Tag Archives: the Comoros

Tropical Cyclone Fantala Weakens Northeast of Madagascar

Thunderstorms near the center of Tropical Cyclone Fantala dissipated and it weakened as moved northeast of Madagascar.  At 5:00 p.m. EDT  on Saturday the center of Tropical Cyclone Fantala was located at latitude 11.5°S and longitude 54.5°E which put it about 350 miles (565 km) east of Antsirañana, Madagascar.  Fantala was moving west-northwest at 10 m.p.h. (16 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 988 mb.

Tropical Cyclone Fantala reversed course again on Saturday and it is moving over the same part of the South Indian Ocean that it already crossed twice during the past few days.  The winds produced by Fantala mixed cooler water up to to the surface of the ocean during its previous passages over the same region.  The cooler water means that there is less energy available to power the circulation of Tropical Cyclone.  Although the winds continue to rotate around the center of circulation, there are no thunderstorms near the core of Fantala.  There are still several thunderstorms in rainbands farther to the east of the center of circulation.

If new thunderstorms do not develop around the core of the circulation, the winds will gradually spin down and the tropical cyclone will dissipate within a few days.  Upper level winds blowing from the west-northwest are also generating some vertical wind shear, which will make it more difficult for new thunderstorms to form.

A subtropical ridge southwest of Fantala is steering the tropical cyclone toward the west-northwest and that general motion is expected to continue for the next several days.  On its anticipated track Tropical Cyclone Fantala is forecast to pass north of Madagascar and move over the Seychelles.  It could be even weaker by the time it gets to the Seychelles.

Tropical Cyclone Fantala Stalls East of Madagascar

Tropical Cyclone Fantala moved into an area of weaker steering currents on Thursday and it stalled about 500 miles (800 km) east of northern Madagascar.  At 5:00 p.m. EDT on Thursday the center of Tropical Cyclone Fantala was located at latitude 13.0°S and longitude 56.7°E which put it about 515 miles (830 km) east of Antsirañana, Madagascar.  Fantala was moving toward the southeast at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 95 m.p.h. (155 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 963 mb.

Although Fantala weakened slightly on Thursday, the structure of the inner core of the circulation remained fairly intact.  A thin ring of thunderstorms was wrapped around an that was obscured on conventional satellite imagery.  Other bands of thunderstorms spiraled around the eyewall.  The thunderstorms in the core of Fantala were generating upper level divergence to the north and east of the center of circulation.  It appears that drier air may be getting pulled into the eastern portion of the circulation outside the core of Fantala.  There only only isolated thunderstorms in the rainbands in that part of the circulation.

The environment is marginally favorable for intensification.  The upper level winds are light enough so there is only a moderate amount of vertical wind shear.  Fantala is over water where the Sea Surface Temperature is near 29°C.  However, because Fantala is moving so slowly, it could mix cooler water to the surface which would reduce the energy available to the tropical cyclone.  In addition the drier air will also limit the supply of energy being transported into the core of the circulation.

Tropical Cyclone Fantala has moved into an area where the steering currents are weak.  It may not move much during the next 24 hours.  A subtropical ridge is forecast to develop southwest of Fantala in a day or two.  When the subtropical ridge develops, it is expected to steer Fantala back toward the west again.  On its anticipated track Tropical Cyclone Fantala could be approaching the northern part of Madagascar in 60 to 72 hours.

Tropical Cyclone Fantala Reorganizes Northeast of Madagascar

Tropical Cyclone Fantala reorganized northeast of Madagascar on Tuesday.  At 8:00 p.m. EDT on Tuesday the center of Tropical Cyclone Fantala was located at latitude 10.0°S and longitude 52.0°E which put it about 240 miles (385 km) northeast of Antsirañana, Madagascar.  Fantala was moving toward the east-southeast at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 952 mb.

The core of the circulation of Tropical Cyclone Fantala became more organized on Tuesday.  A ring of strong thunderstorms surrounded a circular eye that was visible on satellite imagery.  It did still appear that some drier air was wrapping around the eastern and southern sides of the circulation, but the drier air did not appear to be spiraling into the center of the circulation.  Upper level divergence appeared to increase throughout the day.

The environment around Tropical Cyclone Fantala is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is not much vertical wind shear.  The only inhibiting factor is the presence of a band of drier air on the eastern and southern sides of the circulation.  Given the improved organization of the core of the circulation, Tropical Cyclone Fantala could intensify further on Wednesday.

