Tag Archives: HWISI

Hurricane Humberto Strengthens to a Major Hurricane, Warning for Bermuda

Hurricane Humberto strengthened into a major hurricane on Tuesday and a Hurricane Warning was issued for Bermuda.  At 11:00 pm. EDT on Tuesday the center of Hurricane Humberto was located at latitude 31.3°N and longitude 71.0°W which put it about 370 miles (595 km) west of Bermuda.  Humberto was moving toward the east-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 951 mb.

Hurricane Humberto exhibited the structure of a large mature hurricane on Tuesday night.  There was a circular eye at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Hurricane Humberto.  The stronger rainbands were occurring in the northern half of the circulation.  Humberto appeared to be drawing drier air around the southern half of the circulation and bands in that part of the hurricane consisted primarily of showers and lower clouds.

Winds to hurricane force extended out about 45 miles (75 km) from the center of Hurricane Humberto.  Winds to tropical storm force extended out about 150 miles (240 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Humberto was 20.6.  The Hurricane Size Index (HSI) was 16.9 and the Hurricane Wind Intensity Size Index (HWISI) was 37.5.  Hurricane Humberto was capable of causing major wind damage.

Hurricane Humberto will remain in an environment capable of supporting a major hurricane for another 12 to 24 hours.  Humberto will move over water where the Sea Surface Temperature is near 28.5°C.  An upper level trough over the eastern U.S. will produce southwesterly winds which will blow toward the top of the hurricane.  Those winds will cause some vertical wind shear, but the shear may not be strong enough to cause Hurricane Humberto to weaken on Wednesday.

Hurricane Humberto will move around the northern side of a subtropical high pressure system over the Atlantic Ocean.  The high and the upper level trough over the eastern U.S.  will combine to steer Humberto toward the east-northeast on Wednesday.  On its anticipated track the center of Hurricane Humberto could approach Bermuda on Wednesday evening.  Humberto could still be a major hurricane at that time.  If the center of Hurricane Humberto passes just north of Bermuda, then the strongest winds could affect Bermuda.

Elsewhere, Tropical Depression Imelda was dropping heavy rain near Houston, Texas and Tropical Depression Ten was churning toward the northern Leeward Islands.  At 11:00 p.m. EDT on Tuesday the center of Tropical Depression Imelda was located at latitude 29.8°N and longitude 95.5°W which put it about 10 miles (15 km) northwest of Houston, Texas.  Imelda was moving toward the north at 6 m.p.h. (10 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 1007 mb.

At 11:00 p.m. EDT on Tuesday the center of Tropical Depression Ten was located at latitude 13.7°N and longitude 46.7°W which put it about 1030 miles (1660 km) east of the Leeward Islands.  It was moving toward the west-northwest at 10 m.p.h. (16 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 1006 mb.

Typhoon Faxai Strengthens to Equivalent of Major Hurricane South of Tokyo

Typhoon Faxai strengthened into the equivalent of a major hurricane south of Tokyo, Japan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Faxai was located at latitude 31.8°N and longitude 139.7°E which put it about 300 miles (485 km) south of Tokyo, Japan.  Faxai was loving toward the northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 944 mb.

Typhoon Faxai intensified rapidly into the equivalent of a major hurricane on Saturday.  There was a small circular eye at the center of circulation.  The eye was surround by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Faxai.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.

The circulation around Typhoon Faxai became more symmetrical on Saturday.  Winds to typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 140 miles (220 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Faxai was 25.1.  The Hurricane Size Index (HSI) was 15.0 and the Hurricane Wind Intensity Size Index (HWISI) was 40.1.  Typhoon Faxai was capable of causing regional major damage.

Typhoon Faxai will move through an environment favorable for powerful typhoons during the next 12 hours.  Faxai will move over water where the Sea Surface Temperature is near 28°C.  It will move under the middle of an upper level ridge where the winds are weak and there will be little vertical wind shear.  Typhoon Faxai is likely to maintain its intensity during the next 12 hours and it could strengthen a little more.  Typhoon Faxai will reach the coast of Honshu in about 12 hours and Faxai will weaken when it moves over land.  Faxai will move under the westerly winds in the middle latitudes in a day or so and the vertical wind shear will increase when that happens.

