Tag Archives: HWISI

Typhoon Hagibis Rapidly Intensifies Into Equivalent of Major Hurricane

Typhoon Hagibis rapidly intensified into the equivalent of a major hurricane east of the Marianas on Sunday night.  At 11:00 p.m. EDT on Sunday the cener of Typhoon Hagibis was located at latitude 15.3°N and longitude 148.8°E which put it about 320 miles (515 km) east-northeast of Guam.  Hagibis was moving toward the west-northwest at 19 m.p.h. (31 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 953 mb.

Typhoon Warnings were in effect for Tinian, Saipan, Alamagan and Pagan.  Tropical Storm Warnings were in effect for Rota and Agrihan.  A Tropical Storm Watch was in effect for Guam.

Typhoon Hagibis intensified very rapidly on Sunday night.  The maximum sustained wind speed increased from 75 m.p.h. (120 km/h) to 115 m.p.h. (185 km/h) in six hours.  A small circular eye formed at the center of Hagibis and a ring of strong thunderstorms surrounded the eye.  The strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of the typhoon.  Storms near the core were generating strong upper level divergence which was pumping mass away in all directions.  The removal of mass was allowing the minimum surface pressure to decrease rapidly.

The circulation around Typhoon Hagibis was increasing in size.  Winds to typhoon force extended out 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out 175 miles (280 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Hagibis was 20.2.  The Hurricane Size Index (HSI) was 18.1 and the Hurricane Wind intensity Size Index (HWISI) was 38,3,  Typhoon Hagibis was capable of causing major damage.

Typhoon Hagibis will continue to move through an environment very favorable for intensification for another 24 to 36 hours.  Hagibis 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.  Typhoon Hagibis could continue to intensify rapidly and it could strengthen into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale during the next 24 hours.  At some point a rainband is likely to wrap around the existing eye and eyewall and an eyewall replacement cycle will end the intensification of Typhoon Hagibis.

Typhoon Hagibis will move around the southwestern part of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Hagibis toward the west-northwest during the next 12 to 24 hours.  Hagibis will turn more toward the northwest in a day or so.  On its anticipated track Typhoon Hagibis will reach the Marianas in about 12 hours.  The center of Hagibis is likely to pass north of Saipan.  Typhoon Hagibis will bring strong winds and heavy rain.  It will be capable of causing major damage to the Northern Marianas.  Typhoon Hagibis could approach southwestern Japan in four or five days.

Hurricane Lorenzo Brings Wind and Rain to the Azores

Hurricane Lorenzo brought wind and rain to the Azores on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Lorenzo was located at latitude 39.1°N and longitude 32.7°W which put it about 85 miles (135 km) west-southwest of Flores Island, Azores.  Lorenzo was moving toward the northeast at 40 m.p.h. (65 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 the western and central Azores including Flores, Corvo, Faial, Pico, Sao Jorge, Graciosa and Terceira. Tropical Storm Warnings were in effect for the eastern Azores including Sao Miguel and Santa Maria.

Although Hurricane Lorenzo moved into a more extratropical environment, it remained a large and powerful hurricane.  Winds to hurricane force extended out 150 miles (240 km) from the center of circulation.  Winds to tropical storm force extended out 390 miles (630 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 16.5.  The Hurricane Size Index (HSI) was 50.2 and the Hurricane Wind Intensity Size Index (HWISI) was 66.7.  The radius of hurricane force winds was larger in Hurricane Lorenzo than it was in Hurricane Sandy in 2012.  The overall size of Hurricane Lorenzo was similar to the size of Hurricane Sandy.

Hurricane Lorenzo will move into an extratropical environment during the next several days.  Lorenzo will move over water where the Sea Surface Temperature is colder than 24°C.  An upper level trough over the north Atlantic Ocean will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause strong vertical wind shear.  The colder water and strong shear will cause Hurricane Lorenzo to weaken gradually.  The cooler, more strongly sheared environment will also cause Hurricane Lorenzo to make a transition into a strong extratropical cyclone during the next 48 hours.

The upper level trough will steer Hurricane Lorenzo rapidly toward the northeast during the next 24 to 36 hours.  Lorenzo will turn more toward the east later on Thursday.  On its anticipated track Hurricane Lorenzo will bring strong winds, large waves and heavy rain to the Azores on Wednesday.  Lorenzo will be capable of causing extensive serious damage.  The extratropically transitioned Hurricane Lorenzo could approach Ireland and the United Kingdom on Thursday night and Friday.

Hurricane Lorenzo Prompts Watches for the Azores

The risk posed by Hurricane Lorenzo prompted the issuance of watches for the Azores.  At 11:00 p.m. EDT on Sunday the center of Hurricane Lorenzo was located at latitude 27.6°N and longitude 43.5°W which put it about 1195 miles (1920 km) west-southwest of the Azores.  Lorenzo was moving toward the north-northeast at 10 m.p.h. (16 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. (210 km/h).  The minimum surface pressure was 952 mb.

