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Hurricane Irma Makes Landfall on Marco Island, Florida

The center of Hurricane Irma made landfall on the coast at Marco Island, Florida on Sunday afternoon.  The Marco Island Emergency Operations Center reported a wind gust to 135 m.p.h. (217 km/h) when the northern portion of the eyewall passed over.  The airport at Naples, Florida reported sustained winds to 88 m.p.h. (142 km/h) and wind gusts to 135 m.p.h. (217 km/h).

At 5:00 p.m. EDT on Sunday the center of Hurricane Irma was located at latitude 26.2°N and longitude 81.8°W which put it about 5 miles (10 km) north of Naples, Florida.  Irma was moving toward the north at 14 m.p.h. (22 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 938 mb.

A Hurricane Warning was in effect for the portion of the coast from Fernandina Beach to Indian Pass, Florida including the Florida Keys and Lake Okeechobee.  A Hurricane Watch was in effect from Fernandina Beach, Florida to Edisto Beach, South Carolina.  A Tropical Storm Warning was in effect for the portion of the coast from Fernandina Beach, Florida to the South Santee River, South Carolina and from Indian Pass, Florida to the Okaloosa/Walton County line.  A Tropical Storm Watch was in effect for Bimini and Grand Bahama Island.

The intensity of Hurricane Irma decreased gradually on Sunday.  The hurricane began to pull in some drier air over the southeastern U.S. into the west side of the circulation.  In addition an upper level trough over the eastern U.S. caused an increase in the vertical wind shear.  The drier air and increased shear also produced a more asymmetrical wind field around Hurricane Irma.  The area of stronger winds was much larger in the eastern half of the circulation than it was on the western half of the circulation.  Winds to hurricane force extended out 80 miles (130 km) from the center of circulation.  Winds to tropical storm force extended out about 220 miles (350 km) from the center.

Hurricane Irma will gradually weaken as it moves northward over Florida.  Irma is a large hurricane and it will spin down slowly.  Hurricane Irma will move steadily northward.  Irma is forecast to still be a hurricane when the center moves near Tampa and Central Florida.  Hurricane Irma is capable of causing widespread significant wind damage.  Isolated tornadoes could develop in thunderstorms in the outer rainbands.  Hurricane Irma will produce storm surges over a long section of the coast.  There was not much surge on the west coast of Florida on Sunday afternoon, because the winds were blowing the water away from the coast.  However, after the center moves north of an area, the wind will blow from the opposite direction and the water will rise quickly at the coast.  A station on the coast near Naples, Florida reported a water rise of six feet (two meters) in less than two hours after the center of Hurricane passed to the east.  Easterly winds on the eastern fringe of Hurricane Irma were blowing the water toward the coast and there were water rises from Miami, Florida to Charleston, South Carolina.  Strong southwesterly winds were still causing storm surges in the Florida Keys.  Hurricane Irma will also drop heavy rain over a prolonged period and it could cause freshwater flooding of rivers and streams.

Elsewhere over the tropical Atlantic Hurricane Jose moved away from the northern Leeward Islands on Sunday.  At 5:00 p.m. EDT om Sunday the center of Hurricane Jose was located at latitude 22.8°N and longitude 66.9°W which put it about 285 miles (455 km) east-northeast of Grand Turk Island.  Jose was moving toward northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  Hurricane Jose is forecast to stall over the tropical Atlantic east of the Bahamas and it could make a long slow loop during the next week.

Hurricane Irma Batters Florida Keys

Hurricane Irma battered the Florida Keys on Sunday morning.  At 9:00 a.m. EDT on Sunday morning the center of Hurricane Irma was located at latitude 24.5°N and longitude 81.5°W which put it about 30 miles (50 km) east-northeast of Key West, Florida.  Irma was moving toward the north-northwest at 8 m.p.h.  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  Hurricane Irma was a Category 4 hurricane on the Saffir-Simpson Scale.  The minimum surface pressure was 929 mb.

A Hurricane Warning was in effect for the portion of the coast from Fernandina Beach to Indian Pass, Florida including the Florida Keys and Lake Okeechobee.   A Hurricane Watch was in effect for the portion of the coast from Fernandina Beach, Florida to Edisto Beach, South Carolina.  A Tropical Storm Warning is in effect for the portion of the coast from Fernandina Beach to South Santee River, South Carolina and from Indian Pass to the Okaloosa/Walton County line.