Typhoon Faxai will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Faxai toward the north during the next 12 to 18 hours.  The high pressure system and the westerly winds in the middle latitude will turn Typhoon Faxai toward the northeast in 18-24 hours.  On its anticipated track Typhoon Faxai will approach the coast of Honshu near Tokyo in about 12 hours.  Faxai will be capable of causing major damage when it reaches Honshu.

Hurricane Dorian Brings Powerful Winds to Nova Scotia

Hurricane Dorian brought powerful winds to Nova Scotia on Saturday.  At 8:00 p.m. EDT on Saturday the center of Hurricane Dorian was located at latitude 45.0°N and longitude 67.9°W which put it about 45 miles (75 km) northeast of Halifax, Nova Scotia.  Dorian was moving toward the northeast at 30 m.p.h. (48 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 960 mb.

Hurricane Warnings were in effect for Lower East Pubnico to Brule, Nova Scotia and from Indian Harbour to Hawke’s Bay, Newfoundland. Hurricane Watches were in effect for Prince Edward Island and for the Magdalen Islands. Tropical Storm Warnings were issued for Prince Edward Island and from Avonport to Lower East Pubnico, Nova Scotia. A Tropical Storm Warning was in effect for New Brunswick from Fundy National Park to Shediac. A Tropical Storm Warning was issued for the portion of the coast from Indian Harbour to Stone’s Cove, Newfoundland. Tropical Storm Warnings were issued for the portions of the coast from Hawke’s Bay to Fogo Island and from Mutton Bay to Mary’s Harbour.

Hurricane Dorian maintained its intensity and increased in size on Saturday while it sped across the northwestern Atlantic Ocean to the Canadian Maritime provinces.  Winds to hurricane force extended out about 115 miles (185 km) on the southern side of Hurricane Dorian.  Winds to tropical storm force extended out about 300 miles (480 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 16.5.  The Hurricane Size Index (HSI) was 26.3 and the Hurricane Wind Intensity Size Index (HWISI) was 42.8.  Hurricane Dorian was capable of causing widespread serious damage.

There were reports of wind damage and widespread power outages around Nova Scotia even before the center of Hurricane reached that area.  The large circulation around Dorian brought tropical storm force winds to Nova Scotia a few hours before the center made landfall.  The center of Hurricane Dorian officially made landfall south of Halifax, Nova Scotia on Saturday evening.

Hurricane Dorian had almost completed a transition to a large powerful extratropical cyclone.  That transition contributed to the increase in size of the circulation.  The strongest part of Hurricane Dorian will move across Nova Scotia during the next few hours.  The winds are likely to cause additional damage on Saturday night.  Hurricane Dorian will race across Nova Scotia, Cape Breton Island and New Brunswick on Saturday night.  Dorian will move over Newfoundland and southeastern Labrador on Sunday.  Hurricane Dorian has the potential to cause serious damage in all of those locations.

Hurricane Dorian Makes Landfall at Cape Hatteras, Threatens Canadian Maritimes

Hurricane Dorian made an official landfall at Cape Hatteras, North Carolina on Friday morning and posed a serious threat to the Canadian Maritime provinces.  At 5:00 p.m. EDT on Friday the center of Hurricane Dorian was located at latitude 36.9°N and longitude 72.7°W which put it about 330 miles (530 km) south-southwest of Nantucket, Massachusetts.  Dorian was moving toward the northeast at 24 m.p.h. (39 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 surace pressure was 958 mb.

A Tropical Storm Warning was in effect for the portion of the coast from the North Carolina/Virginia border to Fenwick Island, Delaware, and for Chesapeake Bay south of Drum Point.  A Tropical Storm Warning was in effect for the portion of the coast from Woods Hole to Sagamore Beach, Massachusetts including Martha’s Vineyard and Nantucket.  A Tropical Storm Warning was in effect for the portion of the coast from Bar Harbor to Eastport, Maine.  A Hurricane Warning was in effect from Hubbards to Avonport, Nova Scotia.  A Hurricane Watch was issued for Prince Edward Island, Avonport to Hubbards, Nova Scotia, the Magdalen Islands, Parson’s Pond to Indian Harbour, Newfoundland.  Tropical Storm Warnings were issued for Prince Edward Island and from Avonport to Hubbards, Nova Scotia.  A Tropical Storm Watch was in effect for New Brunswick from Fundy National Park to Shediac.  A Tropical Storm Watch was issued for Newfoundland from Francois to Boat Harbor.  A Tropical Storm Watch was  issued for the portion of the coast from Parson’s Pond to Triton, and from Indian Harbour to Stone’s Cove, Newfoundland.

