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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.

Potential Tropical Cyclone Three Prompts Warnings and Watches for Louisiana and Texas

An area of low pressure designated Potential Tropical Cyclone Three moved into the Gulf of Mexico on Monday and the National Hurricane Center issued Tropical Storm Warnings and Watches for Louisiana and Texas.  At 11:00 p.m. EDT on Monday the center of Potential Tropical Cyclone Three was located at latitude 24.4°N and longitude 89.5°W which put it about 380 miles (610 km) south-southeast of Morgan City, Louisiana.  It was moving toward the north-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1000 mb

A Tropical Storm Warning is in effect for the portion of the coast from Intracoastal City, Louisiana to the mouth of the Pearl River.  A Tropical Storm Watch has been issued for the portion of the coast from High Island, Texas to Intracoastal City, Louisiana.

The circulation of Potential Tropical Cyclone 03 is not very well organized.  The system does have a well defined low level center of circulation.  However, there are no thunderstorms near the low level center.  All of the strong showers and thunderstorms are occurring in bands well to the east of the center of circulation.  Some of those bands do contain winds to tropical storm force.  An upper level low over the northwestern Gulf of Mexico is producing strong southwesterly winds which are blowing over the top of the low level center.  The strong vertical wind shear created by those winds is preventing the development of storms closer to the low level center.

The environment around Potential Tropical Cyclone 03 will remain unfavorable for intensification on Tuesday.  The system will move move water where the Sea Surface Temperature is near 29°C.  So, there will be enough energy to support intensification.  However, the upper level low will continue to produce strong vertical wind shear over the low level center of circulation.  The upper low is forecast to move slowly toward the northwest.  It is possible that the strength of the upper level winds over the northwestern Gulf of Mexico could diminish in a day or two.  If the shear decreases, thunderstorms could form closer to the center and if the structure of the system takes on a more tropical appearance, it could be designated Tropical Storm Cindy.

Potential Tropical Cyclone 03 is moving around the western end of the subtropical high over the Atlantic Ocean.  The high is steering the system toward the north-northwest and that general motion is expected to continue.  On its anticipated track Potential Tropical Cyclone 03 is expected to approach the coast of Louisiana in about 48 hours.  The steering winds could weaken when the system gets closer to the coast and the uncertainty about the future track increases after about 48 hours.

Strong southerly flow on the eastern side of Potential Tropical Cyclone 03 will bring very humid air over the southeastern U.S.  The biggest risk is likely to be heavy rain and the potential for floods.  The system will also bring gusty winds and some storm surge to parts of the coast.

Tropical Storm Bret Forms Near Trinidad

An Air Force Reserve Hurricane Hunter aircraft investigated Potential Tropical Cyclone 02 on Monday afternoon as it moved closer to Trinidad and the plane found a closed circulation.  Based on data from the reconnaissance plane the National Hurricane Center classified the system as Tropical Storm Bret.  At 8:00 p.m. EDT on Monday the center of Tropical Storm Bret was located at latitude 9.5°N and longitude 60.5°W which put it about 85 miles (135 km) southeast of Trinidad.  Bret was moving toward the west-northwest at 25 m.p.h. (40 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 1008 mb.

Tropical Storm Warnings are in effect for Grenada, Trinidad, Tobago and the coast of Venezuela from Pedernales to Cumana.  Tropical Storm Watches have been issued for Aruba, Bonaire, and Curacao.

The reconnaissance plane found a well organized center of circulation at the surface.  The strongest winds were occurring in vigorous bands of thunderstorms located north of the center of circulation.  Weaker showers and thunderstorms were occurring in bands south of the center of circulation.  The thunderstorms north of the center were generating upper level divergence which was pumping mass away to the north of the tropical storm.  The circulation of Tropical Storm Bret is fairly small.  Winds to tropical storm force only extend out about 80 miles (130 km) to the north of the center of circulation.

Tropical Storm Bret will move through an environment that will only be marginally favorable for intensification on Tuesday.  Bret will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge east of Bret and an upper level trough to the west are producing southerly winds which are generating moderate vertical wind shear.  The vertical wind shear may be responsible for the asymmetrical distribution of thunderstorms.  The shear will also inhibit intensification during the next 24 hours, although some intensification may possible.  When Bret moves into the Caribbean Sea, the vertical wind shear will increase.  Tropical Storm Bret will also move very close to the north coast of Venezuela.  It could pull drier air from South America into the southern part of the circulation, which would contribute to further weakening.

