Meteorologists are watching the tropical Atlantic with extra close attention as the anticipated ramp-up of an already record-setting hurricane season begins, and one budding system is likely to strengthen into the next named storm of 2020 by this weekend.
A tropical disturbance located about 1,000 miles to the east of the Lesser Antilles was showing early signs of getting better organized on Wednesday with the development of a high altitude cloud shield spiral.
On Wednesday evening, the system had organized further and was designated as Tropical Depression 13 by the National Hurricane Center at 11 p.m. EDT. As of early Thursday morning, the depression had maximum sustained winds of 35 mph and was moving to the west-northwest at 21 mph.
The spiral of clouds aloft indicates that the upper part of the atmosphere is setting up to “vent” thunderstorms erupting just above the surface of the sea. When thunderstorms are well-vented they can become intense. Forecasters say that when thunderstorms cluster around the center of the system, and that cluster begins to rotate, a tropical depression will be born.
In addition to to the depression, there are two other tropical disturbances that also bear monitoring over the equatorial Atlantic; one in southern Caribbean and the other near the coast of Africa. There will continue to be the risk of these features strengthening into organized tropical systems as well this weekend to next week.
Once the circulating winds reach 39 mph or greater, a tropical storm will be given a name. The next name on the 2020 Atlantic list is Laura.
With the likelihood of Laura forming within the next few days, it would shatter the prior “L-storm” early-season formation record, currently held by Luis on Aug. 29, 1995. If the L-storm record is set this season, it would be the ninth early-season formation benchmark set this year with Cristobal, Edouard, Fay, Gonzalo, Hanna, Isaias, Josephine and Kyle now at the top for their designated letters.
Exactly how far north versus south the center forms will, to some extent, determine whether this system passes right over the northern islands of the Caribbean or just to the north or south. But, drenching showers and gusty thunderstorms will extend many miles outward from the center of low pressure.
First in the path of the budding tropical system are the Leeward Islands.
“Regardless of development and exact track, this feature will spread gusty winds and the possibility of periodic heavy rainfall westward over parts of the Leeward Islands from Friday to Saturday,” Kottlowski said.
Depending on how quickly the system strengthens will determine whether the conditions are mild, moderate or severe.
People across the northern islands of the Caribbean, as well as the Turks and Caicos, southern Bahamas, the Florida Keys and the southern part of the Florida Peninsula should be prepared for tropical storm conditions, as an average, as the feature moves along with the potential for more significant conditions, depending on exact track and strength of the feature itself.
Should the system track just north of the northern islands of the Caribbean, conditions there may not be severe, but it could allow the center of the storm to strengthen over warm water with minimal impact from the high mountains in Puerto Rico and Hispaniola. Such a scenario could bring damaging conditions to the Turks and Caicos and part of the southern islands of the Bahamas.
“We expect the system to move across the Florida Straits on Sunday or Monday,” Kottlowski said.
“While there is still about a 20 percent chance of the feature turning northward just east of Florida and correspondingly making a run along the Atlantic coast of the United States, the much more likely path at this point is into the Gulf of Mexico next week,” Kottlowski stated.
Even though it’s not currently predicted, additional strengthening into a hurricane can’t be ruled out at this time if it takes a path over the bath-warm waters of the Florida Straits into the Gulf of Mexico.
This forecast is based on the anticipated strengthening and westward extension of the Bermuda-Azores high pressure area. Should the high fail to strengthen and extend westward, there would be room for an earlier northward turn.
There is another player on the long-range weather maps. That is a southward dip in the jet stream over the South Central states and the Gulf of Mexico.
This southern U.S. feature will be at its peak late this week and is forecast to weaken this weekend to next week. How quickly the weakening occurs may determine whether this jet stream dip tugs the tropical system northward or allows it to continue on a west-northwest path through the Gulf.
