Tag Archives: Puerto Rico

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.

Fred Strengthens Back to a Tropical Storm

Former Tropical Storm Fred strengthened back to a tropical storm over the eastern Gulf of Mexico on Sunday morning. At 11:00 a.m. EDT on Sunday the center of Tropical Storm Fred was located at latitude 26.1°N and longitude 84.9°W which put it about 335 miles (540 km) south-southeast of Pensacola, Florida. Fred was moving toward the north-northwest at 12 m.p.h. (19 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 1008 mb.

A Tropical Storm Warning was in effect for the portion of the coast from the Wakulla/Jefferson County Line to Navarre, Florida. A Tropical Storm Watch was in effect from the portion of the coast from Navarre, Florida to the Alabama/Florida border.

Data from a reconnaissance plane on Sunday morning indicated that a low level center of circulation had redeveloped in Tropical Storm Fred. The circulation around Fred was asymmetrical. The strongest thunderstorms were occurring in bands on the eastern side of Tropical Storm Fred and the strongest winds were occurring in those bands. Bands in the western half of Fred consisted primarily of showers and lower clouds. Storms on the eastern side of Tropical Storm Fred generated upper level divergence that pumped mass away to the north of the tropical storm. Winds to tropical storm force extended out 80 miles (130 km) in the northeastern quadrant of Fred. The winds in the other parts of the circulation were blowing at less than tropical storm force.

Tropical Storm Fred will move through an environment somewhat favorable for intensification during the next 24 hours. Fred will move over water where the Sea Surface Temperatures are near 30°C. It will move between an upper level low over the northern coast of the Gulf of Mexico and an upper level ridge centered over Cuba. The upper low and the ridge will produce southwesterly winds that will blow toward the top of Fred’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but the shear will not be strong enough to prevent Fred from intensifying. Tropical Storm Fred is likely to intensify gradually during the next 24 hours.

Tropical Storm Fred will move around the western end of a subtropical high pressure system over the western Atlantic Ocean. The high pressure system will steer Fred toward the north-northwest during the next 24 hours. On its anticipated track Tropical Storm Fred will approach the coast of Northwest Florida on Monday. Fred will bring gusty winds and locally heavy rain to Northwest Florida. Tropical Storm Fred could also cause a storm surge of up to six feet (1.8 meters) along portions of the coast.

Elsewhere, Tropical Storm Grace was passing south of Puerto Rico. At 11:00 a.m. EDT on Sunday the center of Tropical Storm Grace was located at latitude 17.2°N and longitude 66.0°W which put it about 85 miles (135 km) south of San Juan, Puerto Rico. Grace was moving toward the west-northwest at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 40 m.p.h. (56 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1010 mb.

Tropical Storm Warnings were in effect for Puerto Rico including Culebra and Vieques, and the U.S. Virgin Islands. A Tropical Storm Warning was also in effect for the portion of the coast from Samana, Dominican Republic to the southern border with Haiti. Tropical Storm Watches were in effect for the entire coast of Haiti and from Samana, Dominican Republic to the northern border with Haiti.

Tropical Storm Grace Brings Wind and Rain to Lesser Antilles

Tropical Storm Grace brought wind and rain to the Lesser Antilles on Saturday evening. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Grace was located at latitude 16.8°N and longitude 62.4°W which put it about 170 miles (280 km) east-southeast of St. Croix. Grace was moving toward the west at 20 m.p.h. (32 km/h). The maximum sustained wind speed was 40 m.p.h. (56 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1010 mb.

Tropical Storm Warnings were in effect for Puerto Rico including Culebra and Vieques and the U.S. Virgin Islands. Tropical Storm Warnings were also in effect for Saba and St. Eustatius, St. Martin, St.Bathelemy and St. Maarten. A Tropical Storm Warning was also in effect for the portion of the coast from Cabo Caucedo to Samana, Dominican Republic. Tropical Storm Watches were in effect for the portions of the coast from Cabo Caucedo, Dominican Republic to the southern border with Haiti and from Samana, Dominican Republic to the northern border with Haiti. A Tropical Storm Watch was also in effect for the entire coast of Haiti.

The circulation around Tropical Storm Grace was not very well organized on Saturday evening. There was a broad low level center of circulation. The strongest thunderstorms were occurring in bands in the western half of Grace. Bands on the eastern side of the circulation consisted primarily of showers and lower clouds. Strong easterly winds in the lower levels of the atmosphere were pushing the lower part of Tropical Storm Grace to the west of the middle and upper parts of the circulation. Those winds were causing moderate vertical wind shear and the shear was contributing to the asymmetrical distribution of thunderstorms. Winds to tropical storm force extended out 35 miles (55 km) on the northern side of Grace. Winds in the southern half of the circulation were blowing at less than tropical storm force.

