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Strong Tropical Cyclone Ava Makes Landfall in Madagascar

Strong Tropical Cyclone Ava made landfall on the east coast of Madagascar near Toamasina on Friday.  At 10:00 a.m. EDT on Friday the center of Tropical Cyclone Ava was located near 18.0°S and longitude 49.2°E which put it near Toamasina.  Ava was moving toward the west-southwest 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 959 mb.  Tropical Cyclone Ava was the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale.

Tropical Cyclone Ava intensified rapidly during the past 12 hours and it was still intensifying when it made landfall on the coast of Madagascar.  There was a well defined circular eye at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of the circulation.  Thunderstorms in the core of Tropical Cyclone Ava were generating strong upper level divergence which was pumping away mass and allowed the surface pressure to decrease rapidly.  Winds to hurricane/typhoon force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 180 miles (290 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Ava was 17.8.  The Hurricane Size Index (HSI) was 17.6 and the Hurricane Wind Intensity Size Index (HWISI) was 35.4.  Those indices indicate that Tropical Cyclone Ava is capable of causing regional serious damage.  The core of Tropical Cyclone Ava passed over Toamasina and there is likely to be serious wind damage in that city.  Heavy rain was falling in parts of eastern Madagascar and floods could occur.  Tropical Cyclone Ava could produce a storm surge of 10 feet (3 meters) south of where the center made landfall, because the strong winds will be blowing the water toward the coast.

Tropical Cyclone Ava will weaken while the center moves over land in eastern Madagascar.  However, the rest of the environment is favorable for a tropical cyclone.  The Sea Surface Temperature off the east coast of Madagascar is near 28°C.  The upper level winds are weak and there is little vertical wind shear.  If the inner core of Tropical Cyclone Ava remains intact, then Ava could intensify again when the center moves back over the South Indian Ocean in a day or so.

Tropical Cyclone Ava is moving around the western end of a subtropical ridge which is steering the tropical cyclone toward the west-southwest.  Ava will start to move toward the south when it reaches the end of the ridge in a few hours.  On its anticipated track Tropical Cyclone Ava is forecast to move just inland of the east coast of Madagascar.  Ava is forecast to move back off the coast in 24 to 36 hours.  Tropical Cyclone Ava is capable of causing serious damage along the central east coast of Madagascar.

Tropical Cyclone Ava Strengthens East of Madagascar

Tropical Cyclone Ava intensified east of Madagascar on Thursday.  At 4:00 p.m. EST on Thursday the center of Tropical Cyclone Ava was located at latitude 17.4°S and longitude 50.8°E which put it about 125 miles (205 km) east-northeast of Toamasina, Madagascar.  Ava was moving toward the west-northwest at 5 m.p.h. (8 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 980 mb.

Tropical Cyclone Ava exhibited the classic structure of a tropical cyclone on Thursday.  A clear eye was evident at the center of circulation on microwave satellite imagery.  The eye was surrounded by a nearly complete ring of showers and thunderstorms.  Spiral bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Ava.  Storms in the core of Ava were generating strong upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 140 miles (225 km) from the center of circulation.

Tropical Cyclone Ava will move through an environment favorable for intensification on Friday.  Ava will move over water where the Sea Surface Temperature is near 28.5°C.  Tropical Cyclone Ava is moving near the western end of an upper level ridge, but the upper level winds are weak and there is not much vertical wind shear.  Warm water and little vertical wind shear will allow Tropical Cyclone Ava to intensify during the next 24 hours.  Ava should strengthen into the equivalent of a hurricane/typhoon on Friday.

Tropical Cyclone Ava is moving around the western end of a subtropical ridge, which has been steering Ava mostly toward the west.  Tropical Cyclone Ava is forecast to move more toward the southwest on Friday as it nears the western end of the ridge.  On its anticipated track the center of Tropical Cyclone Ava will move close to the east coast of Madagascar near Toamasina in 18 to 24 hours.  When Ava reaches the western end of the ridge in about 24 hours, it will start to move more toward the south.

Tropical Cyclone Ava will bring strong winds and locally heavy rain to the east coast of Madagascar.  The winds will be strong enough to do damage and they could generate a storm surge at the coast.  Rain is already falling on parts of eastern Madagascar and more heavy rain will create the potential for floods.

Tropical Storm Bolaven Forms Over the South China Sea

Tropical Storm Bolaven formed over the South China Sea near the Spratly Islands on Tuesday.  At 10:00 p.m. EDT on Tuesday the center of Tropical Storm Bolaven was located at latitude 10.4°N and longitude 115.1°E which put it about 620 miles (1000 km) east of Ho Chi Minh City, Vietnam.  Bolaven was moving toward the west-northwest 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 1002 mb.

