US Gulf Coast put on alert for potential tropical threat
By
Alex Sosnowski, AccuWeather senior meteorologist
Updated Jun 16, 2021 1:37 PM EDT
Monday marked the two-week point in the Atlantic hurricane season, and the basin was brimming with activity. As the second named storm of the 2021 Atlantic hurricane season developed off the Eastern Seaboard Monday night, AccuWeather meteorologists continued to warn of the potential for development in the southwestern Gulf of Mexico later this week.
Whether a named tropical system develops in the Gulf or not, AccuWeather forecasters caution that tropical moisture is predicted to arrive in parts of the southern United States that have been dealing with torrential rain and flooding since May, potentially making matters much worse for hard-hit communities.
AccuWeather meteorologists have given the disturbance in the Gulf a high risk of development. The next name on the list of tropical storms for the 2021 Atlantic hurricane season is Claudette.
Clouds, showers and thunderstorms have been forming and dissipating over the southwestern Gulf of Mexico since late last week. Thus far, wind shear, dry air and proximity to land have been keeping tropical system formation at bay. These inhibiting factors are likely to continue through midweek.
However, a tropical disturbance that was churning over the eastern Caribbean Sea Monday is projected to drift toward the region around Thursday and could help to provide a spark to initiate tropical development.
If something does form in the western Gulf of Mexico, odds favor it not becoming very strong, AccuWeather Hurricane Expert Dan Kottlowski said.
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"Wind shear north of the feature is expected to be rather high later this week so any attempt to move northward will likely cause the tops of the thunderstorms to be blown off to the northeast," Kottlowski stated.
Wind shear is the change in the strength or direction of breezes with increasing altitude or over a horizontal area above the Earth's surface.
When wind shear is high or increases relative to a storm's movement, it can cause the system to lean, like a poorly rooted tree. This leaning effect can also affect the circular shape of the moisture associated with the storm and can inhibit strengthening under certain circumstances.
"Wind shear is likely to be a constant negative impact on development as the system tries to move northward later this week," Kottlowski explained.
Such a system may become no stronger than a tropical storm, but a powerful hurricane is not needed to produce torrential rainfall and major flooding.
"Flooding remains the main concern with this feature in the Gulf," warned Kottlowski, adding that will be the case no matter how strong the system becomes, especially as it moves northward toward the southern U.S.
Because of the likelihood of significant southwesterly wind shear as this feature moves northward, a sweep of dry air may keep the bulk of the rain away from much of the Texas coast, except for areas northeast of Galveston Bay.
This may also focus the plume of tropical downpours on Louisiana, Mississippi, Alabama and the Florida Panhandle beginning as early as Friday and perhaps lasting into early next week.
However, exactly how much rain falls and where may depend on the exact track and intensity of the system. A moderate tropical storm may focus heavy rain in a more concentrated area, whereas a poorly organized feature is likely to spread out rain over a wider area with lower precipitation accumulation in any one area.
A track into Louisiana or southern Mississippi may focus more rain along the central and northeastern Gulf Coast. On the other hand, a tropical storm tracking toward the Texas and Louisiana border might trigger heavier rain as far west as the upper Texas coast and especially across southwestern Louisiana.
Although the amount of rain is highly speculative at this early juncture, there is the potential for a foot or more of rain to fall in some locations with a general 3-6 inches of rain possible along and inland of the central Gulf coast.
Rainfall of this magnitude, even if spread over a few days, would lead to low-lying area flooding as well as street and highway flooding at the very least. As runoff works into area bayous and rivers, rising waters could inundate some unprotected communities by next week.
After heavy rain fell last week over part of the South Central states, some rivers from northeastern Texas to northern Mississippi and western Alabama experienced a surge of water that was producing moderate to major flooding, according to the National Weather Service. Portions of rivers that were experiencing significant flooding in the South Central states as of Monday included the Sabine, Quachita, Big Sunflower, Big Black, Yazoo, Pearl and Tombigbee.
Areas near and just inland from the central Texas coast to southern Louisiana and parts of Mississippi have picked up 1-2 feet of rain since the first week in May -- or about 150 to 200% of normal. Ground conditions in these areas and others farther to the north in Arkansas and Tennessee as well as farther to the east in Alabama and Georgia are wet, leaving the region more vulnerable to flooding with any additional rounds of rainfall.
AccuWeather forecasters are cautioning residents and businesses along the Gulf Coast to stay vigilant in the coming days and monitor the progress of the developing system as there is a possibility that the feature will organize and strengthen.
Before the system even moves northward toward the Gulf Coast, drenching showers and gusty thunderstorms will affect portions of southern Mexico and Central America this week with the risk of localized flash flooding and mudslides.
Even beyond the emerging threats in the Atlantic, AccuWeather meteorologists anticipate a very active hurricane season for 2021 with 16-20 named storms and three to five direct impacts on the U.S.
Should the system in the Gulf reach tropical storm status and gather the name Claudette, it would follow Tropical Storm Ana from mid-May and, more recently, Tropical Storm Bill. The second tropical storm of the season formed late Monday evening off the Atlantic coast of the U.S.
