Tag Archives: Potential Tropical Cyclone Seven

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 Franklin Develops Over Northwest Caribbean Sea

A center of circulation developed in a system previously designated as Potential Tropical Cyclone Seven and the National Hurricane Center named the system Tropical Storm Franklin on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Franklin was located at latitude 16.4°N and longitude 83.0°W which put it about 380 miles (610 km) east-southeast of Chetumal, Mexico.  Franklin was moving toward the west-northwest 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 1006 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Chetumal to Campeche, Mexico.  A Tropical Storm Watch is in effect for the portion of the coast from Belize City, Belize northward to the Belize/Mexico border.

Visible satellite images just before sunset suggested that a center of circulation had formed in the tropical wave previously designated Potential Tropical Cyclone Seven and the National Hurricane Center named it Tropical Storm Franklin.  The circulation of Tropical Storm Franklin is still not well organized.  The apparent center is located near the western edge of an area of thunderstorms.  Most of the thunderstorms are still forming east of the system, which indicates that vertical wind shear is probably still affecting the circulation.  The thunderstorms are producing some upper level divergence which is pumping mass away to the east of the tropical storm.

The environment ahead of Tropical Storm Franklin will become more favorable for intensification.  Franklin will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough west of Franklin is producing westerly winds which are causing the vertical wind shear.  The trough is expected to weaken on Monday and when that happens the shear will diminish.  Warm water and less shear should allow Tropical Storm Franklin to strengthen before it reaches the Yucatan peninsula.  Franklin will weaken when it moves over land, but it is likely to re-intensify when it moves over the southern Gulf of Mexico.

Tropical Storm Franklin is being steered toward the west-northwest by a subtropical high centered over the Atlantic Ocean.  A general west-northwesterly motion is expected to continue.  On its anticipated track Tropical Storm Franklin could approach the Yucatan peninsula in about 24 hours.  Franklin will bring gusty winds and locally heavy rain to that area.  The heavy rain could cause flooding in some locations.

Tropical Storm Warning Issued for Mexico Due to Potential Tropical Cyclone Seven

The National Hurricane Center changed the designation of Invest 90L to Potential Tropical Cyclone Seven because of the need to issue a Tropical Storm Warning for portions of Mexico.  At 5: 00 p.m. EDT on Sunday the center of Potential Tropical Cyclone Seven was located at latitude 15.6°N and longitude 82.0°W which put it about 90 miles (145 km) east-northeast of Cabo Gracias a Dios.  It was moving toward the west-northwest at 12 m.p.h. (19 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 1008 mb.

A Tropical Storm Warning has been issued for the portion of the coast from Chetumal to Campeche, Mexico.  A Tropical Storm Watch has been issued for the portion of the coast from Belize City to the Belize/Mexico border.

A broad area of low pressure formed in a strong tropical wave over the northwestern Caribbean Sea.  There is not a well defined center of circulation within the broad area of low pressure.  Most of the thunderstorms are developing in the eastern half of the circulation.  There are few thunderstorms in the western half of the system.  The thunderstorms in the eastern half of the low are generating some upper level divergence which is pumping out mass to the east of the low.

Potential Tropical Cyclone Seven will move through a relatively favorable environment over the northwestern Caribbean Sea.  It will move over water where the Sea Surface Temperature is 30°C.  A small upper level trough to the west of the low is producing westerly winds which are causing moderate vertical wind shear.  The wind shear is probably the reason why most of the thunderstorms are in the eastern side of the circulation.  The upper trough is forecast to weaken and the shear is expected to diminish.  Potential Tropical Cyclone Seven could become a tropical storm over the northwestern Caribbean Sea, which is why the Tropical Storm Warning was issued.

Potential Tropical Cyclone Seven is being steered to the west-northwest by a subtropical high pressure system centered over the Atlantic Ocean.  That general motion is expected to continue for the next several days.  On its anticipated track Potential Tropical Cyclone Seven could reach the Yucatan Peninsula within 36 hours.  It could bring gusty winds and heavy rain when it moves over the Yucatan.  The system could restrengthen when it moves over the southern Gulf of Mexico.