Tag Archives: Gulf of Mexico

Tropical Storm Barry Strengthens South of Louisiana

Tropical Storm Barry strengthened south of Louisiana on Friday morning.  Hurricane Hunters flying into Barry found that the maximum sustained wind speed had increased to 65 m.p.h. (105 km/h).  At 11:00 a.m. EDT on Friday the center of Tropical Storm Barry was located at latitude 28.2°N and longitude 90.4°W which put it about 115 miles (185 km) south-southeast of Morgan City, Louisiana.  Barry was moving toward the west-northwest at 5 m.p.h. (8 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 998 mb.

A Hurricane Warning is in effect for the portion of the coast from Intracoastal City to Grand Isle, Louisiana. Hurricane Watches have been issued for the portions of the coast from the Mouth of the Mississippi River to Grand Isle, Louisiana and from Intracoastal City to Cameron, Louisiana. Tropical Storm Warnings are in effect for the portions of the coast from the Mouth of the Pearl River to Grand Isle, Louisiana and from Intracoastal City to Cameron, Louisiana. A Tropical Storm Watch has been issued for the portion of the coast from the Mouth of the Pearl River to the Mississippi/Alabama border. A Tropical Storm Warning is in effect for Lake Pontchartrain, Lake Maurepas and New Orleans.

The circulation around Tropical Storm Barry exhibited greater organization on Friday morning.  Thunderstorms developed in a band around the southern side of the center of circulation.  More thunderstorms also formed in bands that stretched around the western, southern and eastern sides of the circulation.  Bands in the northern portion of the circulation consisted primarily of showers and lower clouds, although there were some thunderstorms in the parts of those bands over land.  Winds to tropical storm force extended out about 170 miles (280 km) from the center of circulation.  Storms just south of the center were generating upper level divergence which was pumping mass away to the west of Tropical Storm Barry.  The removal of mass allowed the surface pressure to decrease and it was down to 998 mb on Friday morning.

Tropical Storm Barry will move through an environment that is some what favorable for intensification.  Barry will move south of a narrow upper level ridge that stretches from east Texas to south Alabama.  The ridge will produce northeasterly winds which will cause some vertical wind shear.  The shear is one of the reasons why there are fewer thunderstorms in the northern part of the circulation.  Reconnaissance aircraft reported that the middle level center was a little to the south of the surface center.  The tilt of the circulation with height is also the result of the vertical wind shear.  However, the shear will not be strong enough to prevent intensification.  Tropical Storm Barry will move over water where the Sea Surface Temperature is near 30.5°C.  It will extract a lot of energy from the Gulf of Mexico.  Tropical Storm Barry is forecast to strengthen into a hurricane during the next 24 hours.

Tropical Storm Barry is moving around the southwestern part of a ridge of high pressure over the southeastern U.S.  The ridge will steer Barry slowly toward the west-northwest during the next few hours.  Barry will turn more toward the northwest later on Friday.  On its anticipated track the center of Tropical Storm Barry will approach the coast of Louisiana late Friday night.  Barry is forecast to be a hurricane when it reaches the coast.  The broad circulation will cause mostly minor wind damage over a large area.  There could be widespread power outages.  Barry will also generate a storm surge of 6 to 9 feet (2 to 3 meters near where the center makes landfall.  Tropical Storm Barry will drop heavy rain when it moves slowly inland.  Flooding is a serious risk, since soils are nearly saturated and many creeks and rivers are already high.

Tropical Storm Barry Threatens Louisiana

Tropical Storm Barry threatened Louisiana on Thursday.  A low pressure system formerly designated at Potential Tropical Cyclone Two strengthened into Tropical Storm Barry on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Barry was located at latitude 27.8°N and longitude 88.7°W which put it about 95 miles (150 km) south-southeast of the Mouth of the Mississippi River and about 200 miles (320 km) southeast of Morgan City, Louisiana.  Barry was moving toward the west 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 1005 mb.

A Hurricane Watch has been issued for the portion of the coast from the Mouth of the Mississippi River to Cameron, Louisiana.  A Tropical Storm Warning is in effect for the portion of the coast from the Mouth of the Pearl River to Morgan City, Louisiana.  A Tropical Storm Watch has been issued for the portion of the coast from the Mouth of the Pearl River to the Mississippi/Alabama border.  A Tropical Storm Watch has also been issued for Lake Pontchartrain, Lake Maurepas and New Orleans.

