Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Tropical Storm Gordon Nears Gulf Coast

Tropical Storm Gordon moved closer to the Gulf Coast of the U.S. on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Gordon was located at latitude 28.5°N and longitude 86.8°W which put it about 145 miles (235 km) east-southeast of the mouth of the Mississippi River.  Gordon was moving toward the northwest at 15 m.p.h. (24 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 1001 mb.

A Hurricane Warning was in effect for the portion of the coast from the mouth of the Pearl River to the Alabama-Florida border.  Tropical Storm Warnings were in effect for the portions of the coast from Grand Isle, Louisiana to the mouth of the Pearl River including Lake Pontchartrain and from the Alabama-Florida border to the Okaloosa-Walton County line in Florida.

The circulation of Tropical Storm Gordon appeared to be getting more organized on Tuesday morning.  More thunderstorms developed near the center of circulation.  Storms near the center were generating upper level divergence which was pumping mass away to the east of the tropical storm.  Several bands of showers and thunderstorms north and east of the center were moving toward the Gulf Coast.  The bands southwest of the center consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation, but the winds were weaker in the southwestern quadrant of Tropical Storm Gordon.

Tropical Storm Gordon could strengthen into a hurricane before it makes landfall.  Gordon will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the southeastern U.S. was producing southwesterly winds which were blowing toward the top of the circulation.  Those winds were causing some vertical shear, but they will not be strong enough to prevent intensification.  The surface pressure decreased slightly on Tuesday morning.  Increased friction near the coast could cause the circulation to tighten around the center, when Tropical Storm Gordon gets closer to the Gulf Coast.

Tropical Storm Gordon will move around the southwestern end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Gordon in a general northwesterly direction during the next several days.  On its anticipated track the center of Hurricane Gordon is likely to make landfall on the northern Gulf Coast on Tuesday night.  Gordon will produce winds to near hurricane force at the coast.  It could cause a storm surge of 5 to 8 feet (1.5 to 2.5 meters) east of the center where the wind blows water toward the coast.  The highest storm surge will occur in bays and the mouths of streams and rivers where the shape of the coast funnels water into those areas.  Tropical Storm Gordon will also drop heavy rain over portions of northwest Florida, southwest Alabama, Mississippi and eastern Louisiana.  Locally heavy rain could create the potential for flash floods.

Elsewhere over the Atlantic Ocean, former Tropical Storm Florence strengthened into the third Atlantic hurricane of 2018.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Florence was located at latitude 19.7°N and longitude 42.5°W which put it about 1270 miles (2045 km) east-northeast of the Lesser Antilles.  Florence was moving toward the west-northwest 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 990 mb.

Tropical Storm Gordon Forms, Causes Warnings for South Florida

Former Potential Tropical Cyclone Seven developed a distinct center of circulation on Sunday morning and the National Hurricane Center upgraded the system to Tropical Storm Gordon.  At 8:30 a.m. EDT on Sunday the center of Tropical Storm Gordon was located at latitude 25.1°N and longitude 80.6°W which put it about 10 miles (15 km) west of Key Largo, Florida.  Gordon was moving toward the west-northwest at 16 m.p.h. (26 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 1009 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Golden Beach to Bonita Beach, Florida.  A Tropical Storm Warning was in effect for the Florida Keys from Craig Key to Ocean Reef including Florida bay.  A Tropical Storm Warning was in effect for the portion of the coast from the Alabama-Florida border to Morgan City, Louisiana including Lake Pontchartrain.

The circulation of Tropical Storm Gordon became much better organized during the past 12 hours.  A distinct low level center of circulation formed and many more thunderstorms developed.  A C-MAN station on Fowey Rock, Florida reported sustained winds of 49 m.p.h. (80 km/h) supporting the designation as a tropical storm.  The circulation of Tropical Storm Gordon was still organizing.  More thunderstorms were developing in bands northeast of the center of circulation than in other parts of the tropical storm.  Those storms were beginning to generate upper level divergence which was pumping mass away from the core of Gordon.

Tropical Storm Gordon will be moving through an environment favorable for intensification during the next 36 hours.  Gordon will be moving over water where the Sea Surface Temperature is near 30°C.  It will be moving through a region where the upper level winds will be weak and there will be little vertical wind shear.  Tropical Storm Gordon will continue to intensify and it could intensify more rapidly once the inner core becomes better organized.  There is a chance that Gordon could strengthen into a hurricane before it reaches the north coast of the Gulf of Mexico.

