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Tropical Storm Isaias Speeds Past New York City

Tropical Storm Isaias sped past New York City on Tuesday afternoon.  At 2:00 p.m. EDT on Tuesday the center of Tropical Storm Isaias was located at latitude 40.9°N and longitude 75.1°W which put it about 65 miles (105 km) west of New York, New York.  Isaias was moving toward the north-northeast at 40 m.p.h. (65 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 994 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Chincoteague, Virginia to Eastport, Maine including Long Island, Long Island Sound, Block Island, Martha’s Vineyard and Nantucket.

Tropical Storm Isaias sped up the East Coast of the U.S. on Tuesday and the center of circulation was west of New York City by Tuesday afternoon.  Isaias was still generating an area of winds to tropical storm force over the Atlantic Ocean.  A NOAA buoy at the entrance to New York Harbor measured a sustained wind speed of 57 m.p.h. (83 km/h) and a wind gust of 71 m.p.h. (115 km/h).  JFK airport recently reported a wind gust to 70 m.p.h. (113 km/h).

The eastern side of former Hurricane Isaias produced strong wind gusts along the East Coast of the U.S. from North Carolina to Long Island.  A station at Federal Point, North Carolina reported a gust of 99 m.p.h.  (160 km/h).  Wrightsville Beach, North Carolina had a wind gust to 86 m.p.h. (139 km/h).  Stevensville, Maryland measured a gust of 79 m.p.h. (127 km/h).  South Norfolk, Virginia reported a wind gust to 76 m.p.h. (122 km/h) and Nags Head, North Carolina had a gust of 75 m.p.h. (120 km/h).  Ocean City, Maryland measured a gust of 69 m.p.h. (111 km/h).

The strong wind gusts caused widespread power outages.  Shear in the lower levels of the atmosphere also contributed to the spinup of a number of tornadoes.  Tropical Storm isaias dropped heavy rain over parts of the northeastern U.S.  Isaias will continue to speed north-northeastward into Canada during the next 12 hours.  Tropical Storm Isaias will gradually weaken and wind speeds should decrease.  Isaias will continue to drop locally heavy rain over eastern New York, western Massachusetts and Vermont for several more hours.  The potential for flash floods in those areas still exists.

Hurricane Isaias Brings Wind and Rain to MidAtlantic States

Hurricane Isaias brought wind and rain to the MidAtlantic states of the U.S. on Tuesday.  Isaias weakened to a tropical storm on Tuesday morning as it moved over eastern Virginia.  At 8:00 a.m. EDT on Tuesday the center of Tropical Storm Isaias was located at latitude 37.7°N and longitude 76.8°W which put it about 15 miles (25 km) south-southeast of Tappahannock, Virginia.  Isaias was moving toward the north-northeast at 33 m.p.h. (54 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 993 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Surf City, North Carolina to Eastport, Maine including Albemarle Sound, Pamlico, Sound, Long Island, Long Island Sound, Block Island, Martha’s Vineyard and Nantucket.

The center of Hurricane Isaias officially made landfall on the coast at Ocean Isle Beach, North Carolina.  The maximum sustained wind speed at the time of landfall was 85 m.p.h. (135 km/h).  A weather station at Oak Island, North Carolina measured a sustained wind speed of 76 m.p.h. and a wind gust to 87 m.p.h. (140 km/h).

The center of Isaias moved rapidly toward the north-northeast during the overnight hours and it passed between Richmond and Norfolk, Virginia.  The strongest winds were occurring along the coast and over the Atlantic Ocean on Tuesday morning.  A weather station at Duck, North Carolina measured a sustained wind speed of 48 m.p.h. (78 km/h) and a wind gust of 63 m.p.h. (102 km/h).  A weather station at Poquoson, Virginia measured a sustained wind speed of 39 m.p.h. (63 km/h) and a wind gust to 56 m.p.h. (91 km/h).  A weather station on Third Island which is near the Mouth of Chesapeake Bay recently measured a sustained wind speed of 63 m.p.h. (101 km/h) and a wind gust of 77 m.p.h. (124 km/h).

