Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Hurricane Erin Rapidly Intensifies to Cat. 5

Hurricane Erin rapidly intensified to Category 5 on the Saffir-Simpson Scale on Saturday morning.   At 11:00 a.m. EDT on Saturday the center of Hurricane Erin was located at latitude 19.7°N and longitude 62.8°W which put the center about 105 miles (165 km) north of Anguilla.    Erin was moving toward the west at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 917 mb.

Tropical Storm Watches are in effect for  St. Martin, St. Barthelemy, and Sint Maarten.

Hurricane Erin rapidly intensified to a Category 5 hurricane on the Saffir-Simpson Scale on Saturday morning.  A small circular eye with a diameter of 6 miles (10 km) was at the center of Erin’s circulation.  A ring of thunderstorms surrounded the eye and the strongest winds winds occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Hurricane Erin.  Storms near the center of Erin generated strong upper level divergence that pumped large quantities of mass away from the hurricane.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Hurricane Erin is small.  Winds to hurricane force extend out 30 miles (50 km) from the center of Erin’s circulation.  Winds to tropical storm force extend out 140 miles (220 km) in the northern side of Hurricane Erin.  Winds to tropical storm force extend out 60 miles in the southern half of Erin’s circulation.

The Hurricane Intensity Index (HII) is 35.0. The Hurricane Size Index (HSI) is 9.2 and the Hurricane Wind Intensity Size Index (HWISI) is 44.2. Hurricane Erin is similar in intensity to Hurricane Michael in 2018.  Erin is smaller than Michael was.

Hurricane Erin will move through an environment that will be favorable for intensification during the next 24 hours.  Erin 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 Erin is likely to continue to intensify during the next few hours.  However, it is likely that the inner end of a rainband will wrap around the existing eye and eyewall.  That would create concentric eyewalls.  It would also start an eyewall replacement cycle.  An eyewall replacement cycle would cause Hurricane Erin to weaken, at least temporarily.

Hurricane Erin will move around the southern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass north of the Puerto Rico on Saturday night.

Bands in the southern side of Hurricane Erin are likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands and to the Virgin Islands.  Heavy rain could cause flash floods in some locations.  Bands feeding into the southern side of Hurricane Erin could also drop heavy rain on Puerto Rico.

A Flood Watch is in effect for Puerto Rico.

Hurricane Erin Rapidly Intensifies to Cat. 4

Hurricane Erin rapidly intensified to Category 4 on the Saffir-Simpson Scale on Saturday morning.  At 8:00 a.m. EDT on Saturday the center of Hurricane Erin was located at latitude 19.6°N and longitude 62.0°W which put the center about 120 miles (195 km) northeast of Anguilla.   Erin was moving toward the west-northwest at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 935 mb.

Tropical Storm Watches are in effect for  St. Martin, St. Barthelemy, and Sint Maarten.

Hurricane Erin rapidly intensified to a Category 4 hurricane on the Saffir-Simpson Scale early on Saturday morning.  A circular eye with a diameter of 12 miles (19 km) was at the center of Erin’s circulation.  A ring of thunderstorms surrounded the eye and the strongest winds winds occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Hurricane Erin.  Storms near the center of Erin generated strong upper level divergence that pumped large quantities of mass away from the hurricane.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Hurricane Erin is small.  Winds to hurricane force extend out 30 miles (50 km) from the center of Erin’s circulation.  Winds to tropical storm force extend out 130 miles (210 km) in the northern side of Hurricane Erin.  Winds to tropical storm force extend out 60 miles in the southern half of Erin’s circulation.

The Hurricane Intensity Index (HII) is 29.9.  The Hurricane Size Index (HSI) is 8.4 and the Hurricane Wind Intensity Size Index (HWISI) is 38.3.  Hurricane Erin is similar in size and intensity to Hurricane Charley in 2004.

Hurricane Erin will move through an environment that will be very favorable for intensification during the next 24 hours.  Erin 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 Erin will intensity during the next 24 hours.  Erin could strengthen to Category 5 on the Saffir-Simpson Scale.

Hurricane Erin will move around the southern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass north of the Puerto Rico on Sunday.

Bands in the southern side of Hurricane Erin are likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands.  Heavy rain could cause flash floods in some locations.  Bands feeding into the southern side of Hurricane Erin could also drop heavy rain on Puerto Rico.

A Flood Watch is in effect for Puerto Rico.

