Tag Archives: Virgin Islands

Philippe Weakens North of the Virgin Islands

Tropical Storm Philippe weakened north of the Virgin Islands on Tuesday. At 2:00 p.m. EDT on Tuesday the center of Tropical Storm Philippe was located at latitude 19.0°N and longitude 64.4°W which put it about 55 miles (90 km) northeast of St. Thomas. Philippe was moving toward the northwest at 10 m.p.h. (16 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 1004 mb.

A Tropical Storm Watch was in effect for the British Virgin Islands.

Tropical Storm Philippe weakened north of the Virgin Islands on Tuesday. An upper level ridge over the eastern Caribbean Sea produced strong westerly winds that blew across the top of Philippe’s circulation. Those winds caused strong vertical wind shear. The strong upper level winds blew the tops off of most of the thunderstorms in the southeastern part of Tropical Storm Philippe. Most of the bands revolving around the center of Philippe’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 170 miles (275 km) in the eastern side of Philippe’s circulation. The winds in the western side of Tropical Storm Philippe were blowing at less than tropical storm force.

Tropical Storm Philippe will move through a region that will be unfavorable for intensification during the next 24 hours. Philippe will move over water where the Sea Surface Temperatures are near 29°C. However, the upper level ridge over the eastern Caribbean Sea will continue to cause strong vertical wind shear. The wind shear will likely cause Tropical Storm Philippe to weaken more during the next 24 hours.

Tropical Storm Philippe will move around the southwestern part of a high pressure system over the Atlantic Ocean. The high pressure system will steer Philippe toward the north-northwest during the next 24 hours. On its anticipated track, Tropical Storm Philippe will move away from Puerto Rico and the Virgin Islands.

Bands in the southeastern part of Tropical Storm Philippe did drop heavy rain over the Northern Leeward Islands during Monday night and Tuesday morning. Heavy rain fell on parts of Guadeloupe, Antigua, Barbuda, and Anguilla. There were reports of flash floods in some locations.

Tropical Storm Earl Intensifies North of the Virgin Islands

Tropical Storm Earl intensified north of the Virgin Islands on Monday morning. At 11:00 a.m. EDT on Monday the center of Tropical Storm Earl was located at latitude 21.5°N and longitude 65.3°W which put it about 215 miles (345 km) north-northwest of St. Thomas. Earl was moving toward the north-northwest 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 998 mb.

A NOAA Hurricane Hunter plane found that Tropical Storm Earl had intensified during a reconnaissance flight on Monday morning. Even though the circulation around Tropical Storm Earl was stronger, the distribution of thunderstorms was still asymmetrical. Most of the thunderstorms were occurring in bands in the eastern side of Earl’s circulation. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Storms in the eastern half of Earl generated upper level divergence that pumped mass away to the east of the tropical storm. Winds to tropical storm force extended out 100 miles (160 km) from the center of Earl’s circulation.

Tropical Storm Earl will move through an environment favorable for intensification during the next 48 hours. Earl will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the eastern side of an upper level trough near the Bahamas. The upper level trough will produce southwesterly winds that will blow toward the top of Ear;’s circulation. Those winds will cause vertical wind shear. The wind shear will inhibit intensification, but Tropical Storm Earl could continue to intensify slowly. The upper level winds are forecast to weaken in a day or so, and Earl is likely to intensify to a hurricane when that happens.

Tropical Storm Earl will move around the western end of a high pressure system over the Atlantic Ocean. The high pressure system will steer Earl toward the north during the next 48 hours. On its anticipated track, Tropical Storm Earl will move farther away from the Virgin Islands and Puerto Rico. Earl could approach Bermuda by the end of the week.

Elsewhere over the Atlantic Ocean, Hurricane Danielle started to weaken west of the Azores. At 11:00 a.m. EDT on Monday the center of Hurricane Danielle was located at latitude 40.2°N and longitude 43.9°W which put it about 915 miles (1475 km) west-northwest of the Azores. Danielle was moving toward the north-northeast at 8 m.p.h. (13 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 976 mb.