A low level center of circulation developed on the eastern side of a cluster of thunderstorms that moved across the southern Philippines on Monday.  The center exhibited greater organization on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Bolaven.  The structure of Tropical Storm Bolaven is asymmetrical.  The strongest thunderstorms are occurring northwest of the center of circulation.  Thin bands of low clouds and showers were revolving around the center of circulation in the other quadrants of Tropical Storm Bolaven.

Tropical Storm Bolaven is moving around the southern side of an upper level ridge centered east of the Philippines.  The ridge is generating strong southeasterly winds which are blowing across the top of the circulation.  Those winds are causing moderate vertical wind shear.  The wind shear is probably the reason why most of the stronger storms are occurring northwest of the center of circulation.  Although Bolaven will move over water where the Sea Surface Temperature is near 28°C, the vertical wind shear will likely prevent intensification.  In fact if the shear increases, then Bolaven could weaken to a tropical depression.

The ridge north of Bolaven is steering the tropical storm toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Tropical Storm Bolaven could reach the coast of South Vietnam in 24 to 36 hours.  Bolaven will bring gusty winds and locally heavy rain to parts of southern Vietnam.

Tropical Cyclone 03S Forms East of Madagascar

Tropical Cyclone 03S formed east of Madagascar on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone 03S was centered at latitude 15.5°S and longitude 53.2°E which put it about 330 miles (530 km) east-northeast of Toamasina, Madagascar.  It was moving a little south of due west at 9 m.p.h. (15 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 996 mb.

A well defined center of circulation developed within a cluster of thunderstorms passing north of La Reunion on Tuesday.  A primary rainband wrapped around the center of circulation and the system exhibited the characteristics of a tropical cyclone.  The innermost end of the primary  rainband wrapped tightly around the eastern side of the center of circulation, while the rest of the band coiled around the northern and western parts of the tropical cyclone.  Additional bands of showers and thunderstorms were forming outside the core of the system.  Thunderstorms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.

Tropical Cyclone 03S will be moving through an environment favorable for intensification.  It will move over water where the Sea Surface Temperature is near 28.5°C.  Tropical Cyclone 03S is in a region where the upper level winds are weak and there is not much vertical wind shear.  Warm water and little shear will allow Tropical Cyclone 03S to intensify and it could intensify rapidly.  The system is likely to strengthen into the equivalent of a hurricane/typhoon within 36 hours.

Tropical Cyclone 03S is moving along the northwestern periphery of a subtropical ridge.  The ridge is currently steering the system toward the west.  However, Tropical Cyclone 03S is likely to move more toward the southwest when it reaches the western end of the ridge.  On its anticipated track Tropical Cyclone 03S could approach the east coast of Madagascar in 24 to 36 hours.

Tropical Cyclone 03S is likely to intensify into the equivalent of a hurricane/typhoon before it reaches Madagascar.  It will bring strong gusty winds to eastern Madagascar.  The outer rainbands on the western side of Tropical Cyclone 03S are already dropping heavy rain on parts of eastern Madagascar.  Continued heavy could create dangerous floods in some locations.

Former Tropical Cyclone Hilda Drops Heavy Rain Over Western Australia

Former Tropical Cyclone Hilda dropped heavy rain over Western Australia on Friday.  At 11:00 a.m. EST on Friday the center of former Tropical Cyclone Hilda was located at latitude 22.7°S and longitude 123.6°E which put it about 50 miles (80 km) east-northeast of Telfer, Australia.  Hilda was moving toward the southeast at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 999 mb.

Although the center has been over land for more than a day, the circulation of former Tropical Cyclone Hilda is still well organized.  There is a well defined low level center of circulation and strong thunderstorms are occurring around the center.  Several bands of thunderstorms are revolving around the core of the circulation.  Storms near the core are generating strong upper level divergence which is pumping away mass.  The upper level divergence is preventing the surface pressure from increasing and that is allowing the surface low to maintain its intensity.

Storms near the core of former Tropical Cyclone Hilda and the rainbands are dropping heavy rain over parts of Western Australia.  That region is normally dry and the potential for flash floods exists.  The Australian Bureau of Meteorology has issued Flood Warnings for the Sandy Desert and West Kimberly District.  They have also issued Flood Watches for the De Grey River, Salt Lakes and Warburton District Catchments.  The storms generated by former Tropical Cyclone Hilda could also cause localized wind damage, but the greatest risk is posed by the heavy rain.