The circulation around Tropical Storm Barry exhibited more organization on Thursday morning, but there were not a lot of thunderstorms near the center of circulation.  Many of the thunderstorms were occurring in bands wrapping around the western and southern sides of the circulation.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force were occurring in the southeastern part of Tropical Storm Barry.  Winds to tropical storm force extended out about 100 miles (160 km) from the center in that quadrant of Barry.  The winds were weaker in other quadrants of the circulation.

Tropical Storm Barry will move through an environment favorable for intensification during the next 36 hours.  Barry will move over water where the Sea Surface Temperature is near 30.5°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Barry will intensify slowly until more thunderstorms form near the center of circulation.  If thunderstorms consolidate around an inner core, then rapid intensification would be possible.  Tropical Storm Barry is forecast to strengthen into a hurricane on Friday.

Tropical Storm Barry will move around the southwestern part of a ridge of high pressure over the southeastern U.S.  The ridge is likely to steer Barry slowly toward the west during the next 12 to 24 hours.  Tropical Storm Barry will move more toward the northwest when it moves around the southwestern part of the ridge.  There is still some uncertainty about the timing and location of the turn toward the northwest.  Based on its anticipated track Tropical Storm Barry could approach the coast of Louisiana on Friday night.

Tropical Storm Barry is forecast to strengthen into a hurricane before it makes landfall.  It will bring strong, gusty winds to coastal regions of Louisiana.  Those winds will also push a storm surge toward the coast.  The storm surge could be up to 6 to 8 feet (2 to 3 meters) near where the center makes landfall.  Tropical Storm Barry could drop heavy rain when it moves inland.  Many rivers and streams are already high and locally heavy rain could cause flooding in those locations.

NHC Initiates Advisories on Potential Tropical Cyclone Two

The National Hurricane Center (NHC) initiated advisories on Potential Tropical Cyclone Two on Wednesday morning.  NHC initiated the advisories in order to be able to issue watches for a portion of the coast of Louisiana.  At 11:00 a.m. EDT on Wednesday the center of Potential Tropical Cyclone Two was located at latitude 28.5°N and longitude 86.4°W which put it about 170 miles (270 km) east-southeast of the Mouth of the Mississippi River.  It was moving toward the west-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1011 mb.  A Tropical Storm Watch was issued for the portion of the coast from the Mouth of the Mississippi River to Morgan City, Louisiana.

The circulation around Potential Tropical Cyclone Two was not well organized.  There was a large, but relatively weak circulation near the surface.  There was not a well defined center of circulation near the surface.  There was a stronger counterclockwise circulation between about 10,000 feet (3000 meters) and 25,000 feet (7600 meters) above the surface, which was located above the southwestern part of the surface circulation.  Many of the stronger thunderstorms were occurring in bands on the northern and western sides of the circulation above the surface.  There were fewer thunderstorms in the eastern side of the larger, surface circulation.

Potential Tropical Cyclone Two will move through an environment very favorable for development and intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  The system will move through a region where the upper level winds are weak and there will be little vertical wind shear.  It is likely that a center of circulation will form at the surface underneath the counterclockwise circulation above the surface.  Potential Tropical Cyclone Two will strengthen slowly until the surface center is underneath the center higher in the atmosphere.  After the circulation becomes aligned vertically, the system could strengthen more rapidly.  Potential Tropical Cyclone Two is likely to become a hurricane within 48 to 60 hours.

Potential Tropical Cyclone Two will move south of a ridge over the southeastern U.S.  The ridge will steer Potential Tropical Cyclone Two toward the southwest.  It will move more toward the west on Thursday and then turn back more toward the northwest on Friday when it nears the western end of the ridge.  There will be significant uncertainty about the future track of the system until a well defined center of circulation forms at the surface.  On its anticipated track the center of Tropical Cyclone Two could approach the coast of Louisiana and northeast Texas on Friday.  Hurricane Watches and Warnings are likely to be issued for portions of the coast later this week.

Potential Tropical Cyclone Two presents a wide range of hazards.  It will bring hurricane force winds to portions of Louisiana and Texas and it will disrupt operations of offshore facilities in the northwestern Gulf of Mexico.  After the center of the system moves west of New Orleans, southerly winds will force water into the Mouth of the Mississippi River.  The level of the Mississippi River around New Orleans is already near flood stage and any additional rise in the water level could cause serious flooding around the city.  If Potential Tropical Cyclone Two strengthens into a hurricane, as expected, it will cause a significant storm near where the center makes landfall.  The system also has the potential to drop heavy rain and flooding could occur when it moves inland.

