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Tropical Storm Ophelia Brings Wind and Rain to Eastern North Carolina, Virginia

Tropical Storm Ophelia brought wind and rain to eastern North Carolina and Virginia on Saturday morning. At 8:00 a.m. EDT on Saturday the center of Tropical Storm Ophelia was located at latitude 35.1°N and longitude 77.0°W which put it about 40 miles (65 km) northwest of Cape Lookout, North Carolina. Ophelia was moving toward the north at 13 m.p.h. (21 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 983 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Cape Fear, North Carolina to Fenwick Island, Delaware. The Tropical Storm Warning included Albemarle Sound and Pamlico Sound. A Tropical Storm Warning was also in effect for Chesapeake Bay south of North Beach. A Tropical Storm Warning was in effect for the Tidal Potomac south of Cobb Island.

Tropical Storm Ophelia brought wind and rain as it moved inland over eastern North Carolina on Saturday morning. The circulation around Ophelia was large. Tropical Storm Opehila was interacting with a high pressure system over eastern Canada to produce strong winds northeast of the center of circulation. Winds to tropical storm force extended out 310 miles (500 km) in the northeastern quadrant of Ophelia’s circulation. Winds to tropical storm force extended out 140 miles (225 km) in the other parts of Tropical Storm Ophelia.

A weather station in Cape Lookout, North Carolina reported a sustained wind speed of 47 m.p.h. (75 km/h) and a wind gust of 71 m.p.h. (115 km/h). A weather station in Morehead City, North Carolina reported a sustained wind speed of 43 m.p.h. (68 km/h) and a wind gust of 53 m.p.h. (85 km/h). NOAA buoy 41037 near Wrightsville Beach reported a sustained wind speed of 54 m.p.h. (87 km/h) and a wind gust of 83 m.p.h. (134 km/h).

Tropical Storm Ophelia will move around the western side of a high pressure system over the western Atlantic Ocean. The high pressure system will steer Ophelia toward the north during the next 24 hours. On its anticipated track, Tropical Storm Ophelia will move inland over eastern North Carolina and Virginia. Ophelia will bring strong, gusty winds and locally heavy rain to eastern North Carolina, eastern Virginia, southeastern Maryland and southern Delaware.

The heaviest rain was falling in bands in the northern and western parts of Tropical Storm Ophelia. Bands in the eastern and southern parts of Ophelia’s circulation consisted primarily of showers and lower clouds. Locally heavy rain could cause flash floods in some locations. Flood Watches were in effect for eastern North Carolina, eastern Virginia, Maryland and Delaware.

Easterly winds in the northern side of Tropical Storm Ophelia will blow water toward the coast. A storm surge of up to 6 feet (1.8 meters) could occur in some locations. A Storm Surge Warning was in effect for the portion of the coast from Bogue Inlet, North Carolina to Chincoteague, Virginia. The Storm Surge Warning included Albemarle Sound, Pamlico Sound, the Pamlico River and the Neuse River. A Storm Surge Warning was in effect for Chesapeake Bay south of Colonial Beach, Virginia. Large waves will also cause significant beach erosion.

Tropical Storm Ophelia Develops South of Cape Hatteras

Tropical Storm Ophelia developed south of Cape Hatteras on Friday afternoon. At 2:00 p.m. EDT on Friday the center of Tropical Storm Ophelia was located at latitude 32.7°N and longitude 76.0°W which put it about 185 miles (295 km) south of Cape Hatteras, North Carolina. Ophelia was moving toward the north-northwest at 12 m.p.h. (19 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 992 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Cape Fear, North Carolina to Fenwick Island, Delaware. The Tropical Storm Warning included Albemarle Sound and Pamlico Sound. A Tropical Storm Warning was also in effect for Chesapeake Bay south of North Beach. A Tropical Storm Warning was in effect for the Tidal Potomac south of Cobb Island.

The U.S. National Hurricane Center designated a low pressure system south of Cape Hatteras as Tropical Storm Ophelia on Friday afternoon. Drier air was wrapping around the southern and eastern sides of Ophelia’s circulation. The drier air was making the distribution of thunderstorms asymmetrical. Thunderstorms were occurring in bands in the northern and western parts of Tropical Storm Ophelia. Bands in the southern and eastern parts of Ophelia consisted primarily of showers and lower clouds. Storms north and west of the center of Ophelia’s circulation generated upper level divergence that pumped mass away from the tropical storm. The circulation around Tropical Storm Ophelia was large, Winds to tropical storm force extended out 275 miles (445 km) from the center of circulation.

