Monthly Archives: June 2021

Potential Tropical Cyclone Three Reaches Tropical Storm Force

Potential Tropical Cyclone Three reached tropical storm force south of Louisiana on Friday afternoon. At 2:00 p.m. EDT on Friday the center of Potential Tropical Cyclone Three (03L) was located at latitude 27.3°N and longitude 91.1°W which put it about 165 miles (265 km) south of Morgan City, Louisiana. Potential Tropical Cyclone Three was moving toward the north at 14 m.p.h. (22 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 1007 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Morgan City, Louisiana to the Okaloosa/Walton County Line, Florida including New Orleans, Lake Pontchartrain and Lake Maurepas. The Tropical Storm Warning included Biloxi, Mississippi, Mobile, Alabama and Pensacola, Florida.

The circulation around Potential Tropical Cyclone Three strengthened on Friday afternoon. A C-MAN station (BURL1) at Southwest Pass, Louisiana with an anemometer at a height of 38 meters reported a sustained wind speed of 44 m.p.h. (71 km/h) and a wind gust of 51 m.p.h. (82 km/h). The sustained wind speed was equivalent to a speed of 40 m.p.h. (65 km/h) at a standard observation height of 10 meters.

The circulation around Potential Tropical Cyclone Three continued to consist of a broad low pressure system at the surface. The strongest winds were occurring northeast of the center of the broad low pressure system. A high pressure system southeast of the U.S. was contributing to a stronger pressure gradient in that region. The stronger pressure gradient was causing winds to blow at tropical storm force. The winds were weaker in the other parts of Potential Tropical Cyclone Three. There were several smaller circulations revolving counterclockwise around the broader Potential Tropical Cyclone Three. One of the smaller circulations was south of Louisiana and another one was over the southwestern Gulf of Mexico. The strongest thunderstorms were occurring in bands northeast of the broad center and in a long band on the eastern side of the circulation.

Potential Tropical Cyclone Three will move through an environment slightly favorable for intensification during the next few hours. Potential Tropical Cyclone Three will move over an area where the Sea Surface Temperatures are near 29°C. It will move between an upper level low over eastern Texas and an upper level ridge over the eastern Gulf of Mexico. The low and ridge will produce southwesterly winds that will blow toward the top of Potential Tropical Cyclone Three. Those winds will cause moderate vertical wind shear and the shear will inhibit intensification. The upper level ridge will contribute to upper level divergence that will pump mass to the east of Potential Tropical Cyclone Three. There will also be drier air over the northwestern Gulf of Mexico, which will make it difficult for thunderstorms to develop in that area. Potential Tropical Cyclone Three could intensify a little more during the next six hours. If a well defined surface center of circulation develops, the system could be designated as a tropical storm.

Potential Tropical Cyclone Three will move around the western end of the high pressure system southeast of the U.S. The high pressure system will steer it toward the north-northeast during the next 24 hours. On its anticipated track Potential Tropical Cyclone Three will make landfall in southeastern Louisiana on Friday night. The system will move across southeastern Mississippi on Saturday and it could reach Alabama by Saturday night. It will bring gusty winds to southeast Louisiana and the coasts of Mississippi and Alabama. The system could cause a storm surge of 3 to 5 feet (1.0 to 1.5 meters) along parts of the coast. It will drop locally heavy rain when it moves inland. Heavy rain could cause flash floods over parts of the southeastern U.S. Flash Flood Watches were in effect for parts of southeastern Mississippi, Alabama, northwestern Florida, and western Georgia. There may also be enough low level wind shear to produce tornadoes when the rainbands in the eastern side of the circulation when it moves inland.

Tropical Storm Dolores Forms South of Mexico, Warning Issued

Tropical Storm Dolores formed south of Mexico on Friday morning and the government of Mexico issued warnings and watches for portions of the coast. At 11:00 a.m. EDT on Friday the center of Tropical Storm Dolores was located at latitude 14.7°N and longitude 102.5°W which put it about 320 miles (515 km) south-southeast of Manzanillo, Mexico. Dolores was moving toward the west-northwest at 10 m.p.h. (16 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 1004 mb.

A Hurricane Watch was issued for the portion of the coast from Punta San Telmo to Cabo Corrientes, Mexico. A Tropical Storm Warning was in effect for the portion of the coast from Lazaro Cardenas to Cabo Corrientes, Mexico. A Tropical Storm Watch was issued for the portion of the coast from Cabo Corrientes to Escuinapa, Mexico.

