Tag Archives: Virgin Islands

Tropical Storm Isaias Drops Heavy Rain on Puerto Rico

Tropical Storm Isaias dropped heavy rain on Puerto Rico on Thursday.  At 8:00 a.m. EDT on Thursday the center of Tropical Storm Isaias was located at latitude 17.6°N and longitude 68.5°w which put it about 105 miles (165 km) east- southeast of Santo Domingo, Dominican Republic.  The center was about 80 miles (130 km) south of Cabo Engano.  Isaias was moving toward the northwest at 20 m.p.h. (32 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 1003 mb.

Tropical Storm Warnings were in effect for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands, the British Virgin Islands,  the entire coast of the Dominican Republic, Le Mole St. Nicholas, Haiti to the northern border with the Dominican Republic, the Turks and Caicos, the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, the Ragged Islands, Cat Island, the Exumas, Long Island, Rum Cay and San Salvador.  Tropical Storm Watches were in effect for Andros Island, New Providence, Eleuthera, the Abacos, the Berry Islands, Grand Bahama Island and Bimini.

Bands on the eastern side of Tropical Storm Isaias were dropping heavy rain over parts of Puerto Rico on Thursday morning.  Flash Flood Warnings were in effect for parts of the island.  Isaias was also causing winds to tropical storm force in parts in Puerto Rico.  A station at Yabucoa Tanque de Agua reported a sustained wind speed of 46 m.p.h. (74 km/h) and a wind gust to 56 m.p.h. (91 km/h).  A station at Las Mareas reported a sustained wind speed of 3 m.p.h. (69 km/h) and a wind gust of 54 m.p.h. (87 km/h).

The circulation around Tropical Storm Isaias exhibited much more organization on Thursday morning, although the mid-level center did appear to be displaced to the north of the low level center.  There was a center of circulation but the distribution of thunderstorms was asymmetrical.  Most of the stronger thunderstorms were occurring in bands in the eastern side of Tropical Storm Isaias.  Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical storm.  Bands in the western half of Isaias consisted primarily of showers and lower clouds.  Northerly winds on that side of the circulation were sinking over the southern part  of Hispaniola and that could have been suppressing the development of thunderstorms in that region.  The circulation around Tropical Storm Isaias was very still very large.  Winds to tropical storm force extended out 415 miles (665 km) on the northern side of Isaias.

Tropical Storm Isaias could weaken when the low level center of circulation moves across the eastern part of the Dominican Republic.  The low level circulation will be disrupted by the terrain but it looks like Isaias will pass east of the tallest mountains on Hispaniola.  The mid-level center of Tropical Storm Isaias appears to be passing very close to the eastern end of Hispaniola.  The middle and upper portions of the circulation are likely to remain intact and a new low level circulation could form north of Hispaniola.  Tropical Storm Isaias will move through an environment favorable for intensification once it moves past Hispaniola.  Isaias will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Isaias is likely to intensify when it moves north of Hispaniola and it could intensify rapidly once a new low level center of circulation develops.

Tropical Storm Isaias will move around the western end of a subtropical high pressure system over the North Atlantic Ocean.  The high will steer Isaias toward the northwest during the next 48 hours.  it will turn the tropical storm more toward the north on the weekend when Isaias reaches the western end of the high pressure system.  On its anticipated track Tropical Storm Isaias will move across the eastern part of the Dominican Republic today.  Isaias will move over the Bahamas on Friday and it could approach southeast Florida on Saturday.  Tropical Storm Isaias will bring gusty winds and locally heavy rain to Puerto Rico, Hispaniola and the Bahamas.  Flash floods could occur.

Tropical Storm Isaias Develops South of Puerto Rico

Tropical Storm Isaias developed south of Puerto Rico on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Isaias was located at latitude 15.8°N and longitude 67.0°W which put it about 155 miles (250 km) south of Ponce, Puerto Rico.  Isaias was moving toward the west-northwest at 20 m.p.h. (32 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 1004 mb.

