Tropical Cyclone Amphan Develops Quickly Over Bay of Bengal

Tropical Cyclone Amphan developed quickly over the Bay of Bengal on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Amphan was located at latitude 11.2°N and longitude 86.3°E which put it about 430 miles (695 km) west of Port Blair.  Amphan was moving toward the north 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 around a low pressure system over the Bay of Bengal organized quickly on Saturday and the Indian Meteorological Department designated the system as Tropical Cyclone Amphan.  Thunderstorms formed around the center of Amphan and recent microwave images suggested that an eye could be forming.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Amphan.  The stronger bands were in the western half of the circulation.  Storms near the core of the circulation were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Amphan.

Tropical Cyclone Amphan will move through an environment very favorable for intensification.  Amphan will move over water where the Sea Surface Temperature is near 31°C.  It will move under the axis of an upper level ridge over the Bay of Bengal.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Tropical Cyclone Amphan is likely to intensify rapidly during the next 36 hours.  Amphan is likely to strengthen into the equivalent of a hurricane/typhoon within 24 hours and it could become the equivalent of a major hurricane within 36 to 48 hours.

Tropical Cyclone Amphan will move around the eastern end of a high pressure system over southeast Asia.  The high will steer Amphan toward the north during the next several days.  On its anticipated track Tropical Cyclone Amphan could approach the coast of northeast Indian and Bangladesh in 72 hours.  Amphan will likely be the equivalent of a major hurricane when it approaches the coast.  Tropical Cyclone Amphan could generate a catastrophic storm surge along the north coast of the Bay of Bengal.

Tropical Depression One Forms East of Florida

Tropical Depression One formed east of Florida on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Depression One was located at latitude 28.4°N and longitude 78.6°W which put it about 125 miles (200 km) east of Melbourne, Florida.  The depression was moving toward the north-northeast at 13 m.p.h. (20 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 1008 mb.

A Tropical Storm Watch was issued for the portion of the coast from Surf City to Duck, North Carolina including Pamlico and Albemarle Sounds.

Surface observations and data from aircraft reconnaissance indicated that a distinct low pressure system formed east of Florida on Saturday and the National Hurricane Center designated the system as Tropical Depression One.  More thunderstorms developed near the center of circulation.  Storms near the center began to generate upper level divergence which pumped mass away to the east of the depression.  The strongest winds were occurring in the inner part of the circulation, which was consistent with the typical structure of a tropical cyclone.  Bands of showers and thunderstorms were developing.  The strongest bands were in the eastern half of the circulation.

Tropical Depression One will move through an environment favorable for intensification during the next several days.  The depression will move over water where the Sea Surface Temperature is near 25°C.  An upper level trough over the eastern Gulf of Mexico and an upper level ridge east of Florida will interact to produce southerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear but the shear will not be strong enough to prevent intensification.  Tropical Depression One will strengthen into a tropical storm.

The upper level trough and upper level ridge will steer Tropical Depression One toward the north-northeast during the next 36 to 48 hours.  On its anticipated track Tropical Depression One will approach the coast of North Carolina on Monday.  It will be a tropical storm by that time.  It will bring gusty winds and heavy rain to parts of the coast.  Wind blowing water toward the coast will cause the water level to rise and there will be erosion of the beaches.

Tropical Storm Vongfong Brings Wind and Rain to Luzon

Tropical Storm Vongfong brought wind and rain to Luzon on Friday.  At 11:00 am. EDT on Friday the center of Tropical Storm Vongfong was located at latitude 15.6°N and longitude 121.2°E which put it about 45 miles (75 km) northeast of Manila, Philippines.  Vongfong was moving toward the north-northwest at 13 m.p.h. (20 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 990 mb.

Former Typhoon Vongfong weakened to a tropical storm on Friday after the center passed across northern Samar and southeastern Luzon.  The circulation around Tropical Storm Vongfong was small but it remained well organized.  The strongest winds were occurring in rainbands in the eastern half of the circulation which was over the Philippine Sea.  Winds to tropical storm force extended out 50 miles (80 km) from the center of circulation.  The wind speeds were not as strong over land, although stronger winds may have been occurring at locations in mountainous regions.