The circulation around a low pressure system south of Mexico strengthened on Friday morning and the National Hurricane Center designated the system as Tropical Storm Dolores. Dolores exhibited increasing organization on conventional and microwave satellite imagery. Several bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. The removal of mass caused the surface pressure to decrease. Winds to tropical storm force extended out 35 miles (55 km) from the center of Dolores.

Tropical Storm Dolores will move through an environment favorable for intensification during the next 24 hours. Dolores will move over an area where the Sea Surface Temperatures are near 30°C. It will move under the western part of an upper level ridge over southern Mexico and the Eastern North Pacific Ocean. The ridge will produce southerly winds that will blow toward the top of Tropical Storm Dolores. Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification. Tropical Storm Dolores will intensify during the next 24 hours and it could strengthen to a hurricane on Saturday.

Tropical Storm Dolores will move around the western end of a small high pressure system over southern Mexico. The high pressure system will steer Dolores toward the north-northwest during the next 36 hours. On its anticipated track Tropical Storm Dolores could approach the coast of Mexico between Manzanillo and Cabo Corrientes on Saturday. Dolores could be a hurricane when it approaches the coast. Bands on the northern side of Tropical Storm Dolores could drop heavy rain on parts of Colima and Jalisco. Heavy rain could cause flash floods in some locations.

Tropical Storm Warning Issued for Northern Gulf Coast

The National Hurricane Center issued a Tropical Storm Warning for a portion of the northern coast of the Gulf of Mexico on Thursday afternoon. A Tropical Storm Warning was issued for the portion of the coast from Intracoastal City, Louisiana to the Alabama border including New Orleans, Lake Pontchartrain and Lake Maurepas.

At 5:00 p.m. EDT on Thursday the center of Potential Tropical Cyclone Three (03L) was located at latitude 22.9°N and longitude 92.4.W which put it about 475 miles (765 km) south of Morgan City, Louisiana. Potential Tropical Cyclone Three was moving toward the north at 9 m.p.h. (15 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 1008 mb.

The weather system designated as Potential Tropical Cyclone Three consisted of a complex circulation containing of parts of several different weather features. A broad surface low pressure system was over the southwestern Gulf of Mexico. A low pressure system in the middle and upper troposphere was over the western gulf of Mexico. An upper level ridge was over the northwestern Caribbean Sea and the eastern Gulf of Mexico. Thunderstorms were occurring in bands on the eastern periphery of the broad surface low. Drier air in the middle and upper levels of the upper level low was over the southwestern Gulf of Mexico and the drier air was inhibiting the formation of thunderstorms in that region. Several small circulation centers that originally formed within clusters of thunderstorms on the eastern side of the broader low were revolving counterclockwise around the broad center of the surface low.

The environment around Potential Tropical Cyclone Three will become a little more favorable for the formation of a tropical depression during the next 24 hours. Potential Tropical Cyclone Three will move over an area where the Sea Surface Temperatures are near 29°C. The upper level low and the upper ridge will interact to produce southerly winds which will blow toward the top of Potential Tropical Cyclone Three. Those winds will cause moderate vertical wind shear, but they will also produce upper level divergence to the east of Potential Tropical Cyclone Three. The upper level divergence will cause the surface pressure to decrease slowly. The drier air over the western Gulf of Mexico will continue to inhibit the formation of thunderstorms on the western side of the broad low pressure system. The inner end of a rainband will wrap closer to the center, but most of the thunderstorms are likely to remain in the eastern half of Potential Tropical Cyclone Three. The National Hurricane Center could designate the system as a tropical depression if more thunderstorms develop closer to the center of circulation. The maximum sustained wind speed is forecast to increase to tropical storm force by Friday afternoon.

The upper level low and the upper ridge will steer Potential Tropical Cyclone Three slowly toward the north during the next 36 hours. On its anticipated track the system could approach the coast of Louisiana by Friday evening. It is possible that a new center of circulation could form along the northern end of a rainband, which could bring it to the coast sooner. Potential Tropical Cyclone Three could be a tropical depression or a tropical storm when it approaches the coast. It will bring gusty winds to southeast Louisiana and the coasts of Mississippi and Alabama. The system could cause a storm surge of 3 to 5 feet (1.0 to 1.5 meters) along parts of the coast. It will likely drop locally heavy rain when it moves inland. Heavy rain could cause flash floods over parts of the southeastern U.S. There may also be enough low level wind shear to produce tornadoes when the rainbands in the eastern side of the circulation move inland.

