The storm is delivering 50 mph sustained winds extending outward up to 345 miles, and currently sits about 155 miles south of Ponce, Puerto Rico, NHC said.
Isaias is forecast to make landfall over southern Dominican Republic before noon Thursday and then reach near Florida over the weekend.
There is uncertainty where and how strong the storm will be when it nears Florida
Forecast models are split. Some models show a weak storm hitting the West Coast of Florida, while others show a much stronger storm lashing the East side of the state and moving toward the Carolinas.
How the storm interacts over the Hispaniola could impact the intensity of the storm.
“The eventual track will determine Isaias’ strength and potential future development,” CNN Meteorologist Chad Myers said. “A track mainly over water will let the storm get stronger. A path more over land and the mountains of Hispaniola and Cuba will help to tear it apart.”
However, once it gets over warmer waters, the storm could strengthen quickly like what was seen with Hurricane Hanna last weekend. Something, many of the models struggled to pick up on.
Tropical Storm Warnings issued
Rainfall will be the main concern over the next few days. Over 3 to 6 inches could fall across the Virgin Islands, Puerto Rico, Dominican Republic, Turks and Caicos, eastern Cuba and northern Haiti. The southeastern Bahamas could see 4 to 8 inches. This could lead to flash flooding, mudslides and potential riverine flooding.
Tropical storm warnings are issued for Puerto Rico, the US and British Virgin Islands, the entire northern and southern coasts of the Dominican Republic, and the north coast of Haiti from Le Mole St Nicolas to the border with the Dominican Republic. Tropical storm-force winds are expected within the warning areas.
Why it was originally called Potential Tropical Cyclone Nine
Now that it has been given the name Isaias — pronounced (ees-ah-EE-as) — it is the earliest storm to begin with an “I” on record. The previous record was set on August 7, 2005, part of the busiest season to date.
There were Tropical Storm warnings issued before the storm even formed. The reason it was called “Potential Tropical Cyclone Nine” is because the storm did not have a round center of circulation, says CNN meteorologist Chad Myers. Instead, it was very elongated. “When a circular center finally formed, that is when they began to call it a tropical storm.”
By calling it a potential tropical cyclone, it allowed countries to issue watches and warnings.