Tropical Storm Grace will move through an environment somewhat favorable for intensification during the next 24 hours. Grace will move over water where the Sea Surface Temperatures are near 28°C. The winds in the lower levels could weaken a little and there could be a little less vertical wind shear. If the wind shear decreases, it could allow Tropical Storm Grace to become better organized.

Tropical Storm Grace will move south of the subtropical high pressure system over the Atlantic Ocean. The high will steer Grace toward the west-northwest during the next 24 hours. On its anticipated track Tropical Storm Grace could approach Puerto Rico by Sunday afternoon. Grace could approach the Dominican Republic on Sunday night.

Elsewhere, the remnants of former Tropical Depression Fred were slowly reorganizing northwest of Cuba. At 11:00 p.m. EDT on Saturday the center of former Tropical Depression Fred was located at latitude 23.8°N and longitude 84.3°W which put it about 125 miles (200 km) west-northwest of Havana, Cuba. The remnants of Fred were moving toward the west-northwest at 9 m.p.h. (15 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 1012 mb.

The remnants of former Tropical Depression Fred are forecast to reorganize on Sunday and to strengthen back to a tropical storm. Fred is forecast to move toward the northern Gulf Coast. Watches and warnings could be issued for a portion of the coast on Sunday.

Tropical Storm Fred Passes South of Puerto Rico

Tropical Storm Fred was passing south of Puerto Rico on Tuesday night. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Fred was located at latitude 17.6°N and longitude 66.8°W which put it about 45 miles (75 km) south-southwest of Ponce, Puerto Rico. Fred was moving toward the west at 17 m.p.h. (28 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 1009 mb.

Tropical Storm Warnings were in effect for Puerto Rico including Culebra and Vieques and the U.S. Virgin Islands. A Tropical Storm Warning was also in effect for the portion of the coast from Punta Palenque to Cabo Frances Viejo, Dominican Republic. A Tropical Storm Watch was in effect for the portion of the coast from Cabo Frances Viejo to the northern border with Haiti. A Tropical Storm Watch was in effect for the portion of the coast from Gonaives, Haiti to the northern border with the Dominican Republic. Tropical Storm Watches were also in effect for the Southeastern Bahamas and the Turks and Caicos.

A reconnaissance plane was able to identify a low level center of circulation in a low pressure system previously designated at Potential Tropical Cyclone Six on Tuesday evening and the National Hurricane Center upgraded the system to Tropical Storm Fred. The circulation around Tropical Storm Fred was still organizing. The low level center was about 45 miles (75 km) to the north of the center of circulation in the middle levels. The circulation in the middle levels was moving closer to the low level center. The strongest thunderstorms were occurring on the southern side of the low level center and near the center in the middle levels. Winds to tropical storm force extended out 45 miles (75 km) from the center in the northeastern quadrant of Fred. Winds in the other parts of the circulation were blowing at less than tropical storm force.

Tropical Storm Fred will move through an environment favorable for intensification during the next 12 hours. Fred will move over water where the Sea Surface Temperatures are near 28°C. It will be under a small upper level ridge. The upper level winds in the ridge are weak and there will be little vertical wind shear. Tropical Storm Fred is likely to strengthen during the next 12 hours. The center of Fred will be near the eastern part of the Dominican Republic in about 12 hours. Tropical Storm Fred is likely to weaken on Wednesday while the center is near Hispaniola.

Tropical Storm Fred will move of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Fred toward the west-northwest during the next several days. On its anticipated track Tropical Storm Fred will approach the eastern Dominican Republic in 12 hours. Fred could be over the northern coast of Hispaniola on Wednesday night. Bands in the northern side of Tropical Storm Fred will produce gusty winds and locally heavy rain over Puerto Rico on Tuesday night. Fred could drop heavy rain on parts of the Dominican Republic and Haiti on Wednesday. Heavy rain could cause flash floods in some locations.

Potential Tropical Cyclone Six Prompts Watches for Puerto Rico, U.S. Virgin Islands, Dominican Republic

Potential Tropical Cyclone Six prompted the issuance of Tropical Storm Watches for Puerto Rico, the U.S. Virgin Islands, the Dominican Republic and some of the Lesser Antilles on Monday afternoon. At 5:00 p.m. EDT on Monday the center of Potential Tropical Cyclone Six was located at latitude 14.2°N and longitude 59.2°W which put it about 165 miles (270 km) east-southeast of Dominica. The potential tropical cyclone was moving toward the west-northwest at 15 m.p.h. (24 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 1010 mb.

