Tag Archives: Louisiana

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 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.

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.

Tropical Storm Beatriz Brings Heavy Rain to Southern Mexico

Tropical Depression Two-E intensified into Tropical Storm Beatriz on Thursday and Beatriz brought heavy rain to parts of southern Mexico.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Beatriz was located at latitude 15.5°N and longitude 96.8°W which put it about 25 miles (40 km) southwest of Puerto Angel, Mexico.  Beatriz 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 1004 mb.  A Tropical Storm Warning was in effect for the portion of the coast from Salina Cruz to Puerto Escondido.

Tropical Depression Two-E intensified into Tropical Storm Beatriz on Thursday even though its structure evolved into a more asymmetrical system.  Tropical Storm Beatriz appeared to consist of a larger low pressure system which was centered just off the coast of Mexico.  The weather radar from Puerto Angel confirmed that the center of circulation was still offshore.  There were several smaller (mesoscale) counterclockwise rotating circulations that were revolving around the center of the larger low.  At least one of the smaller circulations was already over southern Mexico.  Many of the thunderstorms were occurring in a broad band that wrapped around the eastern and northern portions of the larger low pressure system.  The strongest winds were occurring within this primary rainband.  There were far fewer thunderstorms in the western half of the circulation.  It seemed that after air descended from mountains in Mexico then the air was drawn into the western side of Tropical Storm Beatriz.  The warmer drier air was inhibiting the formation of thunderstorms in the western half of Beatriz.

Although Tropical Storm Beatriz is over water where the Sea Surface Temperature is near 30°C, other environmental factors are unfavorable for intensification.  The proximity to land and the apparent ingestion of drier air are both negative factors.  A narrow upper level ridge oriented from the south-southwest to the north-northeast and a upper level trough to the west of Beatriz are producing brisk southerly winds that are blowing toward the top of the circulation.  Those upper level winds are causing moderate vertical wind shear.  Therefore, Tropical Storm Beatriz is unlike to intensify further during the next several days.

The future track of Tropical Storm Beatriz is uncertain.  If the circulation of Beatriz remains intact then the upper level trough and upper level ridge are likely to steer it toward the north-northeast.  Tropical Storm Beatriz would dissipate over the mountains of Mexico if that scenario occurs.  If the upper level winds are strong enough, the vertical shear could detach the upper portion of the circulation from the low level circulation.  That scenario sometimes occurs when slow moving storms approach the south coast of Mexico.  If that happens, the upper half of the circulation could be transported across Mexico and move over the southern Gulf of Mexico.  Some models are suggesting that a new surface low could form over the southern Gulf in several days, but the wind shear would have to decrease in order for that to occur.  The lower level circulation could be left behind near the coast of Mexico where it would drift slowly near the coast.

Tropical Storm Beatriz is bringing heavy rains to parts of southern Mexico and the heavy rain will continue to fall on Friday.  Locally heavy rain in the more mountainous portions of Oaxaca could create the potential for dangerous flash floods.

Tropical Depressions Form South of Key West & Southeast of Cape Hatteras

Two tropical depressions formed near the U.S. on Sunday.  Tropical Depression Nine formed south of Key West, Florida and Tropical Depression Eight formed southeast of Cape Hatteras, North Carolina.  Both depressions could have an impact on the U.S., but Tropical Depression Nine could pose a greater risk to the southeastern U.S.

At 5:00 p.m. EDT on Sunday the center of Tropical Depression Nine was located at latitude 23.7°N and longitude 81.7°W which put it about 60 miles (95 km) south of Key West, Florida.  It was moving toward the west 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. (70 km/h).  The minimum surface pressure was 1009 mb.

At 5:00 p.m. EDT on Sunday the center of Tropical Depression Eight was located at latitude 31.8°N and longitude 70.9°W which put it about 355 miles (570 km) southeast of Cape Hatteras, North Carolina.  It was moving toward the west 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. (70 km/h).  The minimum surface pressure was 1010 mb.

The circulation of Tropical Depression Nine is still organizing.  A NOAA plane found a distinct center of circulation, but most of the stronger thunderstorms are south and east of the center.  There is a broader counterclockwise rotation with numerous showers and thunderstorms indicated by the National Weather Service radar in Key West.  An upper level low east of Florida is contributing to easterly winds that are blowing across the northern side of the depression.  The vertical wind shear is inhibiting the development of thunderstorms north and west of the center.

The circulation of Tropical Depression Eight was more well organized earlier today.  Strong easterly winds from the same upper level low that is affecting Tropical Depression Nine are creating significant vertical wind shear.  Those winds and the shear they caused blew the upper portion of the depression’s circulation west of the low level center of circulation.  The low level circulation is presently exposed as seen on visible satellite imagery and by an Air Force Reserve Hurricane Hunter aircraft.

The intensity forecast for Tropical Depression Nine is challenging because it is moving through a complex environment.  The depression is moving over water where the Sea Surface Temperature is near 31°C.  So, there is plenty of energy in the upper ocean.  However, as mentioned above, an upper low is causing vertical wind shear which will inhibit intensification.  Tropical Depression Nine could move into a region where there is less shear when it moves over the Gulf of Mexico.  Tropical Depression Nine has a good chance to intensify into a tropical storm, but it is unclear if it could become a hurricane before it reaches the coast.

