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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.

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 Depression Cindy Brings Stormy Weather to Southern U.S.

Tropical Depression Cindy brought stormy weather to parts of the southern U.S. on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Depression Cindy was located at latitude 33.1°N and 93.5°W which put it about 70 miles (115 km) southwest of Little Rock, Arkansas.  Cindy was moving toward the north-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 20 m.p.h. (30 km/h) and there were wind gusts to 30 m.p.h. (50 km/h).  The minimum surface pressure was 1000 mb.

Tropical Storm Cindy made landfall early on Thursday morning near the border between Texas and Louisiana.  Cindy moved steadily northward during the day and it was centered over southwestern Arkansas by Thursday night.  Broad counterclockwise rotation around Cindy transported warm and very humid air over the southern U.S.  Bands of showers and thunderstorms dropped locally heavy rain in some places.  Rivers and streams were above flood stage in several southern states.  Flash Flood Warnings and Flash Flood Watches were issued for portions of the southern U.S. and Ohio River Valley.  Several tornadoes formed in the bands of thunderstorms.  A tornado in Alabama caused property damage.  Southerly winds blowing toward the shore were still causing storm surges along the northern coast of the Gulf of Mexico.

Tropical Depression Cindy is forecast to move northeast toward the Ohio River Valley on Friday.  It will continue to produce locally heavy rain.  A slow moving cold front will approach the region from the west.  A band of stronger convergence could develop where the counterclockwise flow around Cindy interacts with the flow along the cold front.  Higher rainfall totals may occur where this interaction happens.  Wind shear created by the interacting weather systems could also create the potential for some tornadoes.  Tropical Depression Cindy could merge with the cold front during Friday night or Saturday.

Tropical Storm Cindy Nears Northwest Gulf Coast

Tropical Storm Cindy neared the northwestern coast of the Gulf of Mexico on Wednesday evening.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Cindy was located at latitude 28.6°N and longitude 93.4°W which put it about 95 miles (150 km) south-southeast of Port Arthur, Texas.  Cindy was moving toward the north-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 992 mb.

A Tropical Storm Warning is in effect for the portion of the coast from San Luis Pass, Texas to Grand Isle, Louisiana.

Tropical Cyclone Cindy exhibits a hybrid structure in which a broad surface low pressure system is interacting with an upper low centered near the Upper Texas coast.  There is a distinct center of low pressure at the surface.  A band of showers and thunderstorms is northwest of the surface center.  Drier air in the middle and upper levels wraps around the southern and eastern sides of the center and there are no thunderstorms in those quadrants of the core of Tropical Storm Cindy.  A broad flow of moisture is producing bands of showers and thunderstorms in the outer portions of the eastern and northern sides of the circulation.

Tropical Storm Cindy is moving around the western end of a subtropical high pressure system centered over the Atlantic Ocean.  The subtropical high is steering Cindy toward the north-northwest.  On its anticipated track Tropical Storm Cindy will make landfall near the border between Texas and Louisiana on Thursday.  Cindy will turn toward the north and then the tropical storm will move northeastward on Friday.

Some locations will experience prolonged periods of rainfall and fresh water flooding will be possible in those area.  There could also be a storm surge of 3 to 6 feet (1 to 3 meters) near where the center makes landfall.  A few tornadoes could be spun up as rainbands move over the coast.

Tropical Storm Cindy Strengthens Over the Central Gulf of Mexico

Tropical Storm Cindy strengthened on Tuesday night as is moved slowly over the Central Gulf of Mexico.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Cindy was located at latitude 26.4°N and longitude 91.0°W which put it about 305 miles (495 km) southeast of Galveston, Texas.  Cindy was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 70 m.p.h. (110 km/h).  The minimum surface pressure was 997 mb.

A Tropical Storm Warning is in effect for the portion of the coast from San Luis Pass, Texas to the Alabama/Florida border including Metropolitan New Orleans and Lake Pontchartrain.

Although Tropical Storm Cindy does not look very impressive on infrared satellite imagery, data from reconnaissance aircraft and surface observations from buoys and ships indicate that it has strengthened during the past few hours.  Tropical Storm Cindy displays the structure of a highly sheared tropical storm.  There are no thunderstorms near the center of circulation.  Most of the showers and thunderstorms are in bands well to the east and north of the center of circulation.  The circulation of Tropical Storm Cindy is large and winds to tropical storm force extend out about 275 miles (445 km) northeast of the center.

A combination of an upper level low to the northwest of Cindy and an upper level ridge to the east of it have generated enough upper level divergence to cause the surface pressure to decrease.  The lower pressure at the center created a bigger pressure difference with the subtropical high over the Atlantic Ocean and the stronger pressure gradient force accelerated the wind speed.  So, even though the upper level low produced enough vertical wind shear to prevent a classical process of tropical intensification in Tropical Storm Cindy, the larger scale weather features combined to produce a stronger, larger tropical storm.

Tropical Storm Cindy could intensify a little more if the large scale environment pumps out more mass and the surface pressure decreases further.  The tropical storm could also intensify if the upper low moves farther away from Cindy and the wind shear decreases.  It is unlikely that Tropical Storm Cindy will intensify into a hurricane, but there is a slight possibility that could occur before it makes landfall.

The subtropical high over the Atlantic Ocean is steering Tropical Storm Cindy slowly toward the northwest and that general motion is expected to continue for another 12 to 24 hours.  Cindy could gradually turn toward the north as it approaches the coast and the tropical storm will turn toward the northeast after it moves inland.  On its anticipated track the center of Tropical Storm Cindy could approach the northwestern coast of the Gulf of Mexico on Wednesday night.

The large size of the circulation of Tropical Storm Cindy and its slow motion mean that locally heavy rain and flooding are the greater risks.  There is also the potential for rainbands to spin up tornadoes when they move onto the coast.  Southerly winds driving water toward the coast are already causing a storm surge along parts of the coast of Louisiana.  A storm surge of 3 to 6 feet (1 to 2 meters) may be possible where the strongest winds strike the coast.