Tropical disturbance near Bahamas bears watching for impacts in southeastern US
A budding area of showers and thunderstorms has the potential to continue to slowly organize prior to reaching the southeastern United States with downpours and gusty thunderstorms late this week and this weekend, AccuWeather meteorologists say.
Meanwhile, forecasters will continue to monitor a train of disturbances, also known as tropical waves, moving westward from Africa as July comes to a close and August begins.
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On this wide image of the tropical Atlantic basin, a tropical wave was moving just off the coast of Africa (far right). A large tropical wave was located over the eastern Caribbean (left of center). Finally, a tropical wave was kicking up thunderstorms east of the Bahamas (upper left). (AccuWeather Enhanced RealVue™ satellite) |
A tropical wave was located a couple hundred miles to the northeast of the Bahamas Tuesday. A tropical wave represents a narrow zone in the atmosphere where the air is rising and more conducive for showers and thunderstorms to erupt. Under the right conditions, tropical waves can develop an area of circulation and an increase in winds.
"Where this disturbance is located, there is some moisture around and not a great deal of wind shear," AccuWeather Chief On-Air Meteorologist Bernie Rayno said. Wind shear is the sudden change in direction or increase in breezes across the atmosphere and can inhibit tropical development.
"The water is very warm where the feature is now and where it is going," Rayno said.
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Ocean water temperatures as of 9 a.m. EDT on Tuesday, July 25, 2023. |
A water temperature of 78-80 degrees Fahrenheit is the minimum threshold for tropical development. Water temperatures in the vicinity of the disturbance and where it is likely to travel generally range from 83-88 F but are even higher locally.
A general west-to-northwest drift of this disturbance is likely through the end of the week, which would bring it to the coast of Florida or perhaps as far north as Georgia Friday. Disruptive wind shear may increase as the system nears the coast late this week.
"There is not much time for this system to organize and strengthen," Rayno said. However, the system will be watched closely for quick development, especially as it nears the U.S. coast and encounters warm waters in the Gulf Stream where temperatures were in the upper 80s on Tuesday.
While sinking air well ahead of the system may limit thunderstorm activity in parts of Florida and along the Georgia and Carolina coasts for a time into Thursday morning, an uptick in drenching downpours and locally gusty thunderstorms is likely as the system moves closer from Thursday afternoon to Friday.
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Depending on the track and strength of the system as it moves along over the weekend, downpours and thunderstorms may push westward across parts of the Florida Peninsula and perhaps farther inland in Georgia and South Carolina. Even weak tropical systems can bring an uptick in severe weather including waterspouts and short-lived tornadoes. Coastal waters may get choppy for boaters, and rough surf and rip currents may pose hazards to swimmers.
"Should the system take a more westward path across the Florida Peninsula, downpours could be heavy enough to trigger flash flooding in places such as Miami, Fort Lauderdale and West Palm Beach as early as Thursday," AccuWeather Senior Meteorologist Dave Houk said. "It may bring enough rain to help ease severe drought in the hard-hit Florida counties of Manatee and Sarasota, near the Gulf coast, by Friday."
It is possible that downpours from the weak tropical system snap the string of 90-degree days in Miami that began on June 23.
A tropical wave that AccuWeather meteorologists have been tracking for over a week is entering a more hostile zone for development in the Caribbean.
"The tropical wave was located near the Lesser Antilles on Tuesday and was moving into a zone of increasing wind shear and dry air over the Caribbean as it drifted westward," AccuWeather Tropical Meteorologist Alex DaSilva said.
For now, there remains a low chance of development with this large system due to warm waters in the Caribbean.
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"While the broad nature of this tropical wave will bring localized downpours and gusty winds to the islands in the Caribbean as it drifts westward, it is not likely to be a significant long-term threat," DaSilva said.
Downpours and gusty thunderstorms from this system are likely to reach parts of Central America Friday and Saturday.
As July winds down and August ramps up, conditions typically become more favorable for tropical development in the prime zone of the Atlantic between Africa and the Caribbean. The months of August and September are sometimes referred to by meteorologists as the Cabo Verde season, because of the amount of tropical systems that take shape near the group of islands located off the west coast of Africa.
As the train of tropical waves continues to move westward from Africa, there will inevitably be opportunities for development with some of the systems.
During the late summer and first part of autumn, water temperatures are typically at their warmest levels in the tropics and areas of dry air and disruptive wind shear tend to dwindle.
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"A robust tropical wave moved off Africa on Monday and will be closely monitored for development during the end of this week, through this weekend and into next week as it moves generally to the west," DaSilva said. "This tropical wave will encounter dry air from Saharan dust during the next several days, though wind shear may decrease in the system's path toward the end of the week and that may allow the system to organize."
At this time, AccuWeather meteorologists have assigned a low risk of development for the system, with the potential for an increase in development risk later this week.
The next named tropical or subtropical storm in the Atlantic will be called Emily. Don, the most recently named storm to prowl the open waters of the basin, briefly became the first Atlantic hurricane of the year well away from land this past Saturday.
AccuWeather's tropical and long-range meteorologists are expecting a significant uptick in tropical development in the Atlantic during August and into September. However, a quick decrease in activity is possible during the second half of the hurricane season as El Niño's impacts on the basin increase.
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