Category Archives: Tropical Cyclones

Information about tropical cyclones

Tropical Cyclone Megh Moving Slowly West Over the Arabian Sea

Tropical Cyclone Megh moved slowly westward over the Arabian Sea on Friday.  At 4:00 p.m. EDT on Friday the center of Tropical Cyclone Megh was located at latitude 12.9°N and longitude 60.4°E which put it about 420 miles (680 km) east of Socotra Island, Yemen.  Megh was moving toward the west at 7 m.p.h. (11 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 990 mb.

The convection around Tropical Cyclone Megh diminished earlier today, but more thunderstorms have formed near the center of circulation during the past few hours.  Megh has a well formed, symmetrical circulation with an eyelike feature at the center.  It is a small cyclone and tropical storm force winds only extend out about 50 miles (80 km) from the center.  The new thunderstorms near the center of circulation are starting to generate upper level divergence.

Aside from the possible drier air, the environment surrounding Tropical Cyclone Megh is favorable for intensification,  It is over water where the Sea Surface Temperature is near 28°C.  The winds in the upper levels are light and there is not much vertical wind shear.  Now that thunderstorms are redeveloping near the core of the circulation, Tropical  Cyclone Megh should begin to intensify and it is still likely to reach hurricane intensity in a day or two.

A ridge north of Megh is steering the tropical cyclone toward the west and that general motion is expected to continue during the weekend.  On its anticipated track, Tropical Cyclone Megh could approach Socotra Island, Yemen in about 36 hours.  It could be the equivalent of a hurricane at that time.  Given the prior damage caused by Tropical Cyclone Chapala, Megh could have a significant impact on Socotra Island.

Disturbance Brings Squally Weather to the Northwest Caribbean Sea

A complicated disturbance over the northwestern Caribbean Sea is bringing squally weather to that area.  A tropical wave over the western Caribbean Sea is interacting with an upper level low over eastern Mexico.  The disturbance is causing thunderstorms over a region that extends from the northwestern Caribbean Sea to the southern Gulf of Mexico.  Upper level divergence east of the upper low has led to the formation of a surface low pressure system east of Belize.  At 7:00 p.m. EST on Thursday the center of the surface low was located at latitude 18°N and longitude 86°W which put it about 150 miles (240 km) east-southeast of Chetumal, Mexico.  The surface low was moving toward the west-northwest at 10 m.p.h. (16 m.p.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 1011 mb.

The disturbance is not very well organized, which is normally the case when a tropical wave interacts with an upper level low.  There is a broken area of thunderstorms that extends around the east and northern sides of the disturbance.  However, there are not many thunderstorms close to the center of the surface low.  The upper low is causing vertical wind shear over the western half of the surface low.  Some upper level divergence is occurring over the eastern half of the surface low.

A large high pressure system over the western Atlantic Ocean is steering the disturbance toward the west-northwest.  That general steering pattern is expected to continue for the next two days.  On its anticipated track the disturbance will move over the Yucatan peninsula and over the southern Gulf of Mexico during the next several days.

The disturbance is in an environment that is marginally favorable for tropical development.  The Sea Surface Temperature of the northwestern Caribbean is near 29°C.  There is vertical wind shear, but it may be just small enough to allow for slow development.  On the other hand, the disturbance will move over the Yucatan peninsula which will further inhibit development.  There may also be a chance for development after the disturbance moves over the southern Gulf of Mexico.  The National Hurricane Center is giving a 20% probability of tropical cyclone formation out of the disturbance.

Tropical Cyclone Megh Forms Over the Arabian Sea

A new tropical cyclone, designated with the name Megh, formed Thursday over the same portion of the Arabian Sea where Tropical Cyclone Chapala developed.  At 4:00 p.m. EST on Thursday the center of Tropical Cyclone Megh was located at latitude 13.6°N and longitude 63.0°E which put it about 640 miles (1030 km) east of Socotra Island, Yemen.  Megh was moving toward the west-southwest at 6 m.p.h. (10 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 994 mb.