The National Hurricane Center determined that the center of Hurricane Dorian passed over Cape Hatteras and identified that as the point of landfall.  Hurricane Dorian has been moving rapidly away from the coast since that time.  Hurricane Dorian remained a large, well organized hurricane.  A circular eye with a diameter of 35 miles (55 km) was apparent on satellite images.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Winds to hurricane force extended out about 80 miles (130 km) from the center of circulation.  Winds to tropical storm force extended out about 230 miles (370 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 13.9.  The Hurricane Size Index (HSI) was 23.3 and the Hurricane Wind Intensity Size Index (HWISI) was 43.2.

Hurricane Dorian will move through an environment favorable for intensification on Saturday.  Dorian will start out over water where the Sea Surface Temperature is near 27°C.  Dorian will move over cooler water later on Saturday.  An upper level trough over the eastern U.S. will contribute to upper level divergence, which may pump out enough mass to allow the surface pressure to decrease.  Hurricane Dorian will start to make a transition to an extratropical cyclone later on Saturday.  The interaction of colder and warmer air could also provide additional energy to the transitioning hurricane.  There is a chance that Hurricane Dorian could strengthen to a Category 2 hurricane on the Saffir-Simpson Scale on Saturday.

The upper level trough over the eastern U.S. will steer Hurricane Dorian rapidly toward the northeast during the weekend.  On its anticipated track, Dorian will pass southeast of Massachusetts on Saturday morning.  Hurricane Dorian could reach Nova Scotia by Saturday afternoon.  Dorian could be one of the strongest hurricanes to affect the Canadian Maritime provinces.  It will be capable of causing widespread serious damage.

Major Hurricane Dorian Moves Toward the Carolinas

Major Hurricane Dorian moved toward the Carolinas on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Dorian was located at latitude 31.3°N and longitude 79.6°W which put it about 105 miles (170 km) south of Charleston, South Carolina.  Dorian was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 115 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (220 km/h).  The minimum surface pressure was 955 mb.

A Hurricane Warning was in effect for the portion of the coast from Savannah River, Georgia to the North Carolina/Virginia border including Albemarle and Pamlico Sounds.  A Hurricane Watch was in effect for the portion of the coast from the mouth of the St. Mary’s River, Florida to Savannah River, Georgia.  Tropical Storm Warnings were in effect for the portions of the coast from the mouth of the St. Mary’s River to Savannah River, Georgia and from the North Carolina/Virginia border to Chincoteague, Virginia.  A Tropical Storm Warning was also in effect for Chesapeak Bay south of Smith Point.  Tropical Storm Watches were in effect for the portion of the coast from Chincoteague, Virginia to Fenwick Island, Delaware, for Chesapeake Bay from Smith Point to Drum Point and for the Tidal Potomac south of Cobb Island.

Hurricane Dorian strengthened back into a major hurricane on Wednesday night as it moved over the warm water in the Gulf Stream.  A large eye with a diameter of 45 miles (75 km) became more circular and symmetrical.  The ring of thunderstorms surrounding the eye became continuous and a little thicker.  The strongest winds were occurring in that ring of storms.  Other bands of showers and thunderstorms revolving around the core of Hurricane Dorian also got stronger.  Storms around the core of Dorian generated upper level divergence which pumped mass away from the hurricane and the surface pressure decreased.

The circulation around Hurricane Dorian increased in size on Wednesday.  Winds to hurricane force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 20.6.  The Hurricane Size Index (HSI) was 22.6 and the Hurricane Wind Intensity Size Index (HWISI) was 43.2.  Hurricane Dorian was capable of causing widespread major damage.

Hurricane Dorian will move through an environment favorable for intensification during the next 12 hours.  Dorian will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there is little vertical wind shear.  Hurricane Dorian could get a little stronger during the night.  An upper level trough over the central U.S. will move toward Hurricane Dorian on Thursday.  The upper level trough will produce southwesterly winds which will blow toward the top of the hurricane.  Those winds will cause the vertical wind shear to increase, which will cause Dorian to start to weaken.