Tropical Storm Ophelia will move through an environment somewhat favorable for intensification during the next 12 hours. Ophelia will move over the Gulf Stream where the Sea Surface Temperatures are near 30°C. It will move under the eastern side of an upper level trough over the eastern U.S. The upper level trough will produce southwesterly winds that will blow toward the top of Ophelia’s circulation. Those winds will cause moderate vertical wind shear. However, the flow of air in the upper levels will also provide divergence aloft that will pump mass away from the tropical storm. The removal of mass will cause the surface pressure to decrease. The drier air in the southern and eastern parts of Tropical Storm Ophelia will inhibit the formation of thunderstorms in those regions. Tropical Storm Ophelia could intensify during the next 12 hours, while it is over the Gulf Stream.

Tropical Storm Ophelia will move around the western side of a high pressure system over the western Atlantic Ocean. The high pressure system will steer Ophelia toward the north-northwest during the next 24 hours. On its anticipated track, Tropical Storm Ophelia will approach the coast of North Carolina on Friday night. Ophelia will bring strong, gusty winds and locally heavy rain to eastern North Carolina, eastern Virginia, southeastern Maryland and southern Delaware. NOAA buoy 41025 at Diamond Shoals, North Carolina reported a sustained wind speed of 47 m.p.h. (76 km/h) and a wind gust of 60 m.p.h. (97 km/h). A NOAA C-MAN station at Cape Lookout, North Carolina reported a sustained wind speed of 45 m.p.h. (72 km/h) and a wind gust of 53 m.p.h. (83 km/h)

Locally heavy rain could cause flash floods in some locations. Flood Watches were in effect for eastern North Carolina, eastern Virginia, Maryland and Delaware.

Easterly winds in the northern side of Tropical Storm Ophelia will blow water toward the coast. A storm surge of up to 6 feet (1.8 meters) could occur in some locations. A Storm Surge Warning was in effect for the portion of the coast from Beaufort Inlet, North Carolina to Chincoteague, Virginia. The Storm Surge Warning included Albemarle Sound, Pamlico Sound, the Pamlico River and the Neuse River. A Storm Surge Warning was in effect for Chesapeake Bay south of Colonial Beach, Virginia. Large waves will also cause significant beach erosion.

Low Pressure System Prompts Tropical Storm Warnings for Mid-Atlantic Coast

A low pressure system formed over the Atlantic Ocean off the coast of the southeast U.S. on Thursday morning. The U.S. National Hurricane Center designated the low pressure system as Potential Tropical Cyclone Sixteen and issued Tropical Storm Warnings for portions of the Mid-Atlantic coast. At 2:00 p.m. EDT on Thursday the center of Potential Tropical Cyclone Sixteen was located at latitude 29.0°N and longitude 75.9°W which put it about 430 miles (690 km) south of Cape Hatteras, North Carolina. Potential Tropical Cyclone Sixteen was moving toward the north at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1012 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Cape Fear, North Carolina to Fenwick Island, Delaware. The Tropical Storm Warning included Albemarle Sound and Pamlico Sound. A Tropical Storm Warning was also in effect for Chesapeake Bay south of Smith Point.

A low pressure system formed over the Atlantic Ocean off the coast of the southeast U.S. on Thursday morning. The low pressure system formed as an extratropical cyclone. There was a large counterclockwise circulation around the low pressure system. There was not a well formed, distinct low level center of the circulation. Thunderstorms were occurring in a band that wrapped around the eastern and northern side of the low pressure systems. Fragmented bands in other parts of the circulation consisted primarily of showers and lower clouds.

Potential Tropical Cyclone Sixteen will move through an environment favorable for intensification of an extratropical cyclone during the next 24 hours. The low pressure system will move over water where the Sea Surface Temperatures are near 28°C. It will move under the eastern side of an upper level trough over the eastern U.S. The upper level trough will produce southwesterly winds that will blow across the top of Potential Tropical Cyclone Sixteen. Those winds will cause moderate vertical wind shear. However, the flow of air in the upper levels will also provide divergence aloft that will pump mass away from the surface low pressure system. The removal of mass will cause the surface pressure to decrease. Potential Tropical Cyclone Sixteen is likely to intensify during the next 24 hours. The low pressure system could make a transition to a tropical storm later on Friday when it moves over the warmer water in the Gulf Stream.

The upper level trough over the eastern U.S. will steer Potential Tropical Cyclone Sixteen toward the north during the next 24 hours. On its anticipated track Potential Tropical Cyclone will approach the coast of North Carolina on Friday night. The low pressure system will bring gusty winds and locally heavy rain to eastern North Carolina, eastern Virginia, southeastern Maryland and southern Delaware. The gusty winds will blow water toward the coast. A storm surge of up to 5 feet (1.5 meters) could occur in some locations. Large waves will cause significant beach erosion. Locally heavy rain could cause flash floods in some locations.

