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Hanna’s Heavy Rain Causes Flash Floods in South Texas

Heavy rain dropped by Hurricane Hanna caused flash floods in South Texas on Sunday.  Radar estimates of the rainfall indicated that 10-15 inches (3 to 5 meters) of rain fell on parts of Lower Rio Grande Valley during the passage of former Hurricane Hanna.  A weather station in McAllen, Texas measured 8.24 inches (209 mm) of rain.  Flash Flood Warnings were in effect for West Central Cameron County, Southern Hidalgo, Southwest Jim Hogg County, and Central Zapata County.  The Arroyo Colorado in Harlingen, Texas rose from 5.2 feet (1.6 meters) to 20.72 feet (6.3 meters) and it was still rising.

Rain was still falling over parts of the Lower Rio Grande Valley even though the center of former Hurricane Hanna had moved over northeastern Mexico.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Hanna was located at latitude 25.6°N and longitude 100.6°W which put it about 35 miles (55 km) west-southwest of Monterrey, Mexico.  Hanna was moving toward the west-southwest 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 1002 mb.

Hurricane Hanna Makes Landfall on Padre Island

The center of Hurricane Hanna officially made landfall on Padre Island 15 miles (25 km) north of Port Mansfield, Texas at 6:00 p.m. EDT on Saturday.  At 6:00 p.m. EDT on Saturday the center of Hurricane Hanna was located at latitude 26.8°N and longitude 97.4°W which put it 15 miles (25 km) north of Port Mansfield, Texas.  Hanna was moving toward the west-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 110 m.p.h. (175 km/h).  The minimum surface pressure was 973 mb.

A Hurricane Warning was in effect for the portion of the coast from Port Mansfield to Port Aransas, Texas.  Tropical Storm Warnings were in effect for the portions of the coast from Barra el Mezquital, Mexico to Port Mansfield and from Port Aransas to Port O’Connor, Texas.

Hurricane Hanna strengthened during Saturday and the maximum sustained wind speed at the time of landfall was 90 m.p.h. (150 km/h).  The minimum pressure decreased to 973 mb during the day.  A circular eye with a diameter of 35 miles (55 km) developed at the center of circulation.  Winds to hurricane force extended out 30 miles (50 km) from the center of Hanna.  Winds to tropical storm force extended out 90 miles from the center of circulation.  A storm surge of up to 6 feet (2 meters) was occurring along the coast of Texas north of where the center made landfall.  There were reports of minor wind damage in Port Mansfield.

Hurricane Hanna will move south of a strengthening high pressure system over the southern U.S.  The high will steer Hanna toward the west-southwest during the next two days.  On its anticipated track the core of Hurricane Hanna will pass north of Brownsville, McAllen and Harlingen, Texas.  The center of Hanna will pass near Monterrey, Mexico on Sunday.  Hurricane Hanna will weaken gradually while it moves inland.  Hanna will drop heavy rain over South Texas and northeast Mexico.  Flash floods will likely occur in parts of the Lower Rio Grande Valley.

Hanna Strengthens to a Hurricane Near South Texas

Former Tropical Storm Hanna strengthened into a hurricane near the coast of South Texas on Saturday morning.  At 8:00 a.m. EDT on Saturday the center of Hurricane Hanna was located at latitude 27.1°N and longitude 96.0°W which put it about 100 miles (160 km) east-southeast of Corpus Christi, Texas.  Hanna was moving toward the west at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (150 km/h).  The minimum surface pressure was 982 mb.

A Hurricane Warning was in effect for the portion of the coast from Port Mansfield to Mesquite Bay, Texas.  Tropical Storm Warnings were in effect for the portions of the coast from Barra de Mezquital, Mexico to Port Mansfield and from Mesquite Bay to High Island, Texas.

A NOAA aircraft detected winds to hurricane force in former Tropical Storm Hanna on Saturday morning and the National Hurricane Center upgraded Hanna to a hurricane.  The circulation around Hurricane Hanna was well organized.  A circular eye with a diameter of 25 miles (40 km) was 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.  Bands of showers and thunderstorms were revolving around the core of Hanna.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 90 miles (150 km) from the center.