Tropical Storm Isaias will move rapidly toward the north-northeast during the next 24 hours.  The center of Isaias will pass west of New York City later today.  Tropical Storm Isaias will gradually weaken, but it could bring tropical storm force winds to the northeastern U.S.  Wind shear in the lower levels of Tropical Storm Isaias’ circulation is contributing to the spin up of tornadoes.  Isaias will drop locally heavy rain and flash floods could occur.

Tropical Storm Isaias will take a track similar to the tracks taken by Hurricane Irene in 2011 and Hurricane Isabel in 2003.  Hurricane Irene was similar in strength and a little bit larger than Isaias when it hit North Carolina in 2011.  Irene was already weakening when it hit the coast while Isaias was strengthening at landfall.  According to the Tropical Cyclone Report on the National Hurricane Center’s (NHC) website, Hurricane Irene caused 15.8 billions dollars of damage in the U.S.

Hurricane Isabel was larger and stronger than Isaias was when it made landfall in North Carolina.  Isabel was also weakening at the time of landfall.  According to the Tropical Cyclone Report on NHC’s website for Hurricane Isabel, it caused 5.4 billion dollars of damage in the U.S.

 

Isaias Strengthens Back into a Hurricane

Isaias strengthened back into a hurricane on Monday evening.  At 9:00 p.m. EDT on Monday the center of Hurricane Isaias was located at latitude 33.1°N and longitude 78.8°W which put it about 55 miles (90 km) south-southeast of Myrtle Beach, South Carolina.  Isaias was moving toward the north-northeast at 18 m.p.h. (30 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 988 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Surf City, North Carolina.  Tropical Storm Warnings were in effect for the portion of the coast from Edisto Beach to South Santee River, South Carolina and from Surf City, North Carolina to Stonington, Maine including Albemarle Sound, Pamlico Sound, Long Island, Long Island Sound, Block Island, Martha’s Vineyard, and Nantucket.  A Tropical Storm Watch was in effect for the portion of the coast from Stonington, to Eastport, Maine.

The circulation around Hurricane Isaias became much better organized on Monday afternoon.  A reconnaissance aircraft investigating Isaias found winds to hurricane force.  An elliptical eye developed at the center of Hurricane Isaias.  A broken ring of thunderstorms surrounded the elliptical eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Isaias.  The strongest rainbands were in the northern half of the circulation.  Bands in the southern half of Hurricane Isaias consisted primarily of showers and lower clouds.  Winds to hurricane force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 125 miles (200 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Isaias was 12.7.  The Hurricane Size Index (HSI) was 15.3 and the Hurricane Wind Intensity Size Index (HWISI) was 28.0.  Hurricane Isaias was capable of causing regional minor damage.

The center of Hurricane Isaias will make landfall between Myrtle Beach, South Carolina and Southport, North Carolina during the next few hours.  Isaias will bring hurricane force winds to the portion of the coast from Myrtle Beach, South Carolina to Surf City, North Carolina.  It will generate a storm surge of 3 to 6 feet (1 to 2 meters) along the coast.  Hurricane Isaias will drop heavy rain over extreme eastern South Carolina, eastern North Carolina and eastern Virginia.  Heavy rain could cause flooding in some locations.

The center of Hurricane Isaias will pass just west of Norfolk, Virginia on Tuesday morning.  isaias will weaken when it passes over land, but it will still bring gusty winds over eastern Virginia.  Isaias will pass near New York City on Tuesday evening and it will bring gusty winds to New England on Tuesday night.  Isaias could cause widespread power outages along the East Coast of the U.S.  It will also drop heavy rain east of the Appalachians and flash floods could occur in that region.