Elsewhere over the Atlantic Ocean, Hurricane Nigel was speeding toward the northeast as it passed southeast of Newfoundland. At 11:00 a.m. EDT on Thursday the center of Hurricane Nigel was located at latitude 42.2°N and longitude 45.0°W which put it about 505 miles (815 km) southeast of Cape Race,, Newfoundland. Nigel was moving toward the northeast at 30 m.p.h. (48 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 977 mb.

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.

 

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 Florence Wobbles Closer to North Carolina

Hurricane Florence wobbled closer to the coast of North Carolina on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Hurricane Florence was located at latitude 34.0°N and longitude 76.8°W which put it about 60 miles east-southeast of Wilmington, North Carolina.  Florence was moving toward the northwest at 6 m.p.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 surface pressure was 956 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Duck, North Carolina including Pamlico and Albemarle Sounds.  A Tropical Storm Warning was in effect for the portion of the coast from Edisto Beach to South Santee River, South Carolina.  A Tropical Storm Warning was also in effect for the portion of the coast from Duck, North Carolina to Cape Charles Light, Virginia and for Chesapeake Bay south of New Point Comfort.

Hurricane Florence is already affecting the coast.  National Data Buoy Center C-MAN station CLKN7 at Cape Lookout, North Carolina reported a sustained wind speed of 81 m.p.h. (131 km/h) and a wind gust of 101 m.p.h. (163 km/h).  Storm surges were already occurring along portions of the coast east of the center of Hurricane Florence where the winds were pushing water toward the coast.  The highest surge appeared to be in the area of the western part of Pamlico Sound near the mouth of the Neuse River.  There were scattered reports of wind damage and power outages.

A high pressure system over the northeastern U.S. is blocking the northward movement of Hurricane Florence.  The high is steering Florence slowly toward the northwest.  On its anticipated track Hurricane Florence will make a landfall near Wilmington, North Carolina on Friday.  Florence could move a little south of due west after landfall.  The center will pass a little north of Myrtle Beach, South Carolina and then move toward Columbia, South Carolina.  Florence is likely to continue to weaken slowly.  Because of the slow movement, many locations will experience extended periods of gusty winds.  Power outages are likely to become more widespread on Friday.  Hurricane Florence will drop locally heavy rain.  Locations where rainbands are essentially station could receive over a foot (0.3 meters) of rain.  Serious fresh water flooding is likely to develop on Friday and Saturday.

Elsewhere over the Atlantic Ocean, Tropical Storm Helene generated a Tropical Storm Watch for all of the Azores, Tropical Storm Isaac sped across the eastern Caribbean Sea and former Subtropical Storm Joyce made a transition to Tropical Storm Joyce.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Helene was located at latitude 28.6°N and longitude 36.5°W which put it about 885 miles (1425 km) southwest of the Azores.  Helene was moving toward the north at 21 m.p.h. (34 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were gusts to 80 m.p.h. (130km/h).  The minimum surface pressure was 992 mb.

At 11:00 p.m. EDT on Thursday the center of Tropical Storm Isaac was located at latitude14.9°N and longitude 64.4°W which put it about 195 miles (315 km) south of St. Croix.  Isaac was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1006 mb.

At 11:00 p.m. EDT on Thursday the center of Tropical Storm Joyce was located latitude 32.9°N and longitude 44.4°W which put it about 1040 miles (1670 km) west-southwest of the Azores.  Joyce was moving toward the south-southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1003 mb.

Hurricane Florence Moves Closer to the Carolinas

Hurricane Florence moved closer to the Carolinas on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Florence was located at latitude 32.0°N and longitude 73.7°W which put it about 280 miles (455 km) east-southeast of Wilmington, North Carolina.  Florence was moving toward the northwest at 17 m.p.h. (28 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 957 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Duck, North Carolina including Pamlico and Albemarle Sounds.  A Hurricane Watch was in effect for the portion of the coast from Edisto Beach, South Carolina to South Santee River, South Carolina.  A Tropical Storm Warning is in effect for the portion of coast from Duck, North Carolina to the North Carolina-Virginia border.  A Tropical Storm Watch was in effect for the portion of the coast from the North Carolina-Virginia border to Cape Charles Light, Virginia and for Chesapeake Bay south of New Point Comfort.