Tropical Storm Vongfong dropped locally heavy rain over southeastern and eastern Luzon.  The center of Vongfong passed west of Legaspi and east of Manila.  Heavy rain may have fallen on the slopes of the Mayon Volcano and flash floods could have occurred in that region.

Tropical Storm Vongfong will move around the western end of a high pressure system centered southeast of Japan.  The high steer Vongfong toward the north during the next 24 hours.  The tropical storm will start to move toward the northeast during the weekend after it moves around the western end of the high pressure system.  On its anticipated track Tropical Storm Vongfong will move over northern Luzon during the next 24 hours.  Vongfong will continue to bring gusty winds and drop locally heavy rain over parts of northern Luzon.

Disturbance South of Florida Keys

A disturbance south of the Florida Keys is currently designated at Invest 90L.  The disturbance could develop into a tropical or subtropical cyclone during the next few days.  At 8:00 p.m. EDT on Thursday the center of Invest 90L was located at latitude 23.9°N and longitude 81.2°W which put it about 55 miles (85 km) south of Marathon, Florida.  It was moving toward the east-northeast at 5 m.p.h. (8 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 1013 mb.

A small trough in the middle troposphere moved over a stationary front south of the Florida Keys on Thursday.  Satellite images and radar loops detected rotation in the middle troposphere.  There was a broad counterclockwise rotation south of the Keys and radar loops also revealed several small counterclockwise rotations within the broader mid-level circulation.  However, there did not appear to be a distinct center of circulation with lower pressure at the surface.

Invest 90L is forecast to move toward the northeast during the next several days.  It will move into an environment more favorable for development into a tropical or subtropical cyclone.  Invest 90L will move over water where the Sea Surface Temperature is near 27°C.  There will be an upper level trough over the eastern Gulf of Mexico, but a small upper level ridge will develop east of Florida.  The combination of the upper level trough and the upper ridge will produce a region of upper level divergence east of Florida.  The upper level divergence will pump mass away and the surface pressure will decrease in that area.  A surface low pressure system is likely to form on Friday or Saturday.  The National Hurricane Center is indicating that there is an 80% probability of the formation of a tropical or subtropical cyclone.  A reconnaissance plane is tentatively scheduled to investigate the system on Friday afternoon, if necessary.

Typhoon Vongfong Makes Landfall on Samar

Typhoon Vongfong made landfall on Samar on Thursday.  At 11:00 a.m. EDT on Thursday the center of Typhoon Vongfong was located at latitude 12.5°N and longitude 124.5°E which put it about 10 miles (15 km) west of Catarman, Philippines.  Vongfong was moving toward the west-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 967 mb.

Typhoon Vongfong made landfall on the coast of Samar north of Dolores on Thursday.  Vongfong was the equivalent of a major hurricane at the time of landfall.  The maximum sustained wind speed was 115 m.p.h. (185 km/h).  After Typhoon Vongfong made landfall, it moved west-northwest along the northern coast of Samar.  The center of Vongfong passed near Laoang and Catarman.  There have been reports of wind damage in northern Samar.  Typhoon Vongfong also dropped heavy rain in some locations and flash floods may have occurred.

Typhoon Vongfong began to weaken after the center moved over Samar.  The eye was no longer evident on conventional satellite images.  The winds speeds were decreasing slowly.  Winds to typhoon extended out 30 miles (50 km) from the center of circulation.  Winds to tropical storm force extended out 80 miles (130 km) from the center.

Typhoon Vongfong will move around the western end of a high pressure system centered southeast of Japan.  The high will steer Vongfong toward the northwest during the next 24 hours.  On its anticipated track Typhoon Vongfong will move across eastern Luzon.  The center of Vongfong will move near Bulan, Ligao, Naga, Daet, and Labo.  Typhoon Vongfong will also bring wind and rain to Sorsogon, Legaspi and Tabaco.  Heavy rain could flash floods in areas of steep terrain.

Typhoon Vongfong Nears Landfall in Samar

Typhoon Vongfong neared landfall in Samar on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Vongfong was located near latitude 12.2°N and longitude 125.8°E which put it about 30 miles (50 km) east of Dolores, Philippines.  Vongfong was moving toward the west at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and  there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 959 mb.

