Tropical storm warnings are in impact for almost all of the northern Lesser Antilles — Antigua, Barbuda, St. Kitts, Nevis, Montserrat, Anguilla, Saba, St. Eustatius, St. Maarten, Guadeloupe, St. Barthelemy and St. Martin. Warnings had additionally been hoisted for Puerto Rico, together with Vieques and Culebra, and the US Virgin Islands as of 11 am The British Virgin Islands and Dominica are beneath a tropical storm watch.
Whereas the winds shall be modest, gusting as much as 50 mph or so close to the storm’s middle because it traverses the islands, the Nationwide Hurricane Middle warned of “appreciable flood impacts” that might be extremely problematic.
“Flash and concrete flooding, together with mudslides in areas of upper terrain” may be anticipated, they wrote.
Climate fashions have been very inconsistent of their simulations of Fiona’s evolution after 72 hours; some contend that the storm will curve northward, slipping harmlessly out to sea. Others paint a state of affairs a bit extra regarding for the Southeast US Others nonetheless cling to the distant chance of a weak system coming into the Gulf of Mexico, however these odds are minimal. Regardless of the way you slice it, Fiona is one to look at.
On Friday morning, Tropical Storm Fiona was centered about 175 miles east of Guadeloupe, drifting due west at 15 mph. It is necessary to not get caught up on the place the middle is, nonetheless. That is as a result of Fiona is a “bare” system. Meaning robust upper-level winds have blown all of the thunderstorms related to Fiona east of its low-level middle of circulation, leaving the middle uncovered.
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Fiona will proceed struggling in opposition to shear, or a disruptive change of wind velocity and/or course with top, although Saturday. There’s an opportunity that shear might calm down a bit in the course of the latter half of the weekend, probably permitting Fiona to flirt with low-end hurricane power.
Affect on the Leeward Islands and Puerto Rico
Fiona’s circulation will cross the Leeward Islands, in all probability close to Guadeloupe, in the course of the late afternoon hours on Friday. Keep in mind although — for the reason that storm is lopsided, the majority of the wind and entirety of the rainfall will maintain off till after the low-level middle passes. Meaning it in all probability will not begin raining till in a single day Friday into Saturday. The heaviest rains, which might complete 3 to six inches, will solely final 18 to 24 hours, however some showers ought to linger into early subsequent week; the US and British Virgin Islands ought to see the same quantity of rain.
For Puerto Rico correct, the rain arrives Saturday evening, however might stick round via Monday because the system slows down its westward progress and probably turns north up the Mona Passage — the ocean move between Hispaniola and western Puerto Rico. Rainfall totals of 4 to eight inches with localized 12-inch quantities are attainable, together with flooding, particularly the place the US territory’s larger terrain turns into an element. That would precipitate a couple of mudslides. Gusts of 35 to 50 mph are probably too.
The heaviest rains are projected within the jap Dominican Republic, the place 6 to 10 inches are attainable, and even as much as 16 inches within the mountains, the place flash flooding and mudslides will develop into a menace.
Fiona’s long-term prospects
Fiona’s long-range forecast is particularly murky.
As Fiona scrapes alongside the south aspect of Puerto Rico, its power will decide how shortly it turns. On the low and mid-levels of the environment, winds are out of the east — pushing Fiona west. On the higher ranges, winds are southerly. As such, a weaker Fiona might proceed progressing westward, but when Fiona strengthens, and subsequently turns into taller, it’s going to start to “really feel” southerly winds and curve to the north.
Image a sailboat. It is perhaps drifting in a single course, but when it hoists its sails excessive sufficient and catches a brand new wind course, it’s going to begin altering course.
The difficult factor about Fiona is that subtleties within the storm’s trajectory may have huge bearings on subsequent steps. If Fiona waits to start a northward curve, which is probably going, she might encounter Hispaniola, a jagged land mass which might in all probability shred the storm’s internal circulation. That would immediate a messy reorganization and an nearly unattainable forecast.
Alternatively, Fiona might escape northward sooner into the southeast Bahamas. From there, its path would hinge on the power of an Atlantic ridge of excessive strain, which can act as a drive discipline to suppress Fiona Westward. A stronger ridge would shunt it nearer to the East Coast, however a weaker excessive would permit it to meander out to sea.
At current, there are too many overlapping uncertainties to hatch a forecast with enough confidence. As such, it is briefly a recreation of wait and see — but it surely’s too early to let one’s guard down.