By AccuWeather senior meteorologist
Two areas of interest or tropical disturbances were spinning over the Atlantic Wednesday, June 30, 2021. One can be seen just left of center of the satellite image above, and another was situated farther to the right. South America appears on the lower left, while Puerto Rico is visible in the upper left. Dust from the Sahara Desert (brown shades) was evident. (CIRA at Colorado State/GOES-East)
Following the rapid development of Tropical Storm Danny and its landfall in the Southeast Monday, not only is the 2021 Atlantic hurricane season running in the same pack as last year's record season, there is the chance it could pull ahead should the "E" storm form in the next week. There are a couple of areas that AccuWeather meteorologists are monitoring for development in the coming days.
Formation of a named tropical system or two is not highly unusual by late June, but on average the second named storm does not brew until early August, according to the National Hurricane Center (NHC). To have four such systems by late June is teetering on record territory. The average date for the fourth named storm to form is Aug. 23 and, for the fifth storm, the average formation date is Aug. 31.
Last year, Dolly missed the record for the earliest fourth-named storm or D-storm by just a few days. In 2016, Danielle formed on June 20, and Dolly formed three days later in 2020 on June 23. However, every storm after Dolly last year set an early-formation record. The "E" storm, which was Ernesto, formed on July 6, 2020. With two potential candidates in the next seven days, there is at least a chance of a record being broken should Elsa, the next name on the 2021 list, take shape.
The 2020 Atlantic hurricane season was the busiest on record with 30 named storms that required the use of the Greek alphabet, once the last name and letter "W" on the list was used up. That was the second-only and last time the NHC will tap into Greek letters to name storms that extend via the original designated list.
2020 Atlantic Hurricane Tracks
The 2021 season is forecast to fall short of the number of named systems from 2020. However, AccuWeather forecasters say that to have a significant amount of tropical disturbances that are originating from Africa this early is a concern.
Typically, through the middle of the summer, vast areas of dry air, dust, wind shear over top of cool ocean temperatures tend to prohibit development of these features, which meteorologists refer to as tropical waves, as they move westward over the Atlantic.
Thus far this year, most named systems, with the exception of Ana that formed over the central Atlantic, developed fairly close to land. That is typical for early in the season, but that may be about to change, AccuWeather forecasters say.
There are two tropical waves on AccuWeather's radar over the south-central Atlantic that are being closely watched. These features originate from Africa and travel westward across the Atlantic. Disturbances that originate from this pattern of tropical waves are called Cabo Verde systems, named after a group of islands off the coast of Africa.
These waves of low barometric pressure ignite clusters of showers and thunderstorms. Many of these waves fail to develop, but a few can evolve into a tropical depressions, storms and hurricanes over time under ideal atmospheric conditions.
So far in 2021, there have been prohibitive conditions in place, but the waves in general emerging from Africa have been more robust than usual for so early in the season. In a sense, the pattern resembles that of August rather than late June or early July.
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While tropical waves have succumbed to the inhibiting factors thus far, there are indications that at least one of systems currently drifting westward may have more fight than predecessors and may cause trouble as it approaches and moves through the Caribbean.
Since these long-track disturbances tend to spend more time over water, they tend to have more time to organize, develop a circulation and strengthen, when compared to near-shore systems (also called homebrew storms). Because of that, they could potentially pose a more significant threat to lives and property as they approach land areas.
One lead tropical wave was approaching the Lesser Antilles on Wednesday has been dubbed 95L by NHC and continues to track westward.
"Satellite images from Wednesday morning show a cluster of showers and thunderstorms associated with this weak area of low pressure, AccuWeather Senior Meteorologist Rob Miller said.
"While 95L is now moving over warm waters, the system is also moving into an environment with strong wind shear and dry air," Miller explained.
Weighing the conducive factor of warmer water with the inhibiting factor of wind shear and dry air, some low-end tropical development is possible over the next few days as it moves across the eastern and northern Caribbean. However, the risk of development has lowered compared to a couple of days ago.
Regardless, locally heavy showers and thunderstorms, along with some gusty winds, are expected to impact the Leeward Islands Wednesday and the British and U.S. Virgin Islands and Puerto Rico by Thursday.
Beyond this area, further development and track is questionable due to possible degradation caused by interaction with the land of the Greater Antilles. Should the system survive and jog north or south of these larger islands, then there may be a greater chance for the system to strengthen.
There is a system several hundred miles farther east of 95L, which has been given an investigative identification by the NHC of 97L.
Satellite images on Tuesday began to reveal some spin about the clouds associated with this feature. That spin was more evident on Wednesday.
This trailing feature has a more favorable environment for development, since 95L may help to moisten up the atmosphere and displace some of the dust in the region. There is less wind shear in the vicinity of 97L as well.
This feature is tracking a bit farther south than 95L and has a better chance at moving into open waters of the middle of the Caribbean, rather than brush the islands on the northern edge of the basin.
"This disturbance is likely to develop as it moves into and travels through the Caribbean into early July," Miller said.
Expected to cross the Windward Islands at the end of the week, 97L will bring another uptick in showers and thunderstorms.
Should the system hold together, it is forecast to drift west-northwestward over open waters of the Caribbean Sea spanning July 3-5. It could enter the Gulf of Mexico on or about July 6. Waters in both of these basins are generally in low to middle 80s F and plenty warm enough to support tropical development or sustain an established tropical system.
All interests in the Caribbean should closely monitor the progress of these two disturbances as conditions are at least marginally favorable for development over the next several days or more. If one system should fizzle out, there is still a significant risk that the second system may continue on.
In addition to these two main areas of concern, patches of showers and thunderstorms have persisted over the Gulf of Mexico thus far this week.
"The Gulf of Mexico will probably remain an area where there is at least a very low risk of a weak system popping up very close to the coast over the next week or so," AccuWeather Senior Meteorologist Dave Houk said.
AccuWeather meteorologists are forecasting 16-20 named systems for the Atlantic basin for the 2021 season with seven to 10 hurricanes and three to five direct impacts on the U.S. Both Danny from June 28-29 and Claudette from June 19-23 tracked over the Southeastern states.
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