Tag Archives: 19S

Tropical Cyclone Savannah Forms North of Cocos Island

Tropical Cyclone Savannah formed over the southeast Indian Ocean north of Cocos Island on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Savannah was located at latitude 11.3°S and longitude 96.7°E which put it about 60 miles (100 km) north of Cocos Island.  Savannah was moving toward the south-southwest at 8 m.p.h. (13 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 997 mb.  The Australian Bureau of Meteorology has issued a Tropical Storm Warning for Cocos Island.

More thunderstorms formed near an area of low pressure over the southeastern Indian Ocean west of Australia and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Savannah.  The distribution of thunderstorms around Savannah was asymmetrical.  Several bands of showers and thunderstorms developed in the western half of the circulation.  Rainbands in the eastern half of the circulation consisted primarily of showers and lower clouds.  Tropical Cyclone Savannah was moving south of an upper level ridge.  The ridge was generating easterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they were contributing to the asymmetrical distribution of thunderstorms.

Tropical Cyclone Savannah will move through an environment favorable for intensification during the next several days.  Savannah will move over water where the Sea Surface Temperature is near 28°C.  The upper level ridge will continue to cause vertical wind shear, but the shear could decrease during the next 48 hours.  Tropical Cyclone Savannah is likely to intensify during the next day or two.

Tropical Cyclone Savannah will move near the western end of a strengthening subtropical ridge over Australia.  The ridge will steer Savannah toward the south-southwest during the next day or two.  On its anticipated track Tropical Cyclone Savannah will bring gusty winds and locally heavy rain to Cocos Island during the next 24 hours.

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.

Tropical Cyclone Fantala Almost Equal to Cat. 5 Hurricane

Tropical Cyclone Fantala intensified further on Saturday and it is almost the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  At 8:00 p.m. EDT on Saturday the center of Tropical Cyclone Fantala was located at latitude 11.1°S and longitude 53.4°E which put it about 620 miles north of St. Denis, La Reunion.  Fantala was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 922 mb.

Tropical Cyclone Fantala increased in both intensity and size again on Saturday.  Hurricane force winds now extend out about 60 miles (95 km) south of the center of circulation.  The Hurricane Intensity Index (HII) for Fantala is 33.3.  The Hurricane Size Index (HSI) is 18.7 and the Hurricane Wind Intensity Size Index (HWISI) is 52.0.

The circulation of Tropical Cyclone Fantala is very well organized.  It has a clearly visible eye on satellite imagery.  The eye is surrounded by a ring of strong thunderstorms.  Additional bands of thunderstorms are rotating around the core of the circulation.  The thunderstorms are generating strong upper level divergence which is pumping out mass in all directions.

The environment around Tropical Cyclone Fantala is 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.  Tropical Cyclone Fantala could intensify a little more during the next 24 hours.  If one of the rainbands wraps around the existing eye, and eyewall replacement cycle could cause fluctuations of intensity.

A subtropical ridge southwest of Fantala is steering the tropical cyclone toward the west-northwest.  That general motion is expected to continue for another 24 to 36 hours.  In a day or so Fantala will move into an area where the steering currents are weaker and it could slow down or stall.  Eventually a northwesterly flow is forecast turn Tropical Cyclone Fantala back toward the southeast.  However, guidance from numerical models differs on when and where the southeasterly turn will occur.

On its anticipated track Tropical Cyclone Fantala could be near the northern end of Madagascar in a day or two.  The current size and intensity of Fantala means that it could produce regional significant damage if it were to hit land.  The future track of Fantala will determine if the tropical cyclone has an impact on Madagascar.

Tropical Cyclone Fantala Intensifies to Equivalent of Cat. 4 Hurricane

Tropical Cyclone Fantala continued to get stronger on Friday and it is now 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 Fantala was located at latitude 12.4°S and longitude 57.6°E which put it about 530 miles (860 km) north of Port Louis, Mauritius.  Fantala was moving toward the west at 8 m.p.h. (13 km/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 926 mb.

Tropical Cyclone Fantala is very well organized.  There is a ring of strong thunderstorms surrounding a well formed eye.  Other spiral bands are rotating near the core of the circulation.  Thunderstorms are generating upper level divergence which is pumping out large amounts of mass and allowing the surface pressure to decrease further.  The Hurricane Intensity Index (HII) for Tropical Cyclone Fantala is 31.6.  The Hurricane Size Index (HSI) is 18.4 and the Hurricane Wind Intensity Size Index (HWISI) is 50.0.

