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Tropical Cyclone Alvaro Starts Extratropical Transition

Tropical Cyclone Alvaro started to make a transition to an extratropical cyclone over the Southwest Indian Ocean south of La Reunion on Wednesday. At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Alvaro was located at latitude 26.8°S and longitude 54.9°E which put it about 405 miles (655 km) south of St. Denis, La Reunion. Alvaro was moving toward the southeast at 21 m.p.h. (33 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 998 mb.

Tropical Cyclone Alvaro began a transition to an extratropical cyclone on Wednesday. Alvaro moved over cooler water. In addition, an upper level ridge over the Southwest Indian Ocean produced strong westerly winds that blew toward the top of Alvaro’s circulation. Those winds caused strong vertical wind shear. The combination of cooler water and strong vertical wind shear caused the structure of Tropical Cyclone Alvaro to change. Thunderstorms were occurring in bands in the southeastern part of Alvaro’s circulation. Bands in the other parts of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 150 miles (240 km) from the center of Tropical Cyclone Alvaro.

Tropical Cyclone Alvaro will move through an environment unfavorable for a tropical cyclone during the next 24 hours. Alvaro will move over water where the Sea Surface Temperatures are colder than 26°C. It will continue to move under the southern part of an upper level ridge over the Southwest Indian Ocean. The upper level ridge will continue to cause strong vertical wind shear. The colder water and strong vertical wind shear will cause Tropical Cyclone Alvaro to continue its transition to an extratropical cyclone.

The upper level ridge over the Southwest Indian Ocean will steer Tropical Cyclone Alvaro toward the southeast during the next 24 hours. On its anticipated track, Tropical Cyclone Alvaro will pass south of Mauritius on Thursday.

Tropical Cyclone Alvaro Moves East of Madagascar

Tropical Cyclone Alvaro moved east of Madagascar on Tuesday. At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Alvaro was located at latitude 23.1°S and longitude 50.3°E which put it about 150 miles (240 km) east of Farafangana, Madagascar. Alvaro was moving toward the east-southeast at 13 m.p.h. (21 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 999 mb.

Tropical Cyclone Alvaro weakened to the equivalent of a tropical depression before it moved over the Southwest Indian Ocean east of Madagascar on Tuesday. Alvaro began to intensify slowly after it moved back over water. More thunderstorms began to develop in bands revolving around the center of Tropical Cyclone Alvaro. Those thunderstorms generated upper level divergence that pumped mass away to the east of the tropical cyclone. Winds to tropical storm force extended out 75 miles (120 km) from the center of Alvaro’s circulation.

Tropical Cyclone Alvaro will move through an environment somewhat favorable for intensification during the next 24 hours. Alvaro will move over water where the Sea Surface Temperatures are near 27°C. It will move under the southern part of an upper level ridge over the Southwest Indian Ocean. The upper level ridge will produce westerly winds that will blow toward the top of Alvaro’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but the shear may not be enough to prevent some intensification. Tropical Cyclone Alvaro could continue to slowly intensify on Wednesday.

The upper level ridge over the Mozambique Channel will steer Tropical Cyclone Alvaro toward the east-southeast during the next 24 hours. On its anticipated track, Tropical Cyclone Alvaro will move farther east of Madagascar. Alvaro will pass south of La Reunion and Mauritius in 36 hours.

Tropical Cyclone Alvaro Brings Wind and Rain to Southern Madagascar

Tropical Cyclone Alvaro brought wind and rain to southern Madagascar on Monday. At 10:00 p.m. EST on Monday the center of Tropical Cyclone Alvaro was located at latitude 21.5°S and longitude 45.3°E which put it about 40 miles (65 km) north of Fianarantsoa, Madagascar. Alvaro was moving toward the east at 12 m.p.h. (19 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 997 mb.

The center of Tropical Cyclone Alvaro made landfall on the coast of southwest Madagascar north of Morombe on Monday. Alvaro was near hurricane/typhoon intensity at the time of landfall. A circular eye was at the center of Alvaro’s circulation at the time of landfall. Winds to tropical storm force extended out 85 miles (135 km) from the center of circulation. Tropical Cyclone Alvaro moved eastward across southern Madagascar and the center was north of Fianarantsoa on Sunday night. Heavy rain was falling over parts of southern Madagascar.