Hurricane Dorian will move around the western end of a subtropical ridge over the western Atlantic Ocean.  The ridge will steer Dorian toward the north on Wednesday night.  The upper level trough will turn Hurricane Dorian toward the northeast on Thursday.  On its anticipated track Hurricane Dorian could approach the coast of South Carolina on Thursday morning.  Dorian will move along the coast of North Carolina on Thursday afternoon and Thursday night.

Even if the center of Hurricane Dorian stays just south of the coast of South Carolina and North Carolina, the large circulation means that locations near the coast are likely to get hurricane force winds.  Winds blowing water toward the coast could cause storm surges of 5 to 8 feet (1.5 to 2.5 meters) in some locations.  Dorian could also drop locally heavy rain and cause flash flooding  near the coast.

Elsewhere, Tropical Storm Fernand made landfall north of La Pesca, Mexico on Wednesday and Tropical Storm Gabrielle developed south of the Azores.  Ar 11:00 p.m. EDT on Wednesday the center of Tropical Depression Fernand was located at latitude 25.0°N and longitude 99.0°W which put it about 100 miles (160 km) west-northwest of La Pesca, Mexico.  Dorian was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1007 mb.

At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Gabrielle was located at latitude 21.5°N and longitude 34.4°W which put it about 1220 miles (1965 km) south-southwest of the Azores.  Gabrielle was moving toward the northwest at 7 m.p.h. (11 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 m/h).  The minimum surface pressure was 1002 mb.

Hurricane Dorian Moves Parallel to Florida Coast

Hurricane Dorian moved parallel to the east coast of Florida on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Dorian was at latitude 28.4°N and longitude 79.0°W which put it about 95 miles (155 km/h) east of Cape Canaveral, Florida.  Dorian was moving toward the north-northwest at 6 m.p.h. (9 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (215 km/h).  The minimum surface pressure was 959 mb.

Hurricane Warnings were in effect for the portions of the coast from Sebastian Inlet to Ponte Vedra Beach, Florida and from Savannah River, Georgia to Surf City, North Carolina.  Hurricane Watches were in effect for the portion of the coast from Ponte Vedra Beach to Savannah River, Georgia and from Surf City, North Carolina to the North Carolina/Virginia border including Albemarle and Pamlico Sounds.  Tropical Storm Warnings were in effect for the portion of the coast from Jupiter Inlet to Sebastian Inlet, Florida and from Ponte Vedra Beach, Florida to Savannah, River, Georgia.  Tropical Storm Watches were also in effect for the Northwestern Bahamas including the Abacos and Grand Bahama Island.  Tropical Storm Watches were in effect for the portion of the coast from the North Carolina/Virginia border to Chincoteague, Virginia and for Chesapeake Bay south of Smith Point.

Although Hurricane Dorian was moving again, it exhibited the structure of a hurricane that had been stationary for a day and had undergone an eyewall replacement cycle.  There was a large ragged eye with a diameter of 35 miles (55 km) at the center of circulation.  The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Multiple bands of showers and thunderstorms were revolving around the large core of Hurricane Dorian.  Storm near the core were generating upper level divergence which was pumping mass away from the hurricane.

An eyewall replacement cycle caused the size of the circulation around Hurricane Dorian to increase.  Winds to hurricane force extended out about 60 miles (95 km) from the center of circulation.  Wind to tropical storm force extended out about 175 miles (285 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 19.2.  The Hurricane Size Index (HSI) was 19.9 and the Hurricane Wind Intensity Size Index (HWISI) was 39.1.

Hurricane Dorian will move through an environment favorable for intensification on Wednesday.  Dorian 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.  However, the large size of Hurricane Dorian will limit potential intensification.  Hurricane Dorian could intensify a little on Wednesday.  An upper level trough over the U.S. will approach Dorian on Wednesday night.  The trough will produce southwesterly winds which will cause more vertical wind shear on Thursday.

