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.

Powerful Tropical Cyclone Mekunu Lashes Western Oman

Powerful Tropical Cyclone Mekunu lashed western Oman late on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Mekunu was located at latitude 16.8°N and longitude 53.7°E which put it about 30 miles (50 km) south-southwest of Salalah, Oman.  Mekunu was moving toward the west-northwest at 5 m.p.h.  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 954 mb.

Tropical Cyclone Mekunu intensified into the equivalent of a major hurricane on Friday as it approached the coast of western Oman.  The circulation contracted around a small circular eye.  A well formed ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several bands of strong thunderstorms were revolving around the core of Tropical Cyclone Mekunu.

Winds to hurricane/typhoon force extended out about 30 miles (50 km) from the center of Tropical Cyclone Mekunu.  Winds to tropical storm force extended out about 120 miles (195 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Tropical Cyclone Mekunu was 20.6.  The Hurricane Size Index (HSI) was 11.3 and the Hurricane Wind Intensity Size Index was 31.9.  These indices indicate that Tropical Cyclone Mekunu is capable of causing regional major damage.

Winds near the core of Tropical Cyclone Mekunu will be capable of causing major damage near the coast of western Oman.  The rainbands revolving around the core will cause minor damage within 100 miles (160 km) of the center of Mekunu.  Strong winds near and east of the center of circulation will be capable of causing a storm surge of 9 to 13 feet (3 to 4 meters) at the coast.  Strong thunderstorms will drop heavy rain, especially in places where the air flows up slopes.  Significant flash flooding will be possible in normally arid locations.

Subtropical Storm Alberto Forms Over Northwest Caribbean Sea

Subtropical Storm Alberto formed over the northwestern Caribbean Sea on Friday morning.  The National Hurricane Center (NHC) designated an area of low pressure as Subtropical Storm Alberto on Friday morning based on data from buoys and ship reports.  At 5:00 p.m. EDT on Friday the center of Subtropical Storm Alberto was located at latitude 19.4°N and longitude 86.3°W which put it about 85 miles (135 km) south-southeast of Cozumel, Mexico.  Alberto was moving toward the east at 2 m.p.h. (3 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1005 mb.

A Tropical Storm Watch has been issued for the portion of the U.S. coast from Indian Pass, Florida to Grand Isle, Louisiana including New Orleans.  The government of Mexico issued a Tropical Storm Watch for the portion of the coast from Tulum to Cabo Catoche.  The government of Cuba issued a Tropical Storm Watch for the province of Pinar del Rio.

The circulation around Subtropical Storm Alberto was asymmetrical.  The low level center of circulation was located just to east of the Yucatan Peninsula.  The strongest thunderstorms were occurring in a band located about 100 miles (160 km) east and north of the center.  Flow around an upper level trough over the Gulf of Mexico was producing westerly winds which were blowing toward the top of the circulation.  Those winds were causing strong vertical wind shear which was the reason why the thunderstorms were occurring well to the east of the center of circulation.

Subtropical Storm Alberto will move through an environment marginally favorable for intensification during the next 24 to 36 hours.  Alberto will move over water where  the Sea Surface Temperature is near 28°C.  So, there is sufficient energy in the upper ocean to support intensification.  However, the upper level trough will continue to cause moderate to strong vertical wind shear during the next day or so.  The wind shear will inhibit intensification.  Some gradual strengthening is possible.  The winds are weaker near the axis of the upper level trough.  If Alberto moves under the axis of the trough when it reaches the northern Gulf of Mexico, then the wind shear will decrease.  Alberto could strengthen more quickly if that happens.  There is a chance that Alberto could reach hurricane intensity.  If more thunderstorms form closer to the center of circulation, then NHC could change the designation of Alberto to a tropical storm.

