Tag Archives: Florida

Powerful Hurricane Irma Approaches Bahamas, Watches Issued for Florida

Powerful Hurricane Irma move north of the Dominican Republic on its approach to the Bahamas on Thursday morning.  Hurricane Watches were issued for south Florida because of the potential impact of Hurricane Irma.  At 11:00 a.m. EDT on Thursday the center of Hurricane Irma was located at latitude 20.4°N and longitude 69.7°W which put it about 120 miles (190 km) southeast of Grand Turk Island and about 785 miles (1265 km) east-southeast of Miami, Florida.  The maximum sustained wind speed was 175 m.p.h. (280 km/h) and there were wind gusts to 200 m.p.h. (320 km/h).  The minimum surface pressure was 921 mb.

Hurricane Warnings were in effect for the portion of the coast from Cabo Engano, Dominican Republic to Le Mole St. Nicholas, Haiti, the Turks and Caicos, the southeastern Bahamas including the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana and the Ragged Islands, the central Bahamas including Cat Island, the Exumas, Long Island, Rum Cay and San Salvador, the northwestern Bahamas including the Abacos, Andros Island, Berry Island, Bimini, Eleuthera, Grand Bahama Island and New Providence.

A Hurricane Watch was in effect for the portion of the coast from Jupiter Inlet to Bonita Beach, Florida including the Florida Keys and Lake Okeechobee and from Matanzas province to Guantanamo province in Cuba.

A Tropical Storm Warning is in effect for the portion of the coast from Cabo Engano, Dominican Republic to the southern border with Haiti, from Le Mole St. Nicholas to Port Au Prince, Haiti and for the Cuban provinces of Guantanamo, Holguin and Las Tunas.

Hurricane Irma remains a large and dangerous hurricane.  Irma weakened slightly on Thursday morning, but it still was a Category 5 hurricane on the Saffir-Simpson Scale.  Irma has a large circular eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Winds to hurricane force extend out about 60 miles (95 km) from the center.  Winds to tropical storm force extend out about 185 miles (305 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Irma is 40.4.  The Hurricane Size Index (HSI) is 19.2 and the Hurricane Wind Intensity Size Index (HWISI) is 59.6.  Those indices indicate that Hurricane Irma is capable of causing widespread catastrophic damage.

Hurricane Irma will remain in a favorable environment for the next several days.  Irma will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds will be weak and there will be little vertical wind shear during the next 24 to 36 hours.  When Irma gets farther north it will be near the southern end of a large upper level trough over the eastern U.S.  The trough will produce southeasterly winds which will increase the shear somewhat.  Hurricane Irma will remain a large dangerous hurricane.

Hurricane Irma is moving around the western end of a subtropical high over the Atlantic Ocean.  The high is steering Irma toward the west-northwest and that general motion is expected to continue for another 36 to 48 hours.  The effects of the upper level trough are expected to turn Irma toward the north during the weekend.  On its anticipated track Hurricane Irma will reach the Turks and Caicos on Thursday night.  Irma will move across the southeastern Bahamas on Friday and it could be north of Cuba by Saturday morning.  Hurricane Irma could reach southern Florida by Sunday morning.

Hurricane Irma is capable of causing widespread catastrophic damage.  Irma will generate storm surges as high as 19 feet (6 meters) when it passes over the Bahamas.  Irma will cause widespread wind damage and locally heavy rain could cause flash floods.

The destructive core of Hurricane Irma moved over Barbuda, St. Barthelemy and St. Martin.  There are reports of widespread damage on those islands.  Other nearby islands my have also suffered significant damage.

Hurricane Jose is following in the wake of Hurricane Irma and Watches have been issued for some of the northern Leeward Islands.  At 11:00 a.m. EDT on Thursday the center of Hurricane Jose was located at latitude 14.9°N and longitude 50.6°W which put it about 715 miles (1155 km) east of the Leeward Islands.  Jose was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 986 mb.

Hurricane Watches have been issued for Antigua and Barbuda.  Tropical Storm Watches have been issued for Anguilla, Montserrat, St. Kitts and Nevis.

Hurricane Jose is moving through a favorable environment of warm Sea Surface Temperatures and little vertical wind shear.  Hurricane Jose is forecast to intensify into a major hurricane.  The same subtropical high steering Hurricane Irma is also steering Hurricane Jose.  On its anticipated track Hurricane Jose could reach the northern Leeward Islands on Saturday.  It could be a major hurricane at that time.  If Hurricane Jose moves over some of the same places hit by Hurricane Irma it will serious impede efforts to recover from Irma.