Erin Strengthens to a Hurricane

Former Tropical Storm Erin strengthened to a hurricane east of the Northern Leeward Islands on Friday.  At 11:00 a.m. EDT on Friday the center of Hurricane Erin was located at latitude 18.2°N and longitude 56.1°W which put the center about 460 miles (740 km) east of the Northern Leeward Islands.  Erin was moving toward the west-northwest at 18 m.p.h. (30 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 996 mb.

Tropical Storm Watches are in effect for Anguilla, Barbuda, St. Martin, St. Barthelemy, Saba, St. Eustatius, and Sint Maarten.

Former Tropical Storm Erin strengthened to a hurricane east of the Northern Leeward Islands on Friday.  The inner end of a rainband wrapped around the center of Erin’s circulation.  A small eye with a diameter of 12 miles (19 km) formed at the center of Hurricane Erin.  Bands of showers and thunderstorms were revolving around the center of Erin’s circulation.  Storms near the center generated upper level divergence that was pumping mass away from the hurricane.

The strongest winds were occurring in the northeastern part of Hurricane Erin.  Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Erin’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Hurricane Erin.

Hurricane Erin will move through an environment favorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation. The winds in the lower levels of the atmosphere will also blow from the east, but winds will be stronger in the upper troposphere.  So, there will be some vertical wind shear.  The vertical wind shear will slightly inhibit intensification, but the shear will not be enough to prevent intensification. Hurricane Erin will intensity during the next 24 hours.  Erin is likely to strengthen to a major hurricane during the weekend.

Hurricane Erin will move around the southern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass north of the Northern Leeward Islands on Saturday.

Bands in the southern side of Hurricane Erin are likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands.  Heavy rain could cause flash floods in some locations.  Bands feeding into the southern side of Hurricane Erin could also drop heavy rain on Puerto Rico.

A Flood Watch is in effect for Puerto Rico.

Erin Prompts Tropical Storm Watches for Northern Leeward Islands

The potential risk posed by Tropical Storm Erin prompted the issuance of Tropical Storm Watches for the Northern Leeward Islands on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Erin was located at latitude 16.7°N and longitude 51.2°W which put the center about 790 miles (1270 km) east of the Northern Leeward Islands.  Erin was moving toward the west at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 998 mb.

Tropical Storm Watches are in effect for Anguilla, Barbuda, St. Martin, St. Barthelemy, Saba, St. Eustatius, and Sint Maarten.

Tropical Storm Erin continued to strengthen gradually on Thursday.  Even though Tropical Storm Erin was strengthening, the distribution of thunderstorms was asymmetrical.  Thunderstorms were occurring mainly in bands in the western side of Erin’s circulation.  Bands in the eastern side of Tropical Storm Erin consisted primarily of showers and lower clouds.  Storms near the center of Erin generated upper level divergence that pumped mass away to the west of the tropical storm.  The removal of mass caused the surface pressure to decrease slowly.

The circulation around Tropical Storm Erin is small,  Winds to tropical storm force extend out 60 miles (95 km) from the center of Erin’s circulation.

Tropical Storm Erin will move through an environment mostly favorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation.  The winds in the lower levels of the atmosphere will also blow from the east, but winds will be stronger in the upper troposphere.  So, there will be some vertical wind shear.  The vertical wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Erin will intensity during the next 24 hours.  Erin is likely to strengthen to a hurricane on Friday.

Tropical Storm Erin will move around the southern side of a high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Erin toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Erin will move toward the Northern Leeward Islands.  Erin could approach the Northern Leeward Islands on Friday night.

Tropical Storm Erin is likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands.  Heavy rain could cause flash floods in some locations.

Tropical Storm Erin Strengthens a Little

Tropical Storm Erin strengthened a little on Wednesday as it moved over the Atlantic Ocean east of the Northern Leeward Islands.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Erin was located at latitude 16.3°N and longitude 46.6°W which put the center about 1095 miles (17635 km) east of the Northern Leeward Islands.  Erin was moving toward the west at 16 m.p.h. (26 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 Erin strengthened a little on Wednesday.  More thunderstorms formed near the center of Erin’s circulation.  Thunderstorms were also occurring in bands in the western side of Tropical Storm Erin.  Bands in the eastern side of Erin’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Erin generated upper level divergence that pumped mass away to the west of the tropical storm.

The strongest winds were occurring in the northern side of Tropical Storm Erin.  Winds to tropical storm force extended out 60 miles (95 km) in the northern half of Erin’s circulation.  The winds in the southern side of Tropical Storm Erin were blowing at less than tropical storm force.