Tropical Storm Warnings were in effect for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands, the British Virgin Islands, St. Martin, St. Barthelemy, Saba, St. Eustatius, St. Maarten, the entire coast of the Dominican Republic, Le Mole St. Nicholas, Haiti to the northern border with the Dominican Republic, the Turks and Caicos, the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, the Ragged Islands, Cat Island, the Exumas, Long Island, Rum Cay and San Salvador.  Tropical Storm Watches were in effect for Andros Island, New Providence, Eleuthera, the Abacos, the Berry Islands, Grand Bahama Island and Bimini.

Data from a scatterometer onboard a satellite and observations from a buoy south of Puerto Rico indicated that a distinct center of circulation formed within a large low pressure system over the northeastern Caribbean Sea and the National Hurricane Center designated the system as Tropical Storm Isaias.  The center of circulation formed about 150 miles (240 km) south of Puerto Rico on Wednesday night.  More thunderstorms were developing near the newly formed center.  Many of those thunderstorms were southeast of the center.  Storms near the center were generating upper level divergence which pumped mass away from the tropical storm.  Bands of showers and thunderstorms were also located on the northern periphery  of the circulation and the strongest winds were occurring in those bands.  Winds to tropical storm force extended out 300 miles (485 km) to the northeast of the center of circulation.  Winds to tropical storm force also extended out 130 miles (215 km) to the northwest of the center.  The winds south of the center of Isaias were blowing at less than tropical storm force.

Tropical Storm Isaias will move through an environment favorable for intensification during the next 12 hours.  Isaias will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Isaias will get better organized and strengthen during the first half of Thursday.  A portion of the circulation around Isaias will move over Hispaniola later on Thursday.  Mountains on that island will disrupt the circulation and Tropical Storm Isaias will weaken while the center moves over land.

Tropical Storm Isaias will move around the western end of a subtropical high pressure system over the North Atlantic Ocean.  The high will steer Isaias toward the west-northwest on Thursday.  On its anticipated track Tropical Storm Isaias will move across Hispaniola on Thursday.  Isaias will cause gusty winds and it will drop locally heavy rain when it moves over Hispaniola.  Heavy rain could cause flash floods.

Potential Tropical Storm Prompts Warnings for Puerto Rico, Virgin Islands, Leeward Islands

A low pressure system that has the potential to organize into a tropical storm prompted the issuance of Tropical Storm Warnings for Puerto Rico, the Virgin Islands and many of the Leeward Islands on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Potential Tropical Cyclone Nine was located at latitude 13.8°N and longitude 53.7°W which put it about 585 miles (940 km) east-southeast of the Leeward Islands.  It was moving toward the west at 23 m.p.h. (37 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 1007 mb.

Tropical Storm Warnings were issued for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands, Antigua, Barbuda, the British Virgin Islands, Montserrat, St. Kitts, Nevis, Guadeloupe, Martinique, St. Martin, Saba, St. Eustatius, and St. Maarten.

The circulation around Potential Tropical Cyclone Nine was very broad and it stretched from the southwest toward the northeast.  The stronger thunderstorms were occurring in the southwestern and northeastern ends of the circulation.  There were few thunderstorms or bands in the broad middle of the low pressure system.  Winds to tropical storm force extended out 200 miles (320 km) on the northern side of the circulation.  The winds in the southern half of the low pressure system were blowing at less than tropical storm force.

Potential Tropical Cyclone Nine will move through an environment favorable for intensification during the next two days.  It will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  The large broad circulation will contribute to a slow, gradual intensification.  If thunderstorms consolidate around a center of circulation and an inner core begins to form, then the system may be designated as a tropical storm.