The wind speed in Hurricane Florence decreased on Wednesday but the circulation increased in size.  It appeared that another eyewall replacement cycle could have started.  Satellite microwave images suggested that there could be two eyewalls and a reconnaissance plane reported a double wind maxima.  Both of those things could be evidence of concentric eyewalls.  In addition, counterclockwise flow around a small upper level low near Florida may have produced southerly winds that blew toward the south side of Hurricane Frances.  Those winds may have inhibited the upper level divergence to the south of Florence.  Since the hurricane was unable to pump out as much mass, the surface pressure increased and the wind speed decreased.

The circulation of Hurricane Florence increased in size on Wednesday.  Winds to hurricane force extended out about 80 miles (130 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 Florence was 19.2.  The Hurricane Size Index (HSI) was 25.5 and the Hurricane Wind Intensity Size Index (HWISI) was 44.7.  Those indices are very similar to the numbers for Hurricane Jeanne just before Jeanne made landfall in southeast Florida in 2004.

Hurricane Florence will move through an environment favorable for intensification on Thursday.  Florence will move over water where the Sea Surface Temperature is near 29°C.  Florence will move farther away from the upper low near Florida and the low should not inhibit divergence to the south of the hurricane as much.  In addition, Hurricane Florence will move over the warm water in the Gulf Stream about 6 to 12 hours before it reaches the coast.  It will be able to extract extra energy at that time.  If the inner core becomes more organized, then Hurricane Florence could intensify on Thursday.  If the inner core does not get better organized, then Florence will likely maintain its current intensity or weaken slowly.

Hurricane Florence will move near the western end of the subtropical high pressure system over the western Atlantic Ocean.  The high will steer Florence toward the northwest on Thursday.  On its anticipated track the center of Hurricane Florence will be near the coast of North Carolina on Thursday night.  A ridge over the eastern U.S. is likely to block the northward motion of Hurricane Florence when it reaches the coast.  The ridge will steer Florence slowly toward the west-southwest on Friday and Saturday.

Hurricane Florence will have the impact of a major hurricane regardless of the actual sustained wind speed.  The large circulation and slow rate of movement when Florence reaches the coast means that locations could experience strong winds for extended periods of time.  Wind damage and power outages could be extensive.  Some places in North Carolina had a rainy summer and strong winds could uproot trees.  Hurricane Florence will produce a dangerous storm surge along the coast.  The surge could exceed 10 feet (3 meters) in some locations east of where the center makes landfall.  The slow forward speed also means that Hurricane Florence could drop locally heavy rain and severe flooding could occur.

Elsewhere the rest of the Atlantic Ocean was also very active.  Tropical Storm Isaac was nearing the Lesser Antilles, Hurricane Helene was weakening south of the Azores and Subtropical Storm Joyce formed northwest of Helene.

At 11:00 p.m. EDT on Thursday the center of Tropical Storm Isaac was located at latitude 15.3°N and longitude 58.0°W which put it about 220 miles (355 km) east of Dominica.  Isaac was moving toward the west at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1006 mb.  Tropical Storm Warnings were in effect for Guadeloupe, Martinique and Dominica.  Tropical Storm Watches were in effect for Antigua, Montserrat, St, Kitts and Nevis, Saba and St. Eustatius, St. Martin and St. Maarten.

At 11:00 p.m. EDT on Thursday the center of Hurricane Helene was located at latitude 22.4°N and 36.9°W which put it about 1270 mile (2045 km) south-southwest of the Azores.  Helene was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 983 mb.

At 11:00 p.m. EDT on Thursday the center of Subtropical Storm Joyce was located at latitude 15.3°N and longitude 46.6°W which put it about 910 miles (1465 km) west-southwest of the Azores.  Joyce was moving toward the southwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1006 mb.

Hurricane Warnings Issued for Carolinas for Hurricane Florence

Hurricane Warnings were issued for the Carolinas on Tuesday for the potential impacts of Hurricane Florence.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Florence was located at latitude 28.4°N and longitude 68.7°W which put it about 670 miles (1075 km) east-southeast of Cape Fear, North Carolina.  Florence was moving toward the west-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (270 km/h).  The minimum surface pressure was 946 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Duck, North Carolina.  Hurricane Watches were in effect for the portions of the coast from Edisto Beach to South Santee River, South Carolina and from Duck, North Carolina to the North Carolina-Virginia border.  Tropical Storm Watches were in effect for the portions of the coast from Duck, North Carolina to Cape Charles Light, Virginia and for Chesapeake Bay south of New Point Comfort.

