Tag Archives: SH07

Tropical Cyclone Cebile Meanders South of Diego Garcia

Tropical Cyclone Cebile has meandered south of Diego Garcia throughout this week.  At 4:00 p.m. EST on Thursday the center of Tropical Cyclone Cebile was located at latitude 16.2°S and longitude 75.8°E which put it about 655 miles (1055 km) south-southeast of Diego Garcia.  Cebile was moving toward the southwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 125 m.p.h. (205 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 949 mb.

Although it completed at least one eyewall replacement cycle, Tropical Cyclone Cebile maintains an impressive structure.  There is a circular eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Several rainbands are revolving around the core of the circulation.  The storms in the core are generating upper level divergence which is pumping mass away.  Winds to hurricane/typhoon force extend out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extend out about 250 miles (400 km) from the center.

Tropical Cyclone Cebile remains in an environment favorable for strong tropical cyclones.  It is moving over water where the Sea Surface Temperature is generally near 28°C.  However, Cebile has moved slowly during the past several days and its circulation may have mixed cooler water to the surface in some locations.  The upper level winds are currently weak and there is little vertical wind shear.  Tropical Cyclone Cebile could maintain its intensity for another 24 to 36 hours unless it mixes more cool water to the surface.  An upper level trough approaching from the west will increase the vertical wind shear in a day or two and Cebile could weaken more quickly when that occurs.

Cebile is moving near the western end of a subtropical ridge which has been steering the tropical slowly toward the southwest.  The approaching upper level trough will begin to steer Tropical Cyclone Cebile more toward the southeast in a day or two.  On its anticipated track Tropical Cyclone Cebile is forecast to move farther away from Diego Garcia.

Tropical Cyclone Cebile Intensifies Rapidly Into Equivalent of Major Hurricane

Tropical Cyclone Cebile intensified rapidly on Sunday from a tropical storm to the equivalent of a major hurricane over the South Indian Ocean.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Cebile was located at latitude 14.5°S and longitude 82.5°E which put it about 850 miles (1375 km) southeast of Diego Garcia.  Cebile was moving toward the southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 945 mb.

Tropical Cyclone Cebile intensified very rapidly during the past 24 hours as it moved through a very favorable environment.  The maximum sustained wind speed increased from 50 m.p.h. (80 km/h) to 130 m.p.h. (215 km/h).  The circulation of Tropical Cyclone Cebile is very well organized.  There is a circular eye at the center of circulation.  The eye is surround by a ring of strong thunderstorms and the strongest winds are occurring in the ring of storms.  Rainbands are revolving around the core of the circulation.  Tropical Cyclone Cebile is generating strong upper level divergence which is pumping away mass and allowing the surface pressure to decrease rapidly.

The circulation of Tropical Cyclone Cebile is symmetrical.  Winds to hurricane/typhoon force extend out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extend out about 150 miles (240 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Cebile is 25.1.  The Hurricane Size Index (HSI) is 12.7 and the Hurricane Wind Intensity Size Index (HWISI) is 37.8.

Tropical Cyclone Cebile continues to move through an environment favorable for intensification.  Cebile is moving over water where the Sea Surface Temperature is near 28°C.  The upper level winds are weak and there is little vertical wind shear.  Tropical Cyclone Cebile is likely to intensify further and it could become the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.

Cebile is moving near the western part of a subtropical ridge which is steering the tropical cyclone toward the southwest.  A general southwesterly motion is expected to continue for the next few days.  On its anticipated track Tropical Cyclone Cebile will remain well south of Diego Garcia.

Elsewhere in the tropics, Tropical Cyclone 08S was moving near the northern end of New Caledonia.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone 08S was located at latitude 18.8°S and longitude 162.1°E which put it about 370 miles (600 km) northwest of Noumea, New Caledonia.  It was moving toward the southeast at 11 m.p.h. (17 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 986 mb.

Tropical Cyclone Cebile Forms East of Diego Garcia

After a relatively quiet week in the tropics Tropical Cyclone Cebile formed east of Diego Garcia on Saturday.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Cebile was located at latitude 12.1°S and longitude 84.2°E which put it about 870 miles (1405 km) east-southeast of Diego Garcia.  Cebile was moving toward the southwest 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 998 mb.

Tropical Cyclone Cebile organized rapidly on Saturday.  A primary rainband wrapped most of the way around the center of circulation and an elliptical eye appeared to be developing at the center.  Other bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Cebile.  There were more thunderstorms in the western half of the circulation, but there were rainbands in all quadrants of Cebile.  Storms in the core of the circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.  The removal of mass was causing the surface pressure to decrease and the wind speed to increase.

