Monthly Archives: February 2019

Tropical Cyclone Oma Forms Northwest of Vanuatu

Tropical Cyclone Oma formed over the Coral Sea northwest of Vanuatu on Tuesday.  At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Oma was located at latitude 13.8°S and longitude 165.6°E which put it about 330 miles (535 km) northwest of Port Vila, Vanuatu.  Oma was moving toward the east 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 988 mb.

A distinct low level center of circulation formed within a broader area of low pressure northwest of Vanuatu on Tuesday and the Fiji Meteorological Service designated the system as Tropical Cyclone Oma.  The distribution of thunderstorms around Oma was asymmetrical.  Many of the stronger thunderstorms were occurring in bands northwest of the center of circulation.  Bands southeast of the center consisted primarily of showers and lower clouds.  The thunderstorms northwest of the center were generating upper level divergence which was pumping mass away to the northwest of the tropical cyclone.

An upper level ridge northeast of Vanuatu was producing southeasterly winds which were blowing toward the top of Tropical Cyclone Oma.  Those winds were causing moderate vertical wind shear and they were inhibiting upper level divergence to the southeast of Oma.  The wind shear was the probable cause of the asymmetrical distribution of thunderstorms.

Tropical Cyclone Oma will move through an environment somewhat favorable for intensification during the next several days.  The upper level ridge will continue to cause vertical wind shear.  However, Oma will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone Oma could slowly strengthen during the next day or two.

Tropical Cyclone Oma is currently embedded in a monsoon trough that is steering it toward the east.  A subtropical ridge is forecast to strengthen east of Vanuatu.  Oma will slow down while the ridge builds east of Vanuatu and it could linger northwest of Vanuatu for several days.  The ridge will eventually turn Tropical Cyclone Oma toward the south.  The timing and location of that turn will be important.  If Oma moves farther east before it turns southward, then it could approach northwest Vanuatu in 24 to 36 hours.  If Oma stalls and then turns southward, then the strongest part of the tropical cyclone could pass west of Vanuatu.  Tropical Cyclone Oma could eventually move near New Caledonia in a few days.

Tropical Cyclone Gelena Brings Wind and Rain to Rodrigues

Tropical Cyclone Gelena brought wind and rain to Rodrigues on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Gelena was located at latitude 20.5°S and longitude 63.7°E which put it about 55 miles (90 km) southeast of Rodrigues, Mauritius.  Gelena was moving toward the east-southeast at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 959 mb.

Tropical Cyclone Gelena was the equivalent of a major hurricane when it moved past Rodrigues.  Winds to hurricane/typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 150 miles (240 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Gelena was 20.6.  The Hurricane Size Index (HSI) was 15.9 and the Hurricane Wind Intensity Size Index (HWISI) was 36.5.

The northeastern part of the eyewall of Tropical Cyclone Gelena appeared to cross Rodrigues.  Winds to hurricane/typhoon force may have occurred when that part of the eyewall moved over the island.  Winds to tropical storm force will continue for a few more hours until Gelena moves farther away from Rodrigues.  Conditions on Rodrigues should gradually improve on Sunday while Tropical Cyclone Gelena moves farther away.  Gelena will weaken as it moves over colder water.

Elsewhere over South Indian Ocean, Tropical Cyclone Funani made a transition to an extratropical cyclone.  At 4:00 p.m. EST the center of Tropical Cyclone Funani was located at latitude 31.9°S and longitude 77.4°E which put it about 1390 miles (2245 km) southeast of Mauritius.  Funani was moving toward the southeast at 28 m.p.h. (45 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 996 mb.

Tropical Cyclone Gelena Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Gelena strengthened into the equivalent of a major hurricane on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Gelena was located at latitude 16.8°S and longitude 56.9°E which put it about 265 miles (425 km) north of Port Louis, Mauritius.  Gelena was moving toward the southeast at 15 m.p.h. (24 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. (205 km/h).  The minimum surface pressure was 953 mb.