Subtropical Storm Alberto is moving around the western end of a large high pressure system over the Atlantic Ocean.  The high is steering Alberto slowly toward the north-northeast.  A general motion toward the north is forecast during the next day or so.  When Alberto gets farther north, the upper level trough could steer it more toward the north-northwest.  There is a chance that the steering currents could weaken when Alberto nears the Gulf Coast.  Thus, there is much more uncertainty about the track forecast after that time.

The greatest risk with Subtropical Storm Alberto will be locally heavy rain and the potential for flooding.  Most of the heavy rain is likely to fall north and east of the center.  Much less rain is likely to fall from the western side of Alberto.  The coast of the Gulf of Mexico is very susceptible to storm surges.  The water level will rise along the eastern and northern coasts of the Gulf of Mexico where the winds blow the water toward the shoreline.

Tropical Cyclone Mekunu Nears Western Oman

Tropical Cyclone Mekunu neared western Oman late on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Mekunu was located at latitude 15.5°N and longitude 54.2°E which put it about 125 miles (200 km) south of Salalah, Oman.  Mekunu was moving toward the west-northwest at 7 m.p.h. (11 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 964 mb.

There was a small eye at the center of circulation of Tropical Cyclone Mekunu.  The eye was surrounded by a tight ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of the tropical cyclone.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical cyclone in all directions.  Winds to hurricane/typhoon force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Mekunu was 16.5.  The Hurricane Size Index (HSI) was 21.6 and the Hurricane Wind Intensity Size Index (HWISI) was 38.1.  These indices indicate that Tropical Cyclone Mekunu is capable of producing widespread serious damage.

Tropical Cyclone Mekunu will move through an environment favorable for intensification during the next 12 hours while it approaches the coast.  Mekunu will move over water where the Sea Surface Temperature is near 30°C.  It is moving under the western end of an upper level ridge.  The upper level winds are weak and there is little vertical wind shear.  Tropical Cyclone Mekunu could strengthen a little more before it approaches the coast.  When Tropical Cyclone Mekunu approaches the Arabian Peninsula, it will begin to pull drier air into the western side of the circulation.  Mekunu will start to weaken when the drier air reaches the core of the circulation.

Tropical Cyclone Mekunu is moving around the western end of the upper level ridge.  The ridge will steer Mekunu toward the northwest during the next 24 hours.  On its anticipated track Tropical Cyclone Mekunu will make landfall near the border between Oman and Yemen in 12 to 18 hours.  Mekunu will produce winds to hurricane/typhoon force near where the center makes landfall.  Winds to tropical storm force will occur east and west of the core.  It will drop locally heavy rain and flash flooding will be likely.  There could also be a storm surge of 6 to 10 feet (2 to 3 meters) near where the center makes landfall.

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.

Tropical Cyclone Mekunu Passes By Socotra Island

Tropical Cyclone Mekunu passed by Socotra Island on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Mekunu was located at latitude 13.3°N and longitude 55.5°E which put it about 285 miles (460 km) south-southeast of Salalah, Oman.  Mekunu was moving toward the north-northwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 970 mb.

The inner core of Tropical Cyclone Mekunu passed east of Socotra Island on Wednesday.  However, several strong rainbands in the western half of the tropical cyclone did pass over the island.  Those bands dropped locally heavy rain and they may have produced winds to tropical storm force,  Rain was still falling over parts of the island and the potential for flooding continued.

Tropical Cyclone Mekunu intensified quickly into the equivalent of a hurricane/typhoon on Wednesday.  An eye formed at the center of circulation.  A nearly complete ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  The northeastern part of the ring was the weakest section of the eyewall.  Several bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Mekunu.  The strongest rainbands were south and west of the center of circulation,  Bands northeast of the center consisted primarily of low clouds and showers.  Thunderstorms near the core of Mekunu were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

Winds to hurricane/typhoon force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 230 miles (370 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Mekunu was 13.9.  The Hurricane Size Index (HSI) was 21.9.  The Hurricane Wind Intensity Size Index (HWISI) was 35.8.

