Tropical threat diminishing, but storms to drench southeastern US coast

AccuWeather meteorologists continue to monitor for tropical development along the southern Atlantic coast of the United States into the middle of the week, even though the chance of development is quite low at this point. Despite the chance being low, the struggling feature can still stir dangerous surf and trigger thunderstorms from Florida to the Carolinas this week.

This zone and perhaps one other spot over the western Gulf are the only potential candidates for tropical activity over the Atlantic basin this week.

The showers and thunderstorms off the coast of Georgia and the Carolinas on Tuesday were associated with an old frontal boundary stretched across the area. AccuWeather forecasters say it is not uncommon to see tropical development in this region during late July due to slightly lower atmospheric pressure -- especially in situations where non-tropical systems or their fronts stall in the area -- and warm waters of the Gulf Stream, which can add fuel.

Since late last week, a low-pressure area has been producing a weak circulation and circular motion to the showers and thunderstorms erupting east of Florida. The storms pulsed and waned over the weekend, but the system failed to organize enough to be dubbed a tropical depression.

An area of disturbed weather was situated just off the coast of northeastern Florida and Georgia on Monday, July 26, 2021. (CIRA at Colorado State/GOES-East)

A circular motion was still evident with the cloud cover and sporadic shower and thunderstorm activity just east of Jacksonville, Florida, on Monday, while the feature meandered toward the Georgia coast.

The feature moved onshore into southeastern Georgia during Monday night and lost what little circulation in had from the weekend.

This image, captured on Tuesday morning, July 27, 2021, shows little evidence of a circulation along the southern Atlantic coast. However, there were several thunderstorms with torrential downpours. (CIRA at Colorado State/GOES-East)

A broad area of disturbed weather will remain along the coast and over waters northeast of Florida to the shoals of North Carolina on Tuesday and perhaps into Wednesday.

Even though an organized system is unlikely to develop, the weather pattern will produce rounds of showers and thunderstorms, some of which can bring localized torrential downpours and gusty winds. A couple of waterspouts are also possible in coastal waters.

The main concern will be to bathers in the region as the unsettled atmospheric conditions are forecast to produce stronger and more frequent rip currents than usual along the southern Atlantic coast into at least Wednesday.

Small craft operators should exercise caution for the risk of gusty squalls in coastal and near-shore waters into midweek.

Beginning on Wednesday, a southward dip in the jet stream is predicted along the southern Atlantic coast and is likely to start to push the shower and thunderstorm activity out to sea. Strong winds aloft associated with the jet stream dip will create hostile conditions for tropical development as well.

Farther to the southwest, a storm system in the middle layer of the atmosphere continued to spin westward over the Gulf of Mexico.

As of Tuesday morning, this feature was over the western Gulf and was producing a broad, slowly-spinning area of showers and thunderstorms.

A poorly organized area of showers and thunderstorms was over the western Gulf of Mexico on Monday, July 26, 2021. (CIRA at Colorado State/GOES-East)

AccuWeather forecasters say that this system is highly unlikely to strengthen enough to become a tropical depression. However, it will bring an uptick in showers and thunderstorms along the central and lower Texas coast and northeastern Mexico beginning later Tuesday and lasting into Thursday.

Since the air is rising in the vicinity of this feature, some of the storms can be more robust than average summer downpours. A few communities along the Gulf Coast as well as farther inland over Texas and northern Mexico can be hit with flash flooding and brief strong wind gusts this week. And, just like with the disturbed area along the southern Atlantic coast, an uptick in rip currents is likely.

July can often be a quiet month for tropical activity due to extensive swaths of dry air, dust and strong wind shear that can prevent features that emerge from Africa from becoming better organized as they move westward across the Atlantic. These tropical waves tend to form the backbone of the Atlantic hurricane season from mid-August to mid-October.

With five named storms so far in 2021, which is well above the average pace for late July, AccuWeather long-range meteorologists are still anticipating 16-20 named storms for the season. The average date for the fifth named storm of the season is not until Aug. 30, according to the National Hurricane Center (NHC).

"The Atlantic has seen significant early-season development due to multiple regions of low wind shear relative to average during the late spring and early summer and activity near North America spurred on by frontal systems," AccuWeather Hurricane Expert Dan Kottlowski said.

Three tropical systems, Claudette, Danny and Elsa, have crossed into or formed over the southeastern U.S. already with the likelihood of at least a couple more landfalls.

AccuWeather is projecting a total of six to 10 hurricanes over the entire 2021 Atlantic tropical season, compared to an average of 7.2 hurricanes per year.

Thus far, Elsa is the only system that reached hurricane status in the basin. Elsa was briefly a hurricane over the eastern Caribbean and briefly regained hurricane status while off the coast of Tampa, Florida, in early July. The average date for the first hurricane of the season is Aug. 10, according to NHC.

Many factors during mid- to late July have created "a more hostile environment across the basin," Kottlowski said. Some of the factors include those previously mentioned such as strong wind shear and dry air, and the atmospheric pattern in general has not been favorable, he explained.

That may not change until early August with the exception of anything that takes shape near the Southeast, but the pattern change would depend on many players and how they behave, according to Kottlowski.

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