Category Archives: Tropical Cyclones

Information about tropical cyclones

Tropical Storm Teraji Develops East of Vietnam

Tropical Storm Teraji developed east of Vietnam on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Storm Teraji was located at latitude 11.1°N and longitude 110.1°E which put it about 100 miles (160 km) east of Lien Huong, Vietnam.  Teraji was moving toward the west at 5 m.p.h. (8 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 1004 mb.

A distinct low level center of circulation developed in an area of thunderstorms over the South China Sea east of southern Vietnam on Saturday and the Japan Meteorological Agency designated the system as Tropical Storm Teraji.  The circulation around Teraji was exhibiting evidence of vertical wind shear.  The center of circulation was on the eastern edge of a cluster of thunderstorms.  Tropical Storm Teraji was south of an upper level ridge.  The ridge was producing easterly winds which were causing moderate vertical wind shear.  The stronger thunderstorms were occurring in bands west of the center of circulation, which was likely an effect of the wind shear.

The ridge north of Tropical Storm Teraji will steer the tropical storm westward into southern Vietnam.  On its anticipated track Teraji will move over southern Vietnam on Sunday.  Tropical Storm Teraji will move across southern Cambodia early next week.  Thunderstorms in rainbands in the western half of Teraji could drop locally heavy and floods could occur in some locations.

Elsewhere over the Western North Pacific Ocean Tropical Depression 34W formed southeast of Palau.  At 10:00 p.m. EST on Saturday the center of Tropical Depression 34W was located at latitude 6.6°N and longitude 135.5°E which put it about 90 miles (145 km) southeast of Palau.  It was moving toward the west-southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts tot 45 m.p.h. (75 km/h).  The minimum surface pressure was 1004 mb.

Tropical Cyclone Gaja Makes Landfall in Southern India

Tropical Cyclone Gaja made landfall on the coast of southern India just south of Nagappattinam on Thursday.  At 4:00 p.m. EST on Thursday the center of Tropical Storm Gaja was located at latitude 10.5°N and longitude 79.7°E which put it about 10 miles (15 km) south of Nagappattinam, India.  Gaja was moving toward the west-southwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 974 mb.

Tropical Cyclone Gaja strengthened rapidly into the equivalent of a hurricane/typhoon while it approached the coast of Southern India.  A small circular eye formed at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Gaja.  The circulation of Gaja was small, which allowed it to strengthen quickly before landfall.  Winds to hurricane/typhoon force only extended out about 10 miles (15 km) from the center of circulation.  Winds to tropical storm force only extended out about 65 miles (105 km) from the center.

Tropical Cyclone Gaja produced winds strong enough to cause damage in the area near Nagappattinam.  Those winds could bring a storm surge of 5 to 8 feet (1.5 to 2.5 meters) near where the center made landfall.  The small size of Tropical Cyclone Gaja and the fact it did not intensify until it neared the coast will limit the magnitude of the storm surge.  Gaja is forecast to move westward across southern India.  Tropical Cyclone Gaja will weaken when it moves inland but it will drop locally heavy rain over Tamil Nadu, Kerala and southern Karnataka.  The heavy rain could cause flash flooding in those regions.

Tropical Cyclone Gaja will weaken while it moves across southern India.  The small size of the circulation and mountains in that area will contribute to a fairly rapid weakening.  The circulation in the lower levels could be seriously disrupted when it moves over the mountains, but the circulation in the middle levels may persist.  Some numerical models are forecasting that Tropical Cyclone Gaja could strengthen back into the equivalent of a tropical storm when it moves over the Arabian Sea.

Tropical Cyclone Gaja Moves Closer to Southern India

Tropical Cyclone Gaja moved closer to southern India and strengthened on Wednesday.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Gaja was located at latitude 11.7°N and longitude 83.6°E which put it about 260 miles (420 km) east of Cuddalore, India.  Gaja was moving toward the southwest at 10 m.p.h. (16 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 Gaja strengthened on Wednesday.  More thunderstorms developed near the center of circulation.  Some microwave images exhibited the appearance of an eyelike feature in the lower levels.  The inner end of a rainband appeared to be wrapping around the center of Gaja.  There were several bands of stronger thunderstorms in the western half of Tropical Cyclone Gaja.  Rainbands in the eastern half of the tropical cyclone consisted primarily of showers and lower clouds.  The storms around the center of circulation were generating strong upper level divergence which was pumping mass away to the northeast of Gaja.  The circulation around Tropical Cyclone Gaja was relatively small.  Winds to tropical storm force only extended out about 65 miles (105 km) from the center of circulation.