Hurricane Danielle Starts to Move Northeast

Hurricane Danielle started to move toward the northeast on Sunday night. At 11:00 p.m. EDT on Sunday the center of Hurricane Danielle was located at latitude 39.0°N and longitude 44.7°W which put it about 955 miles (1540 km) west of the Azores. Danielle was moving toward the northeast at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (165 km/h). The minimum surface pressure was 975 mb.

After being nearly stationary over the North Atlantic west of the Azores during much of the weekend, Hurricane Danielle finally started to move toward the northeast on Sunday night. Danielle strengthened on Sunday. A circular eye with a diameter of 30 miles (50 km) was at the center of Hurricane Danielle. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Danielle’s circulation. Winds to hurricane force extended out 25 miles (40 km) from the center of Danielle. Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation.

Hurricane Danielle will move through an environment capable of supporting a hurricane during the next 24 hours. Danielle will move over water where the Sea Surface Temperatures are near 27˚C. It will move through a region where the upper level winds are weak on Monday and there will be little vertical wind shear. Hurricane Danielle could get a little stronger during the next 24 hours. An upper level trough over the North Atlantic Ocean will approach Danielle from the west on later on Monday. The upper level trough will produce southwesterly winds that will cause the vertical wind shear to increase. Danielle will move over cooler water on Tuesday. The combination of more vertical wind shear and cooler water will cause Hurricane Danielle to begin a transition to an extratropical cyclone.

The upper level trough over the North Atlantic Ocean will steer Hurricane Danielle toward the northeast during the next several days. On its anticipated track Hurricane Danielle will pass north of the Azores later this week. Danielle could eventually affect the weather in Western Europe as an extratropical cyclone.

Elsewhere over the Atlantic Ocean, Tropical Storm Earl was spinning north of the Virgin Islands. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Earl was located at latitude 20.2°N and longitude 65.4°W which put it about 125 miles (200 km) north-northwest of St. Thomas. Earl was moving toward the northwest at 3 m.p.h. (5 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 998 mb.

Tropical Storm Earl Moves Northeast of the Virgin Islands

Tropical Storm Earl moved northeast of the Virgin Islands on Saturday night. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Earl was located at latitude 19.5°N and longitude 64.2°W which put it about 90 miles (145 km) northeast of St. Thomas. Earl was moving toward the west-northwest 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 1000 mb.

Tropical Storm Earl strengthened a little on Saturday as it moved northeast of the Virgin Islands. Even though Earl was a little stronger, the distribution of thunderstorms remained asymmetrical. Many of the thunderstorms were occurring in bands in the eastern half of Earl’s circulation. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 100 miles (160 km) in the northern side of Tropical Storm Earl. The winds on the southern side of Earl were blowing at less than tropical storm force.

Tropical Storm Earl will move through an environment somewhat favorable for intensification during the next 48 hours. Earl will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the western part of an upper level ridge over the tropical Atlantic Ocean. The upper level ridge will produce southerly winds that will bow toward the top of Earl’s circulation. Those winds will cause vertical wind shear and the wind shear will inhibit intensification. Tropical Storm Earl could slowly intensify during the next 48 hours. Earl could strengthen to a hurricane next week.

Tropical Storm Earl will move around the southwestern part of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Earl toward the northwest during the next 36 hours. On its anticipated track Tropical Storm Earl will pass north of Puerto Rico on Sunday.

Elsewhere over the Atlantic Ocean, Hurricane Danielle churned west of the Azores. At 11:00 p.m. EDT on Saturday the center of Hurricane Danielle was located at latitude 38.1°N and longitude 45.1°W which put it about 985 miles (1580 km) west of the Azores. Danielle was moving toward the west at 2 m.p.h. (3 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 988 mb.

