Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Potential Tropical Cyclone Six Causes Warning for Cabo Verde Islands

The potential strengthening of Potential Tropical Cyclone Six caused the government of the Cabo Verde Islands to issue Tropical Storm Warnings for some of the southern islands on Thursday.  Tropical Storm Warnings were issued to Santiago, Fogo and Brava.  At 5:00 p.m. EDT on Thursday the center of Potential Tropical Cyclone Six was located at latitude 12.9°N and longitude 19.4°W which put it about 360 miles (580 km) east-southeast of the Cabo Verde Islands.  It was moving toward the west at 9 m.p.h. (15 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.

The circulation of of Potential Tropical Cyclone Six was still organizing.  There was a broad area of low pressure, but there was not a well defined center of circulation.  Numerous bands of showers and thunderstorms were revolving around the circulation of the broad low.  Many of the stronger thunderstorms were in the outer part of the circulation.  Since there were few thunderstorm in the inner portion of the circulation, it had not started to generate upper level divergence.

Potential Tropical Cyclone Six will be moving through an area favorable for intensification.  It will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where there will be little vertical wind shear.  Potential Tropical Cyclone Six is forecast to become a tropical depression during the next 12 hours.  It could strengthen into a tropical storm on Friday and it could intensify into a hurricane during the weekend.

Potential Tropical Cyclone Six will move south of a subtropical ridge over the eastern Atlantic Ocean during the next few days.  The ridge will steer the system toward the west-northwest.  On its anticipated track Potential Tropical Cyclone Six will pass near the southern Cabo Verde Islands on Friday, which is why the Tropical Storm Warning was issued.

Ernesto Makes Transition to Tropical Storm

Former Subtropical Storm Ernesto made a transition to a tropical storm on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Ernesto was located at latitude 43.0°N and longitude 41.0°W which put it about 645 miles (1035 km) east-southeast of Cape Race, Newfoundland.  Ernesto was moving toward the northeast at 18 m.p.h. (30 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 1007 mb.

Even though now Tropical Storm Ernesto moved over water where the Sea Surface Temperature was between 24°C and 25°C, there was enough energy in the upper ocean to cause more thunderstorms to develop.  In addition, many of the thunderstorms developed close to the center of circulation.  The inner bands of showers and thunderstorms became stronger and the bands in the outer parts of the circulation weakened.  Ernesto exhibited a structure like a tropical cyclone and the National Hurricane Center classified the system as a tropical storm in the 5:00 p.m. EDT advisory.

Tropical Storm Ernesto will move over much cooler water during the next 24 hours.  It is likely to make a transition to an extratropical cyclone when it moves over the cooler water.  Ernesto could strengthen when colder air is pulled into the western half of the circulation and a cold front forms south of the center.  The development of the cold front and upper level divergence could strengthen the pressure gradient force which would give the air a stronger push.  An upper level trough east of the U.S. is forecast to steer Ernesto in the general direction of Ireland and the United Kingdom.

Subtropical Storm Ernesto Forms West of the Azores

Subtropical Storm Ernesto formed west of the Azores on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Subtropical Storm Ernesto was located at latitude 38.1°N and longitude 46.0°W which put it about 695 miles (1120 km) southeast of Cape Race, Newfoundland.  Ernesto was moving toward the north at 8 m.p.h. (13 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 1008 mb.

More thunderstorms formed closer to the center of a low pressure system west of the Azores on Wednesday morning and the National Hurricane Center designated the system as Subtropical Storm Ernesto.  Several bands of showers and thunderstorms wrapped around the eastern and northern portions of the circulation.  Bands northwest of the center of Ernesto consisted primarily of showers and lower clouds.  The circulation may have been transporting some cooler, drier, more stable air into that part of the circulation.  Showers and thunderstorms around the center of Ernesto were generating upper level divergence which was pumping mass away to the northeast of the subtropical storm.

Subtropical Storm Ernesto will move through an environment that could support some intensification during the next day or so.  Ernesto will move over water where the Sea Surface Temperature is near 26°C.  It will move through a region where the upper level winds are not too strong and there will not be much vertical wind shear.  Subtropical Storm Ernesto could strengthen during the next 12 to 24 hours.  Ernesto will move over cooler water later on Thursday and it will start to weaken.  An upper level trough east of the U.S. will approach Subtropical Storm Ernesto from the west.  Southwesterly winds ahead of the trough will cause more vertical wind shear and Ernesto could make a transition to an extratropical cyclone.

The southwesterly winds ahead of the upper level trough will steer Subtropical Storm Ernesto in a general northeasterly direction.  On its anticipated track Subtropical Ernesto will pass between the Azores and Greenland.

