Monthly Archives: May 2020

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.

Possible Tropical Development East of Philippines

A tropical cyclone could develop east of the Philippines during the next day or two.  A low pressure system east of Mindanao is currently designated as Invest 95W.  At 11:00 p.m. EDT on Saturday the center of Invest 95W was located at latitude 7.2°N and longitude 131.5°E which put it about 335 miles (540 km) east of Mindanao.  It was moving toward the west-northwest at 5 m.p.h. (8 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 1005 mb.

The area of low pressure currently designated at Invest 95W exhibited great organization on Saturday night.  Microwave satellite imagery revealed a distinct low level circulation.  Many thunderstorms were developing in a band on the southern and eastern side of the circulation.  Bands in the northern and western parts of the circulation consisted primarily of showers and lower clouds.  More thunderstorms began to form near the center of circulation on Saturday night.

Invest 95W will move through an environment favorable for the development of a tropical cyclone during the next several days.  The low pressure system will move over water where the Sea Surface Temperature is near 29°C.  It will move in a region south of an upper level trough northeast of the Philippines, and west of an upper level ridge centered south of Guam.  The trough and ridge will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will probably not be strong enough to prevent the formation of a tropical cyclone.  Invest 95W could develop into a tropical depression during the next 24 hours.

Invest 95W will move around the southwestern part of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer the low pressure system toward the northwest.  On its anticipated track Invest 95W will move slowly toward the northern Philippines.