Tag Archives: IO01

Tropical Cyclone Sagar Brings Wind and Rain to Djibouti, Western Somalia

Tropical Cyclone Sagar brought wind and rain to Djibouti and Western Somalia on Saturday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Cyclone Sagar was centered at latitude 10.1°N and longitude 43.4°E which put it about 100 miles (165 km) south-southeast of Djibouti City, Djibouti.  Sagar was moving toward the southwest at 8 m.p.h. (13 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 988 mb.

Tropical Cyclone Sagar made landfall on the coast of northwestern Somalia near Bullaxaar on Saturday.  Sagar was the equivalent of a strong tropical storm at the time of landfall.  It moving south of an upper level ridge which was generating easterly winds which were blowing toward the top of the tropical cyclone.  Those winds were causing some vertical wind shear.  The stronger thunderstorms were occurring west of the center of circulation, which was probably due to the vertical wind shear.

Thunderstorms in the western half of Tropical Cyclone Sagar may have produced wind gusts to near hurricane force when Sagar made landfall on the coast of northwestern Somalia.  The gusts were capable of causing minor wind damage.  Sagar may have generated a storm surge of 4 to 8 feet (1.2 to 2.4 meters) near where the center made landfall.  Tropical Cyclone Sagar was dropping heavy rain on parts of extreme western Somalia and Djibouti.  The heavy rain was capable of producing flash floods.

Tropical Cyclone Sagar has a small circulation and Sagar will likely weaken quickly as moves inland into drier air over eastern Africa.  Even though it will weaken quickly, Sagar could also drop heavy heavy over parts of eastern Ethiopia and flash floods could occur in that region.

Tropical Cyclone Sagar Strengthens Over Western Gulf of Aden

Tropical Cyclone Sagar strengthened over the western Gulf of Aden on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Sagar was located at latitude 11.2°N and longitude 45.0°E which put it about 105 miles (170 km) south of Aden, Yemen.  Sagar was moving toward the west-southwest at 5 m.p.h. (8 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 986 mb.

A small eye appeared at the center of Tropical Cyclone Sagar on microwave satellite imagery.  The eye was surrounded by a tight ring of thunderstorms and the strongest winds were occurring in the ring of storms.  There was a small break on the southeast side of the ring of storms.  A short, broad band of showers and thunderstorms wrapped around the western and northern sides of the core of the circulation.  A longer, thinner rainband wrapped around the southern and eastern periphery of the circulation.  Storms near the core of Tropical Cyclone Sagar were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 60 miles (95 km) from the center of circulation.

Tropical Cyclone Sagar will be moving through an environment favorable for intensification for about another 12 to 18 hours.  Sagar will move over water where the Sea Surface Temperature is near 29°C to 30°C.  It is moving south of an upper level ridge.  The ridge is generating easterly winds which are blowing toward the top of the circulation.  Those winds are producing some vertical wind shear.  The shear may be the reason why most of the stronger thunderstorms are in the western half of the circulation.  The shear will inhibit intensification, but it will not be strong enough to prevent further strengthening.  Tropical Cyclone Sagar could become the equivalent of a hurricane/typhoon.  Much drier air is over eastern Africa and the Arabian Peninsula.  When Tropical Cyclone Sagar nears the coast of western Somalia, it will pull some of the drier air into the circulation and that will cause Sagar to start to weaken.

The upper level ridge is steering Tropical Cyclone Sagar toward the west-southwest and that general motion is expected to continue for several more days.  On its anticipated track Tropical Cyclone Sagar could make landfall on the coast of western Somalia in 18 to 24 hours.  Sagar will be capable of causing minor wind damage.  It could produce a storm surge of 4 to 8 feet (1.5 to 2.5 meters) near where the center makes landfall.  The core of Tropical Cyclone Sagar could also drop locally heavy rain over parts of western Somalia and eastern Ethiopia.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Sagar Strengthens Over Gulf of Aden

Tropical Cyclone Sagar (01A) strengthened over the Gulf of Aden on Thursday.  At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Sagar was located at latitude 12.8°N and longitude 47.8°E which put it about 210 miles (335 km) east of Aden, Yemen.  Sagar was moving toward the west-southwest at 8 m.p.h. (13 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 992 mb.

The circulation of Tropical Cyclone Sagar became more organized on Thursday.  An eyelike feature appeared at the center of circulation.  A partial ring of thunderstorms wrapped around the northeast, northwest and southwest quadrants of the incipient eye.  There was a break in the ring of storms southeast of the center.  The strongest winds were occurring in the partial ring.  Additional bands of showers and thunderstorms were occurring north and west of the center of circulation.  Bands south and east of the center consisted primarily of low clouds and showers.  Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 70 miles (110 km) from the center of circulation.