A Hurricane Warning is in effect for the Cuban provinces of La Habana and Matanzas.  A Tropical Storm Watch is in effect for Bimini and Grand Bahama Island.

An outer eyewall started to wrap around the original eye of Hurricane Irma, but Irma did not go through an eyewall repacement cycle.  The original eyewall remained intact and the strongest winds were occurring in that eyewall.  The uncompleted formation of an outer eyewall did result in an increase in the size of Hurricane Irma.  Winds to hurricane force extend out about 80 miles (130 km) from the center of circulation.  Winds to tropical storm force extend out over 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Irma was 25.1.  The Hurricane Size Index (HSI) was 24.2 and the Hurricane Wind Intensity Size Index (HWISI) was 49.3.  Hurricane Irma is not quite as strong as Hurricane Charley was when Charley hit southwest Florida.  However, Hurricane Irma is much bigger than Charley was.  Hurricane Irma is stronger than Hurricane Wilma was when Wilma hit south Florida in 2005.  Irma is a little smaller than Wilma was.

Carysfort Reef Light near Key Largo reported a wind gust of 93 m.p.h. (150 km/h).  Hurricane Irma is causing winds to hurricane force over much of the Florida Keys.  Winds to tropical storm force are occurring in areas around Miami, Florida.

Hurricane Irma has turned toward the north.  The core of Hurricane Irma could make a landfall on the southwest coast of Florida between Everglades City and Naples, Florida later this afternoon.  Hurricane Irma could move northward near the west coast of Florida.  The center of Hurricane Irma could reach the Tampa/St. Petersburg area and Central Florida on Sunday night.

Hurricane Irma is large and dangerous hurricane.  It is capable of causing widespread extensive damage.  There are likely to be widespread power outages.  Irma will also generate a storm surge of 15 feet (5 meters) in some locations.  Irma will drop locally heavy rain and flooding could occur in some places.

Hurricane Irma Grinds Along Cuba’s North Coast

Hurricane Irma ground its way along the northern coast of Cuba on Saturday morning.  At 2:00 p.m. EDT on Saturday the center of Hurricane Irma was located at latitude 23.1°N and longitude 80.2°W which put it about 145 miles (235 km) southeast of Key West, Florida.  Irma was moving toward the west at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 125 m.p.h. (205 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 941 mb.

A Hurricane Warning is in effect for the portion of the coast from Aucilla River to Fernandina Beach, Florida including the Florida Keys and Lake Okeechobee.  Hurricane Watches are in effect for the portions of the coast from Auculla River to Indian Pass, Florida and from Fernandina Beach, Florida to Edisto Beach, South Carolina.  Tropical Storm Watches are in effect for the portions of the coast from Indian Pass to the Okaloosa/Walton County line and from Edisto Beach to South Santee River, South Carolina.

A Hurricane Warning is in effect for the Cuban provinces of Camaguey, Ciego de Avila, Sancti Spiritus, Villa Clara, Matanzas, La Habana.  A Hurricane Warning was in effect for Andros Island, Bimini and Grand Bahama Island.  A Hurricane Watch and a Tropical Storm Warning was in effect for the Cuban provinces of Holguin and Las Tunas.

Hurricane Irma weakened on Saturday morning as the center moved along the northern coast of Cuba.  However, the core of Hurricane Irma remained intact.  There was an eye at the center of circulation.  A ring of strong thunderstorms surrounded the eye.  Numerous spiral bands were revolving around the core of Hurricane Irma.  Thunderstorms in the core of Irma were generating upper level divergence which was pumping mass away from the center of the hurricane.

Hurricane Irma is a large hurricane.  Winds to hurricane force extend out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extend out about 185 miles (295 km) from the center.  The Hurricane Intensity Index (HII) for Irma was 23.6.  The Hurricane Size Index (HSI) was 23.6 and the Hurricane Wind Intensity Size Index (HWISI) was 47.2.  Those indices indicate Hurricane Irma is capable of causing widespread major damage.