Hurricane Katia is threatening parts of Mexico.  At 11:00 a.m. EDT on Thursday the center of Hurricane Katia was located at latitude 21.6°N and longitude 94.6°W which put it about 215 miles (345 km) east of Tampico, Mexico.  Katia was stationary.  the maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155km/h)  The minimum surface pressure was 980 mb.

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

 

Cat. 5 Hurricane Irma Moving Over Northern Leeward Islands

Category 5 Hurricane Irma moved over the northern Leeward Islands on Wednesday morning.  At 5:00 a.m. EDT on Wednesday the center of Hurricane Irma was located at latitude 17.9°N and longitude 62.6°W which put it about 35 miles (55 km) east-southeast of St. Martin.  Irma was moving toward the west-northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 185 m.p.h. (295 km/h) and there were wind gusts to 210 m.p.h. (340 km/h).  The minimum surface pressure was 912 mb.

The core of Hurricane Irma moved across Antigua, Barbuda, St. Barthelemy and St. Martin in recent hours.  It will reach Anguilla later this morning.

Hurricane Watches were in effect for Antigua, Anguilla, Barbuda, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, Sint Maarten, St. Martin, St. Barthelemy, the British Virgin Islands, the U.S. Virgin Islands, Puerto Rico, Vieques, Culebra, Guadeloupe, the southeastern Bahamas including the Acklins, Cooked Islands, Long Cay, the Iguanas, Mayaguane, the Ragged Islands, the Turks and Caicos, and the portion of the coast of Cabo Engano, Dominican Republic to the northern border with Haiti.  Hurricane Watches are in effect for the central Bahamas, the portion of the coast from Le Mole St. Nicholas to the northern border with Haiti and from Matanzas province to Guantanamo province in Cuba.  A Tropical Storm Warning is in effect for the portion of the coast from Cabo Engano, Dominican Republic to the southern border with Haiti.  A Tropical Storm Watch is in effect for the portion of the coast from Le Mole St. Nicolas, Haiti to Port Au Prince.

Hurricane Irma maintained its intensity during the northern overnight hours.  It has a circular eye with a diameter of 30 miles (48 km).  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Winds to hurricane force extend out about 60 miles (95 km) from the center.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.

The Hurricane Intensity Index (HII) is 44.1.  The Hurricane Size Index (HSI) is 19.8 and the Hurricane Wind Intensity Size Index (HWISI) is 63.9.  Those indices indicate that Hurricane Irma is capable of causing widespread catastrophic wind damage.

Hurricane Irma will continue to move over an environment very favorable for hurricanes.  Irma will stay over water where the Sea Surface Temperature is near 30°C.  The upper level winds will remain weak for several more days and there will be little wind shear.  An upper level trough over the eastern U.S. will produce strong winds when Irma gets closer to Florida.  The wind shear will increase at that time.  Hurricane Irma could go through eyewall replacement cycles which would cause fluctuations in intensity.

Hurricane Irma is moving near the western end of a subtropical high pressure system over the Atlantic Ocean which is steering Irma toward the west-northwest.  The west-northwesterly motion is expected to continue for several more days.  Eventually, the upper level trough over the eastern U.S. is forecast to turn Hurricane Irma toward the north when it approaches Florida.  On its anticipated track the center of Hurricane Irma is forecast to pass north of Puerto Rico and Hispaniola.

Elsewhere, Tropical Storm Jose is trailing behind Hurricane Irma and Tropical Storm Katia has developed over the southern Gulf of Mexico.  At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Jose was located at latitude 12.5°N and longitude 42.8°W which put it about 1255 miles east of the Leeward Islands.  Jose was moving toward the west at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 1002 mb.

At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Katia was located at latitude 22.1°N and longitude 96.3°W which put it about 105 miles (165 km) east of Tampico, Mexico.  Katia was moving toward the east at 2 m.p.h. (3 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.

Very Dangerous Hurricane Irma Reaches Cat. 5

Very dangerous Hurricane Irma reached category 5 on the Saffir-Simpson Scale on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Irma was located at latitude 12.3°N and longitude 39.1°W which put it about 225 miles (365 km) east of Antigua.  Irma was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 180 m.p.h. (285 km/h) and there were wind gusts to 210 m.p.h. (340 km/h).  The minimum surface pressure was 931 mb.