The subtropical high pressure system over the Atlantic Ocean is steering Tropical Storm Bret rapidly toward the west-northwest.  A fast west-northwesterly motion is forecast to continue for several more days.  On its anticipated track Tropical Storm Bret will move across Trinidad, near the north coast of Venezuela and toward Aruba, Bonaire, and Curacao.  It will bring gusty winds and locally heavy rain to all of those places.

Invest 92L Becomes Potential Tropical Cyclone Two, Warnings Issued for Windward Islands

The National Hurricane Center (NHC) changed the designation of Invest 92L to Potential Tropical Cyclone 02 on Sunday evening.  NHC implemented a new policy for 2017 which allows it to issue tropical cyclone watches and warnings before it officially classifies a system as a tropical cyclone.  NHC issued Tropical Storm Warnings for some of the Windward Islands because of Potential Tropical Cyclone 02 on Sunday evening in accordance with the new policy.

At 11:00 p.m. EDT on Sunday the center of Potential Tropical Cyclone 02 was located at latitude 7.9°N and longitude 52.4°W which put it about 630 miles (1015 km) east-southeast of Trinidad.  It was moving toward the west-northwest at 23 m.p.h. (37 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 1005 mb.

Tropical Cyclone Warnings have been issued for Barbados, St. Vincent, the Grenadines, Grenada, Trinidad, and Tobago.

The circulation of Potential Tropical Cyclone 02 appeared to get better organized on Sunday evening.  Satellite imagery seemed to indicate that a more circular area of thunderstorms was forming around the center of circulation.  The system was already producing sustained winds to 40 m.p.h. (60 km/h) and if a center of circulation develops, it will be classified as a tropical storm.

Potential Tropical Cyclone 02 will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  It will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough over the eastern Caribbean Sea is generating southwesterly winds that are causing some vertical wind shear.  Potential Tropical Cyclone 02 has about 24 to 36 hours before the shear increases significantly.  After that time the system will weaken.

A subtropical high pressure system over the Atlantic is steering Potential Tropical Cyclone 02 toward the west-northwest.  A general west-northwesterly motion is expected to continue.  On its anticipated track Potential Tropical Cyclone 02 will reach the southern Windward Islands later on Monday.  It will bring gusty winds and locally heavy rain when it gets there.

Invests 92L, 93L Monitored for Possible Development

Two weather systems designated as Invest 92L and Invest 93L are being monitored for possible development into tropical cyclones.  Invest 92L is a tropical wave that is speeding toward the Windward Islands.  At 2:00 p.m. EDT on Sunday the center of Invest 92L was located at latitude 7.3°N and longitude 49.4°W which put it about 800 miles (1290 km) east-southeast of the Windward Islands.  It was moving toward the west-northwest at 24 m.p.h. (39 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 1008 mb.

Invest 93L consists of a broad area of low pressure over the northwestern Caribbean Sea.  At 2:00 p.m. EDT on Sunday the surface center of Invest 93L was located at latitude 19.0°N and longitude 87.1°W which put it about 145 miles (230 km) south of Cancun, Mexico.  It was moving toward the north-northwest at 5 m.p.h. (8 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.

Invest 92L is a tropical wave and it has not yet develop a well defined surface center.  There is some evidence of cyclonic rotation on visible satellite imagery and there could be a center in the middle levels of the circulation.  Most of the stronger thunderstorms are located north and west of the center.  The are some bands of showers and thunderstorms south and west of the center.  There is some upper level divergence from the thunderstorms north and west of the center, but it is not well developed at the current time.

Invest 92L is in an environment that is moderately favorable to development of a tropical cyclone.  It is moving over water where the Sea Surface Temperature is near 28°C.  It is in a region of rapid easterly flow, but the wind speed is fairly similar at all levels.  So, there is not a lot of vertical wind shear.  The rapid easterly flow could be inhibiting the formation of a well defined center of circulation.  Invest 92L will be in a moderately favorable environment for about another 36 hours.  An upper level trough over the eastern Caribbean Sea will create increased vertical wind shear when Invest 92L reaches that location.  The National Hurricane Center is indicating that there is a 60% probability that Invest 92L will develop into a tropical cyclone during the next two days.

Invest 92L is being steered rapidly toward the west-northwest by a subtropical high north of it.  A fairly quick motion toward the west-northwest is expected to continue for the next few days.  On its anticipated track Invest 92L could be near the Windward Islands by late Monday.  Even it if does not develop into a tropical cyclone, the system will bring gusty winds and locally heavy rain to those islands.

