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Don Strengthens to a Hurricane over the Gulf Stream

Former Tropical Storm Don strengthened to a hurricane over the Gulf Stream on Saturday afternoon. At 5:00 p.m. EDT on Saturday the center of Hurricane Don was located at latitude 40.1°N and longitude 50.0°W which put it about 480 miles (775 km) south-southeast of Cape Race, Newfoundland. Don was moving toward the north at 12 m.p.h. (19 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 988 mb.

Former Tropical Storm Don intensified to a hurricane as it moved over the warm water in the Gulf Stream on Saturday afternoon. A small circular eye formed at the center of Hurricane Don. 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 Don. Storms near the core generated upper level divergence that pumped mass away from the hurricane. The removal of mass allowed the surface pressure to decrease to 988 mb at the center of Hurricane Don.

The circulation around Hurricane Don was small. Winds to hurricane force extended out 15 miles (25 km) from the center of Don’s circulation. Winds to tropical storm force extended out 70 miles (110 km) from the center of circulation.

Hurricane Don will move into an environment that will be very unfavorable for a hurricane during the next 24 hours. Don will move north of the Gulf Stream where the Sea Surface Temperatures are colder than 26˚C. An upper level trough over eastern Canada will produce southwesterly winds that will blow toward the top of Don’s circulation. Those winds will cause the vertical wind shear to increase on Sunday. The combination of much colder water and more vertical wind shear will cause Hurricane Don to weaken during the next 24 hours.

Hurricane Don will move around the northwestern part of a hurricane pressure system over the eastern Atlantic Ocean. The high pressure system and the upper level trough over eastern Canada will steer Don toward the northeast during the next 24 hours. On its anticipated track, Hurricane Don will stay southeast of Newfoundland.

Tropical Storm Don Spins South-southeast of Newfoundland

Tropical Storm Don was spinning over the Atlantic Ocean south-southeast of Newfoundland on Friday morning. At 11:00 a.m. EDT on Friday the center of Tropical Storm Don was located at latitude 35.8°N and longitude 46.5°W which put it about 825 miles (1330 km) south-southeast of Cape Race, Newfoundland. Don was moving toward the west-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 1002 mb.

The circulation around Tropical Storm Don was well organized on Friday morning. The inner end of a rainband wrapped around the center of Don’s circulation. A clear area was visible on satellite images at the center of Tropical Storm Don. 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 storm. The circulation around Tropical Storm Don was small. Winds to tropical storm force extended out 60 miles (95 km) from the center of circulation.

Tropical Storm Don will move through an environment that will be marginally favorable for intensification during the next 24 hours. Don will move over water where the Sea Surface Temperatures are near 25˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Don could intensify during the next 24 hours. Don will move over the warmer water of the Gulf Stream for a brief time on Saturday. Tropical Storm Don could strengthen while it is over the Gulf Stream, but Don will then move over much colder water when it gets north of the Gulf Stream.

Tropical Storm Don will move around the western part of a high pressure system over the northeastern Atlantic Ocean. The high pressure system will steer Don toward the northwest during the next 24 hours. On its anticipated track, Tropical Storm Don will continue to make a big clockwise loop over the Central Atlantic south of Newfoundland.

Tropical Storm Don Strengthens over the Central Atlantic

Tropical Storm Don strengthened over the Central Atlantic Ocean on Wednesday night. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Don was located at latitude 33.9°N and longitude 40.9°W which put it about 825 miles (1330 km) west-southwest of the Azores. Don was moving toward the west at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 1002 mb.

Tropical Storm Don strengthened on Wednesday night as it continued to make a big clockwise loop over the Central Atlantic Ocean west of the Azores. Don looked more like a tropical storm on satellite images. The shape of the cloud pattern was more circular. Thunderstorms formed along the inner end of a band just to the east of the center of Don’s circulation. Other bands of showers and thunderstorms were revolving around the center of Tropical Storm Don. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 70 miles (110 km) from the center of Don’s circulation.

Tropical Storm Don will move through an environment favorable for intensification during the next 24 hours. Don will move over water where the Sea Surface Temperatures are near 25˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Don will intensify during the next 24 hours.

Tropical Storm Don will move around the southwestern part of a high pressure system over the northeastern Atlantic Ocean during the next 24 hours. The high pressure system will steer Don slowly toward the west. On its anticipated track, Tropical Storm Don will continue to make a big clockwise loop over the Central Atlantic west of the Azores.

Tropical Storm Don Starts Big Loop West of the Azores

Tropical Storm Don started to make a big, clockwise loop over the Atlantic Ocean west of the Azores on Monday. At 11:00 p.m. EDT on Monday the center of Tropical Storm Don was located at latitude 37.4°N and longitude 40.4°W which put it about 735 miles (1180 km) west of the Azores. Don was moving toward the southeast at 13 m.p.h. (20 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1007 mb.