Potential Tropical Cyclone Nine will move south of a subtropical high pressure system over the North Atlantic Ocean.  The high will steer the potential tropical storm toward the west-northwest during the next several days.  On its anticipated track Potential Tropical Cyclone Nine could approach the Leeward Islands on Wednesday morning.  It could approach the Virgin Islands and Puerto Rico by Wednesday night.  The large circulation means that Potential Tropical Nine will bring a prolonged period of gusty winds.  It could also drop heavy rain and cause flash floods on some islands.

Tropical Storm Karen Develops Near Windward Islands

Tropical Storm Karen developed near the Windward Islands on Sunday morning.  At 8:00 a.m. EDT on Sunday the center of Tropical Storm Karen was located at latitude 11.9°N and longitude 60.9°W which put it about 55 miles (90 km) east-southeast of Grenada.  Karen was moving toward the west-northwest 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 1005 mb.

Tropical Storm Warnings were in effect for Trinidad and Tobago, Grenada, and for St. Vincent and the Grenadines.

A center of circulation developed in an area of thunderstorms east of the axis of a strong tropical wave near the Windward Islands on Sunday morning and the National Hurricane Center designated the system as Tropical Storm Karen.  The strongest thunderstorms were forming in bands south and west of the center of circulation.  Bands north and west of the center consisted primarily of showers and lower clouds.   Winds to tropical storm force extended out about 125 miles (200 km) on the eastern side of the tropical storm.

An upper level trough northeast of the Lesser Antilles was producing strong westerly winds which were blowing across the northern side of Tropical Storm Karen.  An upper level ridge over the Caribbean Sea was producing strong northeasterly winds which were blowing across the western part of Karen.  The upper level winds were causing moderate vertical wind shear which was inhibiting the development of thunderstorms in those parts of Tropical Storm Karen.  The center of circulation developed in a region between the stronger upper level westerly and northeasterly winds.  Most of the thunderstorms were forming in that area where the upper level winds were not as strong.

Tropical Storm Karen will move through an environment that will be only marginally favorable for intensification during the next day or two.  Karen will move over water where the Sea Surface Temperature  is near 29°C.  However, the upper level trough and upper level ridge will continue to cause moderate vertical wind shear.  If Tropical Storm Karen remains in the zone where the upper level winds are not as strong, it could strengthen.  However, if Karen moves under stronger upper level winds, it could weaken to a depression.  Tropical Storm Karen is forecast to move closer to the center of the upper level ridge in two or three days.  If that happens, then the upper level winds will be weaker and Karen could intensify.

Tropical Storm Karen will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Karen toward the west-northwest during the next 12 hours.  Karen will move more toward the north when reaches the end of the ridge.  On its anticipated track Tropical Storm Karen will move across the Windward Islands on Sunday.  Karen will bring gusty winds and locally heavy rain.  Flash floods are likely.  Tropical Storm Karen could approach Puerto Rico and the Virgin Islands on Tuesday.  Tropical Storm Watches are likely to be issued for those islands.

Elsewhere over the Atlantic Ocean Tropical Storm Jerry was spinning south of Bermuda.  At 5:00 a.m. EDT on Sunday the center of Tropical Storm Jerry was located at latitude 25.0°N and longitude 66.9°W which put it about 520 miles (835 km) south-southwest of Bermuda.  Jerry was moving toward the north-northwest at 12 m.p.h. (19 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 1002 mb.

Cat. 5 Hurricane Irma Moving Over Northern Leeward Islands

Category 5 Hurricane Irma moved over the northern Leeward Islands on Wednesday morning.  At 5:00 a.m. EDT on Wednesday the center of Hurricane Irma was located at latitude 17.9°N and longitude 62.6°W which put it about 35 miles (55 km) east-southeast of St. Martin.  Irma was moving toward the west-northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 185 m.p.h. (295 km/h) and there were wind gusts to 210 m.p.h. (340 km/h).  The minimum surface pressure was 912 mb.