Hurricane Dorian will move around the western end of a subtropical high pressure system over the western Atlantic Ocean on Wednesday.  The high will steer Dorian toward the north-northwest.  The upper level trough will turn Dorian toward the northeast on Wednesday night.  On its anticipated track Hurricane Dorian will move nearly parallel to the east coast of Florida on Wednesday.  Dorian could approach the coast of South Carolina by Wednesday night.

Elsewhere Tropical Storm Fernand was over the western Gulf of Mexico and Tropical Depression was west of the Cabo Verde Islands.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Fernand was located at latitude 23.2°N and longitude 96.4°W which put it about 100 miles (155 km) east-southeast of La Pesca, Mexico.  Fernand was moving toward the west 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 1000 mb.  A Tropical Storm Warning was in effect for the portion of the coast from Puerto Altimira, Mexico to the Mouth of the Rio Grande, River.

At 11:00 p.m. EDT on Tuesday the center of Tropical Depression Eight was located at latitude 19.1°N and longitude 32.8°W which put it about 615 miles (995 km) west-northwest of the Cabo Verde Islands.  It was moving toward the northwest at 8 m.p.h. (13 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 1006 mb.

Hurricane Dorian Hammers the Northwestern Bahamas

Hurricane Dorian hammered the Northwestern Bahamas on Monday.  After pounding the Abacos on Sunday night, Hurricane Dorian moved slowly across Grand Bahama Island before stalling over that island for much of Monday.  There were reports of significant storms surges, numerous injuries and some fatalities.  Dorian was still battering Grand Bahama Island on Monday night.

At 11:00 p.m. EDT on Monday the center of Hurricane Dorian was located at latitude 26.9°N and longitude 78.5°W which put it about 30 miles (50 km) north-northeast of Freeport, Bahamas and about 100 miles (160 km) east of West Palm Beach, Florida.  Dorian was essentially stationary.  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 946 mb.

Hurricane Warnings were in effect for the Abacos and Grand Bahama Island.  A Hurricane Warning was also in effect for the portion of the Florida coast from Jupiter Inlet to Ponte Vedra Beach.  Hurricane Watches were in effect for the portions of the coast from Deerfield Beach to Jupiter Inlet and from Ponte Vedra Beach, Florida to South Santee River, South Carolina.  A Tropical Storm Warning was also in effect for the portion of the coast from Deerfield Beach to Jupiter Inlet.  Tropical Storm Watches were in effect for the portion of the coast from Golden Beach to Deerfield Beach and for Lake Okeechobee.

Hurricane Dorian weakened slowly on Monday.  As it remained nearly stationary the winds around Dorian mixed cooler water to the surface.  Hurricane Dorian was unable to extract enough energy from the ocean to maintain its extreme intensity,  The circulation in core of Dorian developed two concentric eyewalls.  The concentric eyewalls suggested that the hurricane had started an eyewall replacement cycle which may have also contributed to the reduction of the wind speed.

The concentric eyewalls also produced an increase in the size of the circulation around Hurricane Dorian.  Winds to hurricane force extended out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out abou 150 miles from the center.  The Hurricane Intensity Index (HII) was 25.1.  The Hurricane Size Index (HSI) was 15,2 and the Hurricane Wind Intensity Size Index (HWISI) was 40.3.

Hurricane Dorian was south of a high pressure system over the western Atlantic Ocean.  The high was blocking Dorian and preventing the hurricane from moving toward the north.  The western end of the high is forecast to weaken on Tuesday.  When the end of the high weakens, it will allow Hurricane Dorian to move toward the northwest.  An upper level trough over the U.S. will approach Dorian on Wednesday.  The trough is forecast to turn Dorian toward the northeast.  On its anticipated track Hurricane Dorian could approach the Central Florida coast by Tuesday night.  Dorian could approach the Carolinas on Wednesday night.

Hurricane Dorian will move into an environment favorable for intensification when it starts moving again on Tuesday.  Dorian 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.  However, Hurricane Dorian could still be in the weakening part of the eyewall replacement cycle and Dorian may not intensify despite the favorable environment.  The upper level trough will produce southwesterly winds which will cause wind shear to increase on Wednesday.  The increase in wind shear will likely cause Hurricane Dorian to weaken when it approaches the Carolinas.