Tropical Cyclone Sagar will move through an environment somewhat favorable for intensification during the next 24 to 36 hours.  Sagar will move over water where the Sea Surface Temperature is near 29°C to 30°C.  So, there is plenty of energy in the upper ocean to support intensification.  Sagar is moving south of an upper level ridge.  The ridge is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing some vertical wind shear and they are part of the reason why the strong storm are occurring mainly in the western half of the circulation.  The wind shear is not strong enough to prevent intensification and Tropical Cyclone Sagar is likely to continue to strengthen during the next 24 hours.  It could strengthen into the equivalent of a hurricane/typhoon.  Much drier air is over the Arabian Peninsula and Somalia.  When Sagar approaches the coast of the Gulf of Aden, it will start to pull drier air into the circulation and that will cause Sagar to weaken.

The upper level ridge is steering Tropical Cyclone Sagar toward the west-southwest and that general motion is expected to continue during the next several days.  On its anticipated track Tropical Cyclone Sagar could be south of Aden in about 36 hours.  Sagar could approach the coast of western Somalia and Djibouti in two or three days.  Tropical Cyclone Sagar will bring gusty winds and it could cause some storm surge at the coast.  The greater risk is for locally heavy rain near the coast of Yemen and over north Somalia.  The rain could be heavy enough to produce flash floods in some locations.

Tropical Cyclone 01A Forms Over the Gulf of Aden

Tropical Cyclone 01A formed over the Gulf of Aden on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone 01A was located at latitude 13.0°N and longitude 48.6°E which put it about 265 miles (425 km) east of Aden, Yemen.  It was moving toward the west 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 995 mb.

A distinct low level center of circulation developed in an area of showers and thunderstorms that moved from the Arabian Sea to the Gulf of Aden.  Several bands of stronger thunderstorms formed west of the center of circulation and the strongest winds were occurring in these bands.  Bands in the eastern half of the circulation consisted primarily of low clouds and showers.  The storms west of the center were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 60 miles (95 km) from the center of circulation.

Tropical Cyclone 01A will move through an environment somewhat favorable for intensification during the next 24 to 36 hours.  It will move over water where the Sea Surface Temperature is near 29°C.  Tropical Cyclone 01A is moving south of an upper level ridge.  The ridge is producing westerly winds which were blowing toward the top of the circulation.  Those winds may be part of the reason why the stronger thunderstorms are occurring on the western side of the center  The winds are causing some vertical wind shear, but the shear is not likely to be strong enough to prevent intensification.  Tropical Cyclone 01A is likely to strengthen as long as it stays over the Gulf of Aden and it could intensify into the equivalent of a hurricane.  Much drier air is over the Arabian Peninsula and over eastern Africa.  Tropical Cyclone 01A will likely weaken when it moves closer to land and starts to pull drier air into the circulation.

The upper level ridge is steering Tropical Cyclone 01A toward the west.  The ridge is forecast to strengthen and to steer the tropical cyclone a little to the south of west during the next several days.  On its anticipated track Tropical Cyclone 01A is expected to remain over the Gulf of Aden for several more days.  Bands of showers and thunderstorms could bring locally heavy rain to coastal portions of Yemen and northern parts of Somalia.

Tropical Cyclone Roanu Nearing Bangladesh

Tropical Cyclone Roanu moved closer to the northern coast of the Bay of Bengal on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Roanu was located at latitude 20.3°N and longitude 87.8°W which put it about 200 miles (320 km) south of Kolkata, India and about 355 miles (575 km) west-southwest of Chittagong, Bangladesh.  Roanu was moving toward the northeast at 11 m.p.h. (18 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 983 mb.

On Friday Tropical Cyclone Roanu went through another cycle in which most of the thunderstorms dissipated near the center of circulation and then convection redeveloped rapidly.  Thunderstorm activity is increasing at the core of the circulation and those storms are driving well developed upper level outflow.  Several well formed bands of thunderstorms are rotating around the center of circulation.  Roanu is more organized and it is a little more intense than it was 24 hours ago.

Tropical Cyclone Roanu is in an environment that could support a little more intensification before it makes landfall on the north coast of the Bay of Bengal.  It is over water where the Sea Surface Temperature is near 30.5°C.  Roanu is under an upper level ridge which means the upper level winds are light and there is not much vertical winds shear.  However, Roanu is getting closer to the north coast of the Bay of Bengal and it only has another 12 hours or so to intensify.

A ridge east of Roanu is steering the tropical cyclone toward the northeast and that general motion is expected to continue for the next several days.  On its anticipated track Tropical Cyclone Roanu will be near the coast of Bangladesh in about 12 hours.  Roanu is expected to continue moving toward the northeast after it makes landfall.

Although Tropical Cyclone Roanu could cause some minor wind damage, its main threats will be locally heavy rain and a moderate storm surge.  Tropical Cyclone Roanu could produce locally heavy rainfall, especially if the thunderstorm activity continues to pulse diurnally.  The heavy rain could produce significant fresh water flooding over parts of northeastern India, Bangladesh and Myanmar (Burma).  In addition, the winds on the eastern side of Tropical Cyclone Roanu will be blowing toward the coast of Bangladesh and those winds will push water toward the coast.  The north coast of the Bay of Bengal is particularly susceptible to storms surges and Roanu could bring a moderate storm surge to the coast of Bangladesh.  The surge will be higher in the mouths of rivers and other locations where the shape of the coast funnels the water into specific locations.