Tropical Cyclone Alvaro weakened after it moved over southern Madagascar on Monday, but Alvaro’s circulation continued to exhibit organization. Bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center of Alvaro generated upper level divergence that pumped mass away to the east of the tropical cyclone. Winds to tropical storm force extended out 60 miles (95 km) from the center of Tropical Cyclone Alvaro.

Tropical Cyclone Alvaro will continue to weaken while the center of circulation moves eastward over southern Madagascar. The center of Alvaro’s circulation could move over the southwest Indian Ocean east of Madagascar in 24 hours. Tropical Cyclone Alvaro will move into an environment somewhat favorable for intensification when it moves back over water. Alvaro will move over water where the Sea Surface Temperatures are near 28°C. It will move under the southern part of an upper level ridge over the southwest Indian Ocean. The upper level ridge will produce westerly winds that will blow toward the top of Alvaro’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but the shear may not be enough to prevent some intensification. Tropical Cyclone Alvaro could intensify when the center moves back over water east of Madagascar.

The upper level ridge over the Mozambique Channel will steer Tropical Cyclone Alvaro toward the east-southeast during the next 24 hours. On its anticipated track, Tropical Cyclone Alvaro will continue to move eastward across southern Madagascar. Heavy rain could cause flash floods in some parts of southern Madagascar. Alvaro will move off the coast of southeast Madagascar between Mananjary and Manakara in about 24 hours. Tropical Cyclone Alvaro could pass south of La Reunion and Mauritius later this week.

Tropical Cyclone Alvaro Intensifies to Near Hurricane/Typhoon Force

Tropical Cyclone Alvaro intensified to near hurricane/typhoon force on Monday morning. At 10:00 a.m. EST on Monday the center of Tropical Cyclone Alvaro was located at latitude 21.6°S and longitude 43.2°E which put it about 50 miles (80 km) northwest of Morombe, Madagascar. Alvaro was moving toward the east-southeast at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 989 mb.

Tropical Cyclone Alvaro strengthened to near hurricane/typhoon force as it approached southern Madagascar on Sunday morning. The inner end of a rainband wrapped around the center of Alvaro’s circulation. A circular eye with a diameter of 40 miles (65 km) formed at the center of Tropical Cyclone Alvaro. Bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated upper level divergence that pumped mass away to the east of the tropical cyclone. Winds to tropical storm force extended out 85 miles (135 km) from the center of Tropical Cyclone Alvaro.

Tropical Cyclone Alvaro will move through an environment favorable for intensification during the next few hours. Alvaro will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southern part of an upper level ridge over the Mozambique Channel. The upper level ridge will produce westerly winds that will blow toward the top of Alvaro’s circulation. Those winds will cause some vertical wind shear. The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification. Tropical Cyclone Alvaro could intensify to the equivalent of a hurricane/typhoon during the next few hours hours before it makes landfall in southern Madagascar.

The upper level ridge over the Mozambique Channel will steer Tropical Cyclone Alvaro toward the east-southeast during the next 24 hours. On its anticipated track, Alvaro will make landfall on the coast of southwest Madagascar north of Morombe in a few hours. Tropical Cyclone Alvaro will bring strong winds and locally heavy rain to southern Madagascar. Bands in the eastern side of Alvaro’s circulation were already dropping heavy rain on parts of southern Madagascar. Heavy rain is likely to cause flash floods in some locations. Tropical Cyclone Alvaro could also cause a storm surge of up to seven feet (two meters) along the coast north of Morombe.

Tropical Cyclone Alvaro Forms over the Mozambique Channel

Tropical Cyclone Alvaro formed over the Mozambique Channel on Sunday morning. At 7:00 a.m. EST on Sunday the center of Tropical Cyclone Alvaro was located at latitude 20.5°S and longitude 39.1°E which put it about 380 miles (610 km) west-northwest of Toliara, Madagascar. Alvaro was moving toward the east-southeast at 8 m.p.h. (13 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 1000 mb.

