Tag Archives: Azores

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.

Lorenzo Rapidly Strengthens Into a Major Hurricane

Hurricane Lorenzo rapidly strengthened into a major hurricane west of the Cabo Verde Islands on Thursday.  At 6:00 a.m. EDT on Thursday the center of Hurricane Lorenzo was located at latitude 15.2°N and longitude 39.3°W which put it about 995 miles (1600 km) west of the Cabo Verde Islands.  Lorenzo was moving toward the west-northwest at 15 m.p.h. (24 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 955 mb.

Lorenzo was a large well organized a hurricane.  There was a circular eye 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 Hurricane Lorenzo.  Storms around the core were generating strong upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 210 miles (335 km) from the center.

Hurricane Lorenzo will move through an environment favorable for intensification during the next day or so.  Lorenzo will move over water where the Sea Surface Temperature is near 27°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Lorenzo is likely to strengthen to Category 4 on the Saffir-Simpson Scale during the next 24 hours.  Lorenzo will move over cooler water during the weekend, which will cause the hurricane to weaken.

Hurricane Lorenzo will move around the western end of a ridge of high pressure over North Africa and the eastern Atlantic Ocean.  The ridge will steer Lorenzo toward the north during the weekend.  On its anticipated track Hurricane Lorenzo could approach the Azores next week.

Elsewhere over the Atlantic Ocean Tropical Storm Karen moved farther away from Puerto Rico.  At 5:00 a.m. EDT in Thursday the center of Tropical Storm Karen was located at latitude 25.5°N and longitude 63.5°W which put it about 520 miles (835 km) north-northeast of San Juan Puerto Rico.  Karen was moving toward the north-northeast at 15 m.p.h. (24 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 1004 mb.

Tropical Storm Chantal Forms Southeast of Nova Scotia

Tropical Storm Chantal formed southeast of Nova Scotia on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Chantal was located at latitude 40.2°N and longitude 56.2°W which put it about 485 miles (780 km) southeast of Halifax, Nova Scotia.  Chantal was moving toward the east at 22 m.p.h. (35 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 1010 mb.

A small low pressure system that was near the coast of the Carolinas during the weekend began to exhibit tropical characteristics on Tuesday night and the National Hurricane Center designated the system as Tropical Storm Chantal.  Thunderstorms developed closer to the center of circulation when the low moved near the Gulf Stream and the strongest winds were occurring closer to the center.  Although the circulation around Chantal looked more tropical, the distribution of thunderstorms was still asymmetrical.  Many of the stronger storms were occurring in the eastern half of the circulation.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.  Tropical Storm Chantal was far enough north that it was in the region of westerly winds in the upper levels.  Those winds were causing moderate vertical wind shear and they were the primary reason for the asymmetrical distribution of thunderstorms.

Tropical Storm Chantal will move through an environment only marginally favorable for intensification during the next several days.  Chantal will move over water where the Sea Surface Temperature is near 25°C.  It will continue to be in a region of moderate westerly winds in the upper levels, which will cause vertical wind shear.  Tropical Storm Chantal could intensify slowly if the upper level winds do not get any stronger.  However, Chantal could weaken if the upper level winds do get stronger.

Tropical Storm Chantal will move around the northern end of a ridge in the middle troposphere over the Atlantic Ocean.  The ridge will steer Chantal toward the east during the next 24 hours.  Chantal could move more toward the southeast on Thursday when it nears the western end of the ridge.  On its anticipated track Tropical Storm Chantal is forecast to make a slow loop in the middle of the Atlantic Ocean.

Oscar Strengthens Into a Hurricane Southeast of Bermuda

One time subtropical storm and former Tropical Storm Oscar strengthened into a hurricane southeast of Bermuda on Sunday.  At 5:00 p.m. EDT on Sunday the center of Hurricane Oscar was located at latitude 25.7°N and longitude 55.5°W which put it about 725 miles (1165 km) southeast of Bermuda.  Oscar was moving toward the west at 16 m.p.h. (26 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 989 mb.

A small eye formed at the center of former Tropical Storm Oscar and the National Hurricane Center upgraded Oscar to a hurricane.  A thin ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several short bands of showers and thunderstorms were revolving around the core of Hurricane Oscar.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.

The circulation around Hurricane Oscar is relatively small.  Winds to hurricane force extend out only about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extend out about 115 miles (185 km) from the center.

Hurricane Oscar will move through an environment favorable for intensification for another day or two.  Oscar will move over water where the Sea Surface Temperature is near 27°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Because of its relatively small circulation, Hurricane Oscar could intensify rapidly while it is in a favorable environment.  Oscar will get stronger during the next 36 to 48 hours and some models are forecasting that it will become a major hurricane.  An upper level trough moving off the East Coast of the U.S. will produce southwesterly winds which will cause the vertical wind shear to increase by Wednesday.

Hurricane Oscar will move around the western end of a ridge of high pressure over the Atlantic Ocean on Monday and Tuesday.  The ridge will steer Oscar toward the west for another 12 to 24 hours.  Hurricane Oscar will move more toward the north when it reaches the western end of the ridge.  On its anticipated track Hurricane Oscar will pass east of Bermuda on Tuesday.  The upper level trough will steer Oscar rapidly toward the northeast on Wednesday.

Oscar Transitions to a Tropical Storm

Former Subtropical Storm Oscar transitioned to a tropical storm on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Oscar was located at latitude 25.7°N and longitude 51.4°W which put it about 930 miles (1495 km) east-southeast of Bermuda.  Oscar was moving toward the west-southwest at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 994 mb.