Tropical Storm Gordon will move around the west end of a subtropical high pressure system over the western Atlantic Ocean.  The ridge will steer Gordon in  a general west-northwesterly direction.  On its anticipated track Tropical Storm Gordon will move away from South Florida later today.  Gordon could approach the north coast of the Gulf of Mexico late on Tuesday.  Locally heavy rain could cause floods in South Florida.  Tropical Storm Gordon could produce a storm surge of 6 to 9 feet (2 to 3 meters) along parts of the northern Gulf Coast.

Potential Tropical Cyclone Seven Causes Tropical Storm Watch for U.S. Gulf Coast

Potential Tropical Cyclone Seven caused the National Hurricane Center to issue a Tropical Storm Watch for a portion of the U.S. Gulf Coast on Sunday afternoon.  A Tropical Storm Watch was in effect for the portion of the coast from the Alabama-Florida border to Morgan City, Louisiana including Lake Pontchartrain.  At 5:00 p.m. EDT on Sunday the center of Potential Tropical Cyclone Seven was located at latitude 22.7°N and longitude 77.3°W which put it about 275 miles (445 km) east-southeast of Marathon, Florida.  It was moving toward the west-northwest at 15 m.p.h (24 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 1012 mb.

Bands of showers and thunderstorms began to form in a tropical wave over the Bahamas and the National Hurricane Center designated the system as Potential Tropical Cyclone Seven in order to be able to issue the Tropical Storm Watch for the north coast of the Gulf of Mexico.  The circulation of Potential Tropical Cyclone Seven was still organizing.  A distinct low level center of circulation had not formed.  Bands of showers and thunderstorms were developing and the bands were starting to revolve around the inner part of the weather system.  Thunderstorms were beginning to generate some upper level divergence.

Potential Tropical Cyclone Seven will be moving into an environment favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge is forecast to develop over Potential Tropical Cyclone Seven.  If that occurs, then the upper level winds would be weak and there would be little vertical wind shear.  Potential Tropical Cyclone Seven is forecast to intensify into Tropical Storm Gordon.  If the system moves slowly enough, there is a chance it could strengthen into a hurricane before it reaches the Gulf Coast.

Potential Tropical Cyclone Seven will move around the western end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Potential Tropical Cyclone Seven in a general west-northwesterly direction.  On its anticipated track the system will move over the Florida Keys on Monday.  It will be over the eastern Gulf of Mexico on Tuesday and the system could reach the northern Gulf Coast late on Tuesday or early on Wednesday.

Elsewhere over the tropical Atlantic, Tropical Storm Florence was moving quickly away from the Cabo Verde Islands.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Florence was located at latitude 17.4°N and longitude 34.6°W which put it about 700 miles (1125 km) west of the Cabo Verde Islands.  Florence was moving toward the west-northwest at 15 m.p.h. (24 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 1000 mb.

Tropical Storm Florence Develops West of Cabo Verde Islands

Tropical Storm Florence developed west of the Cabo Verde Islands on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Florence was located at latitude 15.6°N and longitude 29.0°W which put it about 310 miles (500 km) west of the Cabo Verde Islands.  Florence was moving toward the west-northwest at 16 m.p.h. (26 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.

The circulation of former Tropical Depression Six became better organized on Saturday and the National Hurricane Center designated the system as Tropical Storm Florence.  The center of circulation became more well defined and more thunderstorms developed closer to the center.  Numerous bands of showers and thunderstorms began to form.  The forming rainbands were revolving around the center of circulation.  Storms near the center started to generate upper level divergence.

Tropical Storm Florence will be moving through an environment somewhat favorable for intensification during the next day or two.  Florence will move over water where the Sea Surface Temperature is near 26°C.  It will move through a region where the upper level winds will be weak and there will be little vertical wind shear.  Tropical Storm Florence is likely to intensify during the next 24 to 48 hours.

Tropical Storm Florence will be moving south of a subtropical ridge over the eastern Atlantic Ocean.  The ridge will steer Florence in a general west-northwesterly motion during the next two or three days.  On its anticipated track the center of Tropical Storm Florence will move farther away from the Cabo Verde Islands.

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.