Tag Archives: Gulf of Mexico

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.

Subtropical Storm Alberto Strengthens on Its Way to Northwest Florida

Subtropical Storm Alberto strengthened on Sunday as it moved closer to northwest Florida.  At 11:00 p.m. EDT on Sunday the center of Subtropical Storm Alberto was located at latitude 28.5°N and longitude 85.8°W which put it about 95 miles (155 km) south-southwest of Apalachicola, Florida.  Alberto was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and the were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 991 mb.  A Tropical Storm Warning was in effect for the portion of the coast from Suwannee River, Florida to the border between Alabama and Mississippi.

The circulation of Subtropical Storm Alberto became more organized on Sunday.  A band of showers and thunderstorms wrapped around the center of circulation.  A band of drier air wrapped around the circulation just outside the rainband.  The band of drier air kept the circulation from developing a completely tropical structure and the National Hurricane Center continued to classify Alberto as a subtropical storm.  Alberto moved closer to the center of an upper level low over the Gulf of Mexico.  The upper level winds were weaker near the center of the low and the vertical wind shear decreased.  An upper level ridge over the Florida peninsula enhanced upper level divergence to the east of Alberto and the surface pressure decreases on Sunday.

Subtropical Storm Alberto will move through an environment somewhat favorable for intensification on Monday.  Alberto will move over water where the Sea Surface Temperature is near 28°C.  The upper level low will continue to produce some vertical wind shear.  The band of drier air will limit the development of thunderstorms outside the primary rainband.  Some intensification is possible during the next 12 hours, but the wind shear and drier air should limit any strengthening.

The upper low and the ridge over Florida will steer Subtropical Storm Alberto slowly toward the northwest.  On its anticipated track the center of Subtropical Storm Alberto is expected to make landfall over northwest Florida on Monday.  Alberto will be capable of causing minor wind damage.  Wind blowing water toward the coast will produce a storm surge of up to 4 to 7 feet (1.3 to 2.3 meters).  Alberto will drop heavy rain over parts of the southeastern U.S. and flooding could occur in some locations.

Subtropical Storm Alberto Moves Into the Gulf of Mexico

Subtropical Storm Alberto moved over the southeastern Gulf of Mexico on Saturday.  At 11:00 p.m. EDT on Saturday the center of Subtropical Storm Alberto was located at latitude 23.9°N and longitude 84.6°W which put it about 120 miles (195 km) west-southwest of the Dry Tortugas.  Alberto was moving toward the north-northeast at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1001 mb.

Tropical Storm Warnings were in effect for the Dry Tortugas and the portions of the coast from Bonita Beach to Anclote River and from the Aucilla River to the border between Alabama and Mississippi.  A Tropical Storm Watch was in effect from the border between Alabama and Mississippi to the Mouth of the Pearl River.

The circulation of Subtropical Storm Alberto remained poorly organized on Saturday.  Several low level centers dissipated and new low level centers of circulation developed on the southwestern edge of an area of thunderstorms northeast of the center.  Even though the center of circulation reorganized several times, the pressure did decrease slowly during the day.  The strongest wind speeds were occurring in the area of thunderstorms northeast of the center of circulation.  The winds were weaker south and west of the center.

Subtropical Storm Alberto will move through an environment that will become more favorable for intensification during the next 48 hours.  Alberto will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough over the western Gulf of Mexico was producing southwesterly winds which were blowing across the top of the circulation.  Those winds were causing significant vertical wind shear which was inhibiting the intensification of Subtropical Storm Alberto.  The shear was also preventing thunderstorms from persisting near the center of circulation, which was keeping Alberto from making a transition to a tropical storm.  An upper level ridge was forming over Florida.  The ridge was starting to enhance upper level divergence to the east of Subtropical Storm Alberto.

The upper level trough will gradually evolve into a closed upper level low.  The vertical wind shear will slowly decrease during the next several days.  When the shear decreases, it will allow Subtropical Storm Alberto to strengthen.  Less vertical wind shear will also let thunderstorms persist closer to the center of circulation.  If thunderstorms persist near the center, then Alberto could exhibit the structure of a tropical cyclone and it could be designated as a tropical storm.  Subtropical Storm Alberto could intensify into a hurricane over the northern Gulf of Mexico.