The structure of the circulation of former Subtropical Storm Oscar changed to a shape more like a tropical cyclone and the National Hurricane Center reclassified Oscar as a tropical storm.  A band of showers and thunderstorms wrapped more tightly around the eastern side of the center of circulation.  The strongest winds were occurring about 30 miles (50 km) from the center.  Other bands of showers and thunderstorms were starting to form in the eastern half of the circulation.

Tropical Storm Oscar will move through an environment somewhat favorable for intensification during the next 36 hours.  Oscar will move over water where the Sea Surface Temperature is near 27°C.  An upper level low southeast of Oscar will produce northerly winds which will blow toward the top of the tropical storm.  However, the core of Tropical Storm Oscar will remain south of the strongest upper level winds on Sunday.  Tropical Storm Oscar could intensify into a hurricane by Monday.

The upper level low is steering Tropical Storm Oscar quickly toward the west-southwest.  That motion is forecast to continue for anther 24 hours.  A large upper level trough over the eastern U.S.  will produce southwesterly winds which will start to turn Oscar toward the northeast in about 36 to 48 hours.  On its anticipated track Tropical Storm Oscar could be southeast of Bermuda on Monday night.

Leslie Strengthens Into a Hurricane East of Bermuda

Former Tropical Storm Leslie strengthened into a hurricane east of Bermuda on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Hurricane Leslie was located at latitude 29.5°N and longitude 56.8°W which put it about 510 miles (825 km) east-southeast of Bermuda.  Leslie was nearly stationary.  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 975 mb.

After being designated as a subtropical storm, Hurricane Leslie made a transition to an extratropical cyclone and then back to a subtropical storm.  Leslie eventually moved over warmer water and the structure changed to that of a tropical storm, which intensified slowly until it reached hurricane intensity earlier this morning.  It is gradually exhibiting the classical appearance and structure of a hurricane.

There is a circular eye at the center of circulation.  A nearly complete ring of thunderstorms surrounds the eye and the strongest winds are occurring in that ring of storms.  Several bands of showers and thunderstorms are revolving around the core of Hurricane Leslie.  Storms near the core are generating upper level divergence which is pumping mass away from the hurricane, which is causing the surface pressure to decrease.  Winds to hurricane force extend out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extend out about 230 miles (370 km) from the center.

Hurricane Leslie will remain in an environment favorable for intensification for another day or two.  Leslie will remain over water where the Sea Surface Temperature is near 27.5°C.  it will be in a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Leslie is likely to get a little stronger during the next day or so.  Leslie will move over cooler water later this week and it will start to weaken when that happens.

Hurricane Leslie has been in an area where the steering winds were weak which is why it has meandered east of Bermuda during the past few days.  A subtropical ridge southeast of Leslie will strengthen during the next day or two and the ridge will start to steer the hurricane toward the north.  On its anticipated track Hurricane Leslie will move farther away from Bermuda later this week.

Tropical Storm Florence Still Dropping Heavy Rain on the Carolinas

Tropical Storm Florence was still dropping heavy rain on parts of the Carolinas on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Florence was located at latitude 33.6°N and longitude 79.9°W which put it about 45 miles (75 km) south-southwest of Florence, South Carolina.  Tropical Storm Florence was moving toward the west at 2 m.p.h. (3 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 997 mb.  A Tropical Storm Warning was in effect for the portion of the coast from South Santee River, South Carolina to Surf City, North Carolina.

Although the inner core of Tropical Storm Florence continues to spin down slowly, the circulation covers much of North Carolina, South Carolina, and eastern Georgia.  The center and much of the circulation around Florence is over land, but strong inflow east of the center continues to transport moist air over North Carolina.  The strongest winds are occurring over the Atlantic Ocean in two rainbands east of the center.  Winds to tropical storm force extend out about 150 miles (240 km) east of the center of circulation over the Atlantic Ocean.  The winds over North Carolina and South Carolina are generally blowing at less than tropical storm force.  Thunderstorms in some rainbands could produce gusts to tropical storm force.

Tropical Storm Florence has moved very slowly toward the west during the past 24 hours.  The extremely slow motion has allowed bands of showers and thunderstorms to persist over locations and rainfall totals have exceed a foot (0.3 meters) in some places.  Parts of the Cape Fear River and Trent River have already reached major flood levels.  Portions of the Neuse River are at moderate flood levels.  Sections of Interstates 95 and 40 are closed because of high water.

The high pressure system that has been blocking a northward movement of Tropical Storm Florence will start to shift to the east on Sunday.  The eastward movement of the high will allow Tropical Storm Florence to move a little faster and turn toward the northwest.  Florence could be over western North Carolina on Sunday evening.  Wind blowing up the eastern slopes of the will enhance rainfall.  Tropical Storm Florence will continue to drop heavy rain over North Carolina and South Carolina on Sunday.  The heavy rain could cause rivers and streams to go higher.

Elsewhere over the Atlantic Ocean, Tropical Storm Helene neared the Azores, Tropical Storm Isaac weakened to a tropical wave over the Caribbean Sea and Tropical Storm Joyce was pulled northeast in the wake of Helene.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Helene was located at latitude 40.2°N and longitude 32.1°W which put it about 75 miles (120 km) northwest of Flores, Azores.  Helene was moving toward the northeast at 24 m.p.h. (39 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 989 mb.  A Tropical Storm Warning was in effect for all of the Azores.

At 5:00 p.m. EDT on Saturday the center of Tropical Storm Joyce was located at latitude 33.1°N and longitude 39.6°W which put it about 785 miles (1260 km) west-southwest of the Azores.  Joyce was moving toward the east-northeast at 17 m.p.h. (28 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 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.