Tropical Cyclone Cebile will move through an environment favorable for intensification.  It will move over water where the Sea Surface Temperature is near 28°C.  Cebile is moving just to the north of the axis of a subtropical ridge that runs east to west across the Southern Indian Ocean.  The northern half of the ridge is producing easterly winds which are blowing toward the top of the circulation, but the vertical wind shear is not too strong.  A combination of warm water and minimal vertical wind shear will allow Tropical Cyclone Cebile to strengthen and it could intensify rapidly.  Cebile is likely to strengthen into the equivalent of a hurricane/typhoon during the next day or two.  Tropical Cyclone Cebile could intensify into the equivalent of a major hurricane during the next week.

The subtropical ridge is steering Tropical Cyclone Cebile toward the southwest and that general motion is expected to continue for several more days.  On its anticipated track Tropical Cyclone Cebile is expected to move southeast of Diego Garcia.

Tropical Cyclone Victor Moves Toward Tonga

Tropical Cyclone Victor moved slowly westward toward Tonga as it passed south of Niue on Wednesday.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Victor was located at latitude 21.5°S and longitude 169.8°W which put it about 155 miles (250 km) south of Niue and about 370 miles (595 km) east of Tonga.  Victor was moving toward the west at 4 m.p.h. (6 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 977 mb.

Tropical Cyclone Victor still looks like the equivalent of a hurricane on satellite images.  It has a well formed eye which is surrounded by a ring of thunderstorms.  The thunderstorms near the center of Victor are generating a large area of upper level divergence.  Convection outside of the core of Victor is somewhat asymmetrical.  Most of the stronger thunderstorms are located in bands south and east of the center of circulation.  There are few tall thunderstorms in the northwestern part of Victor.

Tropical Cyclone Victor continues to be in an environment that is favorable for intensification.  Victor is moving over water where the Sea Surface Temperature is near 27°C.  The upper level winds near Victor are light and there is no appreciable vertical wind shear.  Tropical Cyclone Victor has the potential to intensify during the next 24 hours.

A subtropical ridge south of Victor is steering the tropical cyclone slowly toward the west.  The ridge is expected to continue to steer Victor toward the west, but at a faster speed, during the next day or two.  On its anticipated track Tropical Cyclone Victor could be approaching Tonga in about 36 hours.

Tropical Cyclone Victor passed far enough south of Niue that the stronger winds and heavy rain did not affect the island.  Large waves and surf may have affected some of the coastal areas.  Tropical Cyclone Victor could bring wind and rain to Tonga in two or three days.

Tropical Cyclone Victor Intensifies East of Niue

Tropical Cyclone Victor intensified on Monday and it is now the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale.  At 4:00 p.m. EST on Monday the center of Tropical Cyclone  Victor was located at latitude 20.2°S and longitude 166.3°W which put it about 175 miles (280 km) east-southeast of Niue.  Victor was moving toward the south-southwest at 5 m.p.h. (8 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. (205 km/h).  The minimum surface pressure was 956 mb.

Tropical Cyclone Victor has an unusual structure.  It has a very large eye, which is about one degree of longitude across.  The eye is surrounded by a narrow eyewall of strong thunderstorms and a couple of thin, primary rainbands.  Winds to tropical storm force extend out about 200 miles (320 km) from the center of circulation.  The thunderstorms in the eyewall are generating strong upper level divergence which is pumping out mass.  The eye has appeared to contract a bit on recent satellite imagery, which could be a sign of further intensification.

Tropical Cyclone Victor is an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 27°C.  An upper level ridge located northeast of Victor is producing some light northwesterly winds over the top of the tropical cyclone.  However, the vertical wind shear is minimal and it is not inhibiting intensification at this time.  Victor could continue to intensify on Tuesday.  Later this week Tropical Cyclone Victor will move into an environment with cooler SSTs and more wind shear.  Victor will start to weakening when it enters that environment.

The ridge northeast of Victor is getting stronger and it is forcing the tropical cyclone to move toward the west-southwest.  That general motion is expected to continue for the next several days.  On its anticipated track the core of Tropical Cyclone Victor with the strongest winds will pass south of Niue during the next 48 hours.  However, Tropical Cyclone Victor could bring a period of strong winds and rain to Niue as it moves south of the islands.  The large wind field around Victor could also generate significant waves and surges.  Tropical Cyclone Victor could be approaching Tonga later this week.