Hurricane Hanna will move through an environment favorable for strengthening during the next few hours.  Hanna 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 Hanna will continue to intensify until it makes landfall on the coast of South Texas.

Hurricane Hanna will move south of a high pressure system that stretches across the southern U.S.  The high will steer Hanna a little to the south of due west.  On its anticipated track the center of Hurricane Hanna will make landfall on Padre Island later today.  The northern part of the eyewall will pass near Corpus Christi and that city could experience winds to hurricane force.  The southern part of the eyewall will pass near Port Mansfield which could also experience hurricane force winds.  The core of Hanna will pass north of Brownsville, but Brownsville, Harlingen and Mcallen could all experience winds to tropical storm force.

Easterly winds will blow water toward the coast of South Texas and they will cause a significant storm surge.  The storm surge could reach 6 to 9 feet (2 to 3 meters) near and just to the north of where the center makes landfall.  Hurricane Hanna will also drop heavy rain over South Texas.  Isolated locations could receive over a foot (0.3 meters) of rain and flash flooding is likely.

Elsewhere, Tropical Storm Gonazalo was quickly nearing Trinidad.  At 8:00 a.m. EDT on Saturday  the center of Tropical Storm Gonzalo was located at latitude 10.3°N and longitude 59.8°W which put it about 100 miles (160 km) east of Trinidad.  Gonzalo was moving toward the west at 18 m.p.h. (30 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 1009 mb.

Tropical Storm Warnings were in effect  for Tobago and Grenada.

Tropical Storm Hanna Prompts Hurricane Warning for Texas

A strengthening Tropical Storm Hanna prompted the issuance of a Hurricane Warning for a portion of the coast of Texas on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Hanna was located at latitude 27.3°N and longitude 94.3°W which put it about 195 miles (310 km) east of Corpus Christi, Texas.  Hanna was moving toward the west at 10 m.p.h. (16 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 999 mb.

A Hurricane Warning was in effect for the portion of the Texas coast from Baffin Bay to Mesquite Bay.  Tropical Storm Warnings were in effect for the portions of the coast from the Mouth of the Rio Grande River to Baffin Bay and from Mesquite Bay to San Luis Pass, Texas.

Tropical Storm Hanna exhibited much more organization on Friday afternoon.  A primary rainband wrapped around the southern and eastern sides of the center of Hanna.  The northern end of the rainband appeared to be wrapping around the rest of the center of circulation and an eye seemed to be forming.  Bands of showers and thunderstorms were revolving around the center of Tropical Storm Hanna.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm.  The removal of mass was allowing the surface pressure to decrease.  Winds to tropical storm force extended out 60 miles (95 km) from the center for circulation.

Tropical Storm Hanna will move through an environment favorable for intensification during the next 18 hours.  Hanna will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Hanna will continue to intensify.  If an eye and eyewall form completely, then Hanna could strengthen rapidly during the 6 to 12 hours prior to landfall.  Tropical Storm Hanna is very likely to intensify into a hurricane.

Tropical Storm Hanna will move south of a high pressure system that stretches across the southern U.S.  The high will steer Hanna toward the west during the next 24 hours.  On its anticipated track Tropical Storm Hanna will reach the coast of Texas near Corpus Christi during the middle of the day on Saturday.

Tropical Storm Hanna is very likely to be a hurricane when it makes landfall.  It will bring strong winds to the portion of the coast near where the eye makes landfall.  Strong winds blowing water toward the coast could create a storm surge of 6 to 8 feet (2 to 3 meters) near and to the north of where the eye makes landfall.

Elsewhere, a trade wind surge hit Tropical Storm Gonzalo from the northeast.  The surge caused increased low level wind shear and it brought drier air.  The increased shear and drier air caused Gonzalo to weaken.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Gonzalo was located at latitude 10.0°N and 55.6°W which put it about 390 miles (625 km) east of the southern Windward Islands.  Gonzalo was moving toward the west at 18 m.p.h. (30 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 1008 mb.