Fantala continues to exist in an environment favorable for intensification.  It is over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Fantala could become the equivalent of a Category 5 hurricane during the next 24 hours.  Fantala appeared to go through an eyewall replacement cycle on Thursday and further cycles could produce additional fluctuations in intensity.

A subtropical ridge located southwest of Fantala is steering the tropical cyclone toward the west.  Movement toward the west or west-northwest is expected during the next 24 to 48 hours.  On its anticipated track Tropical Cyclone Fantala could be northeast of the northern tip of Madagascar by the end of the weekend.  Fantala is a powerful, dangerous tropical cyclone and it would be capable of doing regional serious damage if it made landfall.

Tropical Cyclone Fantala Gets Bigger and Stronger

Tropical Cyclone Fantala grew in size and intensity on Wednesday.  At 8:00 p.m. EDT on Wednesday the center of Tropical Cyclone Fantala was located at latitude 12.7°N and longitude 64.2°E which put it about 700 miles (1130 km) northeast of Port Louis, Mauritius.  Fantala was moving toward the west at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 956 mb.  The Hurricane Intensity Index (HII) was 17.8, the Hurricane Size Index (HSI) was 14.6 and the Hurricane Wind Intensity Size Index (HWISI) was 32.4.

Both the organization and size of the circulation of Fantala increased on Wednesday.  A complete eyewall formed around an eye at the center of the tropical cyclone.  Other well formed bands of thunderstorms developed and wrapped around the core of Fantala.  The structure of the tropical cyclone is much more symmetrical and there are thunderstorms in all quadrants of the circulation.  Winds to hurricane force extended out 35 miles (55 km) from the center of circulation.  Thunderstorms around the core of Fantala generated upper level divergence which pumped out mass and allowed the surface pressure to decrease.

Tropical Cyclone Fantala is an environment favorable for further intensification.  Fantala is over water where the Sea Surface Temperature is near 30°C.  The upper level winds are light and there is very little vertical wind shear.  The structure of Fantala will allow it to use the energy from the ocean very efficiently.  Fantala is likely to continue to intensify on Thursday and it could become the equivalent of a major hurricane.  As Fantala gets stronger, concentric eyewalls could develop and the resulting eyewall replacement cycles could produce fluctuations in intensity.

A subtropical ridge located to the south of Fantala is steering it toward the west and that general steering motion is expected to continue during the next several days.  On its anticipated track Fantala will pass north of Mauritus and La Reunion during the weekend.  Tropical Cyclone Fantala could be near northern Madagascar in a few days.

Tropical Cyclone Fantala Intensifies and Heads Slowly West

Tropical Cyclone Fantala intensified into the the equivalent of a hurricane/typhoon as it headed slowed west across the South Indian Ocean on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Cyclone Fantala was located at latitude 12.8°S and longitude 68.5°E which put it about 465 miles (755 km) south-southwest of Diego Garcia.  Fantala was moving toward the west-northwest at 5 m.p.h. (8 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 975 mb.

The core of Tropical Cyclone Fantala continued to get better organized on Tuesday.  The primary rainband wrapped entirely around the center of circulation and a small eye appeared intermittently on some satellite imagery.  Thunderstorms around the center of circulation began to produce more upper level divergence and high clouds could be seen fanning out in all directions.  The upper level divergence pumped out mass and allowed the surface pressure to decrease.

Fantala is a small tropical cyclone.  Tropical storm force winds only extend about 100 miles (160 km) from the center of circulation.  The Hurricane Size Index for Tropical Cyclone Fantala is only 8.1.

Tropical Cyclone Fantala is in an environment that appears to be mostly favorable for intensification.  It is over water where the Sea Surface Temperature is near 30°C.  The upper level winds are light and there is not much vertical wind shear.  The only possible negative factor is the presence of some drier air around the periphery of the circulation.  Tropical Cyclone Fantala is likely to intensify further and its small size could allow it to intensify rapidly at times.  Tropical Cyclone Fantala could become the equivalent of a major hurricane later this week.

A subtropical ridge located south of Fantala is steering the tropical cyclone toward the west and that general motion is expected to continue for the next several days.  On its anticipated track Tropical Cyclone Fantala could pass north of La Reunion in a few days.  Fantala could be northeast of Madagascar in four or five days.