Tropical Cyclone Hilda Develops on Coast of Western Australia

A Tropical Low near the coast of Western Australia strengthened and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Hilda. At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Hilda was located at latitude 18.0°S and longitude 122.1°E which put it about 10 miles (15 km) west-southwest of Broome, Australia.  Hilda was moving toward the south-southwest at 8 m.p.h. (12 km/h).  The maximum sustained wind speed was 50 m.p.h. (85 km/h) and there were wind gusts to 85 m.p.h. (140 km/h).  The minimum surface pressure was 985 mb.  Broome Port reported a wind gust to 86 m.p.h. (139 km/h).

The center of the Tropical Low moved off the coast of Western Australia and the core of the circulation strengthened.  Thunderstorms in the core of Tropical Cyclone Hilda generated strong upper level divergence which pumped mass away from the center of circulation.  The removal of mass allowed the surface pressure to decrease quickly and the wind speeds increased.  The strongest winds were occurring over water near the center of circulation.  Additional bands of showers and thunderstorms were revolving around the core of the circulation.  Hilda is a small tropical cyclone.  Winds to tropical storm force only extend out about 35 miles (55 km) from the center of circulation.

Tropical Cyclone Hilda will be moving through an environment that will support further intensification during the next 12 hours.  The Sea Surface Temperature of the water near the coast of Western Australia is near 30°C.  Tropical Cyclone Hilda is underneath an upper level ridge and the upper level winds are weak.  There is little vertical wind shear.  The proximity to land is the only factor preventing rapid intensification of Tropical Cyclone Hilda.  Almost half of the circulation is over land and the increased friction is reducing the wind speeds in that part of Tropical Cyclone Hilda.

Tropical Cyclone Hilda is moving around the western end of a subtropical ridge, which is steering the tropical cyclone toward the south-southwest.  A general motion toward the south-southwest is expected to continue for another 12 to 24 hours.  On its anticipated track the center of Tropical Cyclone Hilda could pass near Bidyadanga during the next 6 to 12 hours.  Hilda will bring gusty winds capable of producing localized minor wind damage.  A Warning is in effect for the portion of the coast from Beagle Bay to Pardoo Roadhouse.  The core of Tropical Cyclone Hilda will drop locally heavy rain near the coast of Western Australia and flash flooding is possible.

Tropical Low Develops Near Coast of Western Australia

A distinct low level center of circulation developed in an area of thunderstorms near the coast of Western Australia on Tuesday and the Australian Bureau of Meteorology classified the system as a Tropical Low.  At 10:00 p.m. EST on Tuesday the center of the Tropical Low as located at latitude 17.2°N and 122.3°E which put it just inland east of Coulomb Point and about 55 miles (85 km) north of Broome, Australia.  The Tropical Low was moving toward the southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.

Although the center of circulation was over land, the circulation of the Tropical Low became much better organized on Tuesday.  There was a well defined center of circulation and weather radar images indicated an eyelike feature at the center of the Tropical Low.  Several bands of showers and thunderstorms wrapped around the center of circulation.  Storms in the core of the Tropical Low were generating well developed upper level divergence which was pumping mass away in all directions.

The Tropical Low will move through an environment favorable for intensification during the next 24 to 36 hours.  The Sea Surface Temperature of the water off the coast of Western Australia is near 30°C.  The Tropical Low is underneath an upper level ridge and the upper level winds are not very strong.  There is little vertical wind shear.  The only factor inhibiting intensification is the fact that the center is still inland over Western Australia.  If the center moves over water as is forecast, the Tropical Low will intensify and it could intensify rapidly.

The Tropical Low is moving around the western end of a mid-level ridge which is steering it toward the southwest.  The ridge is forecast to steer the Tropical Low toward the southwest for another 12 to 24 hours.  When the Tropical Low reaches the western end of the ridge, it will move more toward the south.  On its anticipated track the center of the Tropical Low will move off the coast of Western Australia and over water during the next 6 to 12 hours.  The center of the Tropical Low is expected to pass west of Broome.  The Tropical Low could approach the coast of Western Australia between Bidyadanga and Wallal Downs in about 36 hours.

The Tropical Low will drop heavy rain along the coast of Western Australia during the next 48 hours.  It will also bring gusty winds and a Warning has been issued for the portion of the coast from Cape Leveque to De Grey.

Tropical Depression Tembin Passes Near Southern Tip of Vietnam

The center of Tropical Depression Tembin passed near the southern tip of Vietnam on Monday night.  At 10:00 p.m. EST on Monday the center of Tropical Depression Tembin was located at latitude 8.5°N and longitude 104.6°E which put it about 200 miles (320 km) southwest of Ho Chi Minh City, Vietnam.  Tembin was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1005 mb.

