Tropical storm Fiona is gradually gaining strength as it sweeps into the eastern Caribbean, prompting a hurricane warning for Puerto Rico. Over 12 inches of rain and damaging winds are forecast to batter the island between Saturday night and Sunday night, probably leading to flooding and power outages.
The storm, the long-term track of which is still uncertain, needs to be monitored by residents along the U.S. East Coast. However, the majority of computer models suggest it should curl out over the open waters of the Atlantic Ocean after exiting the Caribbean Sea.
Into early next week, Fiona does look to be a problem for the Virgin Islands, Puerto Rico, the Dominican Republic and the Turks and Caicos. As it swept over Guadeloupe in the northern Lesser Antilles, the storm unloaded up to 16.65 inches of rain, causing severe flooding and at least one death.
The storm’s peak winds increased from 50 to 60 mph between Friday and Saturday and are expected to approach 75 mph by Sunday - which is hurricane strength - when its center will be passing just to Puerto Rico’s south.
“Hurricane conditions are expected across portions of Puerto Rico Sunday and Sunday night, and are possible across the U.S. Virgin Islands tonight and Sunday,” the National Hurricane Center wrote Saturday morning.
Downpours and tropical-storm-force winds are anticipated sooner, arriving in the Virgin Islands during the day Saturday and by Saturday night in Puerto Rico.
Rainfall is the hazard of greatest concern, with some parts of the Virgin Islands and Puerto Rico projected to see double digit amounts.
“This rainfall is likely to produce considerable flood impacts including flash and urban flooding, along with mudslides in areas of higher terrain, particularly in Puerto Rico,” the Hurricane Center wrote.
The Hurricane Center is projecting the following rainfall totals:
-Virgin Islands: 4 to 6 inches, with localized totals up to 10 inches.
-Puerto Rico: 12 to 16 inches, with localized totals up to 20 inches in eastern and southeastern areas.
-Dominican Republic: 4 to 8 inches, with localized totals up to 12 inches along the far eastern coast.
-Haiti: 1 to 3 inches, with localized totals up to 4 inches.
-Turks and Caicos: 4 to 6 inches.
In addition to the rain, some coastal areas could see a storm surge, or rise in ocean waters above normally dry land, of 1 to 3 feet.
The storm, centered about 130 miles southeast of St. Croix in the U.S. Virgin Islands Saturday morning, is headed westward around 8 mph. The Hurricane Center reported that the storm appeared better organized Saturday morning as hostile high altitude winds, which had previously disrupted its circulation, eased.
Through the weekend, environmental conditions are favorable for more strengthening. “Intensification is anticipated, and Fiona is likely to be near or at hurricane strength while it moves near Puerto Rico on Sunday,” the Hurricane Center wrote.
After Fiona passes north of Puerto Rico, splitting the gap between the western part of the island and the Dominican Republic, known as the Mona Passage, its peak winds are projected to increase to 100 mph or more early next week. By then, it’s forecast to be positioned east of the Bahamas.
Compared to Friday, computer models have come into better agreement that Fiona will head out in the open Atlantic after passing north of the Bahamas, rather than turning westward toward the U.S. East Coast. However, some outlier simulations still track Fiona close to the Southeast so it’s premature to sound the all-clear signal.
Bermuda also should monitor the storm’s long term track as some simulations bring it perilously close late next week.