Tropical Storm Watches were issued for the U.S. Virgin Islands and Puerto Rico including Culebra and Vieques. A Tropical Storm Watch was issued for the coast of the Dominican Republic from Punta Palenque to the northern border with Haiti. Tropical Storm Watches were also issued for Dominica, Guadeloupe and Martinique.

The National Hurricane Center designated a low pressure system east of the Lesser Antilles (formerly designated at Invest 94L) as Potential Tropical Storm Six on Monday afternoon in order to issue the Tropical Storm Watches. The circulation around Potential Tropical Cyclone Six exhibited more organization on Monday. More thunderstorms formed in bands revolving around the center of the low pressure system. Storms near the center of circulation began to generate upper level divergence that pumped mass away from the low pressure system. The removal of mass should allow the surface pressure to decrease.

Potential Tropical Cyclone Six will move through an environment favorable for intensification during the next 24 hours. It will move over water where the Sea Surface Temperatures are near 28°C. The low pressure system will move under a small upper level ridge near the Lesser Antilles. The upper level winds are weak in the ridge and there will be little vertical wind shear. Potential Tropical Cyclone Six could develop into a tropical storm by the time it reaches the Lesser Antilles.

Potential Tropical Cyclone Six will move south of a subtropical high pressure system over the Atlantic Ocean. The high will steer the low pressure system toward the west-northwest during the next several days. On its anticipated track Potential Tropical Cyclone Six will move over the central Lesser Antilles on Monday night. It will bring gusty winds and locally heavy rain. Heavy rain could cause flash floods in some locations. Potential Tropical Cyclone Six could approach Puerto Rico later on Tuesday.

Tropical Storm Marco Strengthens, Hurricane Watch for New Orleans

Tropical Storm Marco strengthened on Saturday and a Hurricane Watch was issued for a portion of the central Gulf Coast.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Marco was located at latitude 21.9°N and longitude 68.1°W which put it about 50 miles (80 km) west of the western tip of Cuba.  Marco 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 992 mb.

A Hurricane Watch was issued for the portion of the coast from Intracoastal City, Louisiana to the Mississippi/Alabama border including Lake Pontchartrain, Lake Maurepas and New Orleans.  A Tropical Storm Watch was in effect for the portion of the coast from the Mississippi/Alabama border to the Alabama/Florida border.  A Tropical Storm Warning was in effect for the Cuban province of Pinar del Rio.

Tropical Storm Marco exhibited much better organization on Saturday.  Weather radar on a reconnaissance plane and from Cuba as well as visible satellite images indicated that a small eye developed at the center of Marco.  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 Tropical Storm Marco.  Storms near the core were generating upper level divergence which was pumping away to the north of the tropical storm.  The circulation around Marco was small.  Winds to tropical storm force extended out 100 miles (160 km) to the east of the center of circulation.  Winds to tropical storm force only extended out 50 miles (80 km) on the western side of the tropical storm.

Tropical Storm Marco will move through an environment favorable for intensification during the nextt 24 hours.  Marco will move over water where the Sea Surface Temperature is near 30°C.  It will move east of an upper level trough over the Gulf of Mexico.  The trough will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear is not likely to be enough to prevent intensification.  Tropical Storm Marco is likely to intensify into a hurricane during the next 24 hours.  Since he circulation around Marco is small, the tropical storm could strengthen or weaken quickly if the environment changes.

The upper level trough and a subtropical high pressure system over the Atlantic Ocean will steer Tropical Storm Marco toward the north-northwest during the next 36 to 48 hours.  On its anticipated track Marco could approach southeastern Louisiana by Monday afternoon.  Marco could be a hurricane when it approaches the coast.

Elsewhere, Tropical Storm Laura dropped heavy rain over Puerto Rico and it prompted the issuance of a Tropical Storm Watch for the Florida Keys.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Laura was located at latitude 18.0°N and longitude 68.1°W which put it about 125 miles (200 km) east-southeast of Santo Domingo, Dominican Republic.  Laura was moving toward the west at 18 m.p.h. (30 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 the U.S. Virgin Islands, Puerto Rico, Vieques and Culebra.  A Tropical Storm Warning was in effect for the northern coast of Hispaniola from Le Mole St. Nicholas, Haiti to Cabo Engano, Dominican Republic.  Tropical Storm Warnings were in effect for the Turks and Caicos, the Acklins, Long Key, Crooked Island, the Inaguas, and the Ragged Islands.  A Tropical Storm Warning was also in effect for the Cuban provinces of Las Tunas, Holguin, Santiago de Cuba, Guantanamo and Granma.

A Tropical Storm Watch was issued for the Florida Keys from Ocean Reef to Key West.  Tropical Storm Watches were in effect for the Central Bahamas and for Andros Island.

Tropical Storm Marco is forecast to move over HIspaniola and the mountains there are likely to disrupt the circulation.

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.