Tropical Storm Fiona, churning toward the Leeward Islands on Friday evening with 50 mph winds, will strengthen into a hurricane in the coming days, the US National Hurricane Center said.
Although the storm is presently bearing down upon Guadeloupe, extreme wind shear has pushed Fiona’s powerful thunderstorms onto its eastern side, meaning the island chain has seen almost no rain, even though Fiona’s eye is just 20 miles off the coast.
Tropical storm warnings have been issued for the Leeward Island nations, and tropical storm watches have been issued for Dominica and parts of the Dominican Republic. In addition to its damaging winds, Fiona could bring between 12 and 16 inches of rain, as well as a dangerous storm surge, causing both coastal and inland flooding.
After passing through the islands, Fiona is expected to head westward and then hook to the north, toward the Bahamas, where it will continue to strengthen over the open sea and possibly reach hurricane strength by next week. That milestone is marked by sustained winds of 75 mph.
Where it goes from there is a matter of debate, though. Some computer models show it moving toward Florida, while others have it continuing to hook northward and then eastward and out to sea.
“Winds at the low and mid levels are out of the east. High aloft, out of the south. As Fiona grows stronger/thunderstorms get taller, they reach into the southerly winds aloft more/get pushed north,” meteorologist Matthew Cappucci tweeted on Friday.
“Picture a sailboat hoisting its sails and suddenly ‘feeling’ the tug of wind. Same premise here. In this case, if Fiona raises its sails in the form of stronger/taller thunderstorms, it gets pushed north,” he explained.
“Notice the deal here. All the green represent weaker scenarios – those are the Gulf/Caribbean seedlings if Fiona keep struggling. If it strengthens, it curves north and then gets stronger.”
In the eye wall, where the hurricane’s strongest and most intense storms are found, the clouds can reach 50,000 feet high - well into Earth’s stratosphere.