northern Leeward Islands. Heavy rain is likely to cause flash in some locations. Hurricane Tammy could cause a storm surge of up to seven feet (two meters) along the coasts of some of the islands.