Tropical Cyclone Megh exhibited increased organization on Thursday.  A core of thunderstorms developed near the center of circulation and a primary rainband spirals around the northern and western sides of the tropical cyclone.  The thunderstorms near the core of Megh are beginning to generate upper level divergence, especially toward the east.

Tropical Cyclone Megh is an environment favorable for intensification.  It is over water where the Sea Surface Temperature is near 28°C.  An upper level ridge north of Megh is generating light northeasterly winds over the top of the tropical cyclone, but the vertical wind shear is modest.  Megh should continue to intensify and it could reach the equivalent of hurricane intensity in a day or two.

The ridge is steering Tropical Cyclone Megh a little south of due west and that general steering motion is expected to continue for several days.  On its anticipated track, Tropical Cyclone Megh could approach Socotra Island, Yemen in 48 to 60 hours.  Since the outer portions of Tropical Cyclone Chapala caused damage on Socotra Island, a direct hit by Tropical Cyclone Megh could have a significant impact there.

Tropical Cyclone Chapala Makes Landfall in Yemen

Tropical Cyclone Chapala made landfall in Yemen just west of Al Mukalla as the equivalent of a hurricane.  At 10:00 p.m. EDT on Monday the center of Tropical Cyclone Chapala was located at latitude 13.9°N and longitude 48.7°E which put it 30 miles (50 km) south of Al Mukalla, Yemen.  Chapala was moving toward the west-northwest 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 105 m.p.h. (170 km/).  The minimum surface pressure was 979 mb.

Tropical Cyclone Chapala reached the western end of the ridge that was steering it toward the west and it turned north toward the coast of Yemen on Monday.  When Chapala reached the western end of the ridge, southerly winds in the upper levels generated vertical wind shear and the circulation of the tropical cyclone tilted toward the north.  In addition, as the core of the circulation neared the coast, it drew in drier air from the Arabian peninsula.  The combination of more wind shear and drier air started to weaken Chapala, but the tropical cyclone was still the equivalent of a hurricane when it made landfall.

The core of Tropical Cyclone Chapala will bring strong winds and heavy rain to the coast.  Although Chapala will weaken fairly quickly as it moves into the dry interior of the Arabian peninsula, the circulation will be capable of producing locally heavy rainfall and flash floods as the tropical cyclone spins down.

Tropical Cyclone Chapala Poised to Enter Gulf of Aden

Tropical Cyclone Chapala continued to move steadily westward on Sunday and it was poised to enter the Gulf of Aden.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Chapala was located at latitude 13.2°N and longitude 52.2°E which put it about 230 miles (370 km) east-southeast of Al Mukalla, Yemen.  Chapala was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 959 mb.

Chapala is still a very well organized tropical cyclone and it is the equivalent of a major hurricane.  Chapala has a 25 mile (40 km) wide eye, which is surrounded by numerous thunderstorms.  Those storms are generating upper level divergence which is pumping out enough mass to balance the air flowing into the center near the surface.  The balance of inflow and outflow allowed Chapala to maintain its intensity on Sunday.

Tropical Cyclone Chapala is over water where the Sea Surface Temperature is around 28.5°C and the upper level winds are light.  There is little vertical wind shear and most environmental factors support the ability of Tropical Cyclone Chapala to maintain its intensity.  However, once Chapala enters the Gulf of Aden it will have very dry air to its north over the Arabian peninsula and dry air to its south over east Africa.  Chapala will remain a strong tropical cyclone as long as the dry air does not reach its core.  However, as Tropical Cyclone Chapala moves closer to the coast of Yemen, the drier air will probably cause it to start to weaken.

A ridge north of Chapala is steering the tropical cyclone toward the west.  Chapala will reach the western end of the ridge on Monday and the tropical cyclone will turn toward the northwest.  On its anticipated track Chapala will make landfall on the coast of Yemen near Al Mukalla in 24 to 30 hours.  It will bring strong winds and heavy rain to the coast.  Chapala is likely to dissipate quickly as it moves inland over the Arabian peninsula, but it could bring heavy rain and flash floods before it does so.