A low pressure system over the Mozambique Channel intensified on Sunday morning and Meteo France la Reunion designated the system as Tropical Cyclone Alvaro. More thunderstorms formed around the center of Alvaro’s circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical cyclone. Thunderstorms were also forming in bands in the eastern side of Tropical Cyclone Alvaro. Bands in the western side of Alvaro’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 80 miles (130 km) in the eastern half of Alvaro. The winds in the western side of Tropical Cyclone Alvaro were blowing at less than tropical storm force.

Tropical Cyclone Alvaro will move through an environment favorable for intensification during the next 24 hours. Alvaro will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southern part of an upper level ridge over the Mozambique Channel. The upper level ridge will produce westerly winds that will blow toward the top of Alvaro’s circulation. Those winds will cause some vertical wind shear. The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification. Tropical Cyclone Alvaro will intensify during the next 24 hours.

The upper level ridge over the Mozambique Channel will steer Tropical Cyclone Alvaro toward the east-southeast during the next 24 hours. On its anticipated track, Alvaro will approach the coast of southwest Madagascar near Morombe on Monday. Tropical Cyclone Alvaro will bring strong winds and locally heavy rain to southern Madagascar. Heavy rain is likely to cause flash floods in some locations.

Tropical Cyclone Sarai Moves Toward Tonga

Tropical Cyclone Sarai moved toward Tonga on Sunday.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Sarai was located at latitude 20.7°S and longitude 178.3°E which put it about 220 miles (355 km) west of Nuku Alofa, Tonga.  Sarai was moving toward the east-southeast at 4 m.p.h. (6 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 985 mb.

Tropical Cyclone Sarai weakened on Sunday.  An upper level ridge north of Sarai produced strong westerly winds which blew toward the top of the circulation.  Those winds caused strong vertical wind shear which disturbed the circulation around Tropical Cyclone Sarai.  The inner core became less well organized and there was no evidence of an eye on satellite images.  The stronger thunderstorms were occurring in bands in the eastern half of the circulation.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.  The circulation around Tropical Cyclone Sarai was still large.  Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation.

Tropical Cyclone Sarai will continue to move through an environment unfavorable for intensification during the next several days.  Sarai will move over water where the Sea Surface Temperature is near 28°C.  However, the upper level ridge will continue to produce strong westerly winds and vertical wind shear is likely to cause Tropical Cyclone Sarai to weaken further.

Tropical Cyclone Sarai will move south of a subtropical high pressure system over the South Pacific Ocean.  The high pressure system will steer Sarai toward the east during the next several days.  On its anticipated track Tropical Cyclone Sarai will move across Tonga in about 24 hours.  Although Sarai will weaken, it will bring winds to tropical storm force and heavy rain to parts of Tonga.

Tropical Low Forms Over Western Australia

A Tropical Low formed over Western Australia on Monday and a Tropical Cyclone Watch was issued for a portion of the coast.  At 2:00 p.m. EST on Monday the center of the Tropical Low was located at latitude 15.9°S and longitude 126.1°E which put it about 135 miles (220 km) west-southwest of Wyndham, Australia.  It was moving toward the southwest a 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 20 m.p.h. (30 km/h) and there were wind gusts to 50 m.p.h. (85 km/h).  The minimum surface pressure was 1005 mb.  The Australia Bureau of Meteorology has issued a Tropical Cyclone Watch for the portion of the coast of Western Australia from Kuri Bay to Wallal Downs including Broome.

The circulation of the Tropical Low is still organizing.  There is a broad low level center of circulation, but there are not many showers and thunderstorms near the center.  There are numerous bands of showers and storms developing in bands on the eastern and western peripheries of the circulation.  The strongest wind gusts are occurring in those storms.  The lack of storms near the center of circulation is keeping the system from generating much upper level divergence.

The core of the Tropical Low is likely to remain over land for another 12-24 hours, which will inhibit the organization of the circulation.  When the center moves off the coast and over the South Indian Ocean, it will move into an environment favorable for intensification.  The Sea Surface Temperature of the water west of the coast of Western Australia is near 30°C.  The Tropical Low is moving north of the axis of a subtropical ridge.  The ridge is producing easterly winds which are blowing toward the top of the circulation, but there is not a lot of vertical wind shear.  The Tropical Low is likely to strengthen when it moves over water and it could intensify rapidly if a more concentrated center of circulation develops.

