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Potential Tropical Cyclone One Produces Tropical Storm Force Winds

Potential Tropical Cyclone One produced tropical storm force winds over the southeastern Gulf of Mexico on Friday morning. Tropical Storm Warnings were in effect for South Florida, all of the Florida Keys, western Cuba and the Northwestern Bahamas. At 8:00 a.m. EDT on Friday the center of Potential Tropical Cyclone One was located at latitude 22.4°N and longitude 86.8°W which put it about 420 miles (675 km) southwest of Ft. Myers, Florida. Potential Tropical Cyclone One was moving toward the northeast at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1002 mb.

Tropical Storm Warnings were in effect for the coast of Florida from Longboat Key on the west coast to the Volusia/Brevard County Line on the east coast and for all of the Florida Keys. Tropical Storm Warnings were also in effect for the Northwestern Bahamas and the Cuban provinces of Mayabeque, La Habana, Artemisa, and Pinar del Rio. Tropical Storm Watches were in effect for the Cuban provinces of Matanzas and the Isle of Youth.

A U.S. Air Force Reserve Hurricane Hunter reconnaissance flight found that Potential Tropical Cyclone One was producing winds to tropical storm force over the southeastern Gulf of Mexico on Friday morning. The distribution of thunderstorms around Potential Tropical Cyclone One was asymmetrical due to vertical wind shear caused by an upper level trough over the western Gulf of Mexico. The strongest thunderstorms were occurring in a band in the eastern half of Potential Tropical Cyclone One. Those thunderstorms generated upper level divergence that pumped mass to the east of the system. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 60 miles (95 km) in the eastern half of Potential Tropical Cyclone One. The winds in the western half of the circulation were blowing at less than tropical storm force.

Potential Tropical Cyclone One will move through an environment that will be somewhat favorable for intensification during the next 24 hours. Potential Tropical Cyclone One will move over water where the Sea Surface Temperatures are near 28˚C. The upper level trough over the western Gulf of Mexico and an upper level ridge over the Northwest Caribbean Sea will interact to produce southwesterly winds that will blow toward the top of Potential Tropical Cyclone One. Those winds will cause moderate vertical wind shear. The vertical shear will somewhat inhibit intensification. However, the upper level ridge will also enhance the upper level divergence over Potential Tropical Cyclone One. More upper level divergence would cause the surface pressure to decrease. Potential Tropical Cyclone One is forecast to strengthen to a tropical storm during the next 24 hours.

The upper level trough over the western Gulf of Mexico and the upper level ridge over the Northwest Caribbean Sea will steer Potential Tropical Cyclone One toward the northeast during the next several days. On its anticipated track, Potential Tropical Cyclone One will approach Southwest Florida on Saturday morning. Potential Tropical Cyclone One will bring gusty winds and heavy rain to South Florida, the Florida Keys, western Cuba and the Northwestern Bahamas. Heavy rain is likely to cause flash floods in some locations.

Tropical Storm Watches Issued for South Florida and Western Cuba

The National Hurricane Center issued Tropical Storm Watches for South Florida and all of the Florida Keys on Thursday afternoon. The government of Cuba also issued Tropical Storm Watches for western Cuba. The National Hurricane Center designated former Invest 91L as Potential Tropical Cyclone One on Thursday afternoon. At 5:00 p.m. EDT on Thursday the center of Potential Tropical Cyclone One was located at latitude 21.4°N and longitude 87.5°W which put it about 75 miles (120 km) north-northwest of Cozumel, Mexico. Potential Tropical Cyclone One was moving toward the north at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1003 mb.

A Tropical Storm Watch was issued for the coast of Florida from Longboat Key on the west coast to the Volusia/Brevard County Line on the east coast. A Tropical Storm Watch was also issued for all of the Florida Keys. The government of Cuba issued Tropical Storm Watches for the provinces of Matanzas, Mayabeque, La Habana, Artemisa, Pinar del Rio and the Isle of Youth.