Tropical Cyclone Gaja will move through an environment favorable for intensification during the next 24 hours.  Gaja will move over water where the Sea Surface Temperature is near 29°C.  It will move southwest of an upper level ridge.  The ridge will produce southeasterly winds which will blow toward the top of the circulation.  Those winds will restrict upper level divergence to the southeast of Gaja.  They will also cause moderate vertical wind shear, which is probably the reason why most of the stronger thunderstorms are occurring in the western half of the circulation.  The wind shear will slow intensification, but Tropical Cyclone Gaja will strengthen during the next 24 hours.  Gaja could intensify to the equivalent of a hurricane/typhoon.

Tropical Cyclone Gaja will move south of a ridge in the middle troposphere during the next 48 hours.  The ridge will steer Gaja on a track that is a little south of straight westward.  On its anticipated track Tropical Cyclone Gaja will approach the coast of southern India in about 24 hours.  Gaja will make landfall in Tamil Nadu between Cuddalore and Nagappattinam in a little over a day.  It could be the equivalent of a hurricane/typhoon when it makes landfall.  Gaja will bring strong winds and it could cause a storm surge of 5 to 8 feet (1.5 to 2.5 metres) at the coast.  Tropical Cyclone Gaja will drop locally heavy rain over portions of Tamil Nadu, Karnataka and Kerala.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Gaja Forms Over Bay of Bengal

Tropical Cyclone Gaja formed over the Bay of Bengal on Sunday.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Gaja was located at latitude 12.9°N and longitude 86.7°E which put it about 500 miles (805 km) east of Chennai, India.  Gaja was moving toward the west-southwest 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 1002 mb.

An area of low pressure moving over the Bay of Bengal strengthened on Sunday and the India Meteorological Department classified the system as Tropical Cyclone Gaja.  The circulation around Tropical Cyclone Gaja is still organizing.  There is a distinct low level center of circulation.  A short band of thunderstorms is west and north of the center.  Several other bands of showers and thunderstorms are developing in other parts of Tropical Cyclone Gaja.  One stronger band is east of the center of circulation and another stronger band is southeast of the center.  Storms near the center are beginning to generate upper level divergence which will pump mass away from the tropical cyclone.

Tropical Cyclone Gaja will move through an environment somewhat favorable for intensification during the next 48 hours.  Gaja will move over water where the Sea Surface Temperature is near 29°C.  It will move south of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of the circulation.  The winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Gaja will intensify and it could be nearly equivalent to a hurricane/typhoon in two or three days.

The upper level ridge will steer Tropical Cyclone Gaja in a generally west-southwesterly direction.  On its anticipated track Tropical Cyclone Gaja will approach the coast of southern India in about 72 hours.  Gaja could be nearly the equivalent of a hurricane/typhoon at that time.

Elsewhere, over the South Indian Ocean Tropical Cyclone Alcide still was moving slowly east of the northern end of Madgascar and Tropical Cyclone Bouchra developed between Diego Garcia and Cocos Island.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Alcide was located at latitude 12.3°N and longitude 51.9°E which put it about 170 miles (275 km) east of Antisiranana, Madagascar.  Alcide was moving toward the northwest at 4 m.p.h. (6 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 997 mb.

At 4:00 p.m. EDT on Sunday the center of Tropical Cyclone Bouchra was located at latitude 5.4°S and longitude 89.1°E which put it about 700 miles (1130 km) northwest of Cocos Island, Australia.  Bouchra was moving toward the east at 2 m.p.h. (3 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 Alcide Stalls East of Madgascar

Tropical Cyclone Alcide stalled east of northern Madagascar on Friday.  At 4:00 p.m. EDT on Friday the center of Tropical Cyclone Alcide was located at latitude 13.4°N and longitude 53.1°E which put it about 250 miles (400 km) east of Antisiranana, Madagascar.  Alcide was moving toward the south at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 978 mb.

Tropical Cyclone Alcide weakened during the past 36 hours.  An eye is no longer apparent on visible satellite images, although an eyelike feature persists on microwave satellite images.  There are breaks in the ring of thunderstorms surrounding the eye.  Winds to hurricane/typhoon force are occurring in the broken ring of storms.  Alcide moved very slowly during the past day or so.  Its slow movement may have allowed its winds to mix cooler water to the surface of the ocean.  If there is cooler water at the surface, then there is less energy available to support the circulation of Tropical Cyclone Alcide.  The circulation of Alcide remains relatively small.  Winds to tropical storm force extend out about 100 miles (160 km) from the center of circulation.

Tropical Cyclone Alcide is in an area where the steering currents are weak.  Alcide could meander over the same area for another day or so.  If it remains over the same cooler water, then Alcide will slowly weaken further.  As the circulation gets weaker, thunderstorms will not rise as high into the atmosphere and Tropical Cyclone Alcide will be steered by winds at lower levels.  If Alcide eventually moves over warmer water, and the upper level winds are not too strong, then new thunderstorms could develop.