Tropical Cyclone Mekunu will move through an environment favorable for intensification during the next 24 to 36 hours.  Mekunu will move over water where the Sea Surface Temperature is near 30°C.  It will move near the western end of an upper level ridge.  The ridge will produce weak southerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent further intensification.  Tropical Cyclone Makunu could strengthen into the equivalent of a major hurricane.

The upper level ridge steered Tropical Cyclone Mekunu toward the north-northwest on Wednesday and that general motion is expected to continue for several more days.   On its anticipated track Tropical Cyclone Mekunu could approach the coast of western Oman and eastern Yemen within 48 hours.  Mekunu will bring strong winds and locally heavy rain when it reaches the coast.

Tropical Cyclone Mekunu Intensifies Over the Arabian Sea

Tropical Cyclone Mekunu intensified over the Arabian Sea on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Cyclone Mekunu was located at latitude 11.0°N and longitude 55.9°E which put it about 120 miles (195 km) southeast of Socotra Island.  Mekunu was moving toward the 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 985 mb.

The circulation of Tropical Cyclone Mekunu became much better organized on Tuesday.  A primary rainband wrapped around the center of circulation and eye was evident at the center of circulation on microwave satellite images.  Several bands of showers and thunderstorms developed and began to revolve around the core of Tropical Cyclone Mekunu.  The strongest rainbands were in the western and northern parts of the circulation.  Storms near the core generated upper level divergence which pumped mass away from the tropical cyclone.  Winds to tropical storm force extended out about 95 miles (155 km) from the center of circulation.

Tropical Cyclone Mekunu will move through an environment favorable for intensification during the next several days.  Mekunu will move over water where the Sea Surface Temperature is near 30°C.  It is moving around the western end of an upper level ridge.  The ridge is producing southerly winds which were blowing toward the top of the circulation.  Those winds will generate some vertical shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Mekunu is likely to intensify into the equivalent of a hurricane/typhoon during the next 24 hours.

The upper level ridge was steering Tropical Cyclone Mekunu toward the northwest.  A general motion toward the north-northwest is forecast for the next two to three days.  On its anticipated track Tropical Cyclone Mekunu will approach Socotra Island within 24 hours.  The strongest part of Mekunu will pass over Socotra Island.  It will bring gusty winds and locally heavy rain.  Flash floods could occur.  Tropical Cyclone Mekunu could approach the coast of western Oman and eastern Yemen in about three days.

Tropical Cyclone 02A Develops Over the Arabian Sea

Tropical Cyclone 02A formed over the Arabian Sea on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone 02A was located at latitude 9.3°N and longitude 57.1°E which put it about 285 miles (460 km) southeast of Socotra Island.  It was moving toward the 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 999 mb.

A center of circulation began to consolidate within a broader area of low pressure over the Arabian Sea on Monday.  Thunderstorms formed west and north of the developing center.  There were fewer thunderstorms in the eastern half of the circulation.  Storms west of the center began to organize into several bands and the circulation began to exhibit the characteristics of a tropical cyclone.  Thunderstorms near the core of the circulation began to generate upper level divergence which was pumping mass away from the developing tropical cyclone.  Winds to tropical storm force extended out about 110 miles (175 km) from the center of circulation.

Tropical Cyclone 02A will move through an area favorable for intensification during the next several days.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge is east of the tropical cyclone.  The ridge is producing southerly winds which are blowing toward of the top of the circulation.  Those winds will generate some vertical wind shear, but the shear will not be strong enough to prevent intensification.  The circulation of Tropical Cyclone 02A will continue to organize on Tuesday.  It will strengthen and it could become the equivalent of a hurricane/typhoon by the middle of the week.

The ridge to the east of Tropical Cyclone 02A is steering the cyclone toward the northwest.  A general motion toward the north-northwest is expected during the next two or three days.  On its anticipated track the center of Tropical Cyclone 02A will pass west of Socotra Island.  It could bring gusty winds and locally heavy rain to that location.  Tropical Cyclone 02A could approach western Oman and eastern Yemen in three or four days.  It could be the equivalent of a hurricane/typhoon at that time.

