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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.

Tropical Storm Harvey’s Record Rains Continue Over Texas and Louisiana

The record setting rainfall from Tropical Storm Harvey continued over southeastern Texas and Louisiana on Tuesday morning.  A rain gauge southeast of Houston near Mary’s Creek at Winding Road has measured 49.20 inches (125 cm) of rain from Tropical Storm Harvey as of 9:00 a.m. CDT on Tuesday.  This total sets a new record for the most rainfall from a tropical cyclone over the contiguous 48 states of the U.S.  The previous record was 48 inches (122 cm) dropped by Tropical Cyclone Amelia in 1978 over Medina, Texas.

At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Harvey was located at latitude 28.4°N and longitude 94.3°W which put it about 115 miles (185 km) south-southwest of Cameron, Louisiana.  Harvey was moving toward the north-northeast at 5 m.p.h. (8 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 is in effect for the portion of the coast from Port O’Connor, Texas to Morgan City, Louisiana.  A Tropical Storm Watch is in effect for the portion of the coast from Morgan City to Grand Isle, Louisiana.

The center of Tropical Storm Harvey moved back over the Gulf of Mexico late on Monday and it is currently over the northwestern Gulf.  Harvey is still producing heavy rain over southeastern Texas and parts of Louisiana.  There is still a well defined center and strong counterclockwise rotation in the lower levels of the atmosphere.  Dry air wrapped around the circulation of Harvey and there are mainly lighter showers near the center of the tropical storm.  There are several stronger bands of thunderstorms on the eastern periphery of the circulation.  Those bands are dropping heavier rain over eastern Louisiana and parts of Mississippi.  The strong counterclockwise rotation is transporting moist air over land.  Increased friction over the land is causing more convergence which is pushing the air upwards.  Stronger rising motion is generating areas of heavier rain over southeast Texas and southern Louisiana.  In addition, the land is warming during the day, which is making the lower atmosphere more unstable and contributing to the heaver rain.

Flood Watches and Warnings are in effect from Northwest Florida to Southeast Texas because of the potential for more heavy rain.  Tropical Storm Harvey is finally starting to move slowly toward the north-northeast.  It should make a landfall on the coast of Louisiana early on Wednesday.  Tropical Storm Harvey will weaken as it moves farther inland and it should move over the Lower Mississippi River Valley as a tropical depression late this week.  The rain over southeastern Texas and southern Louisiana should end once Harvey moves farther inland.

Elsewhere, a low pressure system designated Potential Tropical Cyclone Ten was bringing gusty winds and higher waves to portions of the Mid-Atlantic coast.  At 11:00 a.m. EDT on Tuesday the center of Potential Tropical Cyclone Ten was located at latitude 34.4°N and longitude 77.2°W which put it about 35 miles (60 km) west-southwest of Cape Lookout, North Carolina.  It was moving toward the northeast at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1006 mb.  A Tropical Storm Warning was in effect from Cape Lookout to Duck, North Carolina including Pamlico and Albemarle Sounds.  Potential Tropical Cyclone Ten is forecast to merge with a front and become a strong extratropical cyclone over the western Atlantic Ocean.

Tropical Storm Ian Forms in the Middle of the Atlantic

Tropical Storm Ian formed on Monday in the middle of the Atlantic Ocean.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Ian was located at latitude 21.8°N and longitude 50.4°W which put it about 1140 miles (1840 km) southeast of Bermuda.  Ian was moving toward the northwest at 13 m.p.h. (21 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. (95 km/h).  The minimum surface pressure was 1007 mb.

The circulation of Tropical Storm Ian is not well organized.  A large upper low west of Ian is generating strong southwesterly winds which are blowing across the top of the tropical storm.  There is a large cyclonic circulation in the lower levels, but there are no thunderstorms near the center of circulation.  The thunderstorms are forming northeast of the center in a rainband that is well removed from the core of the storm.

Tropical Storm Ian will through a hostile environment during the next several days.  Although Ian will move over water where the Sea Surface Temperature is near 29°C, the upper level trough will continue to cause strong vertical wind shear.  Ian is not likely to strengthen in the short term.  Eventually, later this week Ian will move farther from the upper level trough and it could strengthen somewhat at that time, if the low level circulation persists.

Tropical Storm Ian is moving around the western end of a subtropical ridge which is steering it toward the northwest and that general motion is expected to continue for another day or two.  When Ian moves farther north, it will turn toward the northeast and the tropical storm will begin to move faster.

Tropical Storm Ida Forms West of the Cape Verde Islands

The circulation within a tropical disturbance west of the Cape Verde Islands organized on Friday and it was classified as Tropical Storm Ida by the National Hurricane Center.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Ida was located at latitude 13.7°N and longitude 37.5°W which put it about 915 miles (1470 km) west of the Cape Verde Islands.  Ida was moving toward the 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 1006 mb.

Tropical Storm Ida has a much larger circulation than many of the tropical storms that have formed over the eastern Atlantic Ocean in 2015.  It has a well formed spiral rainband that curls around the southern and eastern side of the center of circulation.  The upper level winds over Ida are not very strong and upper level divergence is beginning to occur in all directions.  Ida is over water where the Sea Surface Temperature is near 28°C.  There is little vertical wind shear and the environment favors intensification.   A period of rapid intensification is possible if the inner core organizes and an eye and eyewall develop.  Ida has a chance to become a hurricane during the next several days.

A subtropical ridge north of Ida is steering the tropical storm toward the northwest and that general steering pattern is expected to continue for the next day or two.  The guidance from the numerical models is less consistent for early next week and that means there is more uncertainty about the longer term track for Ida.