A subtropical ridge is current steering the Tropical Low toward the southwest, but a general motion toward the west-southwest is expected during the next 24 to 48 hours.  The Tropical Low will reach the western end of the ridge in about two days and then it will turn more toward the south.  On its anticipated track the center of the Tropical Low is expected to move off the coast between Kuri Bay and Derby on Tuesday.  The center is forecast to pass near Cape Leveque and then turn south toward Wallal Downs.

Elsewhere over the South Indian Ocean, Tropical Cyclone Ava continued to swirl near southern Madagascar and stronger Tropical Cyclone Irving was passing well to the south of Diego Garcia.  At 4:00 p.m. EST on Monday the center of Tropical Storm Ava was located at latitude 27.7°S and longitude 46.8°E which put it about 180 miles (295 km) south of Farodofay, Madagascar.  Ava was moving toward the west-southwest at 17 m.p.h. (27 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.

At 4:00 p.m. EST on Monday the center of Tropical Cyclone Irving was centered at latitude 19.6°S and longitude 76.1°E which put it about 875 miles (1415 km) south-southeast of Diego Garcia.  Irving was moving toward the west-southwest at 18 m.p.h. (29 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 960 mb.  Tropical Cyclone Irving was the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale.

Tropical Cyclone Ava Drops Heavy Rain on Madagascar

Tropical Cyclone Ava dropped heavy rain over Madagascar on Saturday.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Ava was located at latitude 21.4°S and longitude 48.2°E which put it about 70 miles (110 km) north-northwest of Mananjary, Madagascar.  Ava was moving toward the south-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 994 mb.

Tropical Cyclone Ava weakened into the equivalent of a tropical storm during the day it spent moving over Madagascar.  The strongest winds were occurring in bands of thunderstorms over the water.  The center made landfall on Friday near Toamasina.  The center then passed near Moramanga, Anosibe An’ala, and Marolambo.  There is still a distinct center of circulation and several bands of showers and thunderstorms are revolving around the center.  Some of the storms dropped heavy rain over parts of Madagascar.  There was stronger rising motion in places where the winds blew up the sides of mountains and the rainfall was heavier in those locations.  The potential for flooding exists in places that received heavy rain.

The center of Tropical Cyclone Ava is likely to move back over the water of the South Indian Ocean during the next few hours.  Tropical Cyclone Ava will move into an environment that is favorable for intensification when it moves back over water.  The Sea Surface Temperature of the water east of Madagascar is near 28°C.  Ava is moving under the axis of an upper level ridge and the upper level winds are relatively weak.  So, there is not a lot of vertical wind shear.  Tropical Cyclone Ava is likely to strengthen once the center moves back over water.

Tropical Cyclone Ava is moving around the western end of a subtropical ridge which is steering Ava toward the south-southeast.  The ridge is forecast to steer Tropical Cyclone Ava toward the south for another day or two.  When Tropical Cyclone Ava moves farther to the south in about 48 hours, an upper level trough will cause northwesterly winds, which will start to steer the tropical cyclone toward the east-southeast.  On its anticipated track the center of Tropical Cyclone Ava is expected to move off the coast of Madagascar near Mananjary in a few hours.

Elsewhere over the South Indian Ocean, Tropical Cyclone Irving was strengthening east-southeast of Diego Garcia.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Irving was located at latitude 13.3°S and longitude 87.5°E which put it about 1145 miles (1845 km) east-southeast of Diego Garcia.  Irving was moving toward the west-southwest at 13 m.p.h. (21 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 991 mb.

Satellite imagery suggested that Tropical Cyclone Irving could be strengthening rapidly.  A primary rainband was wrapping around the center of circulation.  An eye appeared to be forming at the center of Irving.  Tropical Cyclone Irving will move through an environment favorable for intensification.  Irving is likely to intensify into the equivalent of a hurricane/typhoon while it passes well to the south of Diego Garcia during the next several days.

