Tag Archives: Mexico

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.

 

Tropical Storm Lidia Weakens, Still Raining on Baja California

Tropical Storm Lidia has weakened but it is producing rain over Baja California.  At 2:00 p.m. EDT on Saturday the center of Tropical Storm Lidia was located at latitude 28.3°N and longitude 114.6°W which put it about 40 miles (65 km) northeast of Punta Eugenia, Mexico.  Lidia was moving toward the northwest at 12 m.p.h. (19 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 999 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Punta Abreojos to San Jose de Las Palomas, from Mulege to Isla San Luis and from Guaymas to Puerto Libertad, Mexico.

Tropical Storm Lidia weakened during the past 24 hours as it slowly moved northwest over Baja California.  There are some indications that the upper portion of the circulation may have decoupled from the lower half of Tropical Storm Lidia.  The upper portion of the circulation appears to be over the Gulf of California.  There are stronger thunderstorms over the Gulf of California because the Sea Surface Temperature is near 32°C in that body of water.  Those thunderstorms are producing heavy rain over parts of the eastern side of Baja California and the western part of Mexico adjacent to the Gulf of California.  The lower level center appears to be located northeast of Punta Eugenia over the Pacific Ocean just west of Baja California.  There are showers and thunderstorms near the low level center and they are dropping heavy rain in that area.  The potential for flash floods still exists in the areas where heavy rain is falling.

The low level center of Tropical Storm Lidia is forecast to continue to move toward the northwest.  Lidia will continue to weaken because the low level center is moving over water where the Sea Surface Temperature is near 23°C.  It will take several more days for the low level center to spin down and it could still produce locally heavy rain over the northern part of Baja California during that time.  The upper level portion of the circulation will likely be absorbed by the larger scale environmental flow in those levels.  Some clouds and moisture in the upper levels could flow over the southwestern U.S.

Tropical Storm Lidia Brings Wind and Heavy Rain to Baja California

Tropical Storm Lidia brought gusty winds and very heavy rain to Baja California on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Lidia was located at latitude 23.3°N and longitude 110.4°W which put it about 40 miles (65 km) northwest of Cabo San Lucas, Mexico.  Lidia was moving toward the north-northwest at 4 m.p.h. (6 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 991 mb.

A Hurricane Watch was in effect for the portion of the coast from Puerto Cortes to La Paz, Mexico including Cabo San Lucas.  A Tropical Storm Warning was in effect for the portion of the coast from Punta Eugenia to Bahia San Juan Bautista including Cabo San Lucas and from Bahia Tempehuaya to Bahia Kino.  A Tropical Storm Watch was in effect for the portion of the coast from Punta Eugenia to San Juan de Las Palomas and from Bahia San Juan Bautista to Isla San Luis and from Bahia Kino to Puerto Libertad.

Tropical Storm Lidia intensified as it approached the southern tip of Baja California on Thursday.  Several bands of showers and thunderstorms wrapped around the center of circulation and a partial eyewall appeared to form.  The airport at Cabo San Lucas reported sustained winds of 58 m.p.h. (83 km/h) and a Mexican automated station reported a sustained wind of 70 m.p.h. (113 km/h) and gusts to 90 m.p.h. (145 km/h) at a height of 735 feet (244 meters).  Tropical Storm Lidia has a large circulation.  Winds to tropical storm force extend out about 185 miles (295 km) from the center of circulation.

The large size of Tropical Storm Lidia meant that it was bringing tropical storm winds to the southern part of Baja California and parts of the west coast of Mexico.  Lidia was also producing very heavy rain over Baja California.  Flash floods are likely in places where steep terrain causes water to run off quickly.

Tropical Storm Lidia is forecast to move slowly north-northwest over Baja California.  The slow motion will prolong the period of gusty winds.  It will also cause the rain totals to be higher and increase the risk for floods.  Much of the circulation will remain over water and the large size of Lidia will mean that the tropical storm will weaken slowly.

Tropical Storm Lidia Threatens Baja California

Tropical Storm Lidia became an increased threat to Baja California as it moved closer on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Lidia was located at latitude 20.7°N and longitude 109.2°W which put it about 160 miles (255 km) south-southeast of the southern tip of Baja California.  Lidia was moving toward the north-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 1001 mb.

A Hurricane Watch is in effect for the portion of the coast from Puerto Cortes to La Paz, Mexico including Cabo San Lucas.  A Tropical Storm Warning is in effect for the portion of the coast from Puerto Cortes to San Evaristo including Cabo San Lucas and from Tempehuaya to Huatabampito, Mexico.  A Tropical Storm Watch is in effect for the portion of the coast from San Evaristo to Loreto, Mexico and from Puerto Cortes to Puerto Andresito.

A distinct center of circulation began consolidating in a large area of low pressure previously designated Potential Tropical Cyclone Fourteen-E on Wednesday.  Numerous bands of showers and thunderstorms started developing around the consolidating center.  There were more showers and thunderstorms in the southern half of the circulation than there were in the northern half of the circulation.  Thunderstorms southwest of the center of circulation were beginning to generate some upper level divergence, but it was not well developed.  Tropical Storm Lidia formed out of a large low pressure system and it still has a large circulation.  Winds to tropical storm force extend out about 120 miles (195 km) from the center on the eastern side of Lidia.

Tropical Storm Lidia was in an environment that was marginally favorable for intensification on Wednesday.  Lidia was moving over water where the Sea Surface Temperature was near 30°C.  An upper level ridge to the east of Lidia was producing westerly winds which were causing moderate vertical wind shear, especially over the northern half of the circulation.  The environment around Tropical Storm Lidia is forecast to become a little more favorable for intensification on Thursday.  The upper level winds are forecast to become weaker, which would reduce the wind shear.  Lidia will still be moving over very warm water and it should intensify on Thursday.  The rate of intensification could increase as the core of the tropical storm becomes more organized.  There is a chance that Lidia could strengthen into a hurricane which is why there is a Hurricane Watch for part of Baja California.

