Sun Sentinel: FORT LAUDERDALE, Florida – Forecasters hoisted a hurricane warning Saturday for Puerto Rico and watches for the U.S. Virgin Islands and the Dominican Republic’s southern coast as heavy rains from Tropical Storm Fiona pummeled large sections of the Caribbean.

A warning means that hurricane conditions are expected somewhere within the area where a storm is likely to strike. A watch is issued when a tropical cyclone with winds of 74 mph or higher poses a possible threat within 48 hours. The winds may be accompanied by storm surge and coastal flooding and river flooding.

“We are now forecasting Fiona to approach or to move over portions of Puerto Rico as a hurricane on Sunday during the day or Sunday evening,” said Mike Brennan, acting deputy director of the National Hurricane Center on a Facebook Live briefing. For that reason, he said, the center issued its warning and watches.

Heavy rains were forecast for the islands Saturday, and into the Dominican Republic to the west of Puerto Rico on Sunday, according to the hurricane center’s update.

The storm is now forecast to reach at least Category 2 strength by Thursday, with top winds of 105 mph. At that point, the storm’s center is expected to be somewhere in a broad area that encompasses the southern Bahamas. It is considered unlikely to threaten Florida, according to the weather service.

Flash and urban flooding with mudslides are expected in higher terrain, “particularly in Puerto Rico,” forecasters said.

The storm’s top wind speed has remained unchanged for the past several hours. At 11 p.m. Saturday, the storm was producing top winds of 60 mph, with its center located about 150 miles southeast of Ponce, Puerto Rico.

Fiona which had been moving west since its inception more than three days ago, began its forecasted directional shift at 5pm Saturday, and at 11pm Saturday was moving west-northwest at 8 mph, according to the National Hurricane Center. Fiona’s tropical-storm-force winds extend outward up to 140 miles from the center.

Fiona would be the third hurricane of the Atlantic hurricane season, which so far has been less active than forecasters predicted.

The hurricane center said the storm should strengthen as it enters an area of increased humidity and lower wind shear, the high-level winds that can disrupt a storm’s structure.

“Fiona could be very near hurricane strength as it approaches the southern coast of the Dominican Republic,” the hurricane center said. “The terrain of Hispaniola is likely to disrupt Fiona’s circulation, but the global models suggest that Fiona shouldn’t have much trouble reorganizing itself once over the far southwestern Atlantic, and the NHC forecast now calls for the cyclone to become a hurricane by the end of the 5-day forecast period.”

The center of the storm is expected to move near or just south of the Virgin Islands and Puerto Rico through Sunday, and approach the southern or eastern coast of the Dominican Republic Sunday night and Monday.

Forecasters also are tracking one other disturbance. As of late Saturday night, disorganized showers and thunderstorms over the central Atlantic are associated with the northern portion of a tropical wave. Some slow development of this system is possible during the early or middle part of next week while it moves slowly northwestward to northward.

In the past 50 years, there have been four hurricane seasons without a major hurricane (at least 111 mph sustained windspeed): 2013, 1994, 1986, 1972. In the other 46 years in that span, the latest in a season that a Category 3 storm or higher has been born has been Sept. 22 (both with Emily in 1987 and Ellen in 1973). In that past half-century, in addition to Emily and Ellen, only Hurricane Isidore in 2002 became a season’s first major hurricane later than Sept. 18, intensifying to a Category 3 on Sept. 21.

It’s now past the statistical peak of the Atlantic hurricane season with five previous named storms before Fiona. AccuWeather notes that “not a single hurricane has come within striking distance of the East Coast or Gulf Coast” this season.

The next storm to form would be Gaston.

“The Atlantic hurricane season’s slow pace so far in 2022 has … led to a startling disparity in the number of mainland US landfalls through mid-September compared to the last two years,” The Weather Channel reported.

Forecasters say dry air, Saharan dust and wind shear have been among the reasons there haven’t been more storms this year.

“The lack of tropical storms and hurricanes in the Atlantic has been particularly noticeable considering recent hyperactive hurricane seasons with many impacts to the U.S. and Caribbean. Even though the season overall may end up near average or even slightly below average, it only takes one storm to threaten lives and create a major disaster,” according to AccuWeather Chief Meteorologist Jonathan Porter.

The 2020 hurricane season set a record with 30 named systems, while 2021′s season was the third-most active with 21 named systems. An average year calls for 14 named storms.

Hurricane season ends Nov. 30.

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