Potential Tropical Development Over Northern Gulf of Mexico

The potential exists for the development of a tropical cyclone over the northern Gulf of Mexico this week.  A low pressure system was over Georgia on Monday afternoon.  The low was drifting slowly southward, but it was forecast to move more toward the south-southwest during the next two days.  Several numerical models were predicting that the low pressure system would strengthen into a tropical depression or a tropical storm after it moves over the northern Gulf of Mexico later this week.  The National Hurricane Center was indicating that the low pressure system, currently designated as Invest 92L, had a 30% probability of developing into a tropical cyclone during the next two days and an 80% probability of developing into a tropical cyclone during the next five days.

The low pressure system exhibited a surface circulation on Monday afternoon, but the wind speed was near 15 m.p.h. (25 km/h).  Bands of showers and thunderstorms formed during the daytime heating over land, but they weakened at night.  There was also a counterclockwise rotation in the lower and middle troposphere which may have been the remnants of a mesoscale convective vortex (MCV), which developed over the Middle Mississippi River Valley a few days ago.  The low was not generating upper level divergence on Monday afternoon.

If the low pressure system does move over the northern Gulf of Mexico on Tuesday or Wednesday, it will move into an environment more favorable for the development of a tropical depression.  The Sea Surface Temperature of the water in the northeastern Gulf of Mexico is near 30°C.  The low pressure system will move southeast of an upper level ridge over the southern U.S.  The ridge will produce northeasterly winds, but the winds will be relatively weak and the vertical wind shear will not be too strong.  More thunderstorms are likely to develop when the low pressure system moves over the warm water.  If those thunderstorms generate upper level divergence that pumps mass away, then the surface pressure will decrease and a tropical depression will form.

The upper level ridge is forecast to steer the low pressure system toward the west after it moves over the Gulf of Mexico later this week.  On its anticipated track the low pressure system will move slowly toward the coast of Louisiana and Texas.  The future intensity of the system will be determined by how far the system moves into the Gulf of Mexico.  If the low pressure system takes a track along or near the north coast of the Gulf of Mexico, then it will likely become a tropical depression or a weak tropical storm.  Even if the low only strengthens into a tropical depression, it could drop heavy rain and the potential for flooding exists along the northern Gulf Coast.  If the low pressure system moves farther out into the Gulf of Mexico and remains over warm water for a longer period, then it might intensify into a hurricane.  Residents along the Gulf Coast should monitor this system carefully.

Michael Strengthens to a Major Hurricane

Hurricane Michael strengthened into a major hurricane on Tuesday afternoon.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Michael was located at latitude 26.0°N and longitude 86.4°W which put it about 290 miles (470 km) south of Panama City, Florida.  Michael was moving toward the north at 12 m.p.h. (19 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 957 mb.

A Hurricane Warning is in effect for the portion of the coast from the Alabama-Florida border to the Suwanee River, Florida.  Tropical Storm Warnings are in effect for the portions of the coast from the Alabama-Florida border to the Alabama-Mississippi border, from Suwanee River to Chassahowitzka, Florida and from Fernandina Beach, Florida to South Santee River, South Carolina on the Atlantic Coast.  Tropical Storm Watches are in effect for the portions of the coast from the Alabama-Mississippi border to the Mouth of the Pearl River, from Chassahowitzka to Anna Maria Island, Florida and from South Santee, River South Carolina to Duck, North Carolina including Albemarle and Pamlico Sounds.

The inner core of Hurricane Michael tightened on Tuesday afternoon.  The diameter of the eye decreased from 30 miles (50 km) to 22 miles (35 km).  The ring of thunderstorms around the eye tightened around the smaller eye and the strongest winds were closer to the center of circulation.  Storms around the core of Michael were generating upper level divergence which was pumping mass away from the hurricane.  The removal of mass allowed the surface pressure to decrease from 965 mb to 957 mb during the past six hours.

Winds to hurricane force extend out about 45 miles (75 km) from the center of Hurricane Michael.  Winds to tropical storm force extend out about 170 miles (280 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Michael is 22.1.  The Hurricane Size Index (HSI) is 14.6 and the Hurricane Wind Intensity Size Index (HWISI) is 36.7.  Hurricane Michael is capable of causing regional major damage.