Former Subtropical Storm Don went through several stages as it made a transition to a tropical storm. Don weakened to a subtropical depression on Sunday while it was over cooler water and in a region with more vertical wind shear. It made a transition from a subtropical depression to a tropical depression on Monday morning, when more thunderstorms developed in the northeastern part of the circulation. Don then strengthened to a tropical storm on Monday evening.

Tropical Storm Don was over water where the Sea Surface Temperatures were near 24˚C on Monday evening. The distribution of thunderstorms in Tropical Storm Don remained asymmetrical. Most of thunderstorms were occurring in bands in the northeastern part of Don’s circulation. The strongest winds were also occurring in that part of Tropical Storm Don. Winds to tropical storm force extended out 105 miles (165 km) in the northeastern part of Don. Bands in the other parts of Tropical Storm Don consisted primarily of showers and lower clouds. The winds in the other parts of Don’s circulation were blowing at less that tropical storm force.

Tropical Storm Don will move through an environment that will be only marginally favorable for intensification during the next 36 hours. Don will move over water where the Sea Surface Temperatures are near 25˚C. It will move under the eastern side of an upper level low over the Central Atlantic Ocean. The upper level low will produce southwesterly winds that will blow toward the top of Don’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification. Tropical Storm Don could strengthen a little during the next 36 hours, but its intensity may not change much.

Tropical Storm Don will move around the northern part of a high pressure system over the Central Atlantic Ocean during the next 36 hours. The high pressure system will steer Don toward the south during the next 36 hours. Don is likely to move toward the west on later this week. On its anticipated track, Tropical Storm Don will make a big, clockwise loop west of the Azores during the next few days.

Subtropical Storm Don Spins over the Central Atlantic

Subtropical Storm Don was spinning over the Central Atlantic Ocean on Saturday. At 11:00 a.m. EDT on Saturday the center of Subtropical Storm Don was located at latitude 36.5°N and longitude 48.8°W which put it about 1200 miles (1930 km) west of the Azores. Don was moving toward the northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1006 mb.

Subtropical Storm Don weakened a little on Saturday as the environment became less favorable. Many of the bands revolving around the center of Don’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 175 miles (280 km) in the eastern side of Subtropical Storm Don. Winds in the western side of the circulation were blowing at less than tropical storm force. Subtropical Storm Don moved over slightly cooler water and less energy was transferred from the ocean to the atmosphere. In addition, the center of Don’s circulation was under the southeastern part of an upper level low over the Central Atlantic. The upper level low was producing southeasterly winds that were blowing across the top of Subtropical Storm Don. Those winds were causing moderate vertical wind shear. The cooler water and moderate vertical wind shear caused Subtropical Storm Don to weaken.

Subtropical Storm Don will move through an environment unfavorable for intensification during the next 24 hours. Don will move over water where the Sea Surface Temperatures are near 25˚C. The upper level low will continue to cause moderate vertical wind shear. The upper level low could also circulate sinking, drier air around the southern side of Don’s circulation. Subtropical Storm Don could weaken a little more during the next 24 hours, but its intensity may not change much.

Subtropical Storm Don will move around the northwestern part of a subtropical high pressure system over the Atlantic Ocean during the next 24 hours. The high pressure system will steer Don toward the north during the next 24 hours. Don is likely to move toward the east on Sunday. On its anticipated track, Subtropical Storm Don will meander west of the Azores during the next few days.

Subtropical Storm Don Develops West of the Azores

Subtropical Storm Don developed west of the Azores on Friday morning. At 5:00 a.m. EDT on Friday the center of Subtropical Storm Don was located at latitude 32.9°N and longitude 46.8°W which put it about 1165 miles (1875 km) west-southwest of the Azores. Don was moving toward the north at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 1005 mb.

A large low pressure system over the central Atlantic Ocean west of the Azores exhibited more organization on Friday morning and the U.S. National Hurricane Center designated the system as Subtropical Storm Don. A distinct low level center of circulation was evident on visible satellite images. However, Subtropical storm Don was under an upper level trough. The bands near the center of Don consisted primarily of showers and lower clouds. Thunderstorms were occurring in a band that curled around the eastern and northern part of Don’s circulation. The strongest winds were occurring in that band of storms. Winds to tropical storm force extended out 200 miles (320 km) in the eastern side of Subtropical Storm Don. Winds in the western side of Don were blowing at less than tropical storm force.