The reformations of the low level center of circulation increase the uncertainty of track forecasts.  The upper level trough is likely to steer Subtropical Storm Alberto toward the north on Sunday.  Alberto could turn more toward the north-northwest when the trough changes into an upper level low.  On its anticipated track Subtropical Storm Alberto could approach the coast of the northern Gulf of Mexico within 48 hours.  Alberto could be a strong tropical storm or a hurricane at that time.

Subtropical Storm Alberto will be capable of causing minor wind damage when it makes landfall.  Alberto will drop locally heavy rain north and east of the center of circulation.  Flood Watches have been issued for several states in the southeastern U.S.  The Gulf Coast is very susceptible to storm surge.  There will be increases in the water level along the eastern and northern Gulf Coast where the winds blow water toward the shore.

Cyclone Likely to Form Over Gulf of Mexico

A cyclone is likely to form over the Gulf of Mexico during the upcoming weekend.  A broad area of low pressure at the surface is currently centered over the Yucatan Peninsula.  The area of low pressure is currently designated as Invest 90L.  The circulation around the low pressure system is not well organized at the current time.  The center of the surface low is over the Yucatan Peninsula.  Showers and lower clouds are occurring near the center of the low.  Stronger thunderstorms are occurring on the eastern side of the low over the northwestern Caribbean Sea.  Sustained winds of 20 m.p.h. to 30 m.p.h. (30 km/h to 50 km/h) were blowing across the northwestern Caribbean Sea.  The winds were weaker over land near the center of circulation.

An upper level trough over the Gulf of Mexico was producing strong westerly winds which were blowing over the top of the surface low.  Those winds were causing strong vertical wind shear and the wind shear was one of the reasons why the stronger thunderstorms were occurring east of the center of circulation.  Sinking motion in the western portion of the upper level trough was bringing drier air to the surface and the drier air was inhibiting the formation of thunderstorms in the western side of the surface low.

The National Hurricane Center (NHC) indicated in a Special Tropical Weather Outlook at 2:00 p.m. EDT on Thursday that there is a 70% probability of the formation of a subtropical or tropical depression during the next 48 hours.  NHC has tentatively tasked a reconnaissance aircraft to investigate the low pressure system on Friday afternoon if necessary.

The wind speeds are slower near the axis of the upper level trough.  If the surface low pressure system moves under the axis of the upper level trough, then there would be less vertical wind shear and a cyclone could form.  If thunderstorms develop near the center of circulation after the center moves over the northwestern Caribbean Sea or southeastern Gulf of Mexico, then NHC would likely designate the system as a tropical depression.  If the thunderstorms develop farther away from the center of circulation and the circulation does not exhibit a tropical appearance, then NHC could classify the system as a subtropical depression.  NHC would issue advisories on the cyclone even if it is designated a subtropical depression.

There is a strong high pressure system over the Atlantic Ocean and the high is likely to steer the surface low toward the north.  The Sea Surface Temperature of the water in the southeastern Gulf of Mexico is near 27°C.  So, there is enough energy to support the formation of a tropical cyclone.  Most of the stronger thunderstorms are likely to continue to form in the eastern side of the circulation because of the vertical wind shear and drier air to the northwest of the surface low.  The low pressure system could slowly organize into a tropical storm during the weekend.

Heavy rain and the potential for flooding are the greatest risks with this low pressure system.  There will be some storm surge along the eastern and northern coasts of the Gulf of Mexico as counterclockwise rotation around the low blows water toward the shore.

System Could Bring Heavy Rain to Southeast U.S.

A weather system over the southeastern Gulf of Mexico could bring heavy rain to the southeastern U.S. this week.  An upper level low over the eastern Gulf of Mexico could transfer enough kinetic energy down to the lower troposphere to spin up a low at the surface.  Air flowing around the eastern side of the low is contributing to upper level divergence over Florida.  The divergence enhanced rising motion over Florida and rain fell over parts of the southern and central portions of that state.