Depression Likely to Form over Western Gulf of Mexico

A tropical depression is likely to form over the western Gulf of Mexico during the next 48 hours within a broad area of low pressure currently designated as Invest 92L. At 8:00 p.m. EDT on Wednesday the center of Invest 92L was located at latitude 20.0°N and longitude 93.6.W which put it about 220 miles (355 km) east-southeast of Veracruz, Mexico. Invest 92L was moving toward the north-northeast at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 35 m.p.h. (55 km/h). The minimum surface pressure was 1008 mb.

The weather system designated as Invest 92L was actually a complex circulation consisting of parts of several different weather features. A broad surface low pressure system extended from the Eastern North Pacific Ocean across Mexico over the southwestern Gulf of Mexico. The northern end of a tropical wave at the surface was over the Yucatan Peninsula and the eastern Gulf of Mexico. A low pressure system in the middle and upper troposphere was over the western gulf of Mexico and eastern Mexico. An upper level ridge was over the northwestern Caribbean Sea and the eastern Gulf of Mexico. Thunderstorms were occurring in bands on the eastern periphery of the broad surface low. Drier air in the middle and upper levels was over the western Gulf of Mexico and the drier air was inhibiting the formation of thunderstorms in other parts of Invest 92L. Several small circulation centers formed within clusters of thunderstorms on the eastern side of the broader low during the past two days. Those centers moved toward the west-southwest and dissipated over Mexico.

The environment around Invest 92L will become more favorable for the formation of a tropical depression during the next 36 hours. Invest 92L will move over an area where the Sea Surface Temperatures are near 29°C. The upper level low and the upper ridge will interact to produce southerly winds which will blow toward the top of Invest 92L. Those winds will cause moderate vertical wind shear, but they will also be a source of upper level divergence to the east of Invest 92L. The upper level divergence will cause the surface pressure to decrease slowly . The drier air over the western Gulf of Mexico will continue to inhibit the formation of thunderstorms on the western side of the broad low pressure system. The inner end of a rainband will wrap closer to the center, but most of the thunderstorms are likely to remain in the eastern half of Invest 92L. The National Hurricane Center indicated that the probability is 80% that a tropical depression will form during the next 48 hours.

The upper level low and the upper ridge will steer Invest 92L slowly toward the north during the next 48 hours. On its anticipated track the low pressure system could approach the coast of eastern Texas and Louisiana by Friday night. Invest 92L could be a tropical depression or a tropical storm when it approaches the coast. It will likely drop locally heavy rain when it moves inland.

Tropical Depression Two Strengthens to Tropical Storm Bill

Former Tropical Depression Two strengthened to Tropical Storm Bill east-northeast of Cape Hatteras on Monday night. At 11:00 p.m. EDT on Monday the center of Tropical Storm Bill was located at latitude 36.7°N and longitude 69.8°W which put it about 335 miles (540 km) east-northeast of Cape Hatteras, North Carolina. Bill was moving toward the northeast at 23 m.p.h. (37 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 1003 mb.

The circulation around former Tropical Depression Two intensified on Monday night and the National Hurricane Center upgraded the system to Tropical Storm Bill. Even though the circulation around Bill was stronger, the distribution of thunderstorms was asymmetrical. The strongest thunderstorms were occurring in bands on the eastern side of Tropical Storm Bill. Bands on the western side of Bill consisted mainly of showers and lower clouds. Winds to tropical storm force extended out 70 miles (110 km) in the southeastern quadrant of Tropical Storm Bill. The wind was blowing at less than tropical storm force in the other quadrants of Bill. An upper level trough east of the Great Lakes was producing strong southwesterly winds that were blowing toward the top of Tropical Storm Bill. Those winds were causing moderate vertical wind shear and they were the cause of the asymmetrical distribution of thunderstorms.

Tropical Storm Bill will move through an environment that will be only marginally favorable for intensification during the next 24 hours. Bill will move over the warmer water in the Gulf Stream where the Sea Surface Temperatures are near 27°C on Tuesday. However, the upper level trough east of the Great Lakes will continue to cause moderate vertical wind shear, which will inhibit intensification. Tropical Storm Bill could intensify a little more on Tuesday, but the wind shear is likely to increase by Tuesday night.