The circulation around Tropical Cyclone Gelena strengthened and grew larger on Friday.  An eye appeared intermittently at the center of Gelena on satellite imagery.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in the ring of storms.  More bands of showers and thunderstorms were revolving around the core of the circulation.  Winds to hurricane/typhoon force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 175 miles (280 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Gelena was 23.6.  The Hurricane Size Index (HSI) was 17.3 and the Hurricane Wind Intensity Size Index (HWISI) was 40.9.  Those indices indicated that tropical Cyclone Gelena was capable of causing major regional damage.

Tropical Cyclone Gelena will move through an environment somewhat favorable for intensification for another 12 to 24 hours.  Gelena will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough near Madagascar will produce westerly winds which are blowing toward the top of Tropical Cyclone Gelena.  Those winds will produce some vertical wind shear and they will inhibit upper level divergence toward the western periphery of Gelena.  The wind shear will inhibit intensification, but Tropical Cyclone Gelena could strengthen on Saturday.

Tropical Cyclone Gelena will move south of a subtropical ridge.  The ridge will steer Gelena in a southeasterly direction.  On its anticipated track Tropical Cyclone Gelena will pass north of Mauritius.  However, Gelena could approach Rodrigues within 36 hours.  Tropical Cyclone Gelena could bring strong winds and heavy rain to Rodrigues.

Elsewhere over the southern Indian Ocean, Tropical Cyclone Funani was speeding toward colder water.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Funani was located at latitude 26.3°S and longitude 73.4°E which put it about 805 miles (1295 km) east-southeast of Rodrigues.  Funani was moving toward the southeast at 28 m.p.h. (45 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/h).  The minimum surface pressure was 977 mb.

Stronger Tropical Cyclone Gelena Moves Toward Rodrigues

A stronger Tropical Cyclone Gelena moved toward Rodrigues on Thursday.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Gelena was located at latitude 14.8°S and longitude 54.5°E which put it about 340 miles (550 km) north-northwest of Port Louis, Mauritius.  Gelena was moving toward the south-southeast at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 972 mb.

Tropical Cyclone Gelena strengthened into the equivalent of a hurricane/typhoon on Thursday.  An eye cleared at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.  Several bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Gelena.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 140 miles (225 km) from the center.

Tropical Cyclone Gelena will move through an environment favorable for intensification.  Gelena will move over water where the Sea Surface Temperature is near 29°C.  It will move through an environment where the upper level winds are weak and the there will be little vertical wind shear.  Tropical Cyclone Gelena will intensify during the next 24 to 36 hours and it could strengthen rapidly at times.  Gelena will likely become the equivalent of a major hurricane during the next 36 hours.

Tropical Cyclone Gelena will move south of a subtropical ridge which will steer the tropical cyclone toward the southeast.  On its anticipated track the core of Gelena will pass north of Mauritius in about 24 hours.  Tropical Cyclone Gelena could approach Rodrigues in 36 to 48 hours.  Gelena could be the equivalent of a major hurricane at that time.

Elsewhere over the Southwest Indian Ocean Tropical Cyclone Funani intensified into the equivalent of a major hurricane as it moved away from Rodrigues.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Funani was located at latitude 22.2°S and longitude 69.3°E which put it about 430 miles (690 km) east-southeast of Rodrigues, Mauritius.  Funani was moving toward the southeast at 16 m.p.h. (26 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 950 mb.

Tropical Cyclone Funani Brushes Rodrigues, Gelena Also a Threat

The western edge of Tropical Cyclone Funani brushed Rodrigues on Wednesday and Tropical Cyclone Gelena also posed a threat to the island.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Funani was located at latitude 18.1°S and longitude 65.1°E which put it about 515 miles (830 km) east-northeast of Port Louis, Mauritius and about 155 miles (250 km) northeast of Rodrigues.  Funani was moving toward the southeast at 7 m.p.h. (11 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 968 mb.