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
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News / Hurricane
US Gulf Coast put on alert for potential tropical threat
By Alex Sosnowski, AccuWeather senior meteorologist
Updated Jun 16, 2021 1:37 PM EDT
Monday marked the two-week point in the Atlantic hurricane season, and the basin was brimming with activity. As the second named storm of the 2021 Atlantic hurricane season developed off the Eastern Seaboard Monday night, AccuWeather meteorologists continued to warn of the potential for development in the southwestern Gulf of Mexico later this week.
Whether a named tropical system develops in the Gulf or not, AccuWeather forecasters caution that tropical moisture is predicted to arrive in parts of the southern United States that have been dealing with torrential rain and flooding since May, potentially making matters much worse for hard-hit communities.
AccuWeather meteorologists have given the disturbance in the Gulf a high risk of development. The next name on the list of tropical storms for the 2021 Atlantic hurricane season is Claudette.
Clouds, showers and thunderstorms have been forming and dissipating over the southwestern Gulf of Mexico since late last week. Thus far, wind shear, dry air and proximity to land have been keeping tropical system formation at bay. These inhibiting factors are likely to continue through midweek.
However, a tropical disturbance that was churning over the eastern Caribbean Sea Monday is projected to drift toward the region around Thursday and could help to provide a spark to initiate tropical development.
If something does form in the western Gulf of Mexico, odds favor it not becoming very strong, AccuWeather Hurricane Expert Dan Kottlowski said.
CLICK HERE FOR THE FREE ACCUWEATHER APP
"Wind shear north of the feature is expected to be rather high later this week so any attempt to move northward will likely cause the tops of the thunderstorms to be blown off to the northeast," Kottlowski stated.
Wind shear is the change in the strength or direction of breezes with increasing altitude or over a horizontal area above the Earth's surface.
When wind shear is high or increases relative to a storm's movement, it can cause the system to lean, like a poorly rooted tree. This leaning effect can also affect the circular shape of the moisture associated with the storm and can inhibit strengthening under certain circumstances.
"Wind shear is likely to be a constant negative impact on development as the system tries to move northward later this week," Kottlowski explained.
Such a system may become no stronger than a tropical storm, but a powerful hurricane is not needed to produce torrential rainfall and major flooding.
"Flooding remains the main concern with this feature in the Gulf," warned Kottlowski, adding that will be the case no matter how strong the system becomes, especially as it moves northward toward the southern U.S.
Because of the likelihood of significant southwesterly wind shear as this feature moves northward, a sweep of dry air may keep the bulk of the rain away from much of the Texas coast, except for areas northeast of Galveston Bay.
This may also focus the plume of tropical downpours on Louisiana, Mississippi, Alabama and the Florida Panhandle beginning as early as Friday and perhaps lasting into early next week.
However, exactly how much rain falls and where may depend on the exact track and intensity of the system. A moderate tropical storm may focus heavy rain in a more concentrated area, whereas a poorly organized feature is likely to spread out rain over a wider area with lower precipitation accumulation in any one area.
A track into Louisiana or southern Mississippi may focus more rain along the central and northeastern Gulf Coast. On the other hand, a tropical storm tracking toward the Texas and Louisiana border might trigger heavier rain as far west as the upper Texas coast and especially across southwestern Louisiana.
Although the amount of rain is highly speculative at this early juncture, there is the potential for a foot or more of rain to fall in some locations with a general 3-6 inches of rain possible along and inland of the central Gulf coast.
Rainfall of this magnitude, even if spread over a few days, would lead to low-lying area flooding as well as street and highway flooding at the very least. As runoff works into area bayous and rivers, rising waters could inundate some unprotected communities by next week.
After heavy rain fell last week over part of the South Central states, some rivers from northeastern Texas to northern Mississippi and western Alabama experienced a surge of water that was producing moderate to major flooding, according to the National Weather Service. Portions of rivers that were experiencing significant flooding in the South Central states as of Monday included the Sabine, Quachita, Big Sunflower, Big Black, Yazoo, Pearl and Tombigbee.
Areas near and just inland from the central Texas coast to southern Louisiana and parts of Mississippi have picked up 1-2 feet of rain since the first week in May -- or about 150 to 200% of normal. Ground conditions in these areas and others farther to the north in Arkansas and Tennessee as well as farther to the east in Alabama and Georgia are wet, leaving the region more vulnerable to flooding with any additional rounds of rainfall.
AccuWeather forecasters are cautioning residents and businesses along the Gulf Coast to stay vigilant in the coming days and monitor the progress of the developing system as there is a possibility that the feature will organize and strengthen.
Before the system even moves northward toward the Gulf Coast, drenching showers and gusty thunderstorms will affect portions of southern Mexico and Central America this week with the risk of localized flash flooding and mudslides.
Even beyond the emerging threats in the Atlantic, AccuWeather meteorologists anticipate a very active hurricane season for 2021 with 16-20 named storms and three to five direct impacts on the U.S.
Should the system in the Gulf reach tropical storm status and gather the name Claudette, it would follow Tropical Storm Ana from mid-May and, more recently, Tropical Storm Bill. The second tropical storm of the season formed late Monday evening off the Atlantic coast of the U.S.
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Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
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