Hurricane Warnings are in effect for Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, Sint Maarten, St. Martin, St. Barthelemy, the British Virgin Islands, the U.S. Virgin Islands, Puerto Rico, Vieques and Culebra.  Tropical Storm Warnings are in effect for Guadeloupe and Dominica.  Hurricane Watches are in effect for Guadeloupe, the southeastern Bahamas including the Acklins, Crooked Islands, Long Cay, the Inaguas, Mayaguana, and the Ragged Islands.  A Hurricane Watch is also in effect for the portion of the the coast from Cabo Engano, Dominican Republic to Le Mole St. Nicholas, Haiti.  Tropical Storm Watches are in effect for the portion of the coast from Le Mole St. Nicholas to Port Au Prince, Haiti and from Cabo Engano to Isla Saona, Dominican Republic.

Hurricane Irma intensified rapidly after the completion of the most recent eyewall replacement cycle.  The structure evolved in a large classic Cape Verde hurricane.  The is a large circular eye at the center of circulation.  A ring of very strong thunderstorms surrounds the eye and the strongest winds are occurring in that ring.  Bands of showers and thunderstorms are revolving around the core of Hurricane Irma.  Winds to hurricane force extend out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.

The Hurricane Intensity Index (HII) for Irma is 44.1.  The Hurricane Size Index (HSI) is 19.8 and the Hurricane Wind Intensity Size Index (HWISI) is 63.9.  Hurricane Irma is as strong as Hurricane Rita was in 2005, but Irma is just slightly smaller than Rita was.  Hurricane Irma is capable of causing widespread catastrophic damage.

Hurricane Irma is moving through an environment that is very favorable for hurricanes.  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.  Hurricane Irma will likely remain very strong as long as it stays over water.  Additional eyewall replacement cycles could occur and they would result in fluctuations in the intensity of Hurricane Irma.

Hurricane Irma is being steered to the west by a very strong subtropical high over the Atlantic Ocean.  Irma is expected to turn a little more toward the west-northwest as it moves closer to the western end of the high.  On its anticipated track Hurricane Irma will move across the northern Leeward Islands during the next 24 hours.  It will be near Puerto Rico on Wednesday and near the Dominican Republic on Thursday.

Hurricane Irma is an very dangerous hurricane.  It is capable of producing widespread catastrophic damage.  Hurricane Irma will also drop extremely heavy rain and flooding is very possible.

Hurricane Irma Strengthens to Cat. 4, Watch in effect for Puerto Rico

Hurricane Irma strengthened to Category 4 on the Saffir-Simpson Scale on Monday and a Hurricane Watch was issued for Puerto Rico and the U.S. Virgin Islands.  At 5:00 p.m. EDT on Monday the center of Hurricane Irma was located at latitude 16.7°N and longitude 54.4°W which put it about 490 miles (790 km) east of the Leeward Islands.  Irma was moving toward the west at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 944 mb.

Hurricane Warnings are in effect for Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, St. Maarten, St. Martin, and St. Barthelemy.  Hurricane Watches are in effect for Guadeloupe, the British Virgin Islands, the U.S. Virgin Islands, Puerto Rico, Vieques and Culebra.  A Tropical Storm Warning is in effect for Guadeloupe.  A Tropical Storm Watch is in effect for Dominica.

The circulation of Hurricane Irma has been going through a series of eyewall replacement cycles.  A plane flying through Irma reported concentric eyewalls earlier today.  The two eyewalls appear to have merged.  A small circular eye is at the center of circulation.  A ring of strong thunderstorms surrounds the eye and the strongest winds are occurring in that ring of storms.  Additional bands of showers and thunderstorms are revolving around the core of Hurricane Irma.  Storms around the center are generating strong upper level divergence which is pumping away mass in all directions from the hurricane.

Hurricane Irma has been increasing in size.  Winds to hurricane force extend out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extend out about 140 miles (225 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Irma is 25.1.  The Hurricane Size Index (HSI) is 13.6.  The Hurricane Wind Intensity Size index (HWISI) is 38.7.

Hurricane Irma will move through an environment very favorable for tropical cyclones.  Irma will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Irma could strengthen further and it has a chance to reach Category 5 on the Saffir-Simpson Scale.  Hurricane Irma is likely to go through additional eyewall replacement cycles, which will cause fluctuations in its intensity, but Irma should remain a strong hurricane as it nears the northern Leeward Islands.

The subtropical high pressure system over the Atlantic Ocean has been steering Hurricane Irma toward the west and that general motion is expected to continue for another 12 to 24 hours.  After that time Irma is expected to turn more toward the west-northwest.  On its anticipated track Hurricane Irma will approach the northern Leeward Islands late on Tuesday.  Hurricane Irma could approach Puerto Rico on Wednesday.