Tropical Cyclone Funani rapidly intensified into the equivalent of a hurricane/typhoon on Wednesday.  An eye was apparent on satellite images.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Storms near the core of Funani generated strong upper level divergence which pumped mass away from the tropical cyclone.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Funani.  There were more bands in the eastern half of the circulation.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 140 miles (225 km) from the center.

Tropical Cyclone Funani will be in an environment favorable for intensification for another 12 to 24 hours.  Funani will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Funani could strengthen into the equivalent of a major hurricane during the next 24 hours.  Funani will move over cooler water at the end of the week and it will start to weaken in a less favorable environment.

Tropical Cyclone Funani is moving south of a subtropical ridge which is steering the tropical cyclone toward the southeast.  A general motion toward the southeast is expected to continue during the next few days.  On its anticipated track the core of Tropical Cyclone Funani will pass east of Rodrigues.  Surface observations on Rodrigues indicate that the western portion of Funani is dropping rain on that island, but winds are generally blowing at less than tropical storm force.

Tropical Cyclone Gelena also poses a threat to Rodrigues.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Gelena was located at latitude 12.5°S and longitude 53.2°E which put it about 535 miles (865 km) north-northwest of Port Louis, Mauritius.  Gelena was moving toward the south-southwest at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 987 mb.

Tropical Cyclone Gelena also intensified rapidly on Wednesday.  A tiny, pinhole eye was apparent on satellite imagery.  A thin ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Storms near the core of Gelena were generating upper level divergence which was pumping mass away from the tropical cyclone.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Gelena.  There were more bands in the northern half of the circulation.  Winds to tropical storm force extended out about 90 miles (150 km) from the center of circulation.

Tropical Cyclone Gelena will also move through an environment favorable for intensification.  Gelena will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Gelena is likely to intensify into the equivalent of a hurricane/typhoon during the next 24 hours.  Gelena could strengthen into the equivalent of a major hurricane during the next several days.

Although Tropical Cyclone Gelena is currently weaker and smaller than Tropical Cyclone Funani, it may pose a greater risk to Rodrigues.  Gelena is forecast to pass closer to Rodrigues than Funani will pass and Gelena may be the equivalent of a major hurricane when it moves near Rodrigues.  Gelena could bring strong winds and heavy rain to Rodrigues in about 48 hours.

Tropical Cyclone Funani Develops Northeast of Mauritius

Tropical Cyclone Funani developed northeast of Mauritius on Tuesday.  At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Funani was located at latitude 15.8°S and longitude 64.0°E which put it about 505 miles (815 km) east-northeast of Port Louis, Mauritius and about 265 miles (425 km) north of Rodrigues.  Funani was moving toward the southwest at 5 m.p.h. (8 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 990 mb.

The circulation around Tropical Cyclone Funani organized quickly on Tuesday.  An inner rainband wrapped around the northern side of the center of circulation.  Bands of showers and thunderstorms developed and were revolving around the core of Funani.  There were more bands on the eastern side of the circulation.  Storms near the core began to generate upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 120 miles (195 km) from the center of circulation.

Tropical Cyclone Funani will be moving through an environment favorable for intensification during the next several days.  Funani will be moving over water where the Sea Surface Temperature is near 29°C.  It will move under an area where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Funani could intensify into the equivalent of a hurricane/typhoon within 24 hours and it could strengthen into the equivalent of a major hurricane in about 48 hours.

Tropical Cyclone Funani will move near the southeastern end of a subtropical ridge.  The ridge and a trough over the southwestern Indian Ocean will steer Funani in a general south-southwesterly direction.  On its anticipated track Tropical Cyclone Funani will remain east of Mauritius and La Reunion.  Funani could be near Rodrigues in about 24 hours.  It could be the equivalent of a hurricane/typhoon at that time.

Elsewhere over the South Pacific Ocean, Tropical Cyclone 13S formed east of Madagascar.  At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone 13S was located at latitude 12.3°S and longitude 53.6°E which put it about 570 miles (920 km) north of Port Louis, Mauritius.  It was moving toward the west-northwest at 10 m.p.h. (16 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 1002 mb.