The National Hurricane Center designated former Invest 91L as Potential Tropical Cyclone One in keeping with its policy on the issuance of watches and warnings. The circulation around Potential Tropical Cyclone One consisted of a broad area of low pressure. One or more smaller centers of circulation were revolving around inside the broad area of low pressure. The National Hurricane Center identified a center near the northeast tip of the Yucatan Peninsula as the center of Potential Tropical Cyclone One. Images from satellites and radar indicated that a middle level center of circulation might be located near the western end of Cuba. The strongest thunderstorms were occurring in bands in the eastern side of Potential Tropical Cyclone One. Those thunderstorms were generating upper level divergence that pumped mass away to the east of the low pressure system. Bands in the western half of the circulation were over the Yucatan Peninsula and those bands consisted primarily of showers and lower clouds.

Potential Tropical Cyclone One will move through an environment that will be somewhat favorable for intensification during the next 36 hours. Potential Tropical Cyclone One will move over water where the Sea Surface Temperatures are near 28˚C. An upper level trough over the western Gulf of Mexico and an upper level ridge over the Northwest Caribbean Sea will interact to produce southwesterly winds that will blow toward the top of Potential Tropical Cyclone One. Those winds will cause moderate vertical wind shear. The vertical shear will somewhat inhibit intensification. However, the upper level ridge will also enhance the upper level divergence over Potential Tropical Cyclone One. More upper level divergence would cause the surface pressure to decrease. Potential Tropical Cyclone One is forecast to strengthen to a tropical storm during the next 36 hours.

The upper level trough over the western Gulf of Mexico and the upper level ridge over the Northwest Caribbean Sea will steer Potential Tropical Cyclone One toward the northeast during the next several days. On its anticipated track, Potential Tropical Cyclone One will approach Southwest Florida on Saturday morning. Potential Tropical Cyclone One will bring gusty winds and heavy rain to western Cuba and South Florida later this week. Heavy rain is likely to cause flash floods in some locations.

Subtropical Storm Ana Forms Northeast of Bermuda

Subtropical Storm Ana formed northeast of Bermuda on Saturday morning. At 8:00 a.m. EDT on Saturday the center of a Subtropical Storm Ana was located at latitude 34.2°N and longitude 64.5°W which put it about 180 miles (290 km) northeast of Bermuda. Ana was moving toward the west-southwest at 3 m.p.h. (5 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 1006 mb.

A Tropical Storm Watch was in effect for Bermuda.

More thunderstorms developed near the center of a low pressure system northeast of Bermuda on Saturday morning and the National Hurricane Center designated the system as Subtropical Storm Ana. Thunderstorms were also occurring in bands southwest and northeast of the center of Ana. Bands in the northwestern and southeastern parts of the circulation consisted primarily of showers and lower clouds. The strongest winds were occurring in the northern half of Subtropical Storm Ana. Winds to tropical storm force extended out 200 miles (320 km) to the north of the center of circulation. Winds in the southern half of Ana were blowing at less than tropical storm force.

Subtropical Storm Ana will be in an environment only marginally favorable for intensification during the next 24 hours. Ana will move over water where the Sea Surface Temperatures are near 23°C. It will be near the center of an upper level low. The winds are weak near the center of the low and there will be little vertical wind shear. Some drier air will wrap around parts of the circulation and the drier air will inhibit the development of thunderstorms. Subtropical Storm Ana could get a little stronger on Saturday. An upper level trough near the East Coast of the U.S. will move toward Ana. The trough will produce southwesterly winds which will cause the vertical wind shear to increase on Sunday. More vertical wind shear will cause Ana to start to weaken.

Subtropical Storm Ana is forecast to remain relatively stationary on Saturday while it is near the center of the upper level low. The upper level trough near the East Coast will steer Ana toward the northeast on Sunday. On its anticipated track the center of Subtropical Storm Ana is forecast to remain northeast of Bermuda.

Tropical Storm Arthur Brings Wind and Rain to Eastern North Carolina

Tropical Storm Arthur brought wind and rain to eastern North Carolina on Monday.  At 8:00 a.m. EDT on Monday the center of Tropical Storm Arthur was located at latitude 34.5°N and longitude 75.9°W which put it about 50 miles (80 km) south-southwest of Cape Hatteras, North Carolina.  Arthur was moving toward the north-northeast at 15 m.p.h. (24 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 1001 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Surf City to Duck, North Carolina including Pamlico and Albemarle Sounds.