Lidia is moving around the western end of a subtropical ridge, which is steering the tropical storm toward the north-northwest.  A general north-northwesterly motion is expected to continue for another day or two.  On its anticipated track the center of Tropical Storm Lidia could reach the southern tip of Baja California by Thursday evening.  In addition to gusty winds Tropical Storm Lidia will produce very heavy rain.  Heavy rain falling on the steep terrain of Baja California creates the risk of flash floods.

Potential Tropical Cyclone Fourteen-E Prompts Hurricane Watch for Baja California

The National Hurricane Center is forecasting that a weather system currently designated as Potential Tropical Cyclone Fourteen-E will become a tropical storm and affect Baja California.  The government of Mexico has issued a Hurricane Watch and a Tropical Storm Warning for the portion of the coast from Todos Santo to Los Barriles including Cabo San Lucas.

At 5:00 p.m. EDT on Tuesday the center of Potential Tropical Cyclone Fourteen-E was located at latitude 17.2°N and longitude 107.2°W which put it about 430 miles (695 km) south-southeast of the southern tip of Baja California.  It was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1006 mb.

The circulation of Potential Tropical Cyclone Fourteen-E is in the early stages of organization.  There is a large counterclockwise circulation over the Eastern North Pacific Ocean west of Mexico.  Numerous showers and thunderstorms are forming within the circulation, but there is no well defined center of circulation.  There are fewer showers and thunderstorms in the eastern portion of the circulation.  An upper level ridge centered over Mexico is generating brisk easterly winds which are blowing over the top of the circulation.  Those winds are causing moderate vertical wind shear and the system has not yet begun to generate much upper level divergence.

Potential Tropical Cyclone Fourteen-E will move through an environment that will be somewhat favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  So, there is plenty of energy in the upper ocean to support intensification.  The strength of the upper level winds is forecast to diminish and the wind shear is likely to decrease.  If the wind shear decreases, then the environment will become more favorable for intensification.  Intensification is likely to be slow while the circulation becomes more organized and develops a distinct low level center.  Potential Tropical Cyclone Fourteen-E could become a tropical storm on Wednesday.  It has a chance to intensify to a hurricane on Thursday.

Potential Tropical Cyclone Fourteen-E is moving around the western end of a subtropical ridge.  The ridge is steering the system toward the northwest and a general northwesterly motion is expected to continue for another day or two.  On its anticipated track the center of Potential Tropical Cyclone Fourteen-E could approach the southern part of Baja California by late on Thursday.  It could be a strong tropical storm or a hurricane at that time.  Locally heavy rain falling on the steep terrain of Baja California always creates a risk for flash floods.

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.

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.

Remnants of Tropical Storm Harvey About to Move Over Gulf of Mexico

The remnants of former Tropical Storm Harvey are about to move over the southern Gulf of Mexico.  At 2:00 p.m. EDT on Tuesday the center of the remnants of Tropical Storm Harvey was located at latitude 20.3°N and longitude 89.8°W which put it about 45 miles (75 km) south-southwest of Merida, Mexico.  It was moving toward the northwest at 15 m.p.h.  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1010 mb.

A broad area of low pressure that contained the remnants of former Tropical Storm Harvey moved across the Yucatan peninsula on Tuesday.  Thin bands of showers were rotating around the broad area of low pressure over land.  Several broken bands of thunderstorms were evident on the northern and northeastern periphery of the low pressure system.  There were several smaller centers rotating around inside the larger area of low pressure, but the circulation appeared to consolidating around a center near Merida.  A few thunderstorms were forming near that center as it neared the coast.

The National Hurricane Center indicated that there is a nearly 100% chance that the low pressure system will strengthen into a tropical cyclone again once it moves over the Gulf of Mexico.  The Sea Surface Temperature (SST) in the southern Gulf of Mexico is near 31°C.  An upper level low over the northwestern Gulf of Mexico was producing some vertical shear over the top of the surface low.  The upper low is forecast to move north and weaken.  An upper level ridge over the northwestern Caribbean Sea is forecast to move over the western Gulf of Mexico.  The upper ridge will produce southerly winds which will cause some vertical wind shear.  However, those winds are expected to be weak enough to allow for intensification.  The southerly winds could actually enhance upper level divergence to the north of the low pressure system in a day or two.

Given the large size of the low pressure system and the lack of a well defined center of circulation, the system will likely start to intensify slowly.  The rate of intensification will increase once a well defined center forms.  A period of very rapid intensification could occur later this week because of very warm SSTs and little vertical wind shear.  The area of low pressure could become a tropical depression within 12 hours.  It is likely to be a tropical storm on Wednesday.  The system has a good chance of becoming a hurricane over the western Gulf of Mexico.  If the system moves slowly and rapid intensification occurs, it could become a major hurricane.

A ridge in the middle troposphere near Florida is steering the low pressure system toward the northwest and a general northwesterly motion is forecast for the next several days.  There will be more uncertainty about the future track until a well developed center of circulation forms.  However, it seems likely that this system will move toward the coast of Texas.  The system could slow and/or turn more toward the north when it nears the coast.  It has the potential to become a significant hurricane by the time it reaches the coast.  It could bring strong gusty winds, which could cause a significant storm surge at the coast.  If the system moves slowly, it could also drop very heavy rain, which would create flash floods.