- Another tropical storm seems increasingly likely near the Lesser Antilles in a few days.
- After that, his future for the rest of the week is quite uncertain.
- The possibilities range from an earlier spread northwards towards the Atlantic to a later development and further spread westwards.
- All interested parties on the Caribbean islands, the Bahamas and the east coast of the USA should follow the forecast closely.
The system currently simmering in the Atlantic, now known as Invest 98L, has a high chance of developing into tropical climes as it approaches the Lesser Antilles early next week, according to the National Hurricane Center. While the likelihood continues to rise that this will be the future Ernesto, the forecast remains uncertain regarding potential impacts on the United States.
Where is it now? About halfway between the West African coast and the Lesser Antilles lies an extensive area of showers and thunderstorms moving toward the west-northwest. It is one of many so-called “tropical waves,” disturbances that move westward through the tropical Atlantic each hurricane season and can be the “seeds” from which tropical storms and hurricanes develop.
Possible NHC development
(The possible areas of tropical development are indicated by polygons color-coded by the likelihood of development over the next seven days, according to the latest forecast from the National Hurricane Center. An “X” indicates the location of a current disturbance.)
Timetable for the Lesser Antilles: We expect this tropical wave to reach the Lesser Antilles either late Monday or Tuesday. Regardless, showers with locally heavy rain and gusty winds are expected across the Leeward and Windward Islands, including Puerto Rico and the Virgin Islands, during this time period.
There is some potential for it to develop into either a tropical depression or Tropical Storm Ernesto either before or as it approaches the Lesser Antilles, as it enters a favorable environment with low wind shear and abundant ocean heat.
Current wind shear
(Areas of strong wind shear, the differences in wind speed and direction with height, are shown in purple. High wind shear is damaging to mature tropical cyclones and those attempting to develop. As in the previous map, the area of potential tropical development is also shown.)
What could happen next: After the Lesser Antilles, the forecast for later in the week is fraught with question marks and in some respects resembles Debby’s ambitious forecast at the end of July.
Computer forecast models indicate that there will be a gap between two high pressure systems – the Bermuda-Azores High and a heat dome in the southern United States. In general, well-developed tropical storms and hurricanes usually move toward this gap between the mountain ridges, turning first to the north and then to the northeast.
Where that gap will be is crucial. If the Bermuda-Azores High is more extensive and that gap is closer to the east coast, the “future Ernesto” could track closer to the east coast as it drifts north and then northeast.
But what if the system doesn’t develop as quickly? In that case, it could stay farther south and/or pass over Hispaniola and Cuba and get far enough west where, even if it develops and then drifts north, it may not be able to avoid at least parts of the United States.
In summary, here are the possibilities for the late week through the weekend of August 17-18:
- Developing rapidly and curling away from the US East Coast
- If it develops later, it could threaten at least parts of the east coast, including Florida
- Develops later and could end in the eastern Gulf of Mexico
The conclusion for now: Since the system has not yet developed into a tropical depression, changes to this forecast are to be expected, as we saw with Debby.
All interested parties from the Lesser Antilles to Puerto Rico, the Virgin Islands, Hispaniola, Cuba, Jamaica, the Bahamas, the US East Coast including Florida, Bermuda and Atlantic Canada should follow this forecast in the coming days.