Tropical Storm Arthur began to move more quickly toward the Outer Banks of North Carolina on Monday morning.  The distribution of thunderstorms and winds around Arthur was asymmetric.  The strong thunderstorms were occurring in bands in the eastern half of the circulation.  The strongest winds were occurring in those bands.  Bands in the western half of Tropical Storm Arthur consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 90 miles (145 km) in the eastern half of Arthur.  The winds in the western half of Arthur were mostly less than tropical storm force.

The asymmetric structure of Tropical Storm Arthur meant that the strongest winds were occurring east of the Outer Banks of North Carolina.  A buoy at Diamond Shoals was reporting a sustained wind speed of 33 m.p.h. (54 km/h) and wind gusts to 47 m.p.h. (76 km/h).  The wind speeds along the coast of North Carolina were much weaker.  Tropical Storm Arthur was dropping moderate rain over eastern North Carolina.   Wind blowing water toward the coast was causing the water level to rise in some locations.  Waves were causing erosion on some beaches.

A large upper level trough will approach Tropical Storm Arthur from the west.  The trough will turn Arthur more toward the east later on Monday.  On its anticipated track, Tropical Storm Arthur should move away from North Carolina on Monday afternoon.  Weather conditions should improve gradually when Arthur moves farther form the coast.

Tropical Storm Arthur Prompts Warning for North Carolina

Tropical Storm Arthur prompted the National Hurricane Center to issue a Tropical Storm Warning for a portion of the coast of North Carolina.  A Tropical Storm Warning was in effect for the portion of the coast from Surf City to Duck, North Carolina including Pamlico and Albemarle Sounds.

At 11:00 a.m. EDT on Sunday the center of Tropical Storm Arthur was located at latitude 30.5°N and longitude 77.4°W which put it about 345 miles (560 km) south-southwest of Cape Hatteras, North Carolina.  Arthur was moving toward the north-northeast 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. (96 km/h).  The minimum surface pressure was 1002 mb.

The circulation around Tropical Storm Arthur exhibited more organization on Sunday morning.  Several bands of showers and thunderstorms were wrapping around the eastern and northern parts of the circulation.  Bands on the western side of Arthur still consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation on the eastern side of Tropical Storm Arthur.  The winds on the western side of Arthur were mostly below tropical storm force.

Tropical Storm Arthur will move through an environment favorable for intensification during the next 24 hours.  Arthur will move over water where the Sea Surface Temperature is near 25°C.  It will move under an upper level ridge centered off the southeast coast of the U.S.  The winds in the upper ridge are relatively weak and there will not be a lot of vertical wind shear.  Tropical Storm Arthur is likely to get stronger during the next 24 hours.

Tropical Storm Arthur will move around the western end of a high pressure system during the next 24 hours.  The ridge will steer Arthur toward the north-northeast during the next day or so.  A large upper level trough over the central U.S. will approach Tropical Storm Arthur on Monday.  The trough will steer Arthur more toward the east.  On its anticipated track Tropical Storm Arthur will approach the coast of North Carolina on Monday.  Arthur will bring gusty winds to the coast.  Wind blowing toward the shore will cause the water level to rise.  Waves will cause beach erosion.

Tropical Depression One Strengthens Into Tropical Storm Arthur

Tropical Depression One strengthened into Tropical Storm Arthur on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Arthur was located at latitude 29.4°N and longitude 77.7°W which put it about 420 miles (675 km) south-southwest of Cape Hatteras, North Carolina.  Arthur 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 1006 mb.

A Tropical Storm Watch remains in effect for the portion of the coast from Surf City to Duck, North Carolina including Pamlico and Albemarle Sounds.

Surface observations and data from aircraft reconnaissance indicated that Tropical Depression One strengthened on Saturday night and the National Hurricane Center designated the system as Tropical Storm Arthur.  Thunderstorms continued to develop near the center of circulation and storms near the center generated upper level divergence which pumped mass away to the east of the depression.  Bands of showers and thunderstorms were developing.  The strongest bands were in the eastern half of the circulation.  Winds to tropical storm force extended out 80 miles (130 km) from the center in the eastern side of Tropical Storm Arthur.  Most of the winds in the western side of the circulation were less than tropical storm force.