Tropical Storm Peter Passes Northeast of Leeward Islands

Tropical Storm Peter passed northeast of the Leeward Islands on Monday. At 11:00 a.m. EDT on Monday the center of Tropical Storm Peter was located at latitude 19.5°N and longitude 60.9°W which put it about 170 miles (275 km) northeast of the Leeward Islands. Peter was moving toward the west-northwest at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 50 m.p.h. (75 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 1007 mb.

An upper level trough north of Puerto Rico and an upper level ridge east of the Leeward Islands were interacting to produce strong southwesterly winds that were blowing across the circulation around Tropical Storm Peter. Those winds were causing strong vertical wind shear. The low level center of circulation was clearly evident on visible satellite images and it was surrounded by showers and lower clouds. Thunderstorms were occurring in bands on the eastern and northern periphery of the circulation around Tropical Storm Peter. Bands in the western and southern parts of Peter consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 125 miles (200 km) in the northeastern quadrant of Peter’s circulation. The winds in the other parts of the circulation were blowing at less than tropical storm force.

Tropical Storm Peter will move through an environment unfavorable for intensification during the next 36 hours. Peter will move over water where the Sea Surface Temperatures are near 29˚C. However, the upper level trough and the upper level ridge will continue to produce strong vertical wind shear. The strong wind shear will inhibit intensification. Tropical Storm Peter could weaken gradually during the next 36 hours.

Tropical Storm Peter will move around the southern side of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Peter toward the west-northwest during the next 36 hours. On its anticipated track Tropical Storm Peter will pass north of the Northern Leeward Islands, the Virgin Islands and Puerto Rico.

Elsewhere over the Atlantic Ocean, Tropical Storm Rose moved away from the Cabo Verde Islands. At 11:00 a.m. EDT on Monday the center of Tropical Storm Rose was located at latitude 17.3°N and longitude 33.4°W which put it about 620 miles (1000 km) west-northwest of the Cabo Verde Islands. Rose was moving toward the northwest at 16 m.p.h. (26 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.

TD 14 Strengthens into Tropical Storm Marco

Former Tropical Depression Fourteen strengthened into Tropical Storm Marco over the northwestern Caribbean Sea on Friday night.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Marco was located at latitude 18.7°N and longitude 84.9°W which puts it about 180 miles (290 km) southeast of Cozumel, Mexico.  Marco was moving toward the north-northwest at 13 m.p.h. (20 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 1003 mb.

A Hurricane Watch was in effect for the portion of the coast from Punta Herrero to Cancun, Mexico.  A Tropical Storm Warning was in effect for the portion of the coast from Punta Herrero to Dzilam, Mexico.

An Air Force Reserve Hurricane Hunter reconnaissance aircraft found winds to tropical storm force in former Tropical Depression Fourteen and the National Hurricane Center upgraded the system to Tropical Storm Marco.  More thunderstorms developed near the center of Marco.  Many of the thunderstorms were occurring in short bands northeast of the center of circulation.  The strongest winds were occurring in those bands.  Storms near the center were generating upper level divergence which was pumping mass away to the northeast of the tropical storm.  Winds to tropical storm force extended 80 miles (130 km) to the northeast of Marco.  The winds in the other parts of the tropical storm were blowing at less than tropical storm force.

Tropical Storm Marco will move through an environment favorable for intensification during the next 24 hours.  Marco will move over water where the Sea Surface Temperature is near 29°C.  It will move east of a large upper level trough over the Gulf of Mexico.  The trough will produce southwesterly winds which will blow toward the top of Tropical Storm Marco.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Marco will intensify on Saturday and it could strengthen quickly because the circulation is small.  Tropical Storm Marco could also weaken quickly if the center moves over the Yucatan Peninsula.

Tropical Storm Marco will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high and the upper level trough will interact to steer Marco toward the northwest during the next 24 to 36 hours.  On its anticipated track the center of Tropical Storm Marco could pass near the northeastern part of the Yucatan Peninsula on Saturday.