Hurricane Irma will move through an environment favorable for intensification for another 12 to 18 hours.  Irma will over water where the Sea Surface Temperature is near 31°C.  The upper level winds are relatively weak and there will be little vertical wind shear.  Hurricane Irma is likely to intensify back to Category 4 on the Saffir-Simpson Scale and it could reach Category 5.  Hurricane Irma will move closer to an upper level trough over the eastern U.S. on Sunday.  Southerly winds on the eastern side of the trough will increase the vertical wind shear and Hurricane Irma will start to weaken.

Hurricane Irma is moving around the western end of a subtropical high pressure system over the Atlantic Ocean.  The subtropical high is steering Hurricane Irma toward the west-northwest.  Hurricane Irma will turn more toward the north-northwest when it reaches the western end of the high.  On its anticipated track the core of Hurricane Irma will move away from Cuba.  The center of Hurricane Irma will be near the Florida Keys by early Sunday morning.  Hurricane Irma could be near the southwest coast of Florida by Sunday afternoon.

Hurricane Irma will be capable of causing widespread extensive damage.  Winds blowing water toward the coast will generate significant storms surges.  Hurricane force winds will cause widespread damage as the Hurricane Irma moves near the west coast of Florida.

Elsewhere over the Atlantic Ocean Hurricane Jose was moving near the northern Leeward Islands.  At 2:00 p.m. EDT the center of Hurricane Jose was located at latitude 18.8°N and longitude 61.9°W which put it about 95 miles (155 km) east-northeast of the northern Leeward Islands.  Jose was moving toward the northwest at 14 m.p.h. (23 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 175 m.p.h. (285 km/h).  The minimum surface pressure was 945 mb.

A Tropical Storm Warning was in effect for Barbuda, Anguilla, Sint Maarten, St. Martin and St. Barthelemy.

The core of Hurricane Jose and the strongest winds will move northeast of the northern Leeward Islands.  The southern part of the circulation will bring gusty winds which will hamper recovery efforts after Hurricane Irma.  Jose is forecast to stall over the Atlantic and there is much uncertainty about the ultimate long term track.

The remnants of Hurricane Katia were raining themselves out over eastern Mexico.  At 11:00 a.m. EDT on Saturday the center of Tropical Depression Katia was located at latitude 20.0°N and longitude 97.9°W which put it about 125 miles (200 km) west-northwest of Veracruz, Mexico.  Katia was moving toward the west-southwest at 5 m.p.h. (8 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 1004 mb.

Hurricane Irma Batters Bahamas, Jose Threatens Leewards, Katia Nears Mexico

The tropical Atlantic Ocean continued to be very active on Friday.  Destructive Hurricane Irma battered the Southeastern Bahamas and Turks and Caicos.  Powerful Hurricane Jose threatened the northern Leeward Islands only 48 hours after Hurricane Irma caused significant damage to them.  Hurricane Katia neared a landfall on the coast of Mexico between Tampico and Veracruz.

At 5:00 p.m. EDT on Friday the center of Hurricane Irma was located at latitude 22.1°N and longitude 76.5°W which put it about 345 miles (555 km) southeast of Miami, Florida.  Irma was moving toward the west at 12 m.p.h.  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 180 m.p.h. (290 km/h).  The minimum surface pressure was 925 mb.

A Hurricane Warning was in effect for the portion of the coast from Anna Maria Island to Sebastian Inlet, Florida including the Florida Keys and Lake Okeechobee.  Hurricane Watches were in effect for the portions of the coast from Anna Maria Island to the Suwannee River and from Sebastian Inlet to the Flagler/Volusia Count line.  A Hurricane Warning was in effect for the Cuban provinces of Camaguey, Ciego de Avila, Sancti Spiritus and Villa Clara.  Hurricane Warnings were in effect for the northwestern Bahamas including the Abacos, Andros island, Berry Island, Bimini, Eleuthera, Grand Bahama Island and New Providence.  Hurricane Warnings were in effect for the central Bahamas including Cat Island, the Exumas, Long Island, Rum Cay and San Salvador.  Hurricane Warnings were in effect for the southeastern Bahamas including the Acklins, Long Cay, Crooked Island, the Inaguas, Mayaguana and the Ragged Islands.