An upper level ridge north of Tropical Depression Tembin continued to produce strong easterly winds which were blowing across the top of the circulation.  Those winds were causing strong vertical wind shear.  The shear was strong enough to prevent thunderstorm from developing in most parts of the circulation of Tropical Depression Tembin.  A few thunderstorms formed in the extreme northwestern portion of the circulation, but most of the circulation consisted of bands of low clouds and showers.  The strong shear and lack of tall thunderstorms caused the wind speeds at the surface to decrease and Tembin weakened to a tropical depression.

Tropical Depression Tembin will remain in an environment that is unfavorable for intensification.  Tembin will move over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the upper ocean to support intensification.  However, the upper ridge will continue to produce strong easterly winds.  The vertical wind shear is likely to cause the circulation of Tropical Depression Tembin to spin down.

The ridge north of Tembin has been steering the tropical depression toward the west and a general westerly motion is expected to continue for another day or two.  On its anticipated track Tropical Depression Tembin will move across the Gulf of Thailand.   The center of Tropical Depression Tembin could reach the coast of Thailand near Sichon in about 36 hours.

Typhoon Tembin Nears Southern Vietnam

Typhoon Tembin moved nearer to southern Vietnam on Sunday.  At 10:00 p.m. EST on Sunday the center of Typhoon Tembin was located at latitude 8.0°N and longitude 109.3°E which put it about 290 miles (470 km) southeast of Ho Chi Minh City, Vietnam.  Tembin was moving toward the west at 13 m.p.h. (21 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 979 mb.

Typhoon Tembin weakened during the past 12 hours as it moved over the South China Sea.  An upper level ridge north of Tembin generated stronger easterly winds on Sunday which increased the vertical wind shear.  The strong upper level winds weakened the rainbands in the eastern half of the circulation of Typhoon Tembin.  Those winds also tilted the upper portion of the circulation toward the west.  The low level circulation of Typhoon Tembin remained well organized, but the storms around the center weakened.  The strongest thunderstorms were occurring in bands west of the core of Tembin.  Winds to typhoon force extended out about 40 miles (65 km) from the center in the northern half of the circulation and about 25 miles (40 km) in the southern half.  Winds to tropical storm force extended out about 155 miles (250 km) from the center.

Typhoon Tembin is likely to continue to weaken on Monday.  Typhoon Tembin will move over water where the Sea Surface Temperature is near 29°C.  However, the upper level ridge is likely to continue to generate strong easterly winds and the significant vertical wind shear will make it difficult for tall thunderstorms to develop around much of the circulation.  The wind shear will probably weaken Tembin to a tropical storm on Monday.

The ridge north of Tembin is steering the typhoon toward the west and a general westerly motion is expected to continue for several more days.  On its anticipated track the center of Typhoon Tembin will pass near the southern tip of Vietnam in about 24 hours.  Tembin will likely move into the Gulf of Thailand as a tropical storm or tropical depression.

The heavy rain with Typhoon Tembin is occurring in bands west of the core of the typhoon.  So, the heavy rain will begin to fall before the center of circulation reaches places.  The heaviest rain will fall over the Mouths of the Mekong River and the part of Vietnam south of that area.  The rain could be heavy enough to cause floods in some locations.  Gusty winds could produce isolated damage as well in the southern part of Vietnam.

Tembin Strengthens to a Typhoon Over South China Sea

Tropical Storm Tembin strengthened into a typhoon on Saturday as it moved over the South China Sea.  At 10:00 p.m. EST on Saturday the center of Typhoon Tembin was located at latitude 8.2°N and longitude 113.6°E which put it about 540 miles (880 km) east of Ho Chi Minh City, Vietnam.  Tembin was moving toward the west at 18 m.p.h. (29 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 976 mb.

Typhoon Tembin became much better organized on Saturday.  A primary rainband wrapped around the center of circulation and an eye became apparent on microwave satellite imagery.  Several other rainbands strengthened outside the core of Typhoon Tembin.  Storms near the core of the circulation generated strong upper level divergence which pumped mass away to the west and northeast of the typhoon.  The removal of mass allowed the surface pressure to decrease and the wind speed to increase.  Winds to typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 155 miles (250 km) from the center.

Typhoon Tembin will move through an environment favorable for intensification during the next 24 hours.  Tembin will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Tempin is producing easterly winds which are blowing toward the typhoon.  However, the easterly winds are blowing at most levels of the atmosphere and there is not a lot of vertical wind shear.  Typhoon Tembin is likely to continue to intensify on Sunday.

The subtropical ridge north of Tembin is steering the typhoon quickly toward the west.  A general motion toward the west is expected to continue.  On its anticipated track Typhoon Tembin could approach the southern part of Vietnam in about 36 hours.  Tembin has the potential to bring strong winds, heavy rain and a storm surge to the southern coast of Vietnam.