The weather system is forecast to move slowly northward during the next several days.  The Sea Surface Temperatures in the southeastern Gulf of Mexico are 24°C to 26°C.  There is enough energy in the upper levels of the water to support the formation of a tropical cyclone.  The upper level low will create southerly winds which will cause moderate vertical wind shear.  The shear will inhibit development, although those winds could contribute to upper level divergence to the east of the weather system.  Upper level divergence could allow the surface pressure to decrease and a low pressure system could form at the surface.  The National Hurricane Center (NHC) issued a special Tropical Weather Outlook on Sunday afternoon on the weather system.  NHC indicated the probability was 40% that a tropical or subtropical cyclone could form during the next five days.

Guidance from numerical models suggest that the weather system will move slowly northward over the eastern Gulf of Mexico during the next few days.  Counterclockwise rotation around the low will transport moist air northward on the eastern side of the low.  The moist air combined with upper level divergence will create the potential for locally heavy rainfall over the southeastern U.S.  Heavy rain could result in floods in some locations.

Hurricane Nate Speeds Toward Gulf Coast

Strengthening Hurricane Nate sped toward the central Gulf Coast on Saturday.  At 11:00 a.m. EDT on Saturday the center of Hurricane Nate was located at latitude 26.6°N and longitude 88.4°W which put it about 265 miles (425 km) south of Biloxi, Mississippi.  Nate was moving toward the north-northwest at 26 m.p.h. (43 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 984 mb.

A Hurricane Warning was in effect for the portion of the coast from Grand Isle, Louisiana to the Alabama/Florida border including New Orleans and Lake Pontchartrain.  A Hurricane Watch was in effect for the portion of the coast from the Alabama/Florida border to the Okaloosa/Walton County line and from Grand Isle to Morgan City, Louisiana.  A Tropical Storm Warning was in effect for the portion of the coast from the Alabama/Florida border to Indian Pass, Florida and from Grand Isle to Morgan City.  A Tropical Storm Watch was in effect for the portion of the coast from Morgan City to Intracoastal City, Louisiana.

Hurricane Nate strengthened on Saturday as it moved over the warm water in the Gulf of Mexico.  An eye with a diameter of 30 miles (50 km) began to form at the center of circulation.  A ring of thunderstorms around the eye was generating strong upper level divergence which pumped mass away from Hurricane Nate.  The strongest winds were occurring in the eastern side of the circulation.  Winds to hurricane force extended out about 35 miles (55 km) east of the center of circulation.  Winds to tropical storm force extend out about 120 miles (195 km) east of the center, but they only extend out about 60 miles (95 km) to the west of the center.

The Hurricane Intensity Index (HII) for Hurricane Nate is 13.9.  The Hurricane Size Index (HSI) is 7.7 and the Hurricane Wind Intensity Size Index (HWISI) is 21.6.

Hurricane Nate will continue to intensify during the next 12 hours until it makes landfall.  Nate will move over water where the Sea Surface Temperature is near 29°C.  An upper low over the western Gulf of Mexico is producing southerly winds which are blowing toward the top of the circulation.  However, there are also southerly winds in the lower levels of the atmosphere and as a result, there is not much vertical wind shear.  Hurricane Nate is likely to intensify to a Category 2 hurricane on the Saffir-Simpson Scale before it makes landfall.  There is a chance Hurricane Nate could intensify to Category 3 before landfall, if it continues to intensify rapidly.

The upper low and an upper level ridge east of Florida are combining to steer Hurricane Nate quickly toward the north-northwest and that motion is expected to continue for the next few hours.  An upper level trough over the Central U.S. will approach Nate on Saturday night as the hurricane nears the coast.  The trough will turn Hurricane Nate more toward the north as it reaches the coast.  The trough should steer Nate quickly toward the north-northeast after it makes landfall.  On its anticipated track the center of Hurricane Nate will pass near the mouth of the Mississippi River on Saturday evening.  The center of Nate will likely make landfall on the coast of Mississippi or near Mobile on Saturday night.

Hurricane Nate will be capable of causing regional serious damage when it makes landfall.  Nate will produce strong winds, especially in locations east of the track of the hurricane.  Nate will also be capable of producing a storm surge of 10 to 12 feet (3 to 4 meters) along the coast.  The surge will be higher in bays, inlets and mouths of rivers that funnel the water into specific areas.  Nate will also be capable of dropping heavy rain as it moves inland.