Typhoon Vongfong was a small but strong tropical cyclone.  There was a small circular eye at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms.  The strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of the circulation.

Winds to typhoon force extended out 20 miles (30 km) from the center of Typhoon Vongfong.  Winds to tropical storm force extended out 75 miles (120 km) from the center.  The Hurricane Intensity Index (HII) for Vongfong was 19.2.  The Hurricane Size Index (HSI) was 5.6 and the Hurricane Wind Intensity Size Index (HWISI) was 24.8.  Typhoon Vongfong was capable of causing localized serious damage.

Typhoon Vongfong will move around the western end of a high pressure system centered southeast of Japan.  The high will steer Vongfong toward the northwest during the next 24 hours.  On its anticipated track the center of Typhoon Vongfong will make landfall on the coast of northern Samar north of Dolores during the next 6 to 12 hours.  The center of Vongfong could be near Laoang in about 12 hours.  Typhoon Vongfong could move over southeastern Luzon later on Thursday.  The center of Vongfong could be near Legaspi in 18 hours.

The small inner core of Typhoon Vongfong will be capable of causing localized serious wind damage in northern Samar and southeastern Luzon.  Vongfong could bring strong winds to Dolores, Laoang, Catarman, Bulan, Sorsogon and Legaspi.  Typhoon Vongfong will drop locally heavy rain over northern Samar, southeastern Luzon and Catanduanes Island.  Flash floods could occur in some locations.  Vongfong could cause a storm surge of up to 10 feet (3 meters) in parts of northern Samar and southeastern Luzon.

Vongfong Rapidly Intensifies Into a Typhoon East of Samar

Former Tropical Storm Vongfong rapidly intensified into a typhoon east of Samar on Wednesday.  At 11:00 a.m. EST on Wednesday the center of Typhoon Vongfong was located at latitude 12.3°N and longitude 127.6°E which put it about 140 miles (225 km) east of Dolores, Philippines.  Vongfong was moving toward the west-northwest 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. (200 km/h).  The minimum surface pressure was 966 mb.

Typhoon Vongfong rapidly intensified on Wednesday from a strong tropical storm into a typhoon.  A small circular eye formed 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.  Bands of showers and thunderstorms were revolving around the core of Typhoon Vongfong.  Storms near the core were generating strong upper level divergence which was pumping mass away from the typhoon in all directions.  The removal of mass was allowing the surface pressure to decrease quickly, which caused the rapid intensification.

The circulation around Typhoon Vongfong was small.  Winds to typhoon force extended out 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out 90 miles (145 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Vongfong was 17.8.  The Hurricane Size Index (HSI) was 6.4 and the Hurricane Wind intensity Size Index (HWISI) was 24.2.  Typhoon Vongfong was capable of causing localized serious damage.

Typhoon Vongfong will move through an environment favorable for intensification during the next 24 hours.  Vongfong will move over water where the Sea Surface Temperature is near 29.5°C.  It will move under a small upper level ridge east of the Philippines.  The upper level winds in the ridge are weak and there will be little vertical wind shear.  Typhoon Vongfong will continue to intensify rapidly in the short term.  Vongfong is likely to strengthen into the equivalent of a major hurricane during the next 6 to 12 hours.

Typhoon Vongfong will move around the western end of a high pressure system centered southeast of Japan.  The high will steer Vongfong toward the west-northwest during the next 24 hours.  Typhoon Vongfong will start to move more toward the north-northwest in a day or so, when it nears the western end of the high pressure system.  On its anticipated track the core of Typhoon Vongfong could approach northern Samar in about 18 hours.  Vongfong could approach Catanduanes Island and southeastern Luzon in about 24 hours.  Outer bands on the western side of Typhoon Vongfong could start to drop heavy rain over parts of Samar during the next 12 to 18 hours.

Possible Development Near the Bahamas

A low pressure system could develop near the Bahamas on Friday or Saturday.  The National Hurricane Center is indicating that there is a 70% probability that the low pressure system could develop into a subtropical cyclone.