Hurricane Watches were in effect for the Cuba provinces of Matanzas, Holguin, Las Tunas and Guantanamo.  Tropical Storm Warnings were in effect for the Cuban provinces of Holguin, Las Tunas and Guantamo.

Hurricane Irma completed an eyewall replacement cycle on Friday morning.  After the inner eyewall dissipated the circulation rapidly concentrated on the outer eyewall.  The eyewall replacement cycle caused some weakening of Hurricane Irma but it remained a powerful Category 4 hurricane on the Saffir-Simpson Scale.  The eyewall replacement cycle resulted in an increase in the size of the circulation of Hurricane Irma.  Winds to hurricane force now extend out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extend out almost 185 miles (295 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Irma is 33.3.  The Hurricane Size Index is 23.0 and the Hurricane Wind Intensity Size Index is 56.3.  Hurricane Irma is stronger, but a little smaller than Hurricane Wilma was when Wilma made landfall in south Florida in 2005.

Hurricane Irma is moving through a very favorable environment.  Irma is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Part of the southern side of the circulation is passing over Cuba, but the core of Hurricane Wilma is remaining over water.  Hurricane Irma should remain a very powerful hurricane during the next 36 hours.

Hurricane Irma is moving near the western end of a large subtropical high that has been steering the hurricane toward the west.  Irma started to move a little more slowly on Friday afternoon as it approached the end of the high.  Hurricane Irma is forecast to continue to move west-northwest for another 12 to 24 hours.  When Hurricane Irma reaches the end of the high, it will start moving toward the north.  On its anticipated track the core of Hurricane Irma will pass north of the north coast of Cuba on Saturday.  Hurricane Irma is forecast to reach the Florida Keys on Saturday night.

Hurricane Irma is a large and dangerous hurricane.  Irma is capable of causing widespread extensive damage.  Hurricane Irma’s winds will be very destructive and they could cause widespread power outages in Florida.  There will be a significant storm surge in the Florida Keys and on both the east and west coast of Florida.

Hurricane Jose intensified rapidly on Friday to Category 4 on the Saffir-Simpson Scale.  Jose now threatens to bring very strong winds to places devastated by Hurricane Irma earlier this week.  At 5:00 p.m. EDT on Friday the center of Hurricane Jose was located at latitude 16.6°N and longitude 58.3°W which put it about 335 miles (540 km) east of the Leeward Islands.  Jose was moving toward the west-northwest at 17 m.p.h.  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 180 m.p.h. (290 km/h).  The minimum surface pressure was 940 mb.

Hurricane Warnings are in effect for Barbuda, Anguilla, St. Barthelemy, Sint Maarten and St. Martin.  A Hurricane Watch is in effect for Antigua.  Tropical Storm Warnings are in effect for Antigua, Saba and St. Eustatius.  Tropical Storm Watches are in effect for Montserrat, St. Kitts, Nevis, the British Virgin Islands, St. Thomas and St. John.

Hurricane Jose has a small, well organized circulation.  There is a clear eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strong winds are occurring in that ring of storms.  Hurricane Jose is much smaller than Hurricane Irma.  Winds to hurricane force extend out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extend out about 140 miles (225 km) from the center.

Upper level divergence from Hurricane Irma is causing some vertical wind shear over Hurricane Jose, but the shear did not prevent Jose from intensifying into a major hurricane.  Hurricane Jose is forecast to remain a major hurricane for several more days.  The same subtropical high steering Hurricane Irma is also steering Jose toward the west north-west.  On its anticipated track Hurricane Jose could reach the northern Leeward Islands late on Saturday.  Some of those islands suffered widespread extensive damage from Hurricane Irma and a direct hit by Jose would be devastating.  Even if the core of Hurricane Jose moves just north of those islands, the strong winds will serious affect efforts to recover from Hurricane Irma.

After being nearly stationary over the southwestern Gulf of Mexico for several days, Hurricane Katia began to move toward the coast of Mexico on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Katia was located near latitude 21.0°N and longitude 96.5°W which put it about 125 miles (225 km) north of Veracruz, Mexico.  Katia was moving toward the west-southwest at 7 m.p.h.  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 972 mb.