Stronger Tropical Storm Nate Speeds Toward Gulf of Mexico, Hurricane Warning for New Orleans

A stronger Tropical Storm Nate sped toward the Gulf of Mexico on Friday afternoon and a Hurricane Warning was issued for the city of New Orleans.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Nate was located at latitude 20.3°N and longitude 85.7°W which put it about 80 miles (125 km) east of Cozumel, Mexico and about 710 miles (1145 km) south-southeast of New Orleans, Louisiana.  Nate was moving toward the north-northwest at 21 m.p.h. (33 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 993 mb.

A Hurricane Warning was in effect for the portion of the coast from Grand Isle, Louisiana to the Alabama/Florida border including New Orleans and Lake Pontchartrain.  A Hurricane Watch was in effect for the portion of the coast from the Alabama/Florida border to the Okaloosa/Walton County line in Florida.  A Tropical Storm Warning was in effect for the portion of the coast from Grand Isle to Morgan City, Louisiana and from the Alabama/Florida border to the Okaloosa/Walton County line.  A Tropical Storm Watch was in effect from Morgan City to Intracoastal City, Lousiana and from the Okaloosa/Walton County line to Indian Pass, Florida.  A Hurricane Watch and a Tropical Storm Warning are in effect for the portion of the coast from Punta Herrero to Rio Lagartos, Mexico.  A Tropical Storm Warning is in effect for Pinar del Rio province in Cuba.  A Tropical Storm Watch is in effect for Isle of Youth province in Cuba.

The inner core of Tropical Storm Nate tightened up on Friday afternoon.  A primary rainband wrapped about three quarters of the way around the center of circulation.  There was an opening to the northeast of the center.  The rainband could develop into an eyewall if it wraps completely around the center of circulation.  Additional bands of showers and thunderstorms formed outside the core of Tropical Storm Nate.  Winds to tropical storm force extended out about 125 miles (200 km) to the east of the center of circulation.  The winds were weaker in the western half of the circulation.  Thunderstorms near the core began to generate stronger upper level divergence which was pumping out mass and the surface pressure decreased on Friday afternoon.

Tropical Storm Nate will move through an environment favorable for intensification on Saturday.  Nate will move over water where the Sea Surface Temperature is near 30°C.  An upper level low over the western Gulf of Mexico is producing southerly winds which are blowing toward the top of the circulation but the vertical wind shear is not too strong.  Tropical Storm Nate will become a hurricane over the Gulf of Mexico.  If an eyewall and an eye form, then Nate could have a period of rapid intensification.

The upper low over the western Gulf of Mexico and a ridge east of Florida are combining to steer Tropical Storm Nate toward the north-northwest and that general motion is expected to continue on Saturday.  An upper level trough approaching from the west will turn Nate toward the northeast when it nears the U.S.  On its anticipated track Tropical Storm Nate will pass near the northeastern end of the Yucatan peninsula and move into the Gulf of Mexico on Friday night.  Nate will approach southeastern Louisiana and Central Gulf Coast on Saturday night.

Nate will be a hurricane when it nears the U.S.  It will be capable of producing serious regional wind damage and power outages.  Nate could cause a storm surge of 10-12 feet (3 to 4 meters) near where the center makes landfall.  Nate could also drop locally heavy rain and cause fresh water flooding when it moves inland in the southern U.S.

Tropical Depression 16 Organizes Near Nicaragua

Tropical Depression Sixteen organized near Nicaragua on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Depression Sixteen was located at latitude 12.8°N and longitude 82.7°W which put it about 95 miles (155 km) south-southeast of Puerto Cabezas, Nicaragua.  It was moving toward the northwest at 6 m.p.h. (10 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 1004 mb.

A Hurricane Watch was in effect for the portion of the coast from Punta Herrero to Cabo Catoche, Mexico.  A Tropical Storm Warning was in effect for the portion of the coast from Sandy Bay Sirpi, Nicaragua to Punta Castilla, Honduras.

The circulation of Tropical Depression Sixteen exhibited more organization on Wednesday.  An Air Force Reserve Hurricane Hunter reconnaissance aircraft found a distinct surface center of circulation on Wednesday afternoon.  More thunderstorms began to form near the center on Wednesday evening.  Bands of showers and thunderstorms developed on the northern and southern sides of the circulation.  There were sustained winds in some of the bands that were near tropical storm force.