Hurricane Dorian Pounds Northwest Bahamas, Warning Issued for Florida

Hurricane Dorian pounded the Northwestern Bahamas on Sunday afternoon and a Hurricane Warning was issued for a portion of the southeast Florida coast.  Dorian was one of the strongest Atlantic hurricanes on record.  At 5:00 p.m. EDT on Sunday the center of Hurricane Dorian was locate at latitude 26.6°N and longitude 77.3°W which put it about 175 miles (280 km) east of West Palm Beach, Florida.  Dorian was moving toward the west at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 185 m.p.h. (295 km/h) and there were wind gusts to 220 m.p.h. (355 km/h).  The minimum surface pressure was 910 mb.

A Hurricane Warning was issued for the portion of the coast of Florida from Jupiter Inlet to the Volusia/Brevard County Line.  Hurricane Warnings were also in effect for the Northwestern Bahamas including the Abacos, Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.  Hurricane Watches were in effect for the portion of the coast from Deerfield Beach to Jupiter Inlet, Florida and from the Volusia/Brevard County Line to the Flagler/Volusia County Line.  A Hurricane Watch was also in effect for Andros Island.  A Tropical Storm Warning was in effect for the portion of the coast from Deerfield Beach to Jupiter Inlet, Florida.  Tropical Storm Watches were in effect for the portion of the coast from  Golden Beach to Deerfield Beach, Florida and for Lake Okeechobee.

The core of Hurricane Dorian moved over Great Abaco Island on Sunday afternoon.  Dorian intensified rapidly to an intense Category 5 hurricane on the Saffir-Simpson Scale when it reached the warm water around the Bahamas.  The pressure decreased rapidly to 910 mb and the winds increased to 185 m.p.h. (295 km/h).  There was a circular eye with a diameter of 12 miles (19 km) at the center of Hurricane Dorian.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Dorian.  Storms near the core were generating strong upper level divergence which was pumping mass away from the hurricane.

The circulation around Hurricane Dorian increased in size on Sunday.  Winds to hurricane force extended out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 140 miles (220 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 44.1.  The Hurricane Size Index (HSI) was 14,3 and the Hurricane Wind Intensity Size Index (HWISI) was 58.4.  Hurricane Dorian was capable of causing regional catastrophic damage.  Dorian was stronger than Hurricane Andrew was when Andrew hit southeast Florida in 1992.

Hurricane Dorian will remain in a favorable environment for intense hurricanes for another 24 to 36 hours.  Dorian 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.  It appeared that an inner rainband may have wrapped around the existing eye and eyewall.  Radar images indicated that there could be two concentric eyewalls.  If there are two eyewalls, then an eyewall replacement cycle is underway.  Hurricane Dorian will weaken, at least temporarily when the inner eyewall dissipates.  However, Dorian will get larger when the strongest winds occur in the outer eyewall.

Hurricane Dorian will move near the western end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Dorian slowly toward the west-northwest during the next 24 to 36 hours.  Eventually, Hurricane Dorian will move more toward the north when it moves around the western end of the high.  On its anticipated track Hurricane Dorian will linger over the Northwestern Bahamas on Sunday night.  The core of Dorian will pass over or very near Grand Bahama Island.  It could cause catastrophic damage on the Abacos and Grand Bahama Island.  Hurricane Dorian could approach the east coast of Florida on Tuesday.

Hurricane Dorian Strengthens to Cat. 5 Near Great Abaco

Hurricane Dorian strengthened to Category 5 on the Saffir-Simpson Scale near Great Abaco Island on Sunday morning.  At 9:30 a.m. EDT on Sunday the center of Hurricane Dorian was located at latitude 26.5°N and longitude 76.5°W which put it about 35 miles (55 km) east of Great Abaco Island, Bahamas and about 225 miles (360 km) east of West Palm Beach, Florida.  Dorian was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 175 m.p.h. (280 km/h) and there were wind gusts to 220 m.p.h. (355 km/h).  The minimum surface pressure was 927 mb.

A Hurricane Warning was in effect for the Northwestern Bahamas including the Abacos, Berry Islands, Bimini, Eleuthera, Grand Bahama Island, and New Providence.  A Hurricane Watch was in effect for Andros Island.  A Tropical Storm Warning was in effect for the portion of the coast from Deerfield Beach to Sebastian Inlet, Florida.  A Tropical Storm Watch was issued for the portion of the coast from Golden Beach to Deerfield Beach, Florida.