A Hurricane Warning was in effect for the portion of the coast from Cabo Rojo to Laguna Verde, Mexico.

Hurricane Katia is a small hurricane.  Winds to hurricane force only extend out about 25 miles (40 km) from the center.  Winds to tropical storm force only extend out about 70 miles (110 km) from the center.

A mid-level ridge over the western Gulf of Mexico is steering Hurricane Katia toward the west-southwest.  On its anticipated track Hurricane Katia will make landfall on the coast of Mexico between Tampico and Veracruz on Friday night.  The center is likely to make landfall near Tecolutla.  Although the small size of Katia’s circulation will limit the wind damage, the hurricane will cause a significant storm surge along the portion of the coast where the center makes landfall.  Katia will also produce heavy rain and a chance for flash floods as it moves inland and dissipates.

Tropical Storm Harvey Moves Into Louisiana, Irma Strengthens Quickly

Tropical Storm Harvey finally moved into Louisiana on Wednesday after lingering for several days over the northwestern Gulf of Mexico.  Harvey weakened to a tropical depression after it moved inland.  At the same time a new tropical storm named Irma strengthened quickly over the eastern Atlantic Ocean.  At 11:00 p.m. EDT on Wednesday the center of Tropical Depression Harvey was located at latitude 31.7°N and longitude 92.3°W which put it about 30 miles (50 km) north-northeast of Alexandria, Louisiana.  Harvey was moving toward the north-northeast 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 998 mb.

After dropping record rainfall and causing destructive floods of parts of southeastern Texas and western Louisiana, Tropical Depression Harvey finally started to move steadily toward the north-northeast on Wednesday.  Harvey was still producing heavy rain over parts of western Louisiana, but the fact that it was moving should limit the total rainfall at any location.  Bands of showers and thunderstorms on the far eastern periphery of Harvey’s circulation were also dropping heavy rain.  Some of those thunderstorms were strong enough to approach severe criteria.  Tropical Depression Harvey is forecast to move toward the Ohio River Valley during the next several days and it will bring windy, wet weather to the Middle Mississippi and Ohio River Valleys.  Rain associated with the circulation of Tropical Depression Harvey could also reach the Mid-Atlantic States later this week.

At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Irma was located at latitude 16.4°N and longitude 32.2°W which put it about 545 miles (875 km) west of the Cabo Verde Islands.  Irma was moving toward the west at 12 m.p.h. (19 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.

The circulation of Tropical Storm Irma organized quickly on Wednesday.  Numerous bands of showers and thunderstorms formed and began to revolve around a well organized center of circulation.  Thunderstorms in the core of Irma generated well developed upper level divergence which pumped away mass in all direction.  There were occasional satellite images which hinted that an eye could be forming at the center of Tropical Storm Irma.

Tropical Storm Irma will be moving through an environment that will be favorable for intensification.  Irma will move over water where the Sea Surface Temperature is near 28°C.  The upper level winds are weak and there is little vertical wind shear.  Irma is likely to become a hurricane on Thursday and it could intensify rapidly if an eye forms.  Tropical Storm Irma is forecast to become a major hurricane and it could become one of the big classic Cape Verde hurricanes.

A strong subtropical high to the north of Irma is steering the tropical storm toward the west and a general westerly motion is forecast to continue for the next few days.  There is more divergence in the model guidance after a few days and the future track of Irma when it nears the Lesser Antilles is more uncertain.  Tropical Storm Irma has the potential to become a big dangerous hurricane and it will need to be watched carefully.

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.

Category 4 Hurricane Harvey Makes Landfall in Texas

Category 4 Hurricane Harvey made landfall near Rockport, Texas on Friday night.  Harvey was the first Category 4 hurricane on the Saffir-Simpson Scale to officially make landfall in Texas since Hurricane Carla in 1961.  Harvey was the first Category 4 hurricane to officially make landfall in the U.S. since Hurricane Charley in 2004.  At 11:00 p.m. EDT on Friday the center of Hurricane Harvey was located at latitude 28.0°N and longitude 97.0°W which put it about 30 miles (50 km) east-northeast of Corpus Christi, Texas.  Harvey was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 938 mb.