Hurricane Michael will move through an environment favorable for intensification for another 12 to 18 hours.  Michael will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough over the Central U.S. is producing westerly winds which are blowing toward the top of Hurricane Michael, but those winds are not causing enough vertical wind shear to prevent intensification.  Hurricane Michael could intensify to Category 4 on the Saffir-Simpson Scale before it makes landfall.

Hurricane Michael is moving between a subtropical high pressure system over the western Atlantic Ocean and the upper level trough over the Central U.S.  Those two weather systems are steering Michael toward the north and that general motion is expected to continue for another 12 hours.  On its anticipated track Hurricane Michael will make landfall near Panama City and Port St. Joe, Florida early on Wednesday afternoon.  The upper level trough will steer Michael more toward the northeast after it makes landfall.  The center of Michael is likely to move between Dothan, Alabama and Tallahassee, Florida and it could pass near Albany, Georgia.

Hurricane Michael will bring strong winds to northwest Florida, extreme southeast Alabama and southern Georgia.  There will be wind damage and widespread power outages could occur.  The coast of the northeastern Gulf of Mexico is very vulnerable to storm surges.  Hurricane Michael will produce a storm surge of 10 to 15 feet (3 to 5 meters) at some points along the coast.  Michael will drop locally heavy rain.  Although Hurricane Michael will weaken when it moves inland, it will bring gusty winds and heavy rain to South Carolina and North Carolina.  Hurricane Michael will hinder efforts in those states to recover from the effects of Hurricane Florence.

Possible Tropical Development Near Yucatan Peninsula

A tropical cyclone could develop near the Yucatan peninsula during the next few days.  At 2:00 p.m. EDT on Friday the center of Invest 91L was located at latitude 16.0°N and longitude 84.3°W which put it about 400 miles (640 km) southeast of Cancun, Mexico.  It was moving toward the northwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1007 mb.

A broad area of low pressure is over the western Caribbean Sea, Central America and the adjacent waters of the Eastern North Pacific Ocean.  Several smaller, mesoscale centers of rotation appear to be revolving around the larger low pressure system.  One of the mesoscale centers is over the Eastern North Pacific Ocean just west of the coast of Central America.  One or two other mesoscale centers appear to be over the western Caribbean Sea near Honduras.  The low level circulation is not currently well organized.  It is broad and diffuse.  Thunderstorms are clustered around the mesoscale centers, but large scale rainbands have not formed.

Westerly winds in the upper levels are are blowing over the top of the system.  Those winds are creating moderate vertical wind shear which is inhibiting the development of the low pressure system.  The upper level winds are forecast to weaken during the next few days and the wind shear will diminish.  The Sea Surface Temperature of the water in the northwestern Caribbean Sea and Gulf of Mexico is near 30°C.  The broad low pressure system could slowly organize during the next two to three days.  The National Hurricane Center is indicating that there is a 70% probability of formation of a tropical cyclone near the Yucatan peninsula or over the southern Gulf of Mexico during the next five days.  A reconnaissance plane is scheduled to investigate the low pressure system on Sunday, if necessary.

The broad low is southwest of a subtropical high pressure system over the Atlantic Ocean.  The high is expected to steer the low toward the northwest during the weekend.  On its anticipated track the low will move over the northwestern Caribbean Sea during the next several days.  it could move into the Gulf of Mexico on Monday.

Elsewhere over the Atlantic Ocean, Tropical Storm Leslie continued to meander northeast of Bermuda.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Leslie was located at latitude 36.2°N and longitude 58.4°W which put it about 455 miles (730 km) northeast of Bermuda.  Leslie was moving toward the north-northwest at 9 m.p.h. (15 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 986 mb.

Tropical Storm Gordon Makes Landfall on the Gulf Coast.

Tropical Storm Gordon made landfall on the Gulf Coast near Pascagoula, Mississippi on Tuesday night.  At 11:30 p.m. EDT on Tuesday the center of Tropical Storm Gordon was located at latitude 30.4°N and longitude 88.4°W which put it about 30 miles (50 km) east of Biloxi, Mississippi.  Gordon was moving toward the northwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 997 mb.

A Hurricane Warning was in effect for the portion of the coast from the Mouth of the Pearl River to the Alabama-Florida border.  A Tropical Storm Warning was in effect for the portion of the coast from the Okaloosa-Walton County line to the Alabama-Florida border.

