Tropical Atlantic could soon wake up from doldrums

·5 min read

The Atlantic has been in the midsummer doldrums, a typical quiet period in tropical activity during mid- to late July. However, there are signs that the basin will soon come alive. AccuWeather forecasters say at least one new tropical feature has a significant chance of developing into a named storm into next week.

"We have been seeing a decline in the extent of dry air and dust over the zone from Africa to the Caribbean this week," AccuWeather Senior Meteorologist Rob Miller said, noting that these are signals that the basin could become more active in the coming days.

Dry air, dust and shifting winds at different levels of the atmosphere, known as wind shear, can deter and prevent tropical development in many cases. These factors are often prevalent during July over the Atlantic basin.

Most of the Atlantic is often free from fronts, which can be the focal point for development earlier in the season, during July and the start of August. So, with no fronts, dry air, dust and high wind shear present, July often brings a quiet period for tropical activity over the basin.

This graphic depicts how tropical activity typically ramps up as August progresses.

Less wind shear was evident on Friday, compared to the start of the week, over the central and eastern part of the Tropical Atlantic and may now be at the point as to not inhibit development.

"There is a chance of some development of tropical waves crossing and emerging from Africa over the next week," Miller said.

AccuWeather meteorologists say the feature with the greatest potential for development is a wave that was moving off the coast of Africa Thursday. It has a 40% chance at gradual development as it moves westward into next week, provided wind shear stays relatively low and the system avoids dry air and dust.

"The immediate environment will be sufficiently moist [for development] over the next few days," AccuWeather Meteorologist Randy Adkins explained, adding that drier air will become an increasing factor early next week, as the system will continue to move to the west-northwest across the central Atlantic.

Water temperatures are largely supportive for development and will not inhibit development of this feature through next week. A critical threshold of around 80 F is needed to sustain tropical storms.

This image, captured on Friday, Aug. 6, 2021, shows some moisture and clouds (white) gathering from the central Atlantic to the coast of Africa (right). Dry air was still extensive from the Caribbean (left of center) to the western part of the tropical Atlantic. (CIRA at Colorado State/GOES-East)

Another weaker tropical wave, which emerged ahead of the one near Africa, will also be monitored closely in the coming days. That will especially be the case early next week as it nears the Lesser Antilles. The feature will interact with a non-tropical system in the area, Adkins said.

"Wind shear may be a limiting factor of this weaker wave that is farther west with intrusions of drier air possibly hampering development as well," Adkins added.

Closer to United States' shores, AccuWeather meteorologists will also be keeping an eye on a frontal boundary along the East coast late this weekend into early next week.

"It is not completely out of the question for a non-tropical storm system to acquire tropical characteristics should it break from the frontal boundary," Adkins said. Winds would also need to weaken for further development to take place.

The next two names on the 2021 list for the Atlantic hurricane season are Fred and Grace.

The tropical waves that emerge from Africa form the backbone of tropical development in the Atlantic from late August through September and into early October. During an average hurricane season, there are typically at least a handful of direct threats and other close calls in terms of impact on the Atlantic Seaboard, and this year may be no exception.

Early in the 2021 Atlantic hurricane season it has shown some vigor by running well ahead of average pace through July. Through the first part of July there have been five named systems, including one hurricane, Elsa. Even though the Atlantic has grown silent in recent weeks, the numbers are still well above average pace.

And an uptick in tropical storms and hurricanes tends to begin during the middle and latter part of this month. By mid-August there are typically only three named systems including one hurricane, according to the National Hurricane Center.

The Atlantic has remained quiet since Elsa's demise on July 9. Despite the typical doldrums in the tropical Atlantic during July, the basin achieved a feat that hadn't occurred since 2009. That was the last year that a storm was not named between July 10 and Aug. 3, according to Philip Klotzbach, Colorado State University meteorologist.

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By Labor Day, it is common for there to be one or more named systems churning in the basin.

AccuWeather's team of hurricane experts is projecting a total of seven to 10 hurricanes this season with five to seven direct impacts on the U.S. This threat includes risk for one or more storms to track near and move northward along the U.S. Atlantic coast as the season progresses.

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