Strong Tropical Cyclone Chapala on Track for Landfall in Yemen

Strong Tropical Cyclone Chapala moved steadily westward on Saturday and it remains on track for a landfall in Yemen.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Chapala was located at latitude 13.6°N and longitude 56.0°E which put it about 265 miles (425 km) south-southeast of Salalah, Oman and about 465 miles (765 km) east of Al Mukalla, Yemen.  Chapala was moving toward the west at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 135 m.p.h. (215 km) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 952 mb.

Chapala continues to be a strong well organized tropical cyclone and it is the equivalent of a major hurricane.  It has a symmetrical circulation with a well formed eye inside a core of thunderstorms.  Multiple rainbands are rotation around the center of circulation.  Upper level divergence is pumping out mass in all directions.

Tropical Cyclone Chapala remains in a favorable environment.  It is over warm Sea Surface Temperatures and the upper level winds are light.  There is not much vertical wind shear and Chapala could maintain its intensity until it approaches the coast of Yemen.  When Chapala gets nearer the coast, it will start to pull in drier air from the Arabian peninsula.  As Chapala ingests the drier air, it will start to weaken.

A ridge north of Chapala is steering the tropical cyclone westward.  As Chapala nears the western end of the ridge, it will start to turn more toward the west-northwest.  On its anticipated track Tropical Cyclone Chapala will approach the central coast of Yemen in 36 to 48 hours.  The core of Chapala will pass north of the island of Socotra on Sunday.

Tropical Cyclone Chapala Becomes Equivalent of Cat. 4 Hurricane

Tropical Cyclone Chapala intensified rapidly on Friday and it became the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Chapala was located at latitude 13.9°N and longitude 59.9°E which put it about 405 miles (655 km) east-southeast of Salalah, Oman.  Chapala was moving toward the west-southwest at 5 m.p.h. (8km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 932 mb.

Tropical Cyclone Chapala is a very well organized tropical cyclone.  It has a well defined eye and a strong core of thunderstorms around the eye.  Those storms generated upper level divergence which pumped out mass and allowed the surface pressure to fall rapidly.

Chapala is an environment favorable for tropical cyclones.  It is over warm Sea Surface Temperatures and the upper level winds are light.  So, there is little vertical wind shear.  However, a secondary eyewall may be developing and eyewall replacement cycles could cause fluctuations in intensity for the next day or two.  When Chapala approaches the Arabian peninsula, it will start to pull in very dry air, and that will weaken the tropical cyclone even before it makes landfall.

A subtropical ridge is steering Chapala toward the west and that general steering motion is expected to continue for another 36 to 48 hours.  As Chapala reaches the western end of the ridge, it could turn more toward the northwest.  Tropical Cyclone Chapala could be approaching the coast of Yemen in 48 to 60 hours.

Tropical Cyclone Chapala Intensifies Rapidly

Tropical Cyclone Chapala intensified rapidly on Thursday and it is almost the equivalent of a major hurricane.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Chapala was located at latitude 14.2°N and longitude 61.5°E which put it about 535 miles (865 km) east-southeast of Salalah, Oman.  Chapala was moving toward the west at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h). The minimum surface pressure was 956 mb.

Chapala has a very well organized, symmetrical circulation.  There is a well formed eye which is surrounded by a ring of strong thunderstorms.  Several spiral bands are rotating around the core of the cyclone.  The thunderstorms surrounding the eye are generating upper level divergence which is pumping out mass in all directions.

Tropical Cyclone Chapala is an environment that favors further intensification.  It is over water where the Sea Surface Temperature is around 28°C.  The upper level winds are light and there is not much vertical wind shear.  Chapala could intensify to the equivalent of a Category 4 hurricane on Friday.  After that time eyewall replacement cycles could cause fluctuations in intensity.