A reconnaissance plane found that Hurricane Dorian had strengthened to Category 5 on Sunday morning.  Dorian exhibited the structure of a classic intense hurricane.  There was a circular eye with a diameter of 15 miles (24 km) at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Storms near the core of Hurricane Dorian were generating strong upper level divergence which was pumping mass away from the hurricane.  Bands of showers and thunderstorms were revolving around the core of the hurricane.

Winds to hurricane force extended out about 30 miles from the center of Hurricane Dorian.  Winds to tropical storm force extended out about 110 miles (180 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 40.4.  The Hurricane Size Index (HSI) was 11.7 and the Hurricane Wind Intensity Size Index (HWISI) was 52.1.  Hurricane Dorian was very similar in size and strengthen to what Hurricane Michael was when Michael hit northwest Florida in 2018.

Hurricane Dorian will remain in an environment very favorable for intense hurricanes during the next several days.  Dorian 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 Dorian is likely to remain a very strong hurricane for several more days.  At some point a rainband is likely to wrap around the existing eye and eyewall.  When that happens, an eyewall replacement cycle will cause fluctuations in the intensity of Dorian.

Hurricane Dorian will move south of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Dorian toward the west on Sunday.  Hurricane Dorian could slow on Sunday night when it nears the western end of the ridge.  On its anticipated track Hurricane Dorian will move over the Abacos and New Providence on Sunday.  Dorian is capable of causing catastrophic damage over portions of the Northwestern Bahamas.  It could generate a storm surge of 15 feet (4.5 meters) where the strongest winds push water toward the coastline.  Hurricane Dorian could eventually approach the coast of southeast Florida as a very strong hurricane.

Dangerous Hurricane Dorian Nears Northwestern Bahamas

Dangerous Hurricane Dorian neared the Northwestern Bahamas on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Dorian was located at latitude 26.3°N and longitude 75.1°W which put it about 125 miles (200 km) east of Great Abaco and about 310 miles (500 km) east of West Palm Beach, Florida.  Dorian was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h)  and there were wind gusts to 185 m.p.h. (315 km/h).  The minimum surface pressure was 940 mb.

Hurricane Warnings were in effect for the Northwestern Bahamas including the Abacos, Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.  A Hurricane Watch was in effect for Andros Island.  A Tropical Storm Watch has been issued for the portion of the coast from Deerfield Beach to Sebastian Inlet, Florida.

Hurricane Dorian remains a very dangerous, well organized storm.  Dorian has maintained Category 4 intensity on the Saffir-Simpson Scale for 24 hours.  A circular eye with a diameter of 15 miles (24 km) was clearly visible on conventional and microwave satellite imagery.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  The maximum sustained wind speed at the surface was 150 m.p.h. (240 km/h) and data from dropsondes indicated that the wind was stronger a few hundred feet above the surface.  Bands of showers and thunderstorms were revolving around the core of Hurricane Dorian.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.

Winds to hurricane force extended out about 30 miles (50 km) from the center of Hurricane Dorian.  Winds to tropical storm force extended out about 105 miles (170 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 33.3.  The Hurricane Size Index (HSI) was 11.7and the Hurricane Wind Intensity Size Index (HWISI) was 45.0.  Hurricane Dorian is capable of causing regional significant damage.

Hurricane Dorian will remain in an environment capable of supporting a very strong hurricane for several more days.  Dorian 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.  There will be a potential for Hurricane Dorian to strengthen to Category 5 on the Saffir-Simpson Scale.  At some point eyewall replacement cycles are likely to cause fluctuations in intensity.

Hurricane Dorian will move around the western end of a subtropical high pressure system during the next 24 to 48 hours.  The high will steer Dorian slowly toward the west.  Hurricane Dorian could move very slowly when it reaches the western end of the ridge.  Eventually, Dorian will turn toward the north when it moves around the end of the ridge.  On its anticipated track Hurricane Dorian will reach the Northwestern Bahamas by Sunday evening.  The core of Dorian will move very close to the Abacos and Grand Bahama Island.  Hurricane Dorian could cause significant wind damage.  Dorian could also produce a storm surge of up to 15 feet (4.5 meters) in places where the wind blows water toward the shoreline.