Elsewhere over the Atlantic Ocean, disorganized Tropical Storm Laura sped across the northern Leeward Islands on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Laura was located at latitude 17.0°N and longitude 84.9°W which put it about 195 miles (315 km) east-southeast of San Juan, Puerto Rico.  Laura was moving toward the west-northwest at 18 m.p.h. (30 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 1008 mb.

Tropical Storm Warnings were in effect Saba, St. Eustatius, St. Maarten, St. Martin, St. Barthelemy, the British Virgin Islands, the U.S. Virgin Islands, Puerto Rico, Vieques, Culebra, the north coast of HIspaniola from Le Mole St. Nicholas, Haiti to Cabo Engano, Dominican Republic, the Turks and Caicos, the Acklins, Crooked Island, Long Cay, the Inaguas, and the Ragged Islands.  A Tropical Storm Watch was in effect for the Central Bahamas.

Tropical Storm Laura Develops, Warnings for Puerto Rico and Leeward Islands

Tropical Storm Laura developed east of the northern Leeward Islands on Friday morning.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Laura was located at latitude 17.0°N and longitude 60.2°W which put it about 210 miles (335 km) east-southeast of the northern Leeward Islands.  Laura was moving toward the west at 18 m.p.h. (30 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 1007 mb.

Tropical Storm Warnings were in effect for Saba, St. Eustatius, St. Maarten, Antigua, Barbuda, St. Kitts, Nevis, Anguilla, St. Martin, St. Barthelemy, the British Virgin Islands, the U. S, Virgin Islands, Puerto Rico, Vieques, and Culebra.

Tropical Storm Watches were in effect for the portion of the north coast of Hispaniola from Le Mole St. Nicholas, Haiti to Cabron, Dominican Republic and for the Turks and Caicos, the Acklins, Crooked Island, Long Cay, the Inaguas, and the Ragged Islands.

A NOAA plane found winds to tropical storm force in former Tropical Depression Thirteen on Friday morning and the National Hurricane Center upgraded the system to Tropical Storm Laura.  Even though the plane found winds to tropical storm force, the circulation around Tropical Storm Laura was not well organized. There were several clusters of thunderstorms in the northern half of the circulation, but there were fewer thunderstorms in the southern half of Laura.  Winds to tropical storm force extended out about 150 miles (240 km) on the northern side of the tropical storm.  The winds in the southern half of the circulation were blowing at less than tropical storm force.

Tropical Storm Laura will move through an environment favorable for intensification during the next 24 hours.  Laura 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.  The lack of organization of the circulation around Laura will limit how quickly the tropical storm can intensify.  Tropical Storm Laura is likely to get stronger during the next 24 hours.

Tropical Storm Laura will move south of a subtropical high pressure system over the North Atlantic Ocean.  The high will steer Laura toward the west-northwest during the next several days.  On its anticipated track Tropical Storm Laura will move across the northern Leeward Islands later today.  Laura could reach Puerto Rico by Saturday.  Tropical Storm Laura will bring gusty winds and locally heavy rain to the islands when it passes over them.

Elsewhere, Tropical Depression Fourteen was getting more organized over the northwestern Caribbean Sea.  At 11:00 a.m. EDT on Friday the center of Tropical Depression Fourteen was located at latitude 16.6°N and longitude 84.1°W which put it about 325 miles (525 km) southeast of Cozumel, Mexico.  The depression was moving toward the northwest at 14 m.p.h. (22 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 Hurricane Watch was in effect for the portion of the coast from Punta Herrero to Cancun, Mexico.  A Tropical Storm Warning was in effect for the Bay Islands, Honduras and from Punta Herrero to Cancun, Mexico.  A Tropical Storm Watch was in effect for the portion of the coast from Cancun to Dzilam, Mexico.

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.