The center of the eye of Hurricane Harvey moved across San Jose Island and it officially made landfall near Rockport, Texas.  The powerful western side of the eyewall moved over Corpus Christi Bay, Port Aransas, Ingleside and Rockport.  Those areas experienced winds of over 100 m.p.h. (160 km/h).  The eye was over Aransas Bay and the winds were weaker in Rockport.  The wind speeds will increase again when the eastern part of the eyewall reaches those locations.  Bands of winds to tropical storm force were revolving inland outside the core of Hurricane Harvey.  Winds to hurricane force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 140 miles (225 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Harvey at landfall was 25.1.  The Hurricane Size Index (HSI) was 11.9 and the Hurricane Wind Intensity Size Index (HWISI) was 37.0.  The indices indicate that Hurricane Harvey is capable of producing regional extensive damage. In terms of wind speed and size Hurricane Harvey is similar to Hurricane Charley.  The HII for Charley when in made landfall in southwest Florida in 2004 was 29.9.  The HSI was 8.1 and the HWISI for Charley was 38.0.  Harvey is not quite as strong as Charley was, but Harvey is a little larger.  So, Hurricane Harvey has approximately the same potential to cause damage that Hurricane Charley had.

Hurricane Harvey completed an eyewall replacement cycle a few hours before it made landfall.  the timing of the eyewall replacement cycle meant that Hurricane Harvey had time to intensify to Category 4 before it reached the Texas coast.  The eye contracted and the wind speed increased right up until Hurricane Harvey made landfall.  Hurricane Harvey was at its maximum intensity when it made landfall.

Hurricane Harvey slowed down as it reached the coast and areas near the core of the hurricane are experiencing prolonged periods of high wind speeds.  The prolonged period of high winds will increase the damage caused by those winds.  The winds north of the center of circulation are driving the water toward the coast and a storm surge of 12 feet (4 meters) is possible in some locations.  Hurricane Harvey could stall or make a slow loop during the next several days.  In either case, Hurricane Harvey will drop very heavy rain in some places and fresh water flooding is a serious risk.

Major Hurricane Harvey Closing in on Texas Coast

Major Hurricane Harvey was closing on the Texas coast on Friday afternoon.  At 4:00 p.m. EDT on Friday the center of Hurricane Harvey was located at latitude 27.4°N and longitude 96.4°W which put it about 70 miles (110 km) east-southeast of Corpus Christi, Texas.  Harvey was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 943 mb.

A Hurricane Warning was in effect for the portion of the coast from Port Mansfield to Sargent, Texas.  A Tropical Storm Warning was in effect for the portion of the coast from the mouth of the Rio Grande River to Port Mansfield and from Sargent to High Island, Texas.  A Tropical Storm Watch was in effect from Boca De Catan, Mexico to the mouth of the Rio Grande River.

Hurricane Harvey has a relatively compact circulation.  Winds to hurricane force extend out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extend out about 140 miles (225 km) from the center.  The current Hurricane Intensity Index (HII) for Harvey is 22.1.  The Hurricane Size Index (HSI) is 10.4 and the Hurricane Wind Intensity Size Index (HWISI) is 32.5.

Hurricane Harvey went through an eyewall replacement cycle earlier today.  A second outer eyewall encircled the original inner eyewall.  The two concentric eyewalls temporarily interrupted the intensification of Harvey.  Most of the air began converging in the outer eyewall and the inner eyewall dissipated.  The eyewall replacement cycle resulted in Harvey becoming a slightly larger hurricane.  After the inner eyewall dissipated, the remaining outer eyewall began to contract and Harvey started to intensify again.

Hurricane Harvey will still be over the warm water of the western Gulf of Mexico for a few more hours.  So, it does have a chance to intensify further.  There is about a 25% chance that Harvey intensifies to Category 4 on the Saffir-Simpson Scale before it makes landfall.

Harvey is being steered toward the northwest by a subtropical ridge located northeast of the hurricane.  On its anticipated track Hurricane Harvey will most likely make landfall on the coast of Texas between Corpus Christi and Freeport in a few hours.  The steering currents are forecast to weaken about the time Harvey makes landfall and it could meander near the coast of Texas during the weekend.  The track forecast becomes very uncertain at that time.  Some models forecast that Harvey will stall inland, while other models predict it will drift back over the Gulf of Mexico.