Tropical Storm Warnings were in effect for Barbados, Tobago, Grenada, and St. Vincent and the Grenadines.

Tropical Depression Eight Strengthens to Tropical Storm Hanna

Former Tropical Depression Eight strengthened to Tropical Storm Hanna on Thursday night and a Tropical Storm Warning was in effect for a large portion of the coast of Texas.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Hanna was located at latitude 26.2°N and longitude 91.4°W which put it about 385 miles (620 km) east-southeast of Corpus Christi, Texas.  Hanna was moving toward the west-northwest 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 1002 mb.

A Tropical Storm Warning was in effect for the portion of the coast from the Mouth of the Rio Grande River to San Luis Pass, Texas.  A Tropical Storm Watch was in effect for the portion of the coast from San Luis Pass to High Island, Texas.

A NOAA aircraft detected winds to tropical storm force in former Tropical Depression Eight on Thursday night and the National Hurricane Center upgraded the system to Tropical Storm Hanna.  The surface pressure was decreasing and Tropical Storm Hanna was exhibiting greater organization.  A band of thunderstorms was wrapping around the southern and eastern sides of the center of circulation.  Thunderstorms were forming in other bands the were revolving around the center of circulation.  Storms near the center began to generate upper level divergence which was pumping mass away from the tropical storm.  The removal of mass allowed the surface pressure to decrease.  Winds to tropical storm force extended out 35 miles (55 km) from the center in the eastern quadrant of Tropical Storm Hanna.  Winds in the other parts of Hanna were blowing at less than tropical storm force.

Tropical Storm Hanna will move through an environment favorable for intensification during the next 36 hours.  Hanna will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Hanna will continue to intensify and there is a chance it could strengthen into a hurricane.

Tropical Storm Hanna will move south of a high pressure system that extends from the Atlantic Ocean across the southern U.S.  The high will steer Hanna slowly toward the west.  On its anticipated track Tropical Storm Hanna will approach the coast of Texas near Corpus Christi on Saturday.  Hanna could be a strong tropical storm or a hurricane when it reaches the coast.

Elsewhere, Tropical Storm Gonzalo continued to churn toward the Windward Islands.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Gonzalo was located at latitude 9.9°N and longitude 50.6°W which put it about 730 miles (1170 km) east of the southern Windward Islands.  Gonzalo was moving toward the west at 14 m.p.h. (22 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. (120km/h).  The minimum surface pressure was 1000 mb.

A Hurricane Watch was in effect for Barbados and St. Vincent and the Grenadines.  A Tropical Storm Watch was in effect for Tobago and Grenada.

Tropical Depression Eight Forms Over Gulf of Mexico

Tropical Depression Eight formed over the Gulf of Mexico on Wednesday night and a Tropical Storm Watch was issued for the coast of Texas.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Eight was located at latitude 25.9°N and longitude 88.2°W which put it about 530 miles (855 km) east-southeast of Port Oconnor, Texas.  The depression was moving toward the west-northwest at 6 m.p.h. (10 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 1009 mb.

A Tropical Storm Watch was issued for the portion of the coast of Texas from Port Mansfield to High Island.

More thunderstorms formed near the center of a low pressure system over the Gulf of Mexico on Wednesday night and the National Hurricane Center designated the system as Tropical Depression Eight.  The thunderstorms were forming in bands in the northern half of the circulation.  Bands in the southern half of the depression consisted primarily of showers and lower clouds.

Tropical Depression Eight will move through an environment favorable for intensification during the next 36 hours.  The depression will move over water where the Sea Surface Temperature is near 30°C.  An upper level low over the southwestern Gulf of Mexico will produce southerly winds which will blow toward the top of the depression.  Those winds will cause some vertical wind shear, but the shear will not be enough to prevent intensification.  Tropical Depression Eight is likely to strengthen into a tropical storm during the next 36 hours.