Tropical Storm Arthur will move through an environment favorable for intensification during the next 24 hours.  Arthur will move over water where the Sea Surface Temperature is near 25°C.  An upper level trough over the eastern Gulf of Mexico and an upper level ridge east of Florida will interact to produce 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 intensification.  Tropical Storm Arthur will strengthen on Sunday.

The upper level trough and upper level ridge will steer Tropical Storm Arthur toward the north-northeast during the next 36 to 48 hours.  On its anticipated track Tropical Storm Arthur will approach the coast of North Carolina on Monday.  It will bring gusty winds and heavy rain to parts of the coast.  Wind blowing water toward the coast will cause the water level to rise and there will be erosion of the beaches.

Tropical Depression One Forms East of Florida

Tropical Depression One formed east of Florida on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Depression One was located at latitude 28.4°N and longitude 78.6°W which put it about 125 miles (200 km) east of Melbourne, Florida.  The depression was moving toward the north-northeast at 13 m.p.h. (20 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.

A Tropical Storm Watch was issued for the portion of the coast from Surf City to Duck, North Carolina including Pamlico and Albemarle Sounds.

Surface observations and data from aircraft reconnaissance indicated that a distinct low pressure system formed east of Florida on Saturday and the National Hurricane Center designated the system as Tropical Depression One.  More thunderstorms developed near the center of circulation.  Storms near the center began to generate upper level divergence which pumped mass away to the east of the depression.  The strongest winds were occurring in the inner part of the circulation, which was consistent with the typical structure of a tropical cyclone.  Bands of showers and thunderstorms were developing.  The strongest bands were in the eastern half of the circulation.

Tropical Depression One will move through an environment favorable for intensification during the next several days.  The depression will move over water where the Sea Surface Temperature is near 25°C.  An upper level trough over the eastern Gulf of Mexico and an upper level ridge east of Florida will interact to produce 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 intensification.  Tropical Depression One will strengthen into a tropical storm.

The upper level trough and upper level ridge will steer Tropical Depression One toward the north-northeast during the next 36 to 48 hours.  On its anticipated track Tropical Depression One will approach the coast of North Carolina on Monday.  It will be a tropical storm by that time.  It will bring gusty winds and heavy rain to parts of the coast.  Wind blowing water toward the coast will cause the water level to rise and there will be erosion of the beaches.

Subtropical Storm Andrea Develops Southwest of Bermuda

Subtropical Storm Andrea developed southwest of Bermuda on Monday afternoon.  An Air Force Reserve Hurricane Hunter aircraft investigated an area of low pressure southwest of Bermuda on Monday afternoon.  The aircraft determined that there was a well defined center of circulation at the surface and the National Hurricane Center designated the system as Subtropical Storm Andrea.  At 11:00 p.m. EDT on Monday the center of Subtropical Storm Andrea was located at latitude 29.5°N and longitude 68.7°W which put it about 300 miles (485 km) southwest of Bermuda.  Andrea was moving toward the north at 12 m.p.h. (19 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.

The circulation around Subtropical Storm Andrea was asymmetrical.  Most of the thunderstorms and the strongest winds were occurring northeast of the center of circulation.  Bands in other parts of the circulation consisted primarily of lower clouds and showers and the winds were weaker in those parts of Andrea.  An upper low northeast of the Bahamas was producing southerly winds which were blowing toward the top of the circulation.  Those winds were creating moderate vertical wind shear and the shear was the primary cause of the asymmetrical structure of Subtropical Storm Andrea.  The asymmetrical structure was the reason why Andrea was classified as a subtropical storm.  Winds to tropical storm force extended out about 65 miles (105 km) from the center of Andrea in the northeastern quadrant of the circulation.