Tropical Storm Erin will move through an environment somewhat favorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation.  The winds in the lower levels of the atmosphere will also blow from the east, but winds will be stronger in the upper troposphere.  So, there will be some vertical wind shear.  The vertical wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Erin will intensity during the next 24 hours.  Erin will move over warmer water on Friday.  Erin is likely to strengthen to a hurricane on by Friday evening.

Tropical Storm Erin will move around the southern side of a high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Erin toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Erin will move toward the Northern Leeward Islands.  Erin could approach the Northern Leeward Islands on Friday night.

Tropical Storm Erin Churns Quickly Westward

Tropical Storm Erin churned quickly westward over the Atlantic Ocean between the Cabo Verde Islands and the Northern Lesser Antilles on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Erin was located at latitude 17.2°N and longitude 36.3°W which put the center about 1765 miles (2835 km) east of the Northern Lesser Antilles.  Erin was moving toward the west at 23 m.p.h. (37 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 1004 mb.

Tropical Storm Erin moved into a region of drier air on Monday night.  The drier air caused many of the thunderstorms in Erin’s circulation to dissipate.  The circulation around Tropical Storm Erin consisted primarily of bands of showers and lower clouds on Tuesday morning.  A few thunderstorms were still occurring in some of the rainbands.

The strongest winds were occurring in the northern half of Tropical Storm Erin.  Winds to tropical storm force extended out 35 miles (55 km) in the northern side of Erin’s circulation.  The winds in the southern side of Tropical Storm Erin were blowing at less than tropical storm force.

Tropical Storm Erin will move through an environment marginally favorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation.  The winds in the lower levels of the atmosphere will also blow from the east.  So, there will be little vertical wind shear.  Erin will continue to move through the region of drier air today.  The drier air will inhibit intensification in the short term.  Tropical Storm Erin is likely to maintain its intensity during the next 24 hours.  Erin will move over warmer water later this week.  Tropical Storm Erin is likely to strengthen to a hurricane later this week.

Tropical Storm Erin will move around the southern side of a high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Erin toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Erin will move toward the Northern Lesser Antilles.  Erin could approach the Northern Lesser Antilles at the end of this week.

Tropical Storm Erin Forms West of Cabo Verde

Tropical Storm Erin formed over the eastern Atlantic Ocean west of the Cabo Verde Islands on Monday morning.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Erin was located at latitude 17.4°N and longitude 28.0°W which put the center about 280 miles (455 km) west-northwest of the Cabo Verde Islands.  Erin was moving toward the west at 20 m.p.h. (32 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 1004 mb.

A low pressure system over the eastern Atlantic Ocean west of the Cabo Verde Islands strengthened on Monday morning and the U.S. National Hurricane Center designated the system as Tropical Storm Erin.

The circulation around Tropical Storm Erin exhibited more organization on Monday morning.  More thunderstorms formed near the center of Erin’s circulation.  Thunderstorms were also occurring in bands revolving around the center of Tropical Storm Erin.  Storms near the center of Erin started to generate upper level divergence that was pumping mass away from the tropical storm.

The strongest winds were occurring in the northern part of Tropical Storm Erin.  Winds to tropical storm force extended out 35 miles (55 km) in the northern half of Erin’s circulation.  The winds in the southern side of Tropical Storm Erin were blowing at less than tropical storm force.

Tropical Storm Erin will move through an environment somewhat favorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation.  The winds in the lower levels of the atmosphere will also blow from the east.  So, there will be little vertical wind shear.  Erin will move through a region of drier air later today.  The drier air will inhibit intensification in the short term.  Tropical Storm Erin could intensify slowly during the next 24 hours.  Erin will move over warmer water later this week.  Tropical Storm Erin is likely to strengthen to a hurricane later this week.

Tropical Storm Erin will move around the southern side of a high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Erin toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Erin will move away from the Cabo Verde Islands.

Tropical Storm Dexter Passes South of Newfoundland

Tropical Storm Dexter passed south of Newfoundland on Wednesday evening.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Dexter was located at latitude 40.2°N and longitude 54.2°W which put the center about 450 miles (730 km) south of Cape Race, Newfoundland.  Dexter was moving toward the east at 17 m.p.h. (28 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 999 mb.