The core of Hurricane Irma moved across Antigua, Barbuda, St. Barthelemy and St. Martin in recent hours.  It will reach Anguilla later this morning.

Hurricane Watches were in effect for Antigua, Anguilla, Barbuda, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, Sint Maarten, St. Martin, St. Barthelemy, the British Virgin Islands, the U.S. Virgin Islands, Puerto Rico, Vieques, Culebra, Guadeloupe, the southeastern Bahamas including the Acklins, Cooked Islands, Long Cay, the Iguanas, Mayaguane, the Ragged Islands, the Turks and Caicos, and the portion of the coast of Cabo Engano, Dominican Republic to the northern border with Haiti.  Hurricane Watches are in effect for the central Bahamas, the portion of the coast from Le Mole St. Nicholas to the northern border with Haiti and from Matanzas province to Guantanamo province in Cuba.  A Tropical Storm Warning is in effect for the portion of the coast from Cabo Engano, Dominican Republic to the southern border with Haiti.  A Tropical Storm Watch is in effect for the portion of the coast from Le Mole St. Nicolas, Haiti to Port Au Prince.

Hurricane Irma maintained its intensity during the northern overnight hours.  It has a circular eye with a diameter of 30 miles (48 km).  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Winds to hurricane force extend out about 60 miles (95 km) from the center.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.

The Hurricane Intensity Index (HII) is 44.1.  The Hurricane Size Index (HSI) is 19.8 and the Hurricane Wind Intensity Size Index (HWISI) is 63.9.  Those indices indicate that Hurricane Irma is capable of causing widespread catastrophic wind damage.

Hurricane Irma will continue to move over an environment very favorable for hurricanes.  Irma will stay over water where the Sea Surface Temperature is near 30°C.  The upper level winds will remain weak for several more days and there will be little wind shear.  An upper level trough over the eastern U.S. will produce strong winds when Irma gets closer to Florida.  The wind shear will increase at that time.  Hurricane Irma could go through eyewall replacement cycles which would cause fluctuations in intensity.

Hurricane Irma is moving near the western end of a subtropical high pressure system over the Atlantic Ocean which is steering Irma toward the west-northwest.  The west-northwesterly motion is expected to continue for several more days.  Eventually, the upper level trough over the eastern U.S. is forecast to turn Hurricane Irma toward the north when it approaches Florida.  On its anticipated track the center of Hurricane Irma is forecast to pass north of Puerto Rico and Hispaniola.

Elsewhere, Tropical Storm Jose is trailing behind Hurricane Irma and Tropical Storm Katia has developed over the southern Gulf of Mexico.  At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Jose was located at latitude 12.5°N and longitude 42.8°W which put it about 1255 miles east of the Leeward Islands.  Jose was moving toward the west at 13 m.p.h. (20 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 1002 mb.

At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Katia was located at latitude 22.1°N and longitude 96.3°W which put it about 105 miles (165 km) east of Tampico, Mexico.  Katia was moving toward the east at 2 m.p.h. (3 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.

Very Dangerous Hurricane Irma Reaches Cat. 5

Very dangerous Hurricane Irma reached category 5 on the Saffir-Simpson Scale on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Irma was located at latitude 12.3°N and longitude 39.1°W which put it about 225 miles (365 km) east of Antigua.  Irma was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 180 m.p.h. (285 km/h) and there were wind gusts to 210 m.p.h. (340 km/h).  The minimum surface pressure was 931 mb.

Hurricane Warnings are in effect for Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, Sint Maarten, St. Martin, St. Barthelemy, the British Virgin Islands, the U.S. Virgin Islands, Puerto Rico, Vieques and Culebra.  Tropical Storm Warnings are in effect for Guadeloupe and Dominica.  Hurricane Watches are in effect for Guadeloupe, the southeastern Bahamas including the Acklins, Crooked Islands, Long Cay, the Inaguas, Mayaguana, and the Ragged Islands.  A Hurricane Watch is also in effect for the portion of the the coast from Cabo Engano, Dominican Republic to Le Mole St. Nicholas, Haiti.  Tropical Storm Watches are in effect for the portion of the coast from Le Mole St. Nicholas to Port Au Prince, Haiti and from Cabo Engano to Isla Saona, Dominican Republic.