Hurricane Florence completed an eyewall replacement cycle and it continues to be a powerful hurricane.  There was a circular eye with a diameter of 30 miles (48 km) at the center of Florence.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  The eyewall replacement cycle resulted in a larger circulation.

Winds to hurricane force extended out about 60 miles (95 km) from the center of circulation of Hurricane Florence.  Winds to tropical storm force extended out about 175 miles (280 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Florence was 28.2.  The Hurricane Size Index (HSI) was 18.9 and the Hurricane Wind Intensity Size Index (HWISI) was 47.1.  Hurricane Florence is capable of causing extensive significant damage.

Hurricane Florence will move through an environment favorable for strong hurricanes during the next 24 to 36 hours.  Florence 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.  Hurricane Florence is likely to maintain its intensity and it could strengthen.  If another eyewall replacement cycle occurs, then there could be fluctuations in intensity.

Hurricane Florence will move around the western end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Florence toward the west-northwest during the next 24 to 36 hours.  On its anticipated track Hurricane Florence could approach the coast of the Carolinas later on Thursday.  The steering winds are forecast to weaken when Florence nears the coast and there is great uncertainty about the track when that occurs.  Hurricane Florence will bring strong winds to coastal North Carolina and eastern South Carolina.  Wind pushing water toward the shore will cause a significant storm surge.  A slow forward speed will mean that Hurricane Florence will drop a lot of rain and there is a risk of significant flooding of rivers and streams.

Elsewhere over the Atlantic Ocean, Tropical Storm Isaac was speeding toward the Lesser Antilles and Hurricane Helene was weakening far south of the Azores.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Isaac was located at latitude 14.5°N and longitude 52.3°W which put it about 580 miles (935 km) east of Martinique.  Isaac was moving toward the west at 16 m.p.h. (26 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 999 mb.  Tropical Storm Warnings were in effect for Dominica, Martinique and Guadeloupe.  Tropical Storm Watches were in effect for Antigua, Montserrat, St. Kitts and Nevis, and Saba and St. Eustatius.

At 11:00 p.m. EDT on Tuesday the center of Hurricane Helene was located at latitude 18.0°N and longitude 35.4°W which put it about 1479 miles (2370 km) south-southwest of the Azores.  Helene was moving toward the northwest at 10 m.p.h. (16 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 973 mb.

Joaquin Becomes a Major Hurricane Near the Bahamas

Hurricane Joaquin intensified very rapidly on Wednesday and it reached Major Hurricane intensity.  At 11:00 p.m. EDT on Wednesday night the center of Hurricane Joaquin was located at latitude 23.8°N and longitude 73.1°W which put it about 90 miles (145 km) east of San Salvador and about 750 miles (1215 km) south-southeast of Cape Hatteras, North Carolina.  Joaquin was moving toward the southwest at 6 m.p.h. (10 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. (220 km/h).  The wind speed made Joaquin a Category 3 hurricane on the Saffir-Simpson Scale and a Major Hurricane.  The minimum surface pressure was 951 mb.  The Hurricane Intensity Index (HII) was 20.6, the Hurricane Size Index (HSI) was 11.6, and the Hurricane Wind Intensity Size Index (HWISI) was 32.2.

A Hurricane Warning has been issued for the Central Bahamas including Cat Island, the Exumas, Long Island, Rum Cay and San Salvador.  A Hurricane Warning has been issued for the Northwestern Bahamas including the Abacos, Berry Islands, Eleuthera, Grand Bahama Island and New Providence.  A Hurricane Watch has been issued for Bimini and Andros Island.  A Tropical Storm Warning has been issued for Andros Island and the Southeastern Bahamas including the Acklins, Crooked Island, Long Cay, the Inaguas, Mayguana and the Ragged Islands.

Joaquin has a well formed structure.  The circulation is fairly symmetrical, although there are more spiral bands of thunderstorms south and east of the center.  The hurricane is over water where the Sea Surface Temperature is near 30°C.  A narrow upper level ridge west of Joaquin is causing light northerly winds over the circulation, but those winds did not inhibit rapid intensification on Wednesday.  The convection generated upper level divergence which pumped out mass and caused the pressure to decrease quickly.  Further intensification is possible during the next 24 hours, although if an eyewall replacement occurs, it would interrupt that process.  An upper level trough over the eastern U.S. will generate more vertical wind shear in a day or two and Joaquin will start to weaken.

A ridge north of Joaquin is blocking the hurricane and forcing it to move toward the southwest.  The ridge will weaken in a day or so and the upper level trough will start to steer Joaquin toward the north.  When the hurricane starts moving northward, it will also begin to move faster.  It could be approaching the Mid-Atlantic Coast by later on Saturday.