There is also significant uncertainty in the track forecast for Tropical Depression Nine.  A ridge over the southeastern U.S. is steering the depression toward the west and that general motion should continue for several more days.  The ridge is forecast to weaken during the middle of the week and that should allow Tropical Depression Nine to turn toward the north.  The timing of that turn and how sharp it will be are still uncertain.

The upper low is expected to continue to generate wind shear over Tropical Depression Eight.  If the upper levels winds remain as strong as they are now, the depression will slowly weaken.  If the upper level winds weaken, then Tropical Depression Eight could strengthen into a minimal tropical storm.  The upper level low is steering the depression west and that general motion is expected to continue in the short term.  The depression could stall just off the coast of North Carolina.

Tropical Depression Nine could intensify and bring wind and rain to the Gulf Coast later this week.  The Gulf Coast is also vulnerable to storm surges.  Given the uncertainty in both the track and intensity, interests along the coast should monitor official sources of information for updates on Tropical Depression Nine.  The primary effects of Tropical Depression Eight are likely to be higher than normal surf, rip currents and some beach erosion along the North Carolina coast.  People along the Mid-Atlantic coast should pay attention to the depression in case the forecast changes.

Disturbance Near Yucatan Could Develop Over Gulf of Mexico

A tropical disturbance over the northwestern Caribbean Sea near the Yucatan peninsula is moving northwest and it could develop into a tropical cyclone when it moves over the southern Gulf of Mexico.  The National Hurricane Center (NHC) has designated the disturbance as Invest 93L and NHC is putting the probability of development into a tropical cyclone during the next two days at 80%.  At 8:00 p.m. EDT the center of Invest 93L was located at latitude 18.5°N and longitude 87.5°W which put it about 170 miles (270 km) south of Cancun, Mexico.  Invest 93L was moving toward the northwest at 11 m.p.h. (17 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. (70 km/h).  The minimum surface pressure was 1005 mb.

Invest 93L consists of a broad area of low pressure at the surface.  Several bands of thunderstorms are occurring in the eastern and northern parts of the circulation.  There is no well defined center of circulation and there are fewer thunderstorms in the inner portion of the circulation.  The strongest winds are occurring in the bands of thunderstorms north and east of the center.  There is some upper level divergence to the east of Invest 93L.

The environment around Invest 93L is not totally favorable for development.  The Sea Surface Temperature in northwest Caribbean Sea is near 30°C, which means there is plenty of energy in the upper ocean.  However, an upper level low near Texas and an upper level ridge east of Invest 93L are combining to generate strong southwesterly winds that are blowing over the top of the disturbance.  Those winds are creating significant vertical wind shear which is inhibiting the development of Invest 93L.  The upper level ridge is enhancing the upper level divergence to the east of the disturbance which allowed the pressure to fall several millibars on Saturday.  The upper winds are lighter near the axis of the ridge which is why the stronger bands of thunderstorms are persisting in that area.

Invest 93L is forecast to move toward the Yucatan peninsula on Sunday.  If the broad area over low pressure moves over land that will prevent it from developing until it moves back over water.  Numerical models are guiding that the disturbance will develop into a tropical cyclone when the area of low pressure moves over the southern Gulf of Mexico.  The upper level ridge is forecast to extend over the southeastern Gulf and if that happens the wind shear could decrease enough to allow development to occur.  Invest 93L could become a tropical depression or a tropical storm over the Gulf of Mexico.

The southwesterly flow over the Gulf of Mexico is forecast to turn Invest 93L toward the northeast.  On its anticipated track the system could reach the west coast of Florida near Cedar Key late Monday or early Tuesday.  The primary risk is likely to be locally heavy rain.  However, the coast in that area is very susceptible to storm surge and there could be some rise in the water level.  The National Hurricane Center has tentatively tasked a reconnaissance plane to investigate Invest 93L on Sunday, if necessary.

Tropical Storm Bills Forms Near Texas

The National Hurricane Center (NHC) classified a low pressure system over the western Gulf of Mexico as Tropical Storm Bill.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Bill was located at latitude 27.1°N and longitude 94.2°W which put it about 160 miles (260 km) east-southeast of Port OConnor, Texas and about 155 miles (250 km) south-southeast of Galveston, Texas.  Bill was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 50 m.p.h. (85 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1005 mb.  A Tropical Storm Warning has been issued for the portion of the coast from Baffin Bay to High Island, Texas.

Bill formed as a result of the interaction between a broad surface low pressure system and an upper level low over the Gulf of Mexico.  Thunderstorms began to form near the center of circulation on Monday afternoon and the structure of the system changed to a more tropical cyclone like pattern.  The thunderstorms near the center began to warm the middle and upper troposphere and create a warm core.  The thunderstorms became substantial enough to generate upper level divergence from the core of the circulation and NHC classified it as Tropical Storm Bill.  Bill is moving over water where the Sea Surface Temperature (SST) is near 29°C.  The vertical wind shear over the system decreased on Monday and Bill has a few hours during which it could intensify before it makes landfall in Texas.

An upper level ridge over the southeastern U.S. is steering Bill northwestward toward the coast of Texas and that motion is expected to continue.  Bill is expected to make landfall in Texas on Tuesday.  Although Bill will bring some wind when it makes landfall, heavy rainfall will be the biggest hazard.  Heavy rain on top of wet soils will create the potential for new flooding in some locations, especially in Texas and Oklahoma.  Winds blowing toward the coast will also create some water level rises and Coastal Flood Warnings and Advisories have been issued for portions of the coast of Texas and Louisiana.