Tropical Storm Isaias Turns Toward the Carolinas

Tropical Storm Isaias turned toward the Carolinas on Monday morning.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Isaias was located at latitude 30.7°N and longitude 80.1°W which put it about 220 miles (350 km) south-southwest of Myrtle Beach, South Carolina.  Isaias was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 998 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Surt City, North Carolina.  Tropical Storm Warnings were in effect for the portions of the coast from Altamaha Sound, Georgia to South Santee River, South Carolina and from Surf City North Carolina to Watch Hill, Rhode Island including Albemarle Sound, Pamlico Sound, Long Island and Long Island Sound.  A Tropical Storm Watch was in effect for the portion of the coast from Watch Hill, Rhode Island to Stonington, Maine including Block Island, Martha’s Vineyard and Nantucket.

Tropical Storm Isaias seemed to begin another cycle where the thunderstorm activity pulsed down during the overnight hours.  However, visible satellite and radar images seemed to indicate that thunderstorms were starting redevelop on Monday morning.  A band of thunderstorms appeared to be wrapping around the northern side of the circulation.  Thunderstorms were also increasing in bands in the northern and eastern parts of Isaias.  Bands in the southern and western sides of Isaias consisted primarily of showers and lower clouds.  The circulation of Tropical Storm Isaias could be pulling in some drier air around the southern and western parts of the storm.  That is a fairly typical occurrence with tropical systems moving up the East Coast of the U.S.  Winds to tropical storm force extended out 125 miles (200 km) in the northern and eastern quadrants of Isaias.  The winds in the southern and western parts of the circulation were mostly at less than tropical storm force.

Tropical Storm Isaias will move through an environment somewhat favorable for intensification during the next 12 hours.  Isaias will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the Central U.S. will produce southwesterly winds which will blow toward the top of Isaias.  Those winds will cause moderate vertical wind shear which will inhibit intensification.  The wind shear is expected to decrease slightly later on Monday, which could allow Isaias to strengthen into a hurricane.

The upper level trough will steer Tropical Storm Isaias toward the north-northeast during the next several days.  On its anticipated track Tropical Storm Isaias will make landfall near Myrtle Beach, South Carolina on Monday night.  Isaias could be a hurricane when it makes landfall.  Isaias will bring gusty winds and a storm surge of 3 to 6 feet (1 to 2 meters) to the coast near and to the east of where the center makes landfall.  The center of Isaias will move across eastern North Carolina and it could be near Norfolk, Virginia on Tuesday morning.  Tropical Storm Isaias could pass near New York City later on Tuesday.

Tropical Storm Isaias will bring gusty winds to the East Coast of the U.S. from South Carolina to Maine.  Isaias will also drop locally heavy rain from eastern South Carolina to New England.  The National Weather Service has indicated that a Moderate Risk of flash floods exists for the region from eastern South Carolina to eastern Pennsylvania.

Tropical Storm Isaias Slightly Stronger, Hurricane Watch Issued for Carolinas

Tropical Storm Isaias strengthened slightly on Sunday afternoon and a hurricane Watch was issued for a portion of the Carolinas’ coast.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Isaias was located at latitude 27.8°N and longitude 79.8°W which put it about 65 miles (105 km) southeast of Cape Canaveral, Florida.  Isaias was moving toward the north-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 994 mb.

A Hurricane Watch was issued for the portion of the coast from South Santee River, South Carolina to Surf City, North Carolina.  A Tropical Storm Warning was in effect for the portion of the coast from Sebastian Inlet, Florida to Ocracoke Inlet, North Carolina.  A Tropical Storm Watch was issued for the portion of the coast from Ocracoke Inlet, North Carolina to Watch Hill, Rhode Island including Albemarle Sound, Pamlico Sound, Long Island and Long Island Sound.

Tropical Storm Isaias strengthened a little on Sunday afternoon, but the middle level center of circulation was displaced to the northeast of the surface center.  An upper level trough over the central U.S. extended to the Gulf of Mexico and it was producing westerly winds which were blowing toward the top of Isaias.  Those winds were causing moderate vertical wind shear and they were also causing the displacement of the middle level center of Tropical Storm Isaias.  Thunderstorms continued to develop around the middle level center of circulation.  Those storms generated upper level divergence which pumped mass away to the east of the tropical storm.  Winds to tropical storm force extended out 115 miles (185 km) on the eastern side of Isaias.  Tropical Storm force winds only extended out 65 miles (105 km) on the western side of the circulation.