The circulation of Tropical Storm Gordon was asymmetrical.  The strongest bands of showers and thunderstorms were north and east of the center of circulation.  The strongest winds were occurring in those bands.  A C-MAN station on Dauphin Island, Alabama reported a sustained wind speed of 62 m.p.h. (100 km/h) and a wind gust of 72 m.p.h. (117 km/h).  The winds were much weaker south and west of the center of Tropical Storm Gordon and there was little rain in those parts of the tropical storm.

Tropical Storm Gordon will start to weaken as the center moves inland.  Gordon will continue to move around the western end of a high pressure system over the western Atlantic Ocean.  The high will steer Tropical Storm Gordon toward the northwest during the next day or two.  On its anticipated track Tropical Storm Gordon will move across southern Mississippi on Wednesday and over Arkansas on Thursday.  The wind will be strong enough to cause minor damage and it will cause some power outages.  Locally heavy rain and the potential for flash floods are the greater risks.  Flash Flood Warnings were in effect for parts of West Florida and Southwest Alabama.  Flash Flood Watches were in effect for Mississippi and Southeastern Arkansas.

Elsewhere over the tropical Atlantic Ocean, Hurricane Florence was continuing to intensify east of the northern Leeward Islands.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Florence was located at latitude 20.7°N and longitude 43.9°W which put it about 1515 miles (2440 km) east-southeast of Bermuda.  Florence was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 100 m.p.h (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 976 mb.

Tropical Storm Gordon Nears Gulf Coast

Tropical Storm Gordon moved closer to the Gulf Coast of the U.S. on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Gordon was located at latitude 28.5°N and longitude 86.8°W which put it about 145 miles (235 km) east-southeast of the mouth of the Mississippi River.  Gordon was moving toward the northwest at 15 m.p.h. (24 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 1001 mb.

A Hurricane Warning was in effect for the portion of the coast from the mouth of the Pearl River to the Alabama-Florida border.  Tropical Storm Warnings were in effect for the portions of the coast from Grand Isle, Louisiana to the mouth of the Pearl River including Lake Pontchartrain and from the Alabama-Florida border to the Okaloosa-Walton County line in Florida.

The circulation of Tropical Storm Gordon appeared to be getting more organized on Tuesday morning.  More thunderstorms developed near the center of circulation.  Storms near the center were generating upper level divergence which was pumping mass away to the east of the tropical storm.  Several bands of showers and thunderstorms north and east of the center were moving toward the Gulf Coast.  The bands southwest of the center consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation, but the winds were weaker in the southwestern quadrant of Tropical Storm Gordon.

Tropical Storm Gordon could strengthen into a hurricane before it makes landfall.  Gordon will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the southeastern U.S. was producing southwesterly winds which were blowing toward the top of the circulation.  Those winds were causing some vertical shear, but they will not be strong enough to prevent intensification.  The surface pressure decreased slightly on Tuesday morning.  Increased friction near the coast could cause the circulation to tighten around the center, when Tropical Storm Gordon gets closer to the Gulf Coast.

Tropical Storm Gordon will move around the southwestern end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Gordon in a general northwesterly direction during the next several days.  On its anticipated track the center of Hurricane Gordon is likely to make landfall on the northern Gulf Coast on Tuesday night.  Gordon will produce winds to near hurricane force at the coast.  It could cause a storm surge of 5 to 8 feet (1.5 to 2.5 meters) east of the center where the wind blows water toward the coast.  The highest storm surge will occur in bays and the mouths of streams and rivers where the shape of the coast funnels water into those areas.  Tropical Storm Gordon will also drop heavy rain over portions of northwest Florida, southwest Alabama, Mississippi and eastern Louisiana.  Locally heavy rain could create the potential for flash floods.

Elsewhere over the Atlantic Ocean, former Tropical Storm Florence strengthened into the third Atlantic hurricane of 2018.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Florence was located at latitude 19.7°N and longitude 42.5°W which put it about 1270 miles (2045 km) east-northeast of the Lesser Antilles.  Florence was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 990 mb.