Debby Makes a Transition to a Tropical Storm

Former Subtropical Storm Debby made a transition to a tropical storm on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Debby was located at latitude 41.2°N and longitude 48.3°W which put it about 1150 miles (1855 km) west-northwest of the Azores.  Debby was moving toward the northeast at 12 m.p.h. (19 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 1003 mb.

The structure of former Subtropical Storm Debby changed on Wednesday and it exhibited the characteristics of a tropical storm.  More thunderstorms formed around the center of circulation and those thunderstorms rose higher into the atmosphere.  Additional bands of showers and thunderstorms developed and revolved around the core of the circulation.  Storms near the core began to generate upper level divergence.  The strongest winds occurred closer to the center of circulation.  The National Hurricane Center designated Debby as a tropical storm based on information from satellites.

Tropical Storm Debby will move into an environment unfavorable for a tropical storm during the next 24 to 48 hours.   Debby was over water where the Sea Surface Temperature was near 26°C, but it will soon move over much cooler water.  It will start to weaken when it moves over the cooler water.  It could take several days for the circulation around Tropical Storm Debby to spin down.

Tropical Storm Debby will be steered toward the northeast as it moves between an upper level trough to the west and an upper level ridge to the east.  On its anticipated track Tropical Storm Debby will move between the Azores and Greenland.

Subtropical Storm Debby Forms West of the Azores

Subtropical Storm Debby formed over the North Atlantic Ocean west of the Azores on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Subtropical Storm Debby was located at latitude 38.9°N and longitude 48.5°W which put it about 1160 miles (1870 km) west of the Azores.  Debby was moving toward the north at 16 m.p.h. (26 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 1008 mb.

A surface low pressure system revolved around the western side of an upper level low over the North Atlantic Ocean during the past few days.  More bands of showers and thunderstorms developed around the surface low on Tuesday morning and its circulation become more circular.  The National Hurricane Center designated the low pressure system as Subtropical Storm Debby based on satellite imagery.  The strongest winds were occurring in a rainband that wrapped around the northern side of the circulation.  Bands south of the center of circulation consisted primarily of showers and lower clouds.

Subtropical Storm Debby will move through an environment somewhat favorable for intensification during the next 24 hours.  Debby will move over water where the Sea Surface Temperature is between 26°C and 27°C.  Subtropical Storm Debby will move between an upper level trough to its west and an upper level ridge to its east.  The trough and ridge will produce southeasterly winds which will cause moderate vertical wind shear.  Subtropical Storm Debby could strengthen during the next 24 hours.  Debby will move over much colder water in about 36 hours and then it will weaken.

The upper level ridge and trough will steer Subtropical Storm Debby in a mainly northerly direction.  On its anticipated track Subtropical Storm Debby will remain west of the Azores.

Beryl Reorganizes as a Subtropical Storm North of Bermuda

A low pressure system associated with former Tropical Storm Beryl reorganized north of Bermuda on Saturday and the National Hurricane Center designated the system as Subtropical Storm Beryl.  At 2:00 p.m. EDT on Saturday the center of Subtropical Storm Beryl was located at latitude 36.4°N and longitude 65.7°W which put it about 575 miles (930 km) south-southwest of Halifax, Nova Scotia.  Beryl was moving toward the 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 1010 mb.

The remnants of former Tropical Storm Beryl moved slowly across the northern Caribbean Sea and then over the southeastern Bahamas to a position northwest of Bermuda.  A low pressure system formed at the surface.  Bands of showers and thunderstorms developed and began to revolve around the the low pressure system.  The low pressure system moved under the eastern side of an upper level trough.  The trough contains colder air in the upper levels and it was also producing southwesterly winds which were blowing toward the top of the surface low pressure system.  The southwesterly winds were generating moderate vertical wind shear and the strongest rainbands were occurring on the eastern side of the surface low.  Some drier air was moving around the western and southern part of the upper level trough, which may have contributed to the weaker bands on the western side of the circulation.  The presence of the upper level trough and the asymmetrical distribution of thunderstorms around the surface low prompted the National Hurricane Center to designate the system as a subtropical storm.

Subtropical Storm Beryl will move through an environment marginally favorable for intensification during the next 24 hours.  Beryl will move over water where the Sea Surface Temperature is near 26°C.  The upper level trough will continue to produce moderate vertical wind shear.  The wind shear and the drier air will inhibit intensification.  Subtropical Storm Beryl could intensify a little more during the next 24 hours.  Beryl will move over colder water later on Sunday and it will start to weaken when that occurs.

The upper level trough was steering Subtropical Storm Beryl toward the northeast and a general motion in that direction is forecast to continue for several more days.  On its anticipated track Subtropical Storm Beryl will pass south of Nova Scotia on Sunday.  Beryl could be near Newfoundland by Tuesday.

