Tag Archives: SH03

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 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.

Tropical Cyclone 03S Moving West of Australia

A tropical cyclone designated 03S moved farther west of Australia and weakened on Saturday.  Tropical Cyclone 03S moved across northern Australia as a low pressure system last week before move off the coast near Broome.  After the center of the low moved over the South Indian Ocean thunderstorms developed near the core of the system and the Australian Bureau of Meteorology classified it as a tropical low.  The tropical low strengthened into the equivalent of a tropical storm on Friday night, but the Australian Bureau of Meteorology did not give the system a name.

At 7:00 p.m. EST on Saturday the center of Tropical Cyclone 03S was located at latitude 19.5°S and longitude 109.8°E which put it about 335 miles (540 km) northwest of Learmonth, Australia.  Tropical Cyclone 03S was moving toward the west at 12 m.p.h. (19 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 994 mb.

Tropical Cyclone 03S has a well defined low level circulation but the distribution of thunderstorms is asymmetrical.  Most of the stronger thunderstorms are forming in bands west of the center of circulation.  There are also bands in the eastern half of the circulation but they consist primarily of low clouds and rain showers.  Strong easterly winds in the upper levels are shearing the tops off of any thunderstorms that develop in the eastern part of the circulation.  The easterly winds are also inhibiting upper level divergence to the east of the center.

Tropical Cyclone 03S will move into an environment that will be unfavorable for intensification.  Tropical Cyclone 03S is moving over water where the Sea Surface Temperature is near 26°C, but it will move over cooler water during the next several days.  An upper level ridge centered over Australia is generating easterly winds which are blowing across the top of the tropical cyclone.  The easterly winds are causing moderate vertical wind shear and are responsible for the asymmetrical distribution of thunderstorms.  Tropical Cyclone 03S is likely to weaken slowly during the next several days.

A subtropical ridge will continue to steer Tropical Cyclone 03S to the west during the next few days.  On its anticipated track Tropical Cyclone 03S is expected to move farther away from Western Australia as it weakens.