Tag Archives: Hispaniola

Tropical Storm Isaias Reorganizes North of Dominican Republic, Watch Issued for South Florida

The circulation around Tropical Storm Isaias reorganized near the northern coast of the Dominican Republic on Thursday afternoon and Tropical Storm Watches were issued for part of the coast of southeast Florida.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Isaias was located at latitude 19.5°N and longitude 70.6°W which put it about 25 miles (40 km) southeast of Puerto Plata, Dominican Republic.  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 999 mb.

Tropical Storm Warnings were in effect for 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, San Salvador, Andros Island, New Providence, Eleuthera, the Abacos, the Berry Islands, Grand Bahama Island and Bimini.  A Tropical Storm Watch was in effect for the portion of the coast from Ocean Reef to Sebastian Inlet, Florida.

The low level center of Tropical Storm Isaias moved across the eastern part of the Dominican Republic on Thursday.  The middle and upper parts of Isaias skirted along the east coast of Hispaniola.  The various levels of Tropical Storm Isaias appeared to be reconsolidating near the northern coast of the Dominican Republic just to the east of Puerto Plata.  New thunderstorms were forming near the reorganizing center of Isaias.  Those storms were generating upper level divergence which pumped mass away from the tropical storm and allowed the pressure to decrease.  Brands of thunderstorms were wrapping around the eastern and northern sides of the circulation.  The strongest winds were occurring in the portions of those bands over water.  The circulation around Tropical Storm Isaias tightened up on Thursday.  Winds to tropical storm force extended out 240 miles (390 km) to the north and east of Isaias in the parts of the circulation that were over water.

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 will intensify when it moves north of Hispaniola and it could intensify rapidly once an inner core consolidates.  Isaias could intensify to a hurricane on Friday and it could strengthen into a major hurricane during the weekend.

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 36 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 over the Turks and Caicos by Friday morning.  Isaias will move over the the Bahamas on Friday and it could approach southeast Florida on Saturday.  Tropical Storm Isaias could approach the coast of the Carolinas on Monday.  Tropical Storm Isaias will bring gusty winds and locally heavy rain to the Turks and Caicos and the Bahamas.  Heavy rain could cause flash floods.

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.

Chris Strengthens to a Hurricane Southeast of Cape Hatteras

Former Tropical Storm Chris strengthened to a hurricane southeast of Cape Hatteras on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Chris was located at latitude 33.7°N and longitude 72.4°W which put it about 205 miles (330 km) east-southeast of Cape Hatteras, North Carolina.  Chris was moving toward the northeast at 10 m.p.h. (16 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 980 mb.

Hurricane Chris strengthened on Tuesday when it moved northeast of cooler water Chris had mixed to the surface while it was meandering off the coast of the Carolinas.  An eye with a diameter of 30 miles (50 km) formed at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in the eastern side of that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Hurricane Chris.  The strongest rainbands were in the eastern half of the circulation.  Drier air near the western half of the circulation was contributing to the weaker bands in that part of the hurricane.  Storms in the core of the circulation were generating upper level divergence which was pumping mass away to the north and east of the hurricane.  Winds to hurricane force extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out about 95 miles (155 km) from the center.

Hurricane Chris will move through an environment favorable for intensification on Wednesday.  Chris will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough over the northeastern U.S. will produce southwesterly winds that will blow toward the top of the hurricane.  The winds speeds are similar at most levels and they will not generate a lot of vertical wind shear during the next 24 hours.  Hurricane Chris will strengthen on Wednesday and it could intensify rapidly.  Chris will move over cooler water when it gets north of the Gulf Stream and it will start to weaken when that occurs.

The trough over the northeastern U.S. will steer Hurricane Chris toward the northeast.  On its anticipated track Chris will move away from the coast of North Carolina.  Chris could be south of Nova Scotia in about 36 hours and it could be near Newfoundland in several days.