Tropical Storm Isaias will move through an environment somewhat favorable for intensification during the next 24 hours.  Isaias will move over water where the Sea Surface Temperature is near 30°C.  The direction of the upper level winds will shift to the southwest as the upper level trough approaches Tropical Storm Isaias.  That will cause the vertical wind shear to decrease.  Tropical Storm Isaias could strengthen into a hurricane, if the shear decreases.

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 north during the next 12 hours.  The upper level trough will steer Tropical Storm Isaias toward the northeast on Monday.  On its anticipated track Isaias will approach the coast of the Carolinas near Myrtle Beach, South Carolina on Monday night.  Isaias could be a hurricane when it makes landfall.  It will bring gusty winds and locally heavy rain to extreme eastern South Carolina, eastern North Carolina and coastal Virginia.  Isaias will cause a storm surge of 3  to 6 feet (1 to 2 meters) near and to the east of where the center makes landfall.  Tropical Storm Isaias will continue to move up the East Coast toward New England.

Isaias Crosses Andros Island, Weakens to Tropical Storm

The center of former Hurricane Isaias crossed Andros Island on Saturday afternoon and it weakened to a tropical storm.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Isaias was located at latitude 25.1°N and longitude 78.7°W which put it about 115 miles (185 km) southeast of Ft. Lauderdale, Florida.  Isaias was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 993 mb.

A Hurricane Warning was in effect for the portion of the coast from Boca Raton, Florida to the Flagler/Volusia County Line.  A Hurricane Waning was also in effect for the Northwestern Bahamas including Andros Island, New Providence, Eleuthera, the Abacos, the Berry Islands, Grand Bahama Island, and Bimini.

Tropical Storm Warnings were in effect for the portions of the coast from Ocean Reef to Boca Raton, Florida and from the Flagler/Volusia County Line to Ponte Vedra Beach, Florida.  A Tropical Storm Warning was also in effect for Lake Okeechobee.  A Tropical Storm Watch was in effect for the portion of the coast from Ponte Vedra Beach, Florida to South Santee River, South Carolina.

The center of former Hurricane Isaias crossed over Andros Island on Saturday afternoon.  Normally, Andros Island does not have much of an impact on hurricanes, but combined with a less favorable environment it contributed to a temporary weakening of Isaias.   Tropical Storm Isaias consisted primarily of bands of showers and lower clouds after crossing Andros Island.  However, new thunderstorms began to develop northeast of the center of circulation during the past several hours and part of the eyewall appeared to be reforming.  Bands in the western and southern parts of Isaias still consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation.

Tropical Storm Isaias will move through an environment somewhat favorable for intensification during the next 36 hours.  Isaias will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the central U.S. will produce westerly winds which blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear, but they are likely to only affect the very top of the tropical storm.  Tropical Storm Isaias will move into a region where there is drier air in the middle and upper troposphere.  The circulation around Tropical Storm Isaias will reorganize and it is likely to strengthen back into a hurricane.

Tropical Storm Isaias will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Isaias toward the northwest during the next 24 hours.  Isaias will move more toward the north later on Sunday.  The upper level trough will turn Isaias toward the northeast on Monday.  On its anticipated track Tropical Storm Isaias is will approach the southeast coast of Florida near Ft. Lauderdale and West Palm Beach on Sunday.  Isaias is likely to be a hurricane when it approaches the coast.

Hurricane Isaias Forces Hurricane Warning for Florida

The threat posed by Hurricane Isaias forced the issuance of a Hurricane Warning for Florida on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of Hurricane Isaias was located at latitude 22.6°N and longitude 75.7°W which put it about 195 miles (320 km) south-southeast of Nassau, Bahamas.  Isaias was moving toward the northwest at 15 m.p.h. (24 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 991 mb.