Subtropical Storm Don will move through an environment only marginally favorable for intensification during the next 24 hours. Don will move over water where the Sea Surface Temperatures are near 26˚C. The upper level trough contains colder air, which will contribute to a more unstable atmosphere. However, the upper level trough will also limit the upper level divergence. There will be little vertical wind shear near the center of the upper level trough. Southerly in the eastern side of the trough will blow over the eastern side of Subtropical Storm Don. Those winds will cause more vertical wind shear in that area. The upper level trough could also circulate sinking, drier air around the western and southern sides of Don’s circulation. Subtropical Storm Don could maintain an equilibrium with its environment during the next 24 hours and its intensity may not change much.

The upper level trough will steer Subtropical Storm Don slowly toward the north during the next 24 hours. A high pressure system south of Greenland will block Don and prevent it from moving north on Sunday. Don is likely to move toward the east early next week. On its anticipated track, Subtropical Storm Don will meander west of the Azores during the next few days.

Hurricane Earl Passes Southeast of Bermuda

Hurricane Earl passed southeast of Bermuda on Thursday night. At 11:00 p.m. EDT on Thursday the center of Hurricane Earl was located at latitude 31.3°N and longitude 63.7°W which put it about 95 miles (150 km) southeast of Bermuda. Earl was moving toward the north-northeast at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (165 km/h). The minimum surface pressure was 964 mb.

A Tropical Storm Warning was in effect for Bermuda.

Hurricane Earl was producing winds to nearly tropical storm force in Bermuda. The L.F. Wade International Airport reported a sustained wind speed of 36 m.p.h. (58 km/h) and a wind gust of 50 m.p.h. (80 km/h). The structure of Hurricane Earl was beginning to resemble a hurricane that was moving from the tropics into the middle latitudes. An eye with a diameter of 60 miles (95 km) was at the center of Earl’s circulation. The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the large core of Hurricane Earl. Storms near the core generated upper level divergence that pumped mass away from the hurricane. Winds to hurricane force extended out 60 miles (95 km) from the center of Earl’s circulation. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation.

Hurricane Earl will move through an environment somewhat favorable for intensification during the next 24 hours. Earl will move over water where the Sea Surface Temperatures are near 29˚C. An upper level trough near the East Coast of the U.S. will produce southwesterly winds that will blow toward the top of Earl’s circulation. Those winds will cause some vertical wind shear and the wind shear will inhibit intensification. The southwesterly winds could also enhance divergence to the northeast of Hurricane Earl. Earl could intensify on Friday if the effect of the enhanced divergence exceeds the effect of the vertical wind shear. The southwesterly winds are forecast to increase during the weekend when the upper level trough moves closer to Hurricane Earl. Stronger vertical wind shear will cause Earl to weaken and to make a transition to an extratropical cyclone.

The upper level trough near the East Coast of the U.S. will steer Hurricane Earl toward the northeast during the next 36 hours. On its anticipated track, Hurricane Earl will move away from Bermuda on Friday. The gusty winds and rain in Bermuda will diminish on Friday when Earl moves farther away.

Bermuda Issues Hurricane Watch for Hurricane Earl

The government of Bermuda issued a Hurricane Watch on Wednesday afternoon because of the potential effects of Hurricane Earl. At 5:00 p.m. EDT on Wednesday the center of Hurricane Earl was located at latitude 26.5°N and longitude 65.5°W which put it about 405 miles (650 km) south of Bermuda. Earl was moving toward the north at 8 m.p.h. (13 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 974 mb.

A Hurricane Watch was in effect for Bermuda. A Tropical Storm Warning was also in effect for Bermuda.

Hurricane Earl exhibited more organization on Thursday afternoon. An circular eye with a diameter of 18 miles (30 km) was at the center of Earl’s circulation. The eye was surrounded by a partial ring of thunderstorms. Thunderstorms surrounded the northern half of the eye. Bands of showers and thunderstorms were revolving around the more organized core of Hurricane Earl. Storms near the center of Earl generated upper level divergence that pumped mass away from the hurricane.

The circulation around Hurricane Earl increased in size on Thursday. Winds to hurricane force extended out 45 miles (75 km) from the center of Earl’s circulation. Winds to tropical storm force extended out 150 miles (240 km) from the center. The Hurricane Intensity Index (HII) for Hurricane Earl was 12.7. The Hurricane Size Index (HSI) was 14.8 and the Hurricane Wind Intensity Size Index (HWISI) was 27.5.

Hurricane Earl will move through an environment favorable for intensification during the next 36 hours. Earl will move over water where the Sea Surface Temperatures are near 29˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Earl will intensify during the next 36 hours. After an inner core with a fully formed eye and eyewall develops, Earl could intensify rapidly. Hurricane Earl could strengthen to a major hurricane within 36 hours.

Hurricane Earl will move around the western end of a high pressure system over the Atlantic Ocean. The high pressure system will steer Earl toward the north during the next 12 hours. An upper level trough near the East Coast of the U.S. will turn Hurricane Earl toward the northeast on Thursday. On its anticipated track, the center of Hurricane Earl will pass southeast of Bermuda on Thursday evening. Bands in the western side of Hurricane Earl could bring strong winds and locally heavy rain to Bermuda.