Based on current projections the forecast Hurricane Intensity Index (HII) for Harvey at landfall is 26.7.  The forecast Hurricane Size Index (HSI) is 11.6 and the forecast Hurricane Wind Intensity Size Index (HWISI) at landfall is 38.3.  Those indices indicate that Harvey could cause regional major damage in Texas.  Harvey will be stronger, but smaller, than Hurricane Ike was when Ike made landfall in Texas in 2008.  The HII for Ike was 19.2, the HSI was 22.5 and the HWISI was 41.7.  Hurricane Harvey is going to be more similar to Hurricane Charley when Charley made landfall in southwest Florida in 2004.  The HII for Charley was 29.9, the HSI was 8.1 and the HWISI was 38.0

Harvey will bring strong damaging winds to Texas.  Harvey will also cause a dangerous storm surge at the coast.  The storm surge could approach 12 feet (4 meters) in some locations.  Harvey will also drop very heavy rain, if it stalls after it moves inland.  Serious fresh water flooding is possible under that scenario.  The strong winds and flooding could also lead to widespread losses of electricity.

Hurricane Harvey Moves Closer to Texas

Hurricane Harvey moved closer to Texas on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Hurricane Harvey was located at latitude 25.2°N and longitude 94.6°W which put it about 250 miles (400 km) southeast of Corpus Christi, Texas.  Harvey was moving toward the northwest at 10 m.p.h. (16 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 973 mb.

A Hurricane Warning was in effect for the portion of the coast from Port Mansfield to Sargent, Texas.  A Hurricane Watch was in effect from the mouth of the Rio Grande River to Port Mansfield.  A Tropical Storm Warning was in effect for the portion of the coast from the mouth of the Rio Grande River to Port Mansfield and from Sargent to High Island, Texas.  A Tropical Storm Watch was in effect from Boca De Catan, Mexico to the mouth of the Rio Grande River.

Hurricane Harvey intensified rapidly for much of Thursday, but the wind speed stopped increasing Thursday evening.  The interruption of the intensification is probably only temporary.  The minimum surface pressure has continued to decrease slowly, but steadily throughout the evening.  An eye with a diameter of 18 miles (29 km) has appeared intermittently.  Although there was a continuous ring of strong thunderstorms around the eye earlier this afternoon, there has been a break in that ring this evening.  It seems as if there are strong thunderstorms at the leading edge of the primary rainband and downdrafts from those storms may be interfering with the eyewall.  The interference with the eyewall may have temporarily paused the intensification of Hurricane Harvey.

Hurricane Harvey is a small hurricane.  Winds to hurricane force extend out about 25 miles from the center, primarily in the northeastern quadrant of the circulation.  Winds to tropical storm force extend out about 105 miles (170 km) from the center.  The current Hurricane Intensity Index (HII) for Harvey is 12.7.  The Hurricane Size Index (HSI) is 6.6 and the Hurricane Wind Intensity Size Index (HWISI) is 19.3.

Hurricane Harvey will move through a very favorable environment on Friday.  Harvey will move over water where the Sea Surface Temperature is near 31°C.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Harvey is likely to strengthen on Friday and it could intensify rapidly again.  Harvey is likely to be a major hurricane by the time it makes landfall on the Texas coast and it has a chance to get to Category 4 on the Saffir-Simpson Scale.

Harvey is being steered toward the northwest by a subtropical ridge located northeast of the hurricane.  A general northwesterly motion is expected to continue on Friday.  On its anticipated track Hurricane Harvey would make landfall on the coast of Texas near Corpus Christi in about 36 hours.  The steering currents are forecast to weaken about the time Harvey makes landfall and it could meander near the coast of Texas during the weekend.  The track forecast becomes very uncertain at that time.

