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Tropical Tracker: Saharan Dust dominates the Atlantic, keeping storm development low

Yearly-occurring phenomenon helps to keep tropical Atlantic quiet

Saharan dust encompasses most of the main development region of the Atlantic Basin. This dry air and increased wind shear associated with the Saharan Air Layer helps limit tropical activity.
Saharan dust encompasses most of the main development region of the Atlantic Basin. This dry air and increased wind shear associated with the Saharan Air Layer helps limit tropical activity.

ORLANDO, Fla.Vibrant sunrises & sunsets possible

The dust rolling in from the Sahara Desert has been the talk of the town over the last ten days or so and it’s finally here to bring stunning sunrises and sunsets to a city near near you. Because of the dust in the atmosphere, you may notice a haze over Central Florida during the daytime.

Dust Sunday morning. The highest concentrations and possible air quality issues for sensitive groups would arrive over the weekend and early next week.
Dust Sunday morning. The highest concentrations and possible air quality issues for sensitive groups would arrive over the weekend and early next week.

Florida produces some of the best sunrises and sunsets around, but with the dust hanging out about 5,000-20,000 feet above the surface, they could get even better.

When the sun is rising or setting, the dust helps to scatter the sun’s rays more than normal, oftentimes providing extremely vibrant colors during sunrise and sunset. The highest concentration of dust will be over the Sunshine State from Friday through about Wednesday, July 1.

Dust Tuesday (June 30) morning.
Dust Tuesday (June 30) morning.

While dust from the Sahara Desert makes a trip across the Atlantic every year, 2020′s dust has been abnormally thick. The video below shows the skies over Puerto Rico from back in May (for comparison) and then what it looked like as the Saharan Dust arrived on the island June 22. Typically the dust is not this thick.

The concentration of dust should not be as high as what it was in Puerto Rico earlier in the week, but sensitive groups should pay close attention to the air quality through the middle of next week. The highest concentration of dust and the bulk of air quality issues for asthma suffers and sensitive groups should stay to the west and north of Florida.

Because of the dry air and increased wind shear within the area of dust, tropical development becomes less likely in the areas where the dust is present. Another round of dust just moved off of the African Plateau, but it is not as robust as the round the Caribbean and Southern U.S. is dealing with.

The nutrients within the dust can help feed the Amazon rain forest. On the flip side, the iron in the dust can feed bacteria in the Gulf of Mexico which can help promote the growth of Red Tide. Saharan Dust is the ultimate catch-22.

Hello, (goodbye) Dolly

If you blinked, you may have missed Tropical Storm Dolly. The fourth named storm of the season developed well off the coast of New England Tuesday. By Wednesday it was already a remnant low.

Dolly was part tropical, meaning it was getting some of its energy from the warm waters it was over and part non-tropical meaning differences in temperature were also fueling the storm.

Dolly became the third-fastest D storm on record to form. Debby formed on the same day in 2012 and Danielle formed a few days earlier in 2016.

Four named storms have developed in the Atlantic Basin through June 25.
Four named storms have developed in the Atlantic Basin through June 25.

Records go back well into the 1800s, but satellites weren't around until 1960, so it is possible storms out at sea were missed. This is only the third time we have had a D storm develop in June.

Another way meteorologists measure tropical systems is by Accumulated Cyclone Energy or ACE.

ACE is a metric that accounts for the intensity and duration of a storm. Combining the ACE from individual storms will give you the ACE for the season. While these four storms to date have been weak, we are also well above average in ACE.

Through June 25, the current ACE for the season is 6.1, the average to date is 1.2.

Looking ahead

Last week we identified the western Gulf of Mexico as a potential region for development during the last few days of June. A healthy cluster of storms has developed in that region, but thankfully, wind shear and dry air are dominating the Gulf of Mexico at this time and development is unlikely.

Cluster of storms in the Southern Gulf. NO tropical development is expected.
Cluster of storms in the Southern Gulf. NO tropical development is expected.

There are several tropical waves coming off of Africa, which is early for that to be happening, but the environment is not conducive for tropical development at this time. No new development is expected over the next five days as highlighted by the National Hurricane Center. There is a weak wave coming off of Africa that bears watching over the last couple of days of June. There is still a lot of dust north and west of this system, but a few computer models try to develop it.

No New Development is expected over the next 5 as forecast from the National Hurricane Center, but a tropical wave that emerged off Africa warrants watching. This cluster of storms is south of the large dust plumes.
No New Development is expected over the next 5 as forecast from the National Hurricane Center, but a tropical wave that emerged off Africa warrants watching. This cluster of storms is south of the large dust plumes.

Beyond that, through July 4th, the Caribbean, specifically around Central America, could be the next location for possible development. It is unclear at this point whether development will be favored on the Eastern Pacific side of Central America or in the Atlantic Basin, but disturbed weather appears likely in this part of the world.


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