A stationary frontal boundary extends from south of Florida across the Bahamas.  A small upper level trough called a shortwave over the southwestern U.S. will move east toward the stationary front later this week.  When the upper level trough approaches the stationary front, a low pressure system is likely to develop near the Bahamas.  If thunderstorms develop near the center of the low pressure system, then it could exhibit the structure of a tropical or subtropical cyclone.  The Sea Surface Temperature near the Bahamas is near 26°C.  So, the water will be warm enough to support the development of a tropical cyclone.  However, the winds blowing around the upper level trough will cause moderate vertical wind shear.  The wind shear may be strong enough to inhibit the development of a tropical cyclone.  However, the shear may not be strong enough to prevent the development of a subtropical cyclone.  If the low pressure system strengthens into a subtropical storm, it will be designated Subtropical Storm Arthur.

Tropical Storm Vongfong Develops East of the Philippines

Tropical Storm Vongfong developed east of the Philippines on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Vongfong was located at latitude 11.6°N and longitude 128.7°E which put it about 165 miles (270 km) east of Samar, Philippines.  Vongfong was moving toward the north-northwest at 7 m.p.h. (11 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.

Former Tropical Depression 01W strengthened on Tuesday and the Japan Meteorological Agency designated the low pressure system as Tropical Storm Vongfong.  The circulation around Vongfong was still organizing.  More thunderstorms were developing near the center of circulation.  Other thunderstorms were occurring in a primary rainband in the eastern side of Tropical Storm Vongfong.  Bands in the northern and western parts of the circulation consisted primarily of showers and lower clouds.  Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical storm.  Winds to tropical storm force extended out 75 miles (120 km) from the center.

Tropical Storm Vongfong will move through an environment favorable for intensification during the next 36 hours.  Vongfong will move over water where the Sea Surface Temperature is near 29°C.  It will move under a small upper level ridge centered east of the Philippines.  The winds in upper ridge are weak and there will be little vertical wind shear.  Tropical Storm Vongfong will continue to intensify and it could strengthen to a typhoon within 24 to 36 hours.  A period of rapid intensification could occur after the inner part of the circulation becomes more organized.

Tropical Storm Vongfong will move around the western end of a high pressure system centered south of Japan.  The high pressure system is forecast to strengthen during the next 36 hours and it will steer Vongfong more toward the west-northwest on Wednesday.  On its anticipated track Tropical Storm Vongfong could approach northern Samar and southeastern Luzon in 36 to 48 hours.  Vongfong could be a typhoon at that time.  It could also drop locally heavy rain and cause flash floods over northeastern parts of the Philippines.

Tropical Depression Forms East of Philippines

A tropical depression formed east of the Philippines on Monday.  At 11:00 a.m. EDT on Monday the center of the tropical depression was located at latitude 8.6°N and longitude 129.0°E which put it about 165 miles (270 km) east of Mindanao.  It was moving toward the northwest at 5 m.p.h. (8 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 1006 mb.

The circulation around a low pressure system east of the Philippines exhibited greater organization on Monday and the Japan Meteorological Agency classified the system as a tropical depression.  More thunderstorms formed near the center of the depression.  The strongest thunderstorms were east of the center of circulation.  Bands of showers and thunderstorms were occurring in the eastern and southern parts of the circulation.  Bands in the northern and western sides of the depression consisted mostly of showers and lower clouds.  Storms near the center of circulation began to generate upper level divergence which was pumping mass away from the tropical depression.

The tropical depression will move through an environment favorable for intensification during the next several days.  The depression will move over water where the Sea Surface Temperature is near 29°C.  It will move under a small upper level ridge that is between an upper trough west of the Philippines and another upper trough northeast of the Philippines.  The upper level winds are weaker in the small ridge and there will be less vertical wind shear.  The tropical depression is likely to intensify into a tropical storm during the next 24 hours and it could strengthen into a typhoon later this week.

The tropical depression will move around the western end of a high pressure system centered south of Japan.  The high will steer the depression slowly toward the northwest during the next few days.  On its anticipated track the depression could approach the northern Philippines later this week.  It could be a typhoon by the time it approaches the northern Philippines.