Tropical Storm Dexter was making a transition to an extratropical cyclone on Wednesday evening.  Dexter was move over water where the Sea Surface Temperatures are near 24°C.  It was moving under the southern part of an upper level trough that is southwest of Greenland.  The upper level trough was producing strong westerly winds that were blowing toward the top of Dexter’s circulation.  Those winds were causing strong vertical wind shear.  The cool Sea Surface Temperatures and the strong vertical wind shear were causing Tropical Storm Dexter to make a transition to an extraropical cyclone.

The transition to an extratropical cyclone was causing changes to the structure of Tropical Storm Dexter.  Thunderstorms were still developing in the eastern side of Dexter’s circulation.  Bands in the other parts of Tropical Storm Dexter consisted primarily of showers and lower clouds.

The size of the circulation around Tropical Storm Dexter increased as Dexter made its transition to an extratropical cyclone.  Winds to tropical storm force extended out 170 miles (275 km) from the center of Dexter’s circulation.

The upper level trough southwest of Greenland will steer Tropical Storm Dexter toward the east-northeast during the next 48 hours.  On its anticipated track, Tropical Storm Dexter will pass south of Greenland and Iceland.

Tropical Storm Dexter will complete the transition to a strong extratropical cyclone on Thursday.  Dexter is likely to strengthen as it completes the transition to an extratropical cyclone.

Tropical Storm Dexter Moves South of Nova Scotia

Tropical Storm Dexter moved south of Nova Scotia on Tuesday evening.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Dexter was located at latitude 38.9°N and longitude 61.3°W which put the center about 410 miles (660 km) south-southeast of Halifax, Nova Scotia.  Dexter was moving toward the east-northeast at 12 m.p.h. (19 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 1005 mb.

The structure of Tropical Storm Dexter did not change much on Tuesday.  Strong westerly winds in the upper troposphere were blowing toward the top of Dexter’s circulation.  Those winds were causing strong vertical wind shear.  The vertical wind shear was making the distribution of thunderstorms asymmetrical.  Thunderstorms were still forming in bands in the eastern side of Tropical Storm Dexter.  Bands in the western side of Dexter’s circulation consisted primarily of showers and lower clouds.

Winds to tropical storm force extended out 80 miles (130 km) from the center of Tropical Storm Dexter.

Tropical Storm Dexter will move through an environment unfavorable for intensification of a tropical cyclone during the next 24 hours.  Dexter will move over water where the Sea Surface Temperatures are near 26°C. An upper level trough over eastern Canada U.S. will continue to cause strong vertical wind shear.  The strong wind shear will prevent Tropical Storm Dexter from intensifying as a tropical cyclone.  However, Tropical Storm Dexter will make a transition to and extratropical cyclone during the next day or two.  Dexter is likely to get stronger when it starts to make a transition to an extratropical cyclone.

The upper level trough over eastern Canada U.S. will steer Tropical Storm Dexter toward the east-northeast during the next 24 hours. On its anticipated track, Tropical Storm Dexter will move south of Newfoundland on Wednesday.

Tropical Storm Dexter Passes North of Bermuda

Tropical Storm Dexter passed north of Bermuda on Monday evening.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Dexter was located at latitude 36.8°N and longitude 65.6°W which put the center about 315 miles (415 km) north of Bermuda.  Dexter was moving toward the northeast at 13 m.p.h. (21 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 1002 mb.

An upper level trough near the east coast of the U.S. was producing strong westerly winds that were blowing toward the top of Tropical Storm Dexter.  Those winds were causing strong vertical wind shear.  The wind shear was affecting the structure of Dexter’s circulation.  Thunderstorms were occurring in bands in the eastern side of Tropical Storm Dexter.  Bands in the western side of Dexter’s circulation consisted primarily of showers and lower clouds.

The strong vertical wind shear and the asymmetrical distribution of thunderstorms were also affecting the distribution of wind speeds in Tropical Storm Dexter.  Winds to tropical storm force extended out 90 miles (145 km) in the eastern side of Dexter’s circulation.  The winds in the western side of Tropical Storm Dexter were blowing at less than tropical storm force.

Tropical Storm Dexter will move through an environment unfavorable for intensification of a tropical cyclone during the next 24 hours.  Dexter will move over water where the Sea Surface Temperatures are near 27°C.  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 prevent Tropical Storm Dexter from intensifying.  Dexter could get stronger when it starts to make a transition to an extratropical cyclone.

The upper level trough near the east coast of the U.S. will steer Tropical Storm Dexter toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Dexter will move farther away from Bermuda.