Elsewhere, the remnants of former Tropical Storm Beryl crossed Hispaniola and they were moving toward the southeastern Bahamas.  At 2:00 p.m. EDT on Tuesday the center of Former Tropical Storm Chris was located at latitude 20.1°N and longitude 72.6°W which put it about 40 miles (65 km) northeast of Port de Paix, Haiti.  It was moving toward the northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1013 mb.  A reconnaissance aircraft is scheduled to investigate the system on Wednesday if there are signs that it could be reorganizing into a tropical cyclone.

Tropical Storm Erika Bringing Heavy Rain to Hispaniola

Tropical Storm Erika is moving across Hispaniola and it is bringing heavy rain to parts of that island.  At 5:00 p.m. EDT the center of Tropical Storm Erika was located at latitude 17.9°N and longitude 71.2°W which put it about 95 miles (155 km) west-southwest of Santo Domingo, Dominican Republic and about 745 miles (1200 km) southeast of Miami, Florida.  Erika was moving toward the west at 21 m.p.h. (33 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 1009 mb.  Tropical Storm Warnings have been issued for the southeastern Bahamas, the Turks and Caicos, for the Dominican Republic, Haiti, for the Central Bahamas including Cat Island, the Exumas, Long Island, Rum Cay and San Salvador.  Tropical Storm Watches have been issued for the northwestern Bahamas including the Abacos, Andros Island, Berry Island, Bimini, Eleuthera, Grand Bahama Island and New Providence, the Cuban provinces of Ciego de Avila, Camaguey, Las Tunas, Holguin and Guantanamo.

The circulation around Tropical Storm Erika is even less well organized today.  At times a small cyclonic rotation appeared on visible satellite images, while at other times Erika looked a lot like a very strong tropical wave.  Vertical wind shear caused by an upper level trough over the western Caribbean Sea has prevented thunderstorms from forming near the core of the circulation.  The lower part of the circulation will be significantly disrupted by the mountains of Hispaniola, but the middle portion may make it across the island.  If the middle level circulation is disrupted as well, then Erika will degenerate into a disorganized area of thunderstorms.  If the middle level circulation is still intact when it emerges west of Hispaniola, then it is possible that momentum could be transferred to the surface and a new low level center spun up.  Erika would most likely be a tropical depression at most at that time.  The water north of Cuba is very warm and if Erika still exists, it could intensify somewhat as it moves toward Florida.

The winds in the lower levels continued to push Erika toward the west-northwest on Friday and that general motion is likely continue for the next 12 to 12 hours.  Erika is getting closer to the western end of the subtropical high and it could turn more toward the north during the weekend.  On its anticipated track Erika or its remnants could be approaching the Florida Keys on Sunday afternoon.  At this time it is almost impossible to know how strong it will be at that time.  If Erika does start to reorganize when it gets west of Hispaniola, watches and/or warnings could be issued for parts of Florida.

Invest 96L

The circulation around the tropical disturbance designated 96L has been disrupted by the mountains on Hispaniola.  There a appears to be a broad low level center near the northern coast of Haiti.  There are several smaller vorticies rotating around within the broader area of low pressure.  The strongest winds are occurring north and east of the center and several reconnaissance flights found winds to tropical storm force north of the center.  The broad center appears to be moving toward the west-northwest at 10-15 m.p.h.   The area of low pressure has produced heavy rain on some of the islands of the northern Caribbean Sea.

It is still possible that 96L could organize into a tropical cyclone as it moves away from Hispaniola.  Once it gets away from the mountains, it will be easier for the flow to consolidate around one primary circulation center.  The Sea Surface Temperatures (SSTs) are very warm around the Bahamas and the upper level winds are not too strong.

There is a large amount of uncertainty about the future track of this system and that will continue until a well defined center of circulation exists.  It appears that the low has been initialized too far to the northeast in some runs of numerical models and that has produced some forecast tracks that are also too far north and east.  It is still possible that this system could head in the general direction of the southeastern U.S.

Development will possibly be slow to occur until the system becomes better organized.  Tropical cyclones can intensify rapidly over the Bahamas and people would be wise to monitor future developments with 96L.