Tropical Cyclone Alcide is not forecast to move much during the next 24 hours.  In a day or so the winds in the lower and middle troposphere are forecast to begin to steer Alcide in a more westerly direction.  On its anticipated track Tropical Cyclone Alcide could move closer to northern Madagascar on Sunday.

Tropical Cyclone Alcide Rapidly Intensifies Into Equivalent of Hurricane/Typhoon

Tropical Cyclone Alcide rapidly intensified into the equivalent of a hurricane/typhoon east of northern Madagascar on Wednesday.  At 10:00 a.m. EDT on Wednesday the center of Tropical Cyclone Alcide was located at latitude 10.6°S and longitude 55.7°W which put it about 675 miles (975 km) north of Port Louis, Mauritius.  Alcide was moving toward the west-southwest at 11 m.p.h. (17 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 972 mb.

The circulation around Tropical Cyclone Alcide organized rapidly during the past 24 hours.  An eye formed at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Alcide.  Storm near the core were generating upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Alcide is relatively small.  Winds to hurricane/typhoon force extend out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extend out about 80 miles (130 km) from the center.

Tropical Cyclone Alcide will move through an environment capable of supporting further intensification during the next 48 hours.  Alcide will move over water where the Sea Surface Temperature is near 27°C.  It will move near the western end of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not prevent intensification.  Tropical Cyclone Alcide could strengthen to the equivalent of a major hurricane during the next day or two.

The upper level ridge will steer Tropical Cyclone Alcide in a west-southwesterly direction.  On its anticipated track Alcide would stay north of Mauritius and La Reunion.  Tropical Cyclone Alcide could be east of northern Madagascar in a few days.

Tropical Cyclone Alcide Forms North of Mauritius

Tropical Cyclone Alcide formed north of Mauritius on Tuesday.  At 10:00 a.m. EDT on Tuesday the center of Tropical Cyclone Alcide was located at latitude 9.7°S and longitude 58.9°E which put it about 740 miles (1190 km) north of Port Louis, Mauritius.  Alcide was moving toward the west-southwest 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 999 mb.

A distinct center of circulation consolidated in an area of thunderstorms over the South Indian Ocean and the system was designated as Tropical Cyclone Alcide.  The circulation around Alcide was slowly becoming better organized.  The inner end of a band of thunderstorms was wrapping around the western side of the center of circulation.  Several other bands were developing south and west of the center.  Bands north and east of the center consisted primarily of showers and lower clouds.  Storms near the center of circulation were starting to generate upper level divergence which was pumping mass away from the core of the tropical cyclone.

Tropical Cyclone Alcide will move through an environment that will support intensification.  Alcide will move over water where the Sea Surface Temperature is near 27.5°C.  It will move around the northwestern side of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear which will slow the rate of intensification, but the winds are not likely to be strong enough to prevent intensification.  Tropical Cyclone Alcide could strengthen into the equivalent of a hurricane/typhoon during the next 48 to 72 hours.

The upper level ridge will steer Tropical Cyclone Alcide slowly toward the west-southwest during the next two or three days.  On its anticipated track Alcide could be northeast of Madagascar in a few days.  It could be the equivalent of a hurricane/typhoon at that time.

Tropical Storm Xavier Causes Warning for Coast of Mexico

Potential impacts of Tropical Storm Xavier caused the government of Mexico to issue a Tropical Storm Warning for a portion of the coast.  The Tropical Storm Warning was in effect from Punta San Telmo to Playa Perula, Mexico.  At 1:00 p.m. EST the center of Tropical Storm Xavier was located at latitude 17.8°N and longitude 105.4°W which put it about 110 miles (175 km) southwest of Manzanillo, Mexico.  Xavier was moving toward the north at 6 m.p.h. (10 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 1003 mb.

An upper level trough is producing strong southwesterly winds which are blowing toward the top of Tropical Storm Xavier.  Those winds are causing significant vertical wind shear and they blew the upper portion of Xavier northeast of the lower level circulation earlier on Sunday morning.  However, new thunderstorms formed around the center of circulation and in a rainband northeast of the center.  There are several bands of showers and thunderstorms west of the center of circulation.  The bands southeast of the center consist primarily of low clouds and showers.  The strongest winds are occurring in the northeast portion of Tropical Storm Xavier.  Winds to tropical storm force extend out about 80 miles (130 km) from the center of circulation.  Winds are blowing to tropical storm force near the coast of Mexico which is why the Tropical Storm Warning was issued.