Hurricane Irma Moves Toward Leeward Islands, Watches Issued

Hurricane Irma moved toward the northern Leeward Islands on Sunday and Hurricane Watches were issued for a number of those islands.  At 11:00 p.m. EDT on Sunday the center of Hurricane Irma was located at latitude 17.2°N and longitude 51.0°W which put it about 710 miles (1145 km) east of the Leeward Islands.  Irma was moving toward the west-southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 961 mb.

Hurricane Watches were in effect for Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, St. Maarten, St, Martin, and St. Barthelemy.

The circulation of Hurricane Irma is very well organized.  There is a nearly circular eye with a diameter of 30 miles (48 km) at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in the northeastern part of the ring.  Bands of showers and thunderstorms are revolving around the core of Hurricane Irma.  Thunderstorms around the core are generating strong upper level divergence which is pumping mass away in all directions from the hurricane.  Winds to hurricane force extend out about 35 miles (55 km) from the center.  Winds to tropical storm force extend out about 140 miles (225 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Irma is 20.6.  The Hurricane Size Index (HSI) is 11.7 and the Hurricane Wind Intensity Size Index (HWISI) is 32.3.

Hurricane Irma will move through an environment favorable for intensification.  Irma will move over water where the Sea Surface Temperature is near 29°C and there is warmer water farther west.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Irma could intensify into a Category 4 hurricane on the Saffir-Simpson Scale.  There is a possibility that Irma could strengthen to Category 5 when it passes near the northern Leeward Islands and moves toward the Bahamas.  Hurricane Irma has already completed several eyewall replacement cycles and there could be more.  Each eyewall replacement cycle could result in fluctuations in the intensity of Hurricane Irma.

A strong subtropical high pressure system over the Atlantic Ocean is steering Hurricane Irma toward the west-southwest.  The high is forecast to weaken just a bit during the next several days and Hurricane Irma is expected to move more toward the west-northwest.  On its anticipated track Hurricane Irma will approach the northward Leeward Islands on Tuesday night.  It will be a strong, dangerous hurricane at that time.

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.

Tropical Depression Harvey Redevelops Southeast of Texas

A tropical depression redeveloped southeast of Texas from the remnants of former Tropical Storm Harvey on Wednesday morning.  The National Hurricane Center (NHC) began issuing advisories on Tropical Depression Harvey again.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Harvey was located at latitude 21.5°N and longitude 92.5°W which put it about 535 miles (860 km) southeast of Port O’Connor, Texas.  Harvey was moving toward the northwest at 9 m.p.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 1006 mb.

A Hurricane Watch was issued for the portion of the coast from Port Mansfield to San Luis Pass, Texas.  A Tropical Storm Watch was issued for the portion of the coast from the mouth of the Rio Grande River to Port Mansfield and from San Luis Pass to High Island, Texas.  NHC also issued a Storm Surge Watch for the portion of the coast from Port Mansfield to High Island.

A reconnaissance aircraft found that a distinct low level center had formed in the remnants of Tropical Storm Harvey on Wednesday morning.  The circulation in Tropical Depression Harvey was still in the process of organizing.  Stronger thunderstorms were forming near the center of circulation.  Additional bands of showers and thunderstorms were forming outside the core of the circulation.  The distribution of showers and thunderstorms was somewhat asymmetrical.  There were more showers and thunderstorms in the eastern half of the circulation.  Although there were fewer showers and thunderstorms in the western half of the circulation, more storms were developing in that part of Tropical Depression Harvey.  The thunderstorms near the core were beginning to generate upper level divergence which was pumping away mass to the northeast of the tropical depression.

Tropical Depression Harvey will move through an environment that will become increasing favorable for intensification.  Harvey will move over water where the Sea Surface Temperature is near 30°C.  An upper level low near the coast of Louisiana is causing some vertical wind shear.  However, the low is forecast to move north and weaken and the shear is forecast to decrease.  Tropical Depression Harvey may strengthen slowly at first while the circulation is organizing.  The rate of intensification will likely increase on Thursday and there could be a period of rapid intensification when the Harvey near hurricane intensity.

Tropical Depression Harvey is moving around the western end of a subtropical high pressure system which is steering Harvey toward the northwest.  Harvey is forecast to continue to move toward the northwest and it will approach Texas in about 48 hours.  The winds are the steering level are forecast to weaken when Harvey approaches Texas and it could move more slowly as it nears the coast.

Tropical Depression Harvey could evolve into a very dangerous storm.  The coast along the western Gulf of Mexico is very susceptible to storm surges.  An intensifying, slow moving hurricane could generate dangerous storm surges along the coast.  If Harvey stalls after it moves inland, it could drop very heavy rain and there is also the potential for dangerous fresh water flooding.