Tropical Cyclone Sagar Brings Wind and Rain to Djibouti, Western Somalia

Tropical Cyclone Sagar brought wind and rain to Djibouti and Western Somalia on Saturday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Cyclone Sagar was centered at latitude 10.1°N and longitude 43.4°E which put it about 100 miles (165 km) south-southeast of Djibouti City, Djibouti.  Sagar was moving toward the southwest at 8 m.p.h. (13 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 988 mb.

Tropical Cyclone Sagar made landfall on the coast of northwestern Somalia near Bullaxaar on Saturday.  Sagar was the equivalent of a strong tropical storm at the time of landfall.  It moving south of an upper level ridge which was generating easterly winds which were blowing toward the top of the tropical cyclone.  Those winds were causing some vertical wind shear.  The stronger thunderstorms were occurring west of the center of circulation, which was probably due to the vertical wind shear.

Thunderstorms in the western half of Tropical Cyclone Sagar may have produced wind gusts to near hurricane force when Sagar made landfall on the coast of northwestern Somalia.  The gusts were capable of causing minor wind damage.  Sagar may have generated a storm surge of 4 to 8 feet (1.2 to 2.4 meters) near where the center made landfall.  Tropical Cyclone Sagar was dropping heavy rain on parts of extreme western Somalia and Djibouti.  The heavy rain was capable of producing flash floods.

Tropical Cyclone Sagar has a small circulation and Sagar will likely weaken quickly as moves inland into drier air over eastern Africa.  Even though it will weaken quickly, Sagar could also drop heavy heavy over parts of eastern Ethiopia and flash floods could occur in that region.

Tropical Cyclone Sagar Strengthens Over Western Gulf of Aden

Tropical Cyclone Sagar strengthened over the western Gulf of Aden on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Sagar was located at latitude 11.2°N and longitude 45.0°E which put it about 105 miles (170 km) south of Aden, Yemen.  Sagar was moving toward the west-southwest 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 986 mb.

A small eye appeared at the center of Tropical Cyclone Sagar on microwave satellite imagery.  The eye was surrounded by a tight ring of thunderstorms and the strongest winds were occurring in the ring of storms.  There was a small break on the southeast side of the ring of storms.  A short, broad band of showers and thunderstorms wrapped around the western and northern sides of the core of the circulation.  A longer, thinner rainband wrapped around the southern and eastern periphery of the circulation.  Storms near the core of Tropical Cyclone Sagar were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 60 miles (95 km) from the center of circulation.

Tropical Cyclone Sagar will be moving through an environment favorable for intensification for about another 12 to 18 hours.  Sagar will move over water where the Sea Surface Temperature is near 29°C to 30°C.  It is moving south of an upper level ridge.  The ridge is generating easterly winds which are blowing toward the top of the circulation.  Those winds are producing some vertical wind shear.  The shear may be the reason why most of the stronger thunderstorms are in the western half of the circulation.  The shear will inhibit intensification, but it will not be strong enough to prevent further strengthening.  Tropical Cyclone Sagar could become the equivalent of a hurricane/typhoon.  Much drier air is over eastern Africa and the Arabian Peninsula.  When Tropical Cyclone Sagar nears the coast of western Somalia, it will pull some of the drier air into the circulation and that will cause Sagar to start to weaken.

The upper level ridge is steering Tropical Cyclone Sagar toward the west-southwest and that general motion is expected to continue for several more days.  On its anticipated track Tropical Cyclone Sagar could make landfall on the coast of western Somalia in 18 to 24 hours.  Sagar will be capable of causing minor wind damage.  It could produce a storm surge of 4 to 8 feet (1.5 to 2.5 meters) near where the center makes landfall.  The core of Tropical Cyclone Sagar could also drop locally heavy rain over parts of western Somalia and eastern Ethiopia.  Heavy rain could cause flash floods in some locations.