The future intensity of Tropical Storm Xavier will be determined by the strength of the upper level winds.  Xavier will move over water where the Sea Surface Temperature is near 28°C.  So, there is plenty of energy in the upper ocean to support a tropical storm.  However, the upper level winds were almost strong enough to shear Xavier apart on Sunday morning.  If the upper level winds do not get any stronger, then Xavier could persist as a tropical storm for another day or two.  If the upper level winds do get stronger, which is the forecast of many numerical models, then Xavier will quickly weaken to a tropical depression.  The official forecast from the National Hurricane Center follows the second scenario and it weakens Xavier to a tropical depression by Monday night.

The upper level trough will also determine future track of Tropical Storm Xavier.  If the upper level winds allow Xavier to persist as a tropical storm, then the trough will steer Xavier north-northeast toward the coast of Mexico.  If the upper level winds blow the top of the circulation away from the lower level circulation, then the winds closer to the surface would turn the lower part of Xavier back toward the west.  The official forecast from the National Hurricane Center follows the second scenario.

Bands of showers and thunderstorms in the northeaster part of Tropical Storm Xavier are already dropping rain over the coastal regions of Colima and Jalisco.  Prolonged heavy rain could cause flash floods in some locations.  Winds could reach tropical storm force along the coast even if the center of Tropical Storm Xavier does not make landfall.  There could also be a minor storm surge where the wind blows water toward the coast.

Tropical Storm Xavier Forms Southwest of Manzanillo

Tropical Storm Xavier formed southwest of Manzanillo, Mexico on Friday night.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Xavier was located at latitude 14.5°N and longitude 108.2°W which put it about 405 miles (650 km) southwest of Manzanillo, Mexico.  Xavier was moving toward the east-northeast 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 1006 mb.

A center of circulation developed in an area of thunderstorms southwest of Mexico on Friday.  When more thunderstorms developed closer to the center of circulation on Friday night, the National Hurricane Center designated the system as Tropical Storm Xavier.  The core of Tropical Storm Xavier was small.  The inner part of a band of showers and thunderstorms was wrapping around the center of circulation.  Storms near the core were generating upper level divergence.  Other short bands of showers and thunderstorms were revolving around the center of Tropical Storm Xavier.  Winds to tropical storm force extended out about 70 miles (110 km) from the center of circulation, but the strongest winds were occurring primarily in the southeastern quadrant of Xavier.

Tropical Storm Xavier will move through an environment somewhat favorable for intensification during the weekend.  Xavier will move over water where the Sea Surface Temperature is near 28°C.  So, there will be plenty of energy in the upper ocean to support intensification.  However, an upper level trough west of Xavier will produce strong southwesterly winds which will blow toward the top of the tropical storm.  Those winds will cause moderate vertical wind shear and they will inhibit upper level divergence to the west of Tropical Storm Xavier.  Xavier is likely to intensify on Saturday, but its small circulation means that it could weaken if the wind shear increases.

The upper level trough will also steer Tropical Storm Xavier in a north-northeasterly direction during the next day or two.  On its anticipated track the center of Tropical Storm Xavier could approach the west coast of Mexico by Sunday night.

Typhoon Yutu Brings Wind and Rain to Luzon

Typhoon Yutu brought wind and rain to Luzon on Monday.  At 5:00 p.m. EDT on Monday the center of Typhoon Yutu was located at latitude 16.8°N and longitude 122.4°E which put it about 45 miles (75 km east of Ilagan, Philippines.  Yutu was moving toward the west at 14 m.p.h. (22 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. (200 km/h).  The minimum surface pressure was 949 mb.

The center of Typhoon Yutu made landfall near Palanan Point on the northeast coast of Luzon late on Monday.  Yutu had a large circulation.  Winds to typhoon force extended out about 80 miles (130 km) from the center of circulation.  Winds to tropical storm force extended out about 270 miles (435 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Yutu was 17.8.  The Hurricane Size Index (HSI) was 25.5 and the Hurricane Wind Intensity Size Index (HWISI) was 43.3.  Typhoon Yutu is capable of causing widespread serious damage.

Typhoon Yutu could cause a storm surge of up to 10 feet (3 meters) on the northeast coast of Luzon.  It will also produce destructive winds as it moves across northern Luzon.  Yutu will move westward across Luzon.  It will move into the South China Sea south of Vigan, Philippines.  Typhoon Yutu will drop very heavy rain over parts of northern Luzon and flash flooding will be very likely.  Rapid runoff into the Cagayan River could cause it to flood.

Typhoon Yutu will move over the Sierra Madre mountains and the Cordillera Central when it moves across northern Luzon.  Those two mountain ranges will disrupt the lower levels of the circulation and Yutu will be weaker when it reaches the South China Sea.  Yutu could still be a typhoon when it moves back over water, but it may weaken to a tropical storm by then.

Typhoon Yutu will move around the western end of a ridge of high pressure over the Western North Pacific Ocean when it reaches the South China Sea.  Yutu will move toward the north when it reaches the western end of the ridge and it could approach China in four or five days.