Hurricane Watches were issued for the western and central Azores including Flores, Corvo, Faial, Pico, Sao Jorge, Graciosa, Terceira.  Tropical Storm Watches were issued for the eastern Azores including Sao Miguel and Santa Maria.

Hurricane Lorenzo weakened on Sunday when it moved into a less favorable environment.  Lorenzo moved over water where the Sea Surface Temperature was a little cooler.  In addition, an upper level trough west of Hurricane Lorenzo was producing southwesterly winds which were blowing toward the top of the circulation.  Those upper level winds were causing more vertical wind shear.  The combination of cooler water and more shear was responsible for weakening Hurricane Lorenzo.

Even though Hurricane Lorenzo weakened on Sunday it remained a large and powerful hurricane.  Winds to hurricane force extended out about 90 miles (145 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 19.2.  The Hurricane Size Index (HSI) 32.6 was and the Hurricane Wind Intensity Size Index (HWISI) was 51.8.  Hurricane Lorenzo was capable of causing widespread serious damage.

Hurricane Lorenzo is likely to continue to weaken slowly during the next several days because of the less favorable environment consisting of cooler water and more vertical wind shear.  Since the circulation around Lorenzo is so large, the hurricane will weaken slowly.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next two or three days.  On its anticipated track Hurricane Lorenzo could reach the Azores by Tuesday night.  Lorenzo could be a large hurricane capable of causing widespread serious damage when it reaches the Azores.

Hurricane Lorenzo Strengthens to Cat. 5 Southwest of the Azores

Hurricane Lorenzo strengthened to Category 5 on the Saffir-Simpson Scale on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Lorenzo was located at latitude 24.2°N and longitude 44.9°W which put it about 1420 miles (2285 km) southwest of the Azores.  Lorenzo was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 925 mb.

Hurricane Lorenzo strengthened to Category 5 farther east in the Atlantic Ocean than other hurricane on record.  Lorenzo appeared to complete an eyewall replacement cycle earlier on Saturday and then it start to strengthen quickly.  A circular eye with a diameter of 35 miles (55 km) became evident at the center of circulation.  A ring of very 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 Lorenzo.

The circulation around Hurricane Lorenzo was large.  Wins to hurricane force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 275 miles (445 km) from the center.  The Hurricane Intensity Index (HII) was 35.0.  The Hurricane Size Index (HSI) was 21.2 and the Hurricane Wind intensity Size Index (HWISI) was 56.2.

Hurricane Lorenzo will remain in a very favorable environment for another 12 to 24 hours.  It will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough will approach Lorenzo from the west later on Sunday.  The trough will produce southwesterly winds which will create more wind shear.  Hurricane Lorenzo will start to weaken when the wind shear increases.  Lorenzo will also move over cooler water on Monday, which will cause more weakening.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next few days.  On its anticipated track Hurricane Lorenzo could approach the Azores on Tuesday night.  Lorenzo is likely to be a hurricane when it reaches the Azores.  Hurricane Lorenzo will eventually make a transition to a strong extratropical cyclone.  It could be near Ireland in four or five days.

Powerful Hurricane Lorenzo Churns Southwest of the Azores

Powerful Hurricane Lorenzo churned southwest of the Azores on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Lorenzo was located at latitude 20.3°N and longitude 43.6°W which put it about 1575 miles (2535 km) southwest of the Azores.  Lorenzo was moving toward the north-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 948 mb.

Hurricane Lorenzo weakened slowly on Friday, but it remained a large and powerful hurricane.  Winds to hurricane force extended out 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 23.6.  The Hurricane Size Index (HSI) was 20.7 and the Hurricane Wind Intensity Size Index (HWISI) was 44.3.  Hurricane Lorenzo was capable of causing major damage.

Hurricane Lorenzo weakened on Friday because it moved into a less favorable environment.  Lorenzo continued to move over water where the Sea Surface Temperature was near 27°C.  However, an upper level trough west of Lorenzo was producing southwesterly winds which were causing moderate vertical wind shear.  in addition, Hurricane Lorenzo appeared to be drawing drier air into the western half of the circulation.  The effects of increased vertical wind shear and drier air caused Lorenzo to weaken.

Hurricane Lorenzo will continue to move through a less favorable environment and weaken.  Since Lorenzo is a large hurricane, it will weaken more slowly than a smaller hurricane would.  As a result, Lorenzo will likely remain a hurricane for several more days.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next few days.  On its anticipated track Hurricane Lorenzo will likely approach the Azores on Tuesday.  Lorenzo is likely to still be a hurricane at that time.

Elsewhere over the Atlantic Ocean, Tropical Depression Karen weakened to a trough southeast of Bermuda on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of former Tropical Depression Karen was located at latitude 29.3°N and longitude 58.5°W which put it about 425 miles (685 km) south-southeast of Bermuda.  Karen was moving toward the northeast at 6 m.p.h. (10 km/h).  The maximum sustained wind sped 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.

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.