Tropical Storm Emily Makes Landfall on West Coast of Florida

Tropical Storm Emily made landfall on the west coast of Florida at Anna Maria Island late Monday morning.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Emily was located at latitude 27.5°N and longitude 82.7°W which put it about 10 miles (15 km) northwest of Bradenton, Florida.  Emily was moving toward the east at 9 m.p.h. (15 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 1005 mb.  A Tropical Storm Warning was in effect for the portion of the coast from Anclote River to Bonita Beach, Florida.

Thunderstorms developed near the center of the non-tropical low pressure system over the eastern Gulf of Mexico.  Latent energy released higher in the atmosphere by condensation in those storms created a warm core and the low pressure system made a transition to Tropical Storm Emily.  Thunderstorms near the core of Emily were generating a small area of upper level divergence.  Thunderstorms near the core, a warm core and upper level divergence are part of the typical structure of a tropical cyclone, which is why the National Hurricane Center classified the system as Tropical Storm Emily.  Emily has a well developed circulation, but most of the bands of showers and thunderstorms are in the eastern half of the tropical storm.  Drier air northwest of Emily and vertical wind shear are the probable causes of the asymmetrical distribution of precipitation.

Tropical Storm Emily is bringing gusty winds and heavy rain to parts of Central Florida.  A surface weather station in Sarasota (KSRQ) reported a sustained wind of 39 m.p.h. (63 km/h) and a wind gust of 49 m.p.h. (80 km/h).  The Skyway Bridge over Tampa Bay was closed due to strong winds.

Tropical Storm Emily is likely to weaken as it moves eastward across Central Florida.  When Emily moves over the Atlantic Ocean, it will move over water where the Sea Surface Temperature is near 29°C.  Emily could strengthen back into a tropical storm at that time.

Emily is being steered toward the east by a high pressure system north of the tropical storm.  An upper level trough over the Midwestern U.S. is forecast to move southeastward.  When Emily reaches the Atlantic Ocean southwesterly winds ahead of the trough will turn the tropical storm toward the northeast.

Non-Tropical Low Forms Over Northeast Gulf of Mexico

A non-tropical low pressure system formed over the northeastern Gulf of Mexico on Sunday.  The low pressure system is currently designated as Invest 98L.  At 2:00 p.m. EDT on Sunday the center of Invest 98L was located at latitude 28.4°N and longitude 85.5°W which put it about 100 miles (160 km) south-southwest of Apalachicola, Florida.  It was moving toward the east at 8 m.p.h. (13 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 1009 mb.

The low pressure system formed along a frontal boundary that stalled over the northeastern Gulf of Mexico.  It is not usual for low pressure systems to form along stationary fronts.  A source of positive vorticity to provide counterclockwise rotation and upper level divergence to pump away mass and allow the surface pressure to decrease will generate a surface low.  The low pressure system does not have a warm core in the middle and upper levels and it is still associated with a frontal system.  So, it is classified as a non-tropical low pressure system.

The low pressure system will be moving through an environment that will be only marginally favorable for a transition to a tropical or subtropical cyclone.  The Sea Surface Temperature in the northeastern Gulf of Mexico is near 30°C.  So, there is plenty of energy to support the formation of a tropical cyclone.  However, an upper level ridge over the central U.S. and a trough over the northeastern U.S. are combining to produce northerly winds of 40 m.p.h. (65 km/h) over the northeastern Gulf of Mexico.  Those winds are generating significant vertical wind shear.  The shear has limited the development of thunderstorms in the northern half of the low and it may be tilting the vertical structure of the low toward the south.  The strong upper level winds will also inhibit divergence on the northern side of the low and they could make it difficult for a warm core to develop in the middle and upper levels.  The air north of the frontal boundary is drier continental air, which is another a negative factor for transition to a tropical cyclone.  Based on all of the environmental factors the National Hurricane Center is indicating that there is a 30% chance the low could make a transition to a tropical or subtropical cyclone.

The low pressure system is moving a little to the south of due east.  A strong surface high pressure system over the eastern U.S. is now pushing the front toward the south as a cold front.  The low is moving slowly eastward along the front.  Combination of the southward motion of the front and eastward motion of the low produces a forecast motion of a little south of due east.  On its anticipated track the low pressure system could reach the west coast of Florida in 24 to 36 hours.  So, the low has about a day, if it is going to transition to a tropical cyclone over the Gulf of Mexico.