The structure of Invest 93L is much more complicated.  There is a very broad but weak surface low pressure system over the Yucatan peninsula and the center of that low is being used as the center of the Invest.  However, there is a strong mid-level center of circulation near latitude 18.7°N and longitude 82.9°W which is about 115 miles (185 km) west-southwest of Grand Cayman.  Invest 93L is producing winds to near tropical storm force and those winds are occurring in thunderstorms associated with the mid-level circulation.  It is possible that downdrafts in those thunderstorms could transport enough momentum to the surface to generate a new surface center beneath the mid-level center.

Invest 93L is moving in an environment that will be favorable for the development of a tropical cyclone.  An upper level ridge is building between the trough over the eastern Caribbean Sea and another upper level trough over the northwestern Gulf of Mexico.  The trough over the northwestern Gulf is producing strong southwesterly winds which are causing vertical wind shear over the surface low over the Yucatan peninsula.  However, the upper level ridge is producing an area of slower winds over the mid-level center and there is less vertical wind shear there.  In fact, the upper level ridge is enhancing upper level divergence over the mid-level center.  If that continues, surfaces pressure will begin to decrease in that region.  The National Hurricane is indicating that there is a 70% probability of development of a tropical cyclone or a subtropical cyclone during the next two days.

Invest 93L is moving slowly north-northwestward around the western end of the subtropical high over the Atlantic Ocean.  A general north-northwesterly motion is expected to continue for another day or two, but there is some spread in the guidance from the numerical models.  If a cyclone forms from the surface low over the Yucatan peninsula, then the greatest risk would be to the western Gulf of Mexico.  If a new surface center forms farther east under the mid-level center, then there would be a greater risk for the central and eastern Gulf of Mexico.  Interests around the Gulf should monitor Invest 93L.

Two Areas to Watch for Potential Tropical Development

There are two areas to watch for the potential development of a tropical cyclone during the next week.  One location to watch for potential development is the area around the western Caribbean Sea, Yucatan peninsula and southern Gulf of Mexico.  The other area to watch is the tropical Atlantic between Africa and the Lesser Antilles.

Numerical models have been suggesting possible development of an area of low pressure somewhere over the western Caribbean Sea, Yucatan peninsula or southern Gulf of Mexico.  The scenario suggested by the models includes a surge of southerly winds across Central America, which contributes to the spinning up of an area of low pressure.  There are currently strong westerly winds in the upper levels over this area.  The strong vertical wind shear will prevent development of a tropical cyclone in the short term.  An upper level ridge could develop over the area in several days.  If that happens, the wind shear would decrease.  Some runs of the numerical models create a broad, weak area of low pressure, which would primarily be a rain threat for the Yucatan peninsula and nearby regions.  Other models develop a low pressure system that is a little stronger, although those lows also weaken when they move over the Yucatan.  The models generally move the low pressure system northwestward over the southern Gulf of Mexico.  However, there are fairly significant deviations in how far north the low moves once it is in the Gulf.  As of 8:00 p.m. EDT on June 14 the National Hurricane Center was indicating that there was a 30% probability of the development of a tropical cyclone in this area during the next five days.

Some numerical models have also been suggesting potential development of a tropical cyclone near latitude 10°N over the tropical Atlantic Ocean between Africa and the Lesser Antilles.  A tropical wave is interacting with the Intertropical Convergence Zone and there has been a persistent area of showers and thunderstorms.  The disturbance is moving slowly toward the west.  There is some vertical wind shear in this region, but the stronger upper level winds are north of the disturbance.  The disturbance is over water where the Sea Surface Temperature is near 27°C.  It would be unusual to see a tropical cyclone develop over the tropical Atlantic in June, but it has happened at least three times in the past.  As of 8:00 p.m. EDT on June 14 the National Hurricane Center is indicating that there is a 20% probability of the development of a tropical cyclone in this region during the next five days.

TD 03E Strengthens Into Tropical Storm Calvin

Tropical Depression 03E strengthened into Tropical Storm Calvin on Monday as it lingered south of Mexico.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Calvin was located at latitude 15.5°N and longitude 95.5°W which put it about 70 miles (110 km) east-southeast of Puerto Angel, Mexico.  Calvin was moving toward the west-northwest 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 1005 mb.  A Tropical Storm Warning remains in effect for the portion of the coast from Boca De Pijijiapan to Punta Maldonado.