A Hurricane Warning was in effect for the portion of the coast from Boca Raton, Florida to the Volusia/ Brevard County Line.  Hurricane Warnings were also in effect for all of the Bahamas including 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.  Hurricane Watches were in effect for the portions of the coast from the Flagler/Volusia County Line to the Volusia/Brevard County Line and from Hallendale Beach to Boca Raton.  Tropical Storm Warnings were in effect for the Turks and Caicos, Ocean Reef to Boca Raton, Florida and Lake Okeechobee.  A Tropical Storm Watch was in effect for the portion of the coast from Flagler. Volusia County Line to Ponte Vedra, Florida.

The core of Hurricane Isaias exhibited greater organization on Friday afternoon.  Images from weather radar in the Bahamas and microwave sensors onboard satellites indicated that an eyewall was wrapping around the center of circulations.  The strongest winds were occurring in the ring of storms in the developing eyewall.  Storms near the center of Isaias were generating upper level divergence which was pumping mass away from the hurricane.  Bands of showers and thunderstorms were revolving around the core of Hurricane Isaias.  Winds to hurricane force extended out 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out 175 miles (280 km) from the center.

Hurricane Isaias will move through an environment favorable for intensification during the next 24 hours.  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.  Hurricane Isaias will strengthen on Saturday and it could intensify more rapidly once the inner core is fully formed.  Isaias could intensify into a major hurricane while it moves over the Bahamas.

Hurricane 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 24 hours.  It will turn the hurricane more toward the north during the weekend when Isaias reaches the western end of the high pressure system.  On its anticipated track Hurricane Isaias will move over the Central Bahamas on Friday night.  Isaias could approach southeast Florida on Saturday.  Hurricane Isaias could approach the coast of the Carolinas on Monday.  Hurricane Isaias will bring strong winds to the southeast coast of Florida.  Those winds will blow the water toward the coast and they will create a dangerous storm surge.  Isaias will continue to produce strong winds and locally heavy rain in the Turks and Caicos and the Bahamas. Heavy rain could cause flash floods. Hurricane Isaias will also generate a dangerous storm surge in parts of the Bahamas.

Isaias Rapidly Intensifies into a Hurricane Southeast of the Bahamas

Former Tropical Storm Isaias rapidly intensified into a hurricane southeast of the Bahamas on Thursday night.  At 11:40 p.m. EDT on Thursday the center of Hurricane Isaias was located at latitude 20.3°N and longitude 72.1°W which put it about 70 miles (110 km) east-southeast of Great Inagua.  Isaias was moving toward the northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 995 mb.

Hurricane Warnings were issued for all of the Bahamas including 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. 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.  A Tropical Storm Watch was in effect for the portion of the coast from Ocean Reef to Sebastian Inlet, Florida.

A reconnaissance plane sampling former Tropical Storm Isaias on Thursday night found winds to hurricane force and a decrease in surface pressure.  The core of Hurricane Isaias organized quickly after it moved over the warm water north of the Dominican Republic.  A band of strong thunderstorms wrapped around the western side of the center of circulation.  Winds to hurricane force extended out about 30 miles to the northeast of the center of circulation.  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.  Thunderstorms near the center of circulations 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.

Hurricane Isaias will move through an environment favorable for intensification during the next 36 hours.  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.  Hurricane Isaias will strengthen on Friday and it could intensify more rapidly once an inner core consolidates.  Isaias could intensify into a major hurricane while it moves over the Bahamas.

Hurricane 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 hurricane more toward the north on the weekend when Isaias reaches the western end of the high pressure system. On its anticipated track Hurricane Isaias will move over the Southeastern Bahamas on Friday morning.  Isaias will move over the Central Bahamas later on Friday and it could approach southeast Florida on Saturday.  Hurricane Isaias could approach the coast of the Carolinas on Monday.  Hurricane Isaias will bring strong winds and locally heavy rain to the Turks and Caicos and the Bahamas.  Heavy rain could cause flash floods.  Hurricane Isaias will also generate a dangerous storm surge in the Bahamas.

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.