Tropical Cyclone Carlos Intensifies Southwest of La Reunion

Tropical Cyclone Carlos intensified on Wednesday as it moved farther southwest of La Reunion.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Carlos was located at latitude 23.9°S and longitude 53.4°E which put it about 240 miles (390 km) south-southwest of St. Denis, La Reunion.  Carlos was moving toward the southeast at 9 m.p.h. (15 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 989 mb.

Tropical Cyclone Carlos is more well organized than it has been during any part of its existence.  A ring of thunderstorms wraps nearly completely around a small eye at the center of circulation.  There is only a small break in the eyewall on the northwest side of the eye.  Several other bands of thunderstorms exist in the eastern half of the circulation.  There are far fewer thunderstorms in the western half of the circulation.  The thunderstorms in the eyewall are generating strong upper level divergence which is pumping out mass in all directions.  The well developed upper level divergence allowed the surface pressure to decrease and the winds increased in response to the lower central pressure.

Tropical Cyclone Carlos moved into an area where the upper level winds were not as strong and the vertical wind shear diminished.  Carlos is currently in an area where there is little vertical wind shear.  It is moving over water where the Sea Surface Temperature is near 28°C.  When the shear diminished the tropical cyclone was able to extract and to use the energy from the ocean more efficiently which allowed it to intensify.  Tropical Cyclone Carlos will continue to move through a favorable environment for another 24 to 36 hours.  It still has a chance to intensify into the equivalent of a hurricane/typhoon.  Eventually, when Tropical Cyclone Carlos moves to a higher latitude, it will move into an area of stronger upper level winds.  When that happens increased wind shear and cooler Sea Surface Temperatures will cause Tropical Cyclone Carlos to weaken.

Tropical Cyclone Carlos has reached the western end of a subtropical ridge.  The counterclockwise flow around the ridge is starting to steer Carlos toward the southeast.  A general southeasterly motion is expected to continue during the next several days.  On its anticipated track the core of Tropical Cyclone Carlos with the strongest winds is expected to pass south of La Reunion.

Tropical Cyclone Carlos Passing West of La Reunion

The core of Tropical Cyclone Carlos passed west of La Reunion on Tuesday.  At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Carlos was located at latitude 21.4°S and longitude 53.2°E which put it about 130 miles (210 km) west-southwest of St. Denis, La Reunion.  Carlos was moving toward the southwest at 7 m.p.h. (11 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 1000 mb.

Limited thunderstorm formation and moderate vertical wind shear caused the low level circulation to weaken slightly on Tuesday.  A few more thunderstorms appeared to develop south of the center of circulation during the past few hours.  Additional thunderstorms seemed to be forming in spiral bands outside the core of the circulation.  The thunderstorms forming south of the core were generating upper level divergence which was pumping mass away from center of circulation,  So, after appearing less organized earlier in the day, the circulation of Tropical Cyclone Carlos seemed to be showing signs of greater organization in recent hours.

An upper level ridge east of Carlos is generating northeasterly winds that are blowing toward the top of the tropical cyclone.  Those winds are producing moderate vertical wind shear, which is inhibiting intensification.  However, Tropical Cyclone Carlos is moving over water where the Sea Surface Temperature is near 28°C.  So, there is plenty of energy in the upper ocean to support strengthening.  The upper level winds could diminish during the next 24 hours.  If the vertical wind shear decreases, then Tropical Cyclone Carlos could intensify during the next 24 to 36 hours.

Carlos is moving around the western end of a subtropical ridge which is steering the tropical cyclone toward the southwest.  Tropical Cyclone Carlos is expected to reach the western end of the ridge in 24 to 36 hours and then it will start to move toward the southeast.  On its anticipated track the core of Tropical Cyclone Carlos will move between La Reunion and Madagascar.  Tropical Cyclone Carlos is expected to pass south of La Reunion after it starts to move toward the southeast.

Tropical Cyclone Carlos brought locally heavy rain to portions of Mauritius and La Reunion.  Outer rainbands could bring some additional rain to parts of La Reunion during the next day or two.