Hurricane Chris Weakens South of Nova Scotia

Hurricane Chris weakened slowly on Wednesday as it passed well south of Nova Scotia.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Chris was located at latitude 39.6°N and longitude 63.0°W.  Chris was moving toward the northeast at 29 m.p.h. (46 km/h).  The maximum sustained wind speed was 85 m.p.h. (140 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 980 mb.

Hurricane Chris exhibited the structure of a hurricane on Thursday, but the clouds did not rise quite as high because it was over slightly cooler water.  There was still an eye at the center of circulation.  Several bands of showers and thunderstorms were revolving around the core of the circulation.  The rainbands were weaker in the southwestern part of the hurricane because some drier air was entering that part of the circulation.  Storms in the core of the circulation were generating upper level divergence.

Hurricane Chris is likely to weaken again on Thursday.  It will start to move over much cooler water where there is less energy in the upper ocean.  In addition an upper level trough over the eastern U.S. will produce southwesterly winds which will blow toward the upper part of the hurricane.  Those winds will cause strong vertical wind shear.  The shear will undercut the upper level divergence and tilt the circulation toward the northeast with height.  Hurricane Chris will start to make a transition to an extratropical cyclone when the effects of the cooler water and stronger shear begin to alter the structure of the hurricane.

The upper level trough was steering Hurricane Chris rapidly toward the northeast and that motion is expected to continue for several more days.  On its anticipated track Hurricane Chris will be near Labrador on Thursday night.  The extratropical cyclone that results from the transition of Hurricane Chris will be near Iceland during the weekend.

Chris Strengthens to a Hurricane Southeast of Cape Hatteras

Former Tropical Storm Chris strengthened to a hurricane southeast of Cape Hatteras on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Chris was located at latitude 33.7°N and longitude 72.4°W which put it about 205 miles (330 km) east-southeast of Cape Hatteras, North Carolina.  Chris was moving toward the northeast 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 980 mb.

Hurricane Chris strengthened on Tuesday when it moved northeast of cooler water Chris had mixed to the surface while it was meandering off the coast of the Carolinas.  An eye with a diameter of 30 miles (50 km) formed at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in the eastern side of that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Hurricane Chris.  The strongest rainbands were in the eastern half of the circulation.  Drier air near the western half of the circulation was contributing to the weaker bands in that part of the hurricane.  Storms in the core of the circulation were generating upper level divergence which was pumping mass away to the north and east of the hurricane.  Winds to hurricane force extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out about 95 miles (155 km) from the center.

Hurricane Chris will move through an environment favorable for intensification on Wednesday.  Chris will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough over the northeastern U.S. will produce southwesterly winds that will blow toward the top of the hurricane.  The winds speeds are similar at most levels and they will not generate a lot of vertical wind shear during the next 24 hours.  Hurricane Chris will strengthen on Wednesday and it could intensify rapidly.  Chris will move over cooler water when it gets north of the Gulf Stream and it will start to weaken when that occurs.

The trough over the northeastern U.S. will steer Hurricane Chris toward the northeast.  On its anticipated track Chris will move away from the coast of North Carolina.  Chris could be south of Nova Scotia in about 36 hours and it could be near Newfoundland in several days.

Elsewhere, the remnants of former Tropical Storm Beryl crossed Hispaniola and they were moving toward the southeastern Bahamas.  At 2:00 p.m. EDT on Tuesday the center of Former Tropical Storm Chris was located at latitude 20.1°N and longitude 72.6°W which put it about 40 miles (65 km) northeast of Port de Paix, Haiti.  It was moving toward the northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1013 mb.  A reconnaissance aircraft is scheduled to investigate the system on Wednesday if there are signs that it could be reorganizing into a tropical cyclone.

Tropical Storm Chris Develops South of Cape Hatteras, Beryl Nears Lesser Antilles

Tropical Storm Chris developed south of Cape Hatteras on Sunday morning, while Tropical Storm Beryl neared the Lesser Antilles.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Chris was located at latitude 32.9°N and longitude 75.0°W which put it about 160 miles (260 km) south of Cape Hatteras, North Carolina.  Chris was nearly stationary.  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.

Thunderstorms developed closer to the center of circulation on Sunday morning and the National Hurricane Center designated former Tropical Depression Three as Tropical Storm Chris.  The circulation of Chris was organizing quickly.  A band of showers and thunderstorms was wrapping around the center of circulation.  Several other rainbands were revolving around the core of the tropical storm.  The bands northwest of the center were weaker because there was drier air in that part of Chris.  The storms near the center of circulation were beginning to generate upper level divergence.

Tropical Storm Chris will remain in an environment favorable for intensification for the next two or three days.  The water in the upper portion of the Atlantic Ocean east of the Carolinas is warmer than normal.  Tropical Storm Chris will be over water where the Sea Surface Temperature is near 28°C.  Chris will be southeast of an upper level trough over the northeastern quarter of the U.S. and it will be under a small upper level ridge.  The upper level winds will be weak and there will be little vertical wind shear.  Tropical Storm Chris will continue to intensify and it could strengthen to a hurricane in the next day or two.