Tropical Depression Eight will move south of a subtropical high pressure system that extends from the western Atlantic Ocean across the southern U.S.  The high will steer the depression toward the west-northwest.  On its anticipated track Tropical Depression Eight could approach the coast of Texas on Friday night.  It is likely to be a tropical storm when it approaches the coast.

Elsewhere, Tropical Storm Gonzalo strengthened as it moved toward the Windward Islands and a Hurricane Watch was issued for Barbados.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Gonzalo was located at latitude 9.9°N and longitude 45.9°W which put it about 1045 miles (1685 km) east of the southern Windward Islands.  Gonzalo was moving toward the west 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 998 mb.

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 Makes Landfall Near Wilmington, North Carolina

Hurricane Florence made landfall near Wilmington, North Carolina on Friday morning.  The National Hurricane Center stated that the center of Hurricane Florence officially made landfall near Wrightsville Beach or about five miles east of Wilmington at 7:15 a.m. EDT on Friday.  The maximum sustained wind speed was 90 m.p.h. (145 km/h) at the time of landfall.  Hurricane Florence moved slowly toward the west after landfall.

At 2:00 p.m. EDT on Friday the center of Hurricane Florence was located at latitude 34.0°N and longitude 78.4°W which put it about 35 miles (55 km/h) east-northeast of Myrtle Beach, South Carolina.  Florence was moving toward the west at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 968 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Bogue Inlet, North Carolina including Pamlico Sound.  Tropical Storm Warnings were in effect for the portions of the coast from Edisto Beach, South Carolina to South Santee River and from Bogue Inlet to Duck, North Carolina including Albemarle Sound.

Hurricane Florence did produce sustained winds to hurricane force when hit North Carolina.  A National Data Buoy Center C-MAN station (CLKN7) 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).  A buoy east of the center of Hurricane Florencereported a wind gust of 112 m.p.h. (180 km/h) near the time of landfall.  The airport at Wilmington, North Carolina reported a wind gust of 87 m.p.h. (140 km/h).

The center of Hurricane Florence has been inland for a few hours and the circulation is gradually spinning down.  There is still a well organized center of circulation, but they eye has filled in with clouds and showers.  The strongest winds are occurring in rainbands that are still out over the Atlantic Ocean.  Friction is reducing the wind speed in the part of the circulation over land.

Hurricane Florence continues to pose serious risks for southeastern North Carolina and eastern South Carolina.  A prolonged period of tropical storm force winds and occasional gusts to hurricane force could bring down trees and add to the widespread power outages.  On the eastern side of Hurricane Florence the wind will push water toward the shore and the threat of coastal flooding continues.  Bands of showers and thunderstorms will drop heavy rain and flash flooding is likely near rivers and streams that are already at bankful.

Elsewhere over the Atlantic Ocean, Tropical Storm Helene was speeding toward the Azores, Tropical Depression Isaac was moving over the eastern Caribbean Sea and Tropical Storm Joyce was moving west of Helene.

At 11:00 a.m. EDT on Friday the center of Tropical Storm Helene was located at latitude 32.9°N and longitude 36.3°W which put it about 655 miles (1055 km) southwest of the Azores.  Helene was moving toward the north  at 23 m.p.h. (37 km/h).  The maximum sustained wind speed was 70 m.p.h. (110km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 988 mb.  A Tropical Storm Warning was in effect for all of the Azores.

At 11:00 a.m. EDT on Friday the center of Tropical Depression Isaac was located at latitude 14.9°N and longitude 67.3°W.  Isaac was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 35 m.p.h. (55km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1007 mb.

At 11:00 a.m. EDT on Friday the center of Tropical Storm Joyce was located at latitude 31.6°N and longitude 44.6°W which put it about 1090 miles (1755 km) west-southwest of the Azores.  Joyce was moving toward the south at 8 m.p.h. (13 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 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.