The upper level trough east of the Great Lakes will steer Tropical Storm Bill rapidly toward the northeast. On its anticipated track Tropical Storm Bill will pass southeast of Nova Scotia on Tuesday. Bill could approach southeast Newfoundland on Tuesday night.

Tropical Depression Two Forms East of Cape Hatteras

Tropical Depression Two formed east of Cape Hatteras on Monday morning. At 11:00 a.m. EDT on Monday the center of Tropical Depression Two was located at latitude 35.0°N and longitude 73.7°W which put it about 105 miles (165 km) east of Cape Hatteras, North Carolina. The tropical depression was moving toward the northeast at 21 m.p.h. (33 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 1006 mb.

More thunderstorms developed near the center of a low pressure system east of North Carolina on Monday morning and the National Hurricane Center designated the system as Tropical Depression Two. Bands of showers and thunderstorms also developed and the bands began to revolve around the center of the depression. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical depression. The removal of mass cause the surface pressure to decrease.

Tropical Depression Two will move through an environment favorable for intensification during the next 24 hours. The tropical depression will move over the warmer water of the Gulf Stream where the Sea Surface Temperatures are near 27°C. An upper level trough east of the Great Lakes will produce southwesterly winds which will blow toward the top of the depression. Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification. Tropical Depression Two will likely strengthen to a tropical storm during the next 12 hours.

The upper level trough east of the Great Lakes will steer Tropical Depression Two rapidly toward the northeast. On its anticipated track Tropical Depression Two will move away from the U.S. It could pass southeast of Nova Scotia on Tuesday.

Low Pressure over Southwest Gulf of Mexico

A broad area of low pressure was over the southwestern Gulf of Mexico on Sunday afternoon. The system was designated as Invest 92L. At 2:00 p.m. EDT on Sunday the center of Invest 92L was located at latitude 20.0°N and longitude 96.0°W which put it about 100 miles (160 km) north-northeast of Veracruz, Mexico. The area of low pressure was nearly stationary. The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 35 m.p.h. (55 km/h). The minimum surface pressure was 1010 mb.

The broad area of low pressure exhibited a little more organization on Sunday afternoon. There was an apparent low level center located north-northeast of Veracruz, Mexico. However, there were few thunderstorms near the apparent center. Most of the thunderstorms were occurring far to the east and north of the apparent center. Some of the stronger winds were occurring in the thunderstorms far to the east and north of that center.

Invest 92L is likely to remain over the southwestern Gulf of Mexico during the next several days. The broad area of low pressure will be in an area somewhat favorable for the development of a tropical depression. Invest 92L will be over an area where the Sea Surface Temperatures are near 29°C. It will be under the northern part of an upper level ridge centered south of Mexico. The ridge will produce westerly winds which will blow across the top of the broad low pressure system. The westerly winds will cause moderate vertical wind shear, which will inhibit the formation of a tropical depression. The upper level ridge could move a little farther north in two or three days, which would cause the westerly winds to weaken. If that happens, then the conditions could become more favorable for the formation of a tropical depression. The National Hurricane Center is indicating that the probability is 50% that a tropical depression forms during the next five days.

Tropical Storm Carlos Forms Southwest of Baja California

Tropical Storm Carlos formed southwest of Baja California on Saturday night. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Carlos was located at latitude 11.9°N and longitude 124.5°W which put it about 1225 miles (1970 km) southwest of the southern tip of Baja California. Carlos was moving toward the west at 7 m.p.h. (11 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.

The circulation around a low pressure system southwest of Baja California exhibited more organization on satellite imagery on Saturday night and the National Hurricane Center designated the system as Tropical Storm Carlos. More thunderstorms were developing near the center of Carlos. Storms near the center of circulation began to generate upper level divergence that pumped mass away from the tropical storm. However, the distribution of thunderstorms was asymmetrical. The strongest thunderstorms were occurring in bands in the southern half of Tropical Storm Carlos. Bands in the northern half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 25 miles (40 km) on the northern side of Carlos. The winds were blowing at less than tropical storm force in the southern half of the circulation.

Tropical Storm Carlos will move through an environment that is somewhat favorable for intensification during the next 24 hours. Carlos will move over an area where the Sea Surface Temperatures are near 28°C. It will move under the southeastern part of an upper level ridge over the Eastern North Pacific Ocean. The ridge will produce northeasterly winds that will blow toward the top of Tropical Storm Carlos. Those winds will cause vertical wind shear and they already contributed to the asymmetrical distribution of thunderstorms. The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification. Tropical Storm Carlos will likely strengthen on Sunday.