Tropical Cyclone Roanu Threatens Northern Bay of Bengal

Tropical Cyclone Roanu intensified on Thursday and it poses an increasing threat to the northern Bay of Bengal.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Roanu was located at latitude 17.9°N and longitude 84.9°E which put it about 125 miles (200 km) east of Visakhapatman, India and about 580 miles (935 km) west-southwest of Chittagong, Bangladesh.  Roanu was moving toward the north-northeast at 14 m.p.h. (23 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 70 m.p.h. (115 km/h).  The minimum surface pressure was 986 mb.

Most of the thunderstorms in Tropical Cyclone Roanu weakened earlier today and at times it did not look much like a tropical cyclone on satellite imagery.  However, a burst of thunderstorm activity near the center of Roanu has occurred in recent hours and an eyelike feature has appeared on conventional satellite imagery.  The structure of the circulation improved as a result of the new burst of thunderstorms.  The primary rainband now coils more tightly about three quarters of the way around the apparent center of circulation.  The thunderstorms near the center of circulation are generating upper level divergence which is pumping out mass in all directions.  Several additional bands of thunderstorms have developed over the eastern half of the circulation and Tropical Cyclone Roanu is stronger than it was 24 hours ago.

Tropical Cyclone Roanu is in an environment favorable for intensification.  It is over water where the Sea Surface Temperature is near 31°C.  Roanu has moved closer to the center of an upper level ridge and the upper levels are not as strong as they were yesterday.  As a result the vertical wind shear is much less and the upper level ridge is actually helping to pump mass away from the center of Roanu.  The center of the tropical cyclone is near the east coast of India, but the core is expected to remain over water on Friday.  Roanu is likely to strengthen further and it could reach hurricane/typhoon intensity.

A ridge east of Roanu is steering the tropical cyclone toward the northeast and that general motion is expected to continue.  On its anticipated track Roanu could be south of Kolkata, India in about 18 hours.  Tropical Cyclone Roanu could be approaching Chittagong, Bangladesh in 24 to 36 hours.

Tropical Cyclone Roanu poses a significant threat to the northern Bay of Bengal.  That area is vulnerable to storm surges.  Since Roanu will approach from the southwest, the winds in its counterclockwise circulation will push water toward the north coast of the Bay of Bengal.  In addition, a strengthening Tropical Cyclone Roanu will be capable of producing locally heavy rain which could cause inland flooding.

Tropical Cyclone 01B Forms Over Bay of Bengal

The structure of a low pressure system north of Sri Lanka changed on Wednesday and it was classified as Tropical Cyclone 01B (TC01B).  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone 01B was located at latitude 15.9°N and longitude 82.3°E which put it about 155 miles (250 km) south-southwest Visakhapatnam, India.  TC01B was moving toward the northeast 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 989 mb.

A low pressure system developed near Sri Lanka several days ago.  The low moved over the east coast of Sri Lanka, which slowed the organization of the circulation.  A more well defined center of circulation began to organize after the low moved north of Sri Lanka.  A primary rainband started to wrap around the western side of the low and several broken spiral bands formed on the eastern side.  The circulation exhibited enough characteristics associated with tropical cyclones to be classified as Tropical Cyclone 01B.

The circulation of TC01B is still not particularly well organized.  A primary rainband curls around the northern and western sides of the circulation.  However, there are not many thunderstorms in the other parts of the tropical cyclone.  An upper level ridge over the northern Bay of Bengal is generating easterly winds over the top of the tropical cyclone.  Those winds are producing moderate vertical wind shear and are contributing to the fact that most thunderstorms are west of the center of circulation.  The fact that the center of circulation is near the coast of India also means a  portion of circulation is over land, where there is more friction and less moisture.

Tropical Cyclone 01B is expected to move into a more favorable environment during the next two days.  It is over water where the Sea Surface Temperature is near 31°C.  TC01B is expected to move closer to the center of the upper level ridge where the winds are not as strong.  That would reduce the vertical wind shear, which would also be favorable for intensification.  However, the proximity of the center to the east coast of India means that a portion of the circulation will remain over land, which will slow the rate of future intensification.

A ridge is east of TC01B is expected to steer the tropical cyclone toward the northeast during the next two to three days.  On its anticipated track, TC01B could be approaching the coast of Bangladesh in 48 to 72 hours.  TC01B caused heavy rain in parts of Sri Lanka and southeast India.  It could produce more heavy rain in parts of northeast India, Bangladesh and Myanmar (Burma).  TC01B could also generate a significant storm surge along the north coast of the Bay of Bengal as it nears the coast.