Elsewhere over the Atlantic Ocean, Hurricane Danielle maintained hurricane intensity northwest of the Azores. At 5:00 p.m. EDT on Wednesday the center of Hurricane Danielle was located at latitude 44.9°N and longitude 34.9°W which put it about 625 miles (1010 km) northwest of the Azores. Danielle was moving toward the northeast at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (150 km/h). The minimum surface pressure was 972 mb.

Tropical Storm Earl Prompts Watch for Bermuda

A potential risk posed by Tropical Storm Earl prompted the issuance of a Tropical Storm Watch for Bermuda on Tuesday afternoon. At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Earl was located at latitude 24.1°N and longitude 65.8°W which put it about 570 miles (915 km) south of Bermuda. Earl was moving toward the north-northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 994 mb.

A Tropical Storm Watch was in effect for Bermuda.

Tropical Storm Earl was close to strengthening to a hurricane on Tuesday afternoon. The inner end of a rainband wrapped around the eastern half of the center of circulation. An eye appeared to be forming at the center of Earl’s circulation. Bands of thunderstorms were located in the eastern and northern parts of Tropical Storm Earl. Bands in the southern and western parts of the circulation still consisted primarily of showers and lower clouds. Storms near the center of circulation generated upper level divergence that pumped mass away to the northeast of the tropical storm. Winds to tropical storm force extended out 125 miles (200 km) from the center of Earl.

Tropical Storm Earl will move through an environment favorable for intensification during the next 48 hours. Earl will move over water where the Sea Surface Temperatures are near 29˚C. An upper level low southwest of Bermuda will produce southwesterly winds that will blow toward the top of Earl’s circulation. Those winds will cause vertical wind shear. The wind shear will inhibit intensification, but Tropical Storm Earl could continue to intensify slowly. The upper level winds are forecast to weaken later on Wednesday, and Earl is likely to intensify to a major hurricane after that happens.

Tropical Storm Earl will move around the western end of a high pressure system over the Atlantic Ocean. The high pressure system will steer Earl toward the north during the next 48 hours. On its anticipated track, Tropical Storm Earl will approach Bermuda on Thursday afternoon. Earl will be a hurricane when it approaches Bermuda.

Elsewhere over the Atlantic Ocean, Hurricane Danielle was moving toward the east-northeast west of the Azores. At 5:00 p.m. EDT on Tuesday the center of Hurricane Danielle was located at latitude 42.5°N and longitude 40.3°W which put it about 765 miles (1230 km) west-northwest of the Azores. Danielle was moving toward the east-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 986 mb.

Tropical Storm Earl Intensifies North of the Virgin Islands

Tropical Storm Earl intensified north of the Virgin Islands on Monday morning. At 11:00 a.m. EDT on Monday the center of Tropical Storm Earl was located at latitude 21.5°N and longitude 65.3°W which put it about 215 miles (345 km) north-northwest of St. Thomas. Earl was moving toward the north-northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 998 mb.

A NOAA Hurricane Hunter plane found that Tropical Storm Earl had intensified during a reconnaissance flight on Monday morning. Even though the circulation around Tropical Storm Earl was stronger, the distribution of thunderstorms was still asymmetrical. Most of the thunderstorms were occurring in bands in the eastern side of Earl’s circulation. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Storms in the eastern half of Earl generated upper level divergence that pumped mass away to the east of the tropical storm. Winds to tropical storm force extended out 100 miles (160 km) from the center of Earl’s circulation.

Tropical Storm Earl will move through an environment favorable for intensification during the next 48 hours. Earl will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the eastern side of an upper level trough near the Bahamas. The upper level trough will produce southwesterly winds that will blow toward the top of Ear;’s circulation. Those winds will cause vertical wind shear. The wind shear will inhibit intensification, but Tropical Storm Earl could continue to intensify slowly. The upper level winds are forecast to weaken in a day or so, and Earl is likely to intensify to a hurricane when that happens.

Tropical Storm Earl will move around the western end of a high pressure system over the Atlantic Ocean. The high pressure system will steer Earl toward the north during the next 48 hours. On its anticipated track, Tropical Storm Earl will move farther away from the Virgin Islands and Puerto Rico. Earl could approach Bermuda by the end of the week.

Elsewhere over the Atlantic Ocean, Hurricane Danielle started to weaken west of the Azores. At 11:00 a.m. EDT on Monday the center of Hurricane Danielle was located at latitude 40.2°N and longitude 43.9°W which put it about 915 miles (1475 km) west-northwest of the Azores. Danielle was moving toward the north-northeast at 8 m.p.h. (13 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.