Tropical Depression Sixteen will move through an environment that will be favorable for intensification during the next several days.  It will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds will be weak and there will be little vertical wind shear.  Some of the western part of the circulation is passing over Nicaragua and the increased friction is the only factor inhibiting intensification.  If the center of circulation stays over water, then the depression will likely strengthen into a tropical storm on Thursday.  If the center of circulation moves over northeastern Nicaragua, then the depression will weaken.  The system is likely to strengthen when it moves over the northwestern Caribbean Sea on Friday.

A ridge of high pressure is steering the tropical depression slowly toward the northwest and that motion is expected to continue for another day or so.  An upper low near the west coast of Florida is going to move west across the Gulf of Mexico.  When the upper low gets northwest of Tropical Depression Sixteen, it will start to pull the depression more toward the north.  On its anticipated track the center of Tropical Depression Sixteen will move near or over northeastern Nicaragua on Thursday.  The depression could drop very heavy rain and cause floods in parts of Nicaragua and Honduras.  It is forecast to move over the northwestern Caribbean Sea on Friday and the depression could be near the northeastern Yucatan peninsula by Friday night.  The depression is expected to move into the Gulf of Mexico on Saturday.  There is more uncertainty about the future track of the system after that time.

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

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

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

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

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

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

Franklin Strengthens Into a Hurricane Northeast of Veracruz

Formerly Tropical Storm Franklin strengthened into a hurricane northeast of Veracruz on Friday afternoon.  Franklin is the first hurricane to form over the Atlantic basin in 2017.  At 5:00 p.m. EDT the center of Hurricane Franklin was located at latitude 20.1°N and longitude 94.9°W which put it about 105 miles (170 km) northeast of Veracruz, Mexico.  Franklin was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 984 mb.

A Hurricane Warning is in effect for the portion of the coast from Puerto de Veracruz to Cabo Rojo, Mexico.  A Hurricane Watch is in effect for the portion of the coast from Cabo Rojo to Rio Panuco.  A Tropical Storm Warning is in effect for the portion of the coast from Puerto Dos Bocas to Puerto de Veracruz and from Tuxpan to Barra del Tordo.

An elliptical eye formed at the center of Hurricane Franklin and a reconnaissance plane detected surface winds in excess of 74 m.p.h. (119 km/h).  Based on data from the plane and an improved appearance on satellite imagery, the National Hurricane Center upgrade Franklin to hurricane status in its 5:00 p.m. EDT advisory.

The structure of Hurricane Franklin improved on Friday.  An elliptical eye oriented north to south formed at the center of circulation.  A ring of thunderstorms completely surrounded the eye.  The strongest winds were occurring in the northeastern part of the ring of storms.  Storms in the core of the circulation were generating upper level divergence which was pumping out mass and allowing the surface pressure to decrease.  A primary band of showers and thunderstorms coiled inward toward the core of Hurricane Franklin,  Additional bands of showers and thunderstorms were revolving around the core of Franklin.  Winds to hurricane force extended out about 35 miles (55 km) northeast of the center of circulation.  Winds to tropical storm force extended out about 140 miles (225 km) on the northern side of Franklin and about 100 miles (160 km) on the southern side of the hurricane).

Hurricane Franklin could intensify further before it makes landfall.  It is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge over northern Mexico is generating northerly winds which are blowing toward the top of the circulation.  However, those winds are not very strong and the vertical wind shear is minor and it did not prevent Franklin from becoming a hurricane.  Hurricane Franklin has about another 6 to 12 hours to strengthen.  Once Franklin makes landfall and moves into the mountains, the surface circulation will weaken quickly.

A subtropical ridge is steering Hurricane Franklin toward the west and that general motion is expected to continue.  Hurricanes often turn slightly south of west when the approach the coast of the southwestern Bay of Campeche.  On its anticipated track the center Hurricane Franklin could make landfall on the coast of Mexico north of Veracruz in less than 12 hours.  The most likely landfall would be between Veracruz and Nautla.

Hurricane Franklin will bring strong gusty winds, a storm surge and heavy rain at the coast.  The storm surge could reach 6 to 9 feet (2 to 3 meters) near and just to the north of where the center makes landfall.  Franklin could produce very heavy rain when it reaches the mountains and flash flooding is a serious risk.