A ridge in north of Chapala is steering the tropical cyclone toward the west.  That same general steering motion is expected to continue for another two or three days.  On its anticipated track Tropical Cyclone Chapala could be approaching the area near the border between Oman and Yemen in 48 to 60 hours.  It could be an intense tropical cyclone at that time.

Tropical Cyclone 04A Organizes in the Arabian Sea

A center of circulation organized quickly within a broader area of thunderstorms over the Arabian Sea on Wednesday and the system was designated Tropical Cyclone 04A.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone 04A was located at latitude 13.7°N and longitude 64.0°E which put it about 705 miles east-southeast of Salalah, Oman.  The tropical cyclone was moving toward the west-northwest at 6 m.p.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 993 mb.

The organization of Tropical Cyclone 04A improved significantly on Wednesday.  A primary rainband wrapped almost entirely around the center of circulation and there were indications on various satellite images that an eye could be forming.  Additional rainbands were beginning to form in the circulation outside the core.  Thunderstorms near the center of circulation were generating upper level divergence, especially on the northeast side of the tropical cyclone.

The environment is favorable for further intensification.  Tropical Cyclone 04A is over water where the Sea Surface Temperature is near 28°C.  Although there are strong upper level westerly winds north of the cyclone, the upper level winds over it are relatively light.  As a result there is not a lot of vertical wind shear over Tropical Cyclone 04A.  The cyclone is likely to intensify during the next several days and it could intensify rapidly.  It could attain hurricane intensity in a day or two and it could eventually become the equivalent of a major hurricane.

A ridge north of Tropical Cyclone 04A is steering it slowly toward the west-northwest.  The ridge is expected to continue steering the cyclone toward the west during the next few days.  On its anticipated track Tropical Cyclone 04A could approach the coast of Oman and Yemen in four or five days.

Patricia Is Strongest East Pacific Hurricane on Record

Hurricane Patricia continued to intensify rapidly during the overnight hours and it is now the strongest hurricane on record for the Eastern North Pacific.  At 11:00 a.m. EDT on Friday the center of Hurricane Patricia was located at latitude 17.6°N and longitude 105.5°W which put it about 125 miles (200 km) southwest of Manzanillo, Mexico.  Patricia was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 200 m.p.h. (320 km) and there were wind gusts to 245 m.p.h. (400 km/h).  The minimum surface pressure was 880 mb.

A Hurricane Warning is in effect for the portion of the coast between Sas Blas and Punta San Telmo, Mexico.  A Tropical Storm Warning and a Hurricane Watch is in effect for the portion of the coast from Punta San Telmo to Lazaro Cardenas, Mexico.

Hurricane Patricia has broken a number of records.  The maximum sustained wind speed increased from 85 m.p.h. to 200 m.p.h. between 5:00 a.m. EDT on Thursday and 5:00 a.m. EDT on Friday.  The rate of increase of 115 m.p.h. in 24 hours is the fastest rate of intensification observed in the Eastern Pacific. It exceeds the 100 m.p.h. in 24 hours that occurred in Hurricane Linda in 1997.  Interestingly, 1997 was also an El Nino year.  The minimum surface pressure of 880 mb is the lowest ever recorded in the National Hurricane Center’s Area of Responsibility which includes the Atlantic and Eastern North Pacific Oceans.  It is lower than the 882 recorded when Hurricane Wilma was over the Caribbean Sea in 2005.

Hurricane Patricia is an extremely dangerous hurricane.  It has a Hurricane Intensity Index (HII) of 50.0, a Hurricane Size Index (HSI) of 11.3 and a Hurricane Wind Intensity Size Index (HWISI) of 61.3.  Those indices mean that Patricia will be capable of causing catastrophic regional damage when it reaches the west coast of Mexico north of Manzanillo later on Friday.  Hurricane Patricia will be capable of causing catastrophic wind damage, generating a potentially destructive storm surge near the coast and producing heavy rain and flooding as it moves inland.