Subtropical Storm Andrea will move through an environment marginally favorable for intensification on Tuesday.  Andrea will move over water where the Sea Surface Temperature is near 25°C.  The upper low will continue to cause moderate vertical wind shear, but the low could weaken slightly on Tuesday.  If the upper level winds weaken, then Andrea could get stronger.  Stronger upper level westerly winds could affect Subtropical Storm Andrea on Wednesday.  Those winds will cause stronger vertical wind shear which will weaken Andrea.

The upper level low northeast of the Bahamas will steer Subtropical Storm Andrea toward the north during the next 12-18 hours.  After that time the upper level westerly winds are likely to steer Andrea more toward the east.  On its anticipated track Subtropical Storm Andrea could be near Bermuda in about 36 hours.  Andrea could bring gusty winds and rain showers to Bermuda on Wednesday.

Unusual Tropical Depression Alberto Reaches Michigan

Unusual Tropical Depression Alberto reached southern Michigan on Wednesday as it continued its northward journey from the Gulf of Mexico.  At 11:00 p.m. EDT on Wednesday the center of Tropical Depression Alberto was located at latitude 42.4°N and longitude 85.3°W which put it about 45 miles southwest of Lansing, Michigan.  Alberto was moving toward the north-northeast at 26 m.p.h. (43 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 996 mb.

The circulation of Tropical Depression Alberto remained intact even though it had been over land for more than two days.  There was a distinct low level center of circulation.  Several bands of showers and thunderstorms were revolving around the center of circulation.  Storms in the core of the circulation were generating upper level divergence.  Tropical Depression Alberto looked like a tropical cyclone on both satellite and radar imagery.

Gusty winds in some of the bands of showers and thunderstorms caused damage to trees and power lines in Indiana and Ohio.  Most of the damage was minor.  The peripheral parts of the circulation of Tropical Depression Alberto interacted with other weather system to produce bands of heavier rain over parts of the southeastern U.S.  The heavy rain contributed to flooding in several states.

Tropical Depression Alberto will move northeast across the Great Lakes and into Canada on Thursday.  The broader circulation around Alberto will again interact with other weather systems to produce bands of heavier rain.  The potential flooding will exist in several states in the southeastern U.S. and Great Lakes region.

Tropical Depression Alberto Drops Heavy Rain Over Southeast U.S.

Tropical Depression Alberto dropped heavy rain over portions of the southeastern U.S. on Tuesday.  At 11:00 p.m. EDT on Monday the center of Tropical Depression Alberto was located at latitude 36.3°N and longitude 87.5°W which put it about 45 miles (75 km) west-northwest of Nashville, Tennessee.  Alberto was moving toward the north at 16 m.p.h. (26 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 999 mb.

The core of Tropical Depression Alberto moved northward across Alabama and into Tennessee on Tuesday.  The circulation remained well developed and there was a band of showers and thunderstorms that surrounded most of the center.  Upper air data from Nashville, Tennessee indicated that the system might have a warm core and the Weather Prediction Center called it a Tropical Depression in the 11:00 p.m. EDT advisory.  A large counterclockwise circulation extended all the way to eastern North Carolina.  Bands of showers and thunderstorms were rotating northward in the eastern half of the circulation.

Those bands of showers and thunderstorms were dropping heavy rain as they passed over some locations.  A weather station in Asheville , North Carolina received nearly two inches of rain on Tuesday.  Heavier rain likely fell over parts of the Appalachians where the wind forced the air to rise up the mountains.  There were reports of flooding in several locations and Flash Flood Warnings were in effect for a number of counties in western North Carolina.  The National Weather Service Forecast Office in Greenville-Spartanburg, South Carolina issued a Flash Flood Emergency for areas downstream of the Lake Tahoma Dam in central McDowell County, North Carolina due to imminent failure of the dam.  Flash Flood Watches remained in effect from Georgia to Virginia and westward to the Lower Ohio River Valley.

The core of Tropical Depression Alberto will move northward across Indiana on Wednesday.  Bands of showers and thunderstorms will continue to drop heavy rain in the eastern half of the circulation.  The greatest risk for flooding will be in locations where bands of heavier rain remain over those areas for several hours.  The ground is already very wet in parts of the eastern U.S.  Water levels in streams and rivers could rise quickly.  Saturated ground could also contribute to potential mudslides in steeper terrain.