Tropical Storm Carlos will move south of a subtropical high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Carlos toward the west during the next 24 hours. The steering currents could weaken during the early part of next week and Tropical Storm Carlos could meander slowly well to the southwest of Baja California.

Tropical Storm Koguma Nears Vietnam

The center of Tropical Storm Koguma moved closer to northern Vietnam on Saturday. At 11:00 a.m. EDT on Saturday the center of Tropical Storm Koguma was located at latitude 20.2°N and longitude 106.9°E which put it about 115 miles (185 km) southeast of Hanoi, Vietnam. Koguma was moving toward the northwest at 20 m.p.h. (32 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 997 mb.

The circulation around former Tropical Depression 05W strengthened slightly on Saturday and the system was upgraded to Tropical Storm Koguma. Even though the circulation around the former tropical depression was a little stronger, the distribution of thunderstorms around Tropical Storm Koguma was still asymmetrical. The strongest thunderstorms were occurring in bands southwest of the center of Koguma. Bands in the other parts of the tropical storm consisted primarily of showers and lower clouds. An upper level ridge centered over southern China was producing moderate northeasterly winds that were blowing toward the top of the depression. Those winds were causing moderate vertical wind shear and they were also causing the asymmetrical distribution of thunderstorms.

Tropical Storm Koguma will move into an environment only marginally favorable for intensification during the next few hours. Koguma will move over an area where the Sea Surface Temperatures are near 30°C. However, the upper level ridge over southern China will continue to produce moderate vertical wind shear. The moderate wind shear will keep Tropical Storm Koguma from strengthening significantly before it reaches Vietnam. The circulation around Koguma will weaken after the center moves over Vietnam.

Tropical Storm Koguma will move around the southern part of a subtropical high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Koguma toward the northwest. On its anticipated track the center of Tropical Storm Koguma will make landfall on the coast of northern Vietnam south of Haiphong in a few hours. Koguma will bring gusty winds to parts of northern Vietnam. Since the heaviest rain is falling southwest of the center of Tropical Storm Koguma, heavy rain is already falling over parts of northern Vietnam, northern Laos and extreme northeastern Thailand. The heavy rain could cause flash floods in some locations.

Tropical Depression Forms South of Hainan Island

A tropical depression formed just to the south of Hainan Island on Friday night. At 11:00 p.m. EDT on Friday the center of Tropical Depression 05W was located at latitude 18.3°N and longitude 109.5°E which put it about 35 miles (55 km) south of Sanya, China. The depression was moving toward the west 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 1000 mb.

Thunderstorms developed closer to the center of a low pressure system south of Hainan Island on Friday night and both the Japan Meteorological Agency and the Joint Typhoon Warning Center designated the system as a tropical depression. The distribution of thunderstorms around Tropical Depression 05W was asymmetrical. The strongest thunderstorms were occurring in bands southwest of the center of the tropical depression. Bands in the other parts of the circulation consisted primarily of showers and lower clouds. An upper level ridge centered over southern China was producing moderate northeasterly winds that were blowing toward the top of the depression. Those winds were causing moderate vertical wind shear and they were also causing the asymmetrical distribution of thunderstorms.

The center of Tropical Depression 05W will move near Hainan Island during the next few hours. The northern half of the circulation around the tropical depression will be over Hainan Island, which will inhibit intensification. Tropical Depression 05W will move into an environment favorable for intensification when it moves west of Hainan Island. The tropical depression will move over an area where the Sea Surface Temperatures are near 30°C. The upper level ridge over southern China will continue to produce moderate vertical wind shear. Even with the moderate wind shear, Tropical Depression 05W is likely to intensify to a tropical storm during the next 24 hours.

Tropical Depression 05W will move around the southern part of a subtropical high pressure system over the Western North Pacific Ocean during the next 36 hours. The high pressure system will steer the tropical depression toward the west-northwest. On its anticipated track the center of Tropical Depression 05W will pass near the southern part of Hainan Island. Since the strongest thunderstorms are in the southwestern part of the circulation, the tropical depression will cause mainly gustier winds over Hainan Island. Tropical Depression 05W could approach northern Vietnam in 24 hours. It could bring gusty winds and locally heavy rain to parts of northern Vietnam. Heavy rain could cause flash floods in some locations.