Since Tropical Storm Chris is under the small upper level ridge, the steering winds are weak.  Chris may not move much during the next 24 to 48 hours.  Tropical Storm Chris is forecast to linger of the coast of the Carolinas for several days.  Eventually an upper level trough will approach from the west and start to push Chris toward the northeast.

Elsewhere, Tropical Storm Beryl was nearing the Lesser Antilles on Sunday morning.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Beryl was located at latitude 14.4°N and longitude 57.9°W which put it about 210 miles (335 km) east of Martinique.  Beryl was moving toward the west-northwest 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 1007 mb.

Tropical Storm Warnings were in effect for Dominica and Guadeloupe.  Tropical Storm Watches were in effect for Saba, St. Eustatius, St. Maarten, St. Martin, Martinique, St. Lucia, and St. Barthelemy.

Thunderstorms continued to develop near the center of Tropical Storm Beryl on Sunday morning and the weakening trend halted at least temporarily.  Beryl remained a small tropical storm.  Winds to tropical storm force only extended out about 45 miles (75 km) from the center of circulation.  There were several bands of showers and thunderstorms in the eastern half of Tropical Storm Beryl.  The bands in the western half of the circulation consisted primarily of showers and low clouds.

Tropical Storm Beryl is forecast to into a region where the easterly winds in the lower levels are stronger.  That would increase the vertical wind shear and make it difficult for the circulation to stay vertically coherent.  Beryl will move over water where the Sea Surface Temperature is near 27°C.  So, there will be enough energy in the upper ocean to support a tropical storm if the wind shear is not too strong.  Tropical Storm Beryl is forecast to weaken when it moves over the eastern Caribbean Sea, but that will depend on how strong the vertical shear gets.

Tropical Storm Beryl is moving south of the subtropical high over the Atlantic Ocean which is steering Beryl toward the west-northwest.  A general motion toward the west-northwest is forecast to continue for several more days.  On its anticipated track Tropical Storm Beryl will bring gusty winds and locally heavy rain to St. Lucia, Martinique, Dominica and Guadeloupe during the next few hours,

Tropical Storm Beryl Weakens East of the Lesser Antilles

Tropical Storm Beryl weakened on Saturday as it move closer to the Lesser Antilles.  At 11:00 p.m. EDT on Saturday the center of circulation was located at latitude 13.1°N and longitude 54.3°W which put it about 495 miles (795 km) east-southeast of the Lesser Antilles.  Beryl was moving toward the west-northwest at 18 m.p.h. (30 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 1005 mb.

Tropical Storm Warnings were in effect for Dominica and Guadeloupe.  Tropical Storm Watches were in effect for Saba, St. Eustatius, St. Maarten, Martinique, St. Martin, St. Barthelemy, Barbados and St. Lucia.

Tropical Storm Beryl moved into a region where the easterly winds in the lower level were stronger and the increased vertical wind shear started to blow the lower part of the circulation to the west of the upper part of Beryl.  It also seemed to move into an area of drier air, which caused most of the stronger thunderstorms to weaken.  There was still a well organized circulation in the lower levels, but it weakened on Saturday.  More thunderstorms developed near the center of circulation and on the eastern side of Tropical Storm Beryl in recent hours.  If those storms persist then Beryl could strengthen again, but if they dissipate quickly, then the tropical storm could weaken again on Sunday.

Tropical Storm Beryl will move through an environment that contains factors that are favorable for intensification and other factors that are unfavorable.  Beryl will move over water where the Sea Surface Temperature is near 27°C.  It will move through an area where the lower level winds are stronger and so there will be more vertical wind shear.  There will be areas of moister air within a larger area of drier air.  If the recently developed thunderstorms persist on Sunday, then the Beryl could strengthen again.  However, if the storms dissipate in a few hours, then Tropical Storm Beryl could weaken further.  The small size of the circulation means that rapid changes in intensity can occur.

Tropical Storm Beryl was moving south of the subtropical high over the Atlantic Ocean.  The high was steering Beryl toward the west-northwest and that general motion is forecast to continue for the next several days.  On its anticipated track Tropical Storm Beryl could reach the Lesser Antilles on Sunday night.  There is a lot of uncertainty about how strong Beryl may be when it reaches those islands.

Elsewhere over the Atlantic Ocean Tropical Depression Three spun south of Cape Hatteras.  At 11:00 p.m. EDT on Saturday the center of Tropical Depression Three was located at latitude 32.9°N and longitude 75.1°W which put it about 160 miles (260 km) south of Cape Hatteras, North Carolina.  It was nearly stationary.  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1014 mb.