Potential Tropical Cyclone Seven Causes Tropical Storm Watch for U.S. Gulf Coast

Potential Tropical Cyclone Seven caused the National Hurricane Center to issue a Tropical Storm Watch for a portion of the U.S. Gulf Coast on Sunday afternoon.  A Tropical Storm Watch was in effect for the portion of the coast from the Alabama-Florida border to Morgan City, Louisiana including Lake Pontchartrain.  At 5:00 p.m. EDT on Sunday the center of Potential Tropical Cyclone Seven was located at latitude 22.7°N and longitude 77.3°W which put it about 275 miles (445 km) east-southeast of Marathon, Florida.  It was moving toward the west-northwest at 15 m.p.h (24 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1012 mb.

Bands of showers and thunderstorms began to form in a tropical wave over the Bahamas and the National Hurricane Center designated the system as Potential Tropical Cyclone Seven in order to be able to issue the Tropical Storm Watch for the north coast of the Gulf of Mexico.  The circulation of Potential Tropical Cyclone Seven was still organizing.  A distinct low level center of circulation had not formed.  Bands of showers and thunderstorms were developing and the bands were starting to revolve around the inner part of the weather system.  Thunderstorms were beginning to generate some upper level divergence.

Potential Tropical Cyclone Seven will be moving into an environment favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge is forecast to develop over Potential Tropical Cyclone Seven.  If that occurs, then the upper level winds would be weak and there would be little vertical wind shear.  Potential Tropical Cyclone Seven is forecast to intensify into Tropical Storm Gordon.  If the system moves slowly enough, there is a chance it could strengthen into a hurricane before it reaches the Gulf Coast.

Potential Tropical Cyclone Seven will move around the western end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Potential Tropical Cyclone Seven in a general west-northwesterly direction.  On its anticipated track the system will move over the Florida Keys on Monday.  It will be over the eastern Gulf of Mexico on Tuesday and the system could reach the northern Gulf Coast late on Tuesday or early on Wednesday.

Elsewhere over the tropical Atlantic, Tropical Storm Florence was moving quickly away from the Cabo Verde Islands.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Florence was located at latitude 17.4°N and longitude 34.6°W which put it about 700 miles (1125 km) west of the Cabo Verde Islands.  Florence was moving toward the west-northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1000 mb.

Subtropical Storm Alberto Makes Landfall in Northwest Florida

Subtropical Storm Alberto made landfall in northwest Florida late on Monday afternoon.  According to the National Hurricane Center the center of Subtropical Storm Alberto officially made landfall near Laguna Beach, Florida.  At 5:00 p.m. the center of Subtropical Storm Alberto was located at latitude 30.3°N and longitude 85.9°W which put it about 15 miles (25 km) west-northwest of Panama City, Florida.  Alberto was moving toward the north at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 994 mb.  A Tropical Storm Warning was in effect for the portion of the coast from Aucilla, River, Florida to the border between Florida and Alabama.

Subtropical Storm Alberto weakened slowly as it approached the coast of northwest Florida.  Several factors contributed to the weakening of Alberto.  Drier air spiraled into the core of the circulation.  The drier air inhibited the development of taller thunderstorms in the eastern and southern quadrants of the circulation.  Most of the stronger storms developed north and west of the center of circulation.  Daytime heating of the land made the atmosphere more unstable and the instability contributed to the development of thunderstorms in rainbands in those parts of Alberto.  Subtropical Storm Alberto also mixed cooler water to the surface as it moved slowly toward the coast of Florida.  The Sea Surface Temperature near the coast was about 26°C before Subtropical Storm Alberto arrived.  However, the layer of warmer water was very thin.  The winds caused by Alberto mixed the water in the upper levels of the Gulf of Mexico.  The mixing brought cooler water to the surface and the Sea Surface Temperature cooled to near 24°C.  The cooler water meant there was less energy to support the circulation around Subtropical Storm Alberto.

The circulation of Subtropical Storm Alberto will weaken slowly as it moves inland.  Winds blowing water toward the coast will continue to produce a storm surge of 3 to 4 feet (1 to 1.3 meters) east of the center of circulation for another 12 to 24 hours.  A large surface high pressure system over the Atlantic Ocean will steer Subtropical Storm Alberto slowly toward the north during the next several days.  Locally heavy rain could produce flooding as Alberto moves northward.  Flood Watches have been issued for areas between the Gulf Coast and the Lower Ohio River Valley.  Flood Watches have also been issued for places as far east as the Carolinas and Virginia.  The risk of flooding is even greater for locations that already received heavy rain from previous weather systems.