Based on current projections the forecast Hurricane Intensity Index (HII) for Harvey at landfall is 25.5.  The forecast Hurricane Size Index (HSI) is 16.0 and the forecast Hurricane Wind Intensity Size Index (HWISI) at landfall is 41.5.  Those indices indicate that Harvey could cause regional major damage in Texas.  Harvey would be stronger, but smaller, than Hurricane Ike was when Ike made landfall in Texas in 2008.  The HII for Ike was 19.2, the HSI was 22.5 and the HWISI was 41.7.

Harvey will bring strong damaging winds to Texas.  Harvey will also cause a dangerous storm surge at the coast.  The storm surge could approach 12 feet (4 meters) in some locations.  Harvey will also drop very heavy rain, if it stalls after it moves inland.  Serious fresh water flooding is possible under that scenario.  The strong winds and flooding could also lead to widespread losses of electricity.

Tropical Storm Harvey Intensifying Rapidly, Hurricane Warning for Texas

Tropical Storm Harvey was intensifying rapidly on Thursday morning and a Hurricane Warning was issued portions of the coast of Texas.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Harvey was located at latitude 24.0°N and longitude 93.3°W which put it about 365 miles southeast of Corpus Christi, Texas.  Harvey was moving toward the north-northwest at 10 m.p.h. (16 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 982 mb.

A Hurricane Warning was in effect for the portion of the coast from Port Mansfield to Matagorda, Texas.  A Hurricane Watch was in effect for the portion of the coast from the mouth of the Rio Grande River to Port Mansfield.  A Tropical Storm Warning was in effect for the portion of the coast from the mouth of the Rio Grande River to Port Mansfield and from Matagorda to High Island, Texas.  A Tropical Storm Watch was in effect for the portion of the coast from Boca De Catan, Mexico to the mouth of the Rio Grande River.

Tropical Storm Harvey intensified very rapidly on Thursday morning.  An eye with a diameter of 18 miles (29 km) formed at the center of circulation.  The eye was surrounded by a ring of very strong thunderstorms.  Additional bands of strong thunderstorms were revolving around the core of Tropical Storm Harvey.  The thunderstorms were generating very strong upper level divergence which was pumping away large amounts of mass in all directions from the tropical storm.  The strong upper level divergence was causing the surface pressure to decrease rapidly.  The minimum surface pressure decreased from 1002 mb to 982 mb in 12 hours.  The rapid decrease in pressure was increasing the pressure gradient force and the winds speeds were increasing accordingly.

Tropical Storm Harvey is in an almost perfect environment for rapid intensification.  Harvey is moving over water where the Sea Surface Temperature is near 31°C.  The upper level winds are very weak and there is almost no vertical wind shear.  Tropical Storm Harvey should continue to intensify rapidly for another 24 to 36 hours.  Harvey will become a hurricane later today and it will likely become a major hurricane before it makes landfall.  Tropical Storm Harvey has the potential to intensify to a Category 4 hurricane on the Saffir-Simpson Scale.

Harvey is being steered toward the north-northwest by a subtropical ridge to the east of the tropical storm.  A general northwesterly motion is forecast continue for another 36 to 48 hours.  On its anticipated track the center of Harvey will approach the coast of Texas on Friday night.  The steering currents are forecast to weaken as Harvey nears the coast.  Some models are forecasting that Harvey drifts slowly toward the west.  Other models stall Harvey and then turn it northeastward.  There is a large degree of uncertainty about the future track of Harvey after it nears the coast.

Based on current projections the forecast Hurricane Intensity Index (HII) for Harvey at landfall is 22.1.  The forecast Hurricane Size Index (HSI) is 18.0 and the forecast Hurricane Wind Intensity Size Index (HWISI) at landfall is 40.1  Those indices indicate that Harvey could cause regional major damage in Texas.  The indices may be conservative if Harvey continues to intensify rapidly up until it makes landfall.  Harvey would be stronger, but a little smaller, than Hurricane Ike was when Ike made landfall in Texas in 2008.  The HII for Ike was 19.2, the HSI was 22.5 and the HWISI was 41.7.

Harvey will bring strong damaging winds to Texas.  Harvey will also cause a dangerous storm surge at the coast.  The storm surge could approach 12 feet (4 meters) in some locations.  Harvey will also drop very heavy rain, if it stalls after it moves inland.  Serious fresh water flooding is possible under that scenario.