A band of thunderstorms wrapped tightly around the southern side of the center of circulation of former Tropical Depression 03E and the National Hurricane Center upgraded the system to Tropical Storm Calvin in its 5:00 p.m. EDT advisory on Monday.  Calvin is a small tropical storm and winds to tropical storm force only extend out about 60 miles (95 km) from the center of circulation.  Additional bands of showers and thunderstorms are occurring in the outer portions of the circulation which are over the Pacific Ocean.

Tropical Storm Calvin is in an environment that is marginally favorable for intensification.  It is over water where the Sea Surface Temperature is near 30°C.  However, Calvin is also very near the coast of Mexico and it could start to pull drier air into the western part of the circulation at any time.  Calvin is under the eastern end of an upper level ridge which is producing northerly winds which are blowing toward the top of the tropical storm.  The northerly winds are producing moderate vertical wind shear and the shear may be contributing to the location of the main band thunderstorms south of the center of circulation.

The future intensity of Tropical Storm Calvin will depend on whether or not it remains over the Pacific Ocean.  If Calvin stays over the open water, then further intensification is possible.  If Calvin moves closer to the coast, then further intensification is much less likely.  If Calvin moves inland, it will dissipate quickly.

Tropical Storm Calvin is in an area where the steering currents are weak and it moved very slowly toward the west-northwest during the past 18 hours.  A subtropical ridge north of Calvin is forecast to begin to steer the tropical storm more quickly toward the west-northwest.  If that happens, Calvin could make landfall on the coast of Mexico near Puerto Angel in 12 to 24 hours.  Locally heavy rainfall remain the biggest risks with Tropical Storm Calvin.

Tropical Storm Merbok Makes Landfall Near Hong Kong

Tropical Storm Merbok made landfall near Hong Kong on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Merbok was located at latitude 23.5°N and longitude 114.9°E which put it about 55 miles (85 km) north-northeast of Hong Kong.  Merbok was moving toward the north at 11 m.p.h. (17 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.

Tropical Storm Merbok intensified before it made landfall and the maximum sustained wind speed was around 55 m.p.h. (85 km/h) at the time of landfall.  Merbok began to weaken after landfall and the strongest winds are now occurring in bands over the the open water.  Merbok is producing locally heavy rain in bands east of the center if circulation.  The heavy rains represent the greatest risk and flooding is possible over parts of eastern China.  Merbok is a fairly small tropical storm and the heavier rain will fall primarily to the east of the track of Merbok.  Merbok should gradually spin down as it moves farther inland.

Formation of Tropical Depression 03E Prompts Mexico to Issue Warning for Coast

Tropical Depression 03E formed out of the cluster of thunderstorms formerly known as Invest 92E and the government of Mexico issued a Tropical Storm Warning for a portion of the south coast.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression 03E was located at latitude 14.5°N and longitude 95.0°W which put it about 105 miles (170 km) southeast of Puerto Angel, Mexico.  The depression was moving toward the northwest at 5 m.p.h. (7 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 1007 mb.  A Tropical Storm Warning is in effect for the portion of the coast from Boca De Pijijiapan to Punta Maldonado, Mexico.

A distinct center of circulation developed within an area of thunderstorms that had been lingering over the Eastern North Pacific Ocean south of Mexico.  More thunderstorms formed closer to the center of circulation and the National  Hurricane Center determined that there was sufficient organization to designate the system as Tropical Depression 03E.  The stronger thunderstorms were occurring in a partial band close to the center of circulation.  Additional bands of showers and thunderstorms were forming in bands in other parts of the circulation.  The thunderstorms near the center have not yet begun to generate significant upper level divergence.

Tropical Depression 03E will be moving through an environment that is marginally favorable for intensification.  The depression will move over water where the Sea Surface Temperature is near 30°C.  It is moving under the western end of an upper level ridge.  The ridge is generating southeasterly winds which are blowing toward the top of the circulation.  Those winds are generating moderate vertical wind shear which is restricting upper level divergence to the east of the circulation.  The shear is inhibiting intensification.  Tropical Depression 03E will probably be able to extract enough energy to intensify into a tropical storm.

Tropical Depression 03E is moving around the western end of a subtropical ridge which is steering it toward the northwest.  A generally northwesterly motion is forecast for the next 24 to 48 hours.  On its anticipated track Tropical Depression 03E could approach the southern coast of Mexico in 24 to 36 hours.  It could be a tropical storm by that time.  Tropical Depression 03E is likely to bring gusty winds, locally heavy rain and the potential for flash floods to parts of southern Mexico.