Hurricane Irma intensified rapidly after the completion of the most recent eyewall replacement cycle.  The structure evolved in a large classic Cape Verde hurricane.  The is a large circular eye at the center of circulation.  A ring of very strong thunderstorms surrounds the eye and the strongest winds are occurring in that ring.  Bands of showers and thunderstorms are revolving around the core of Hurricane Irma.  Winds to hurricane force extend out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.

The Hurricane Intensity Index (HII) for Irma is 44.1.  The Hurricane Size Index (HSI) is 19.8 and the Hurricane Wind Intensity Size Index (HWISI) is 63.9.  Hurricane Irma is as strong as Hurricane Rita was in 2005, but Irma is just slightly smaller than Rita was.  Hurricane Irma is capable of causing widespread catastrophic damage.

Hurricane Irma is moving through an environment that is very favorable for hurricanes.  Irma is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Irma will likely remain very strong as long as it stays over water.  Additional eyewall replacement cycles could occur and they would result in fluctuations in the intensity of Hurricane Irma.

Hurricane Irma is being steered to the west by a very strong subtropical high over the Atlantic Ocean.  Irma is expected to turn a little more toward the west-northwest as it moves closer to the western end of the high.  On its anticipated track Hurricane Irma will move across the northern Leeward Islands during the next 24 hours.  It will be near Puerto Rico on Wednesday and near the Dominican Republic on Thursday.

Hurricane Irma is an very dangerous hurricane.  It is capable of producing widespread catastrophic damage.  Hurricane Irma will also drop extremely heavy rain and flooding is very possible.

Tropical Storm Erika Prompts Warnings for the Caribbean

The imminent approach of Tropical Storm Erika prompted the issuance of watches and warnings for locations in the northeastern Caribbean Sea.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Erika was located at latitude 16.0°N and longitude 54.4°W which put it about 495 miles (800 km) east of Antigua and about 1780 miles (2870 km) east-southeast of Miami, Florida.  Erika was moving toward the west at 18 m.p.h. (30 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.  Tropical Storm Warnings have been issued for Anguilla, Saba, St. Eustatius, and St. Maarten.  Tropical Storm Watches have been issued for Puerto Rico, the U.S. Virgin Islands, the British Virgin Islands, Montserrat, Antigua, Barbuda, St. Kitts, Nevis, Guadeloupe, St. Martin and St. Barthelemy.

For much of Monday the circulation around Tropical Storm Erika consisted of a large swirl of low level clouds and a few thunderstorms well to the southeast of the center.  The minimum surface pressure rose several millibars which was indicative of a weakening storm.  In the past several hours satellite imagery suggests that a few new thunderstorms could be forming closer to the center of circulation.  Erika is moving over water where the Sea Surface Temperature (SST) is between 28°C and 29°C.  So there is plenty of energy in the upper ocean.  The circulation could be pulling in some drier air from farther north of the storm.  There is also some vertical wind shear which may also be inhibiting intensification.    The combination of positive environmental factors like SST and negative environmental factors like drier air and wind shear make the intensity forecast challenging.  Guidance from numerical models is divergent.  Some models predict intensification while others predict that Erika will dissipate like Danny did.  If more thunderstorms continue to develop around the center of circulation, then intensification would be more likely.  On the other hand, if the recently formed thunderstorms dissipate in a few hours, the Erika could weaken to a tropical depression.

A subtropical ridge is steering Erika a little north of due west and that general motion is expected to continue during the next several days.  On its anticipated track Erika would approach the northern Leeward Islands in about 24 hours and it could be near Puerto Rico in less than two days.