A ridge north of Fantala is steering the Tropical Cyclone toward the east-southeast and that general motion is expected to continue for another day or two.  A new subtropical ridge could develop southwest of Fantala and turn it back toward the west later this week.  Tropical Cyclone Fantala could still have an impact on northern Madagascar in a few days.

Tropical Cyclone Fantala Stalls and Weakens North of Madagascar

Tropical Cyclone Fantala stalled north of Madagascar on Monday and it weakened below Category 5 on the Saffir-Simpson Scale.  At 8:00 p.m. EDT on Monday the center of Tropical Cyclone Fantala was located at latitude 9.2°S and longitude 49.6°E which put it about 200 miles (320 km) north of Antsirañana, Madagascar.  Fantala was nearly stationary.  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 933 mb.

The structure of the circulation of Tropical Cyclone Fantala deteriorated on Monday.  An eye was no longer visible in satellite imagery and the ring of thunderstorms that was around the eye appeared to have a gap on the east side.  There were still bands of thunderstorms spiraling around the outer portion of the circulation.  However, it appeared that some drier air may have been pulled into the northeastern part of Fantala.  Thunderstorms were still generating upper level divergence, but it was mainly to the south of the tropical cyclone.  The upper level divergence pumped out less mass than the amount of mass that converged in the lower levels and the surface pressure rose about 20 mb on Monday.

The environment around Tropical Cyclone Fantala contains a mixture of favorable and unfavorable features.  Fantala is over water where the Sea Surface Temperatures are near 29°C.  Upper level winds are blowing a little more strongly from the northeast, but the vertical wind shear is still not too significant.  Fantala does seem to be pulling in some drier air into its circulation.  The tropical cyclone is nearly stationary and its strong winds may be mixing some cooler water to the surface.  Drier air and cooler water would reduce the energy available to drive the circulation of Fantala and it is likely to weaken further on Tuesday.

Fantala is in an area where the steering currents are weak and it may not move much during the next 12 to 24 hours.  Eventually, a ridge is expected to develop northeast of Fantala and start to steer the tropical cyclone toward the southeast.  On its anticipated track the core of strongest winds would pass north of Madagascar.  However, there is still uncertainty about the future track of Fantala and it could still have an impact on northern Madagascar.

 

Tropical Cyclone Fantala Reaches Cat. 5 North of Madagascar

Tropical Cyclone Fantala continued to intensify on Sunday and it reached the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  At 5:00 p.m. EDT on Sunday the center of Tropical Cyclone Fantala was located at latitude 9.7°S and longitude 50.5°E which put it about 190 miles (305 km) north-northeast of Antsirañana, Madagascar.  Fantala was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 175 m.p.h. (280 km/h) and there were wind gusts to 205 m.p.h. (335 km/h).  The minimum surface pressure was 911 mb.

Fantala is an extremely well organized tropical cyclone.  There is a solid ring of thunderstorms surrounding a clear eye.  Other bands of thunderstorms spiral into the core of the circulation.  Hurricane force winds extend out about 30 miles (50 km) south of the center.  The thunderstorms are generating enough upper level divergence to cause the surface pressure to decrease to 911 mb.

Fantala is a very powerful tropical cyclone.  The Hurricane Intensity Index (HII) is 40.4, the Hurricane Size (HSI) is 10.5, and the Hurricane Wind Intensity Size Index (HWISI) is 50.9.

The environment around Tropical Cyclone Fantala is very favorable.  It is over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  Fantala could intensify a little more, but it is likely near its maximum intensity.  Any increase in the speed of the upper level winds would generate more vertical wind shear and start to weaken Fantala.

A subtropical ridge southwest of the tropical cyclone is steering Fantala toward the west-northwest.  That general motion is expected to continue for another 12 to 24 hours.  Guidance from numerical models predicts that in a day or so a second ridge located northeast of Fantala will begin to steer the tropical cyclone back to the southeast.  There is variability in the location and sharpness of the turn to the southeast.  If there is a sharp turn to the southeast, the core of Fantala could remain north of Madagascar.  If the turn occurs later and/or is more gradual the core of Fantala could come closer to the northern end of Madagascar.

Tropical Cyclone Fantala is a very dangerous storm.  It would be capable of causing catastrophic damage if it were to make landfall.