WEATHER NEWS: Fiona to lash Puerto Rico as hurricane with ‘life-threatening’ flooding
Tropical Storm Fiona intensified into a hurricane on Sunday as it battered Puerto Rico. Conditions rapidly deteriorated in the morning as the storm drew close and strengthened, and a slew of serious impacts — damaging winds to hurricane force, extreme rainfall, life-threatening mudslides and coastal rip currents — are expected as the worst arrives Sunday afternoon.
As the wind and rain escalated Sunday morning, over 300,000 power outages had already been reported, according to PowerOutage.us.
A hurricane warning is in effect for the entire U.S. territory, including Vieques and Culebra, and has been expanded to include the eastern Dominican Republic as well. Tropical storm warnings cover the U.S. Virgin Islands and the north coast of the Dominican Republic west to Puerto Plata, regions which are also under a hurricane watch to account for Fiona’s possible intensification.
A flood watch also blankets Puerto Rico and the U.S. Virgin Islands. The National Hurricane Center is warning that “rains will produce life-threatening flash flooding and urban flooding across Puerto Rico and the eastern Dominican Republic, along with mudslides and landslides in areas of higher terrain.”
Complicating matters is Puerto Rico’s beleaguered electrical grid, whose infrastructure problems were brought to international prominence following Hurricane Maria’s catastrophic passage in 2017. In addition to over 300,000 electric customers in Puerto Rico in the dark, roughly 10,000 were without power in the Virgin Islands.
Wind gusts in southeast Puerto Rico and the Virgin Islands had already reached 50 to 70 mph Sunday morning.
As Puerto Rico‘s governor was briefing the island ahead of Fiona‘s impact the lights went out. The governor has already said LUMA Energy – the private company in charge of transmission & distribution of electricity on the island – is on probation with him. pic.twitter.com/YVEnPPcnZp
As of 11 a.m. Sunday, Fiona was a high-end tropical storm with sustained winds of 80 mph. Its center was located 50 miles south of Ponce, Puerto Rico, and it was moving west-northwest at 8 mph. The storm has consistently tracked a few miles to the south of model and human forecasts, and may continue doing so today, with a landfall most likely over the far southwestern portions of Puerto Rico.
On radar, Fiona exhibited a developing eye about 35 to 40 miles wide. That is a sign of intensification. The eye marks a dearth of wind and rainfall resulting from hot, dry, sinking air at the middle of the storm. Surrounding the eye is usually an eyewall-like feature, or a semicontinuous ring of intense thunderstorms that contain a tropical storm’s or hurricane’s strongest winds. That is where any hurricane-force winds will be found.
At present, it looks like Fiona is poised to make landfall near or west of Ponce around lunchtime Sunday into the early afternoon hours, though the greatest hazard, freshwater flooding, will extend far beyond the storm’s eyewall.
Extreme rainfall and flash flooding
A widespread 8 to 12 inches of rain with localized 15 to 25 inch totals is expected across Puerto Rico, with the lesser amounts in the far northern reaches of the island. The heaviest totals will be found in eastern and southeastern Puerto Rico, where a persistent onshore flow east of Fiona’s center will tug ashore a nonstop stream of tropical moisture ripe for a serious deluge. The territory’s high terrain will also enhance torrential rainfall in the mountains.
Sharp rises in flow rate on area rivers has already been noted across Puerto Rico, including along the Río Maunabo at Lizas, which spiked 2.5 feet in four hours. That is a sign of incipient flash flooding, which will become widespread by Sunday afternoon.
That will contribute to potential mudslides and landslides, especially in hilly or mountainous areas, that could prove dangerous or deadly. Travel is discouraged through at least Monday morning as the harsh conditions begin to subside southeast to northwest, although stagnant high water and some mudslide risk will remain.
The strongest winds will remain wrapped around the eye, meaning this will not be a widespread damaging to destructive wind event like Maria was in 2017. Instead, most inland areas can expect wind gusts between 40 and 50 mph. That may be enough to result in large tree limbs falling or to spur scattered power outages, but widespread structural damage is unlikely.
Near the south coast of Puerto Rico, winds may gust closer to 60 mph east of the storm’s center, except in the eastern eyewall, where a few 80 to 85 mph gusts are likely at the beaches. The greatest likelihood of strong eyewall gusts is somewhere west of Ponce, perhaps in the vicinity of Guanica, La Parguera or especially Rojo Cabo. Winds of that magnitude may cause minor roof damage and could down trees, which could result in pockets of structural damage.
Storm surge and rip currents
The size and strength of Fiona are not sufficient to produce more than a minor storm surge, or risen in ocean water above normally dry land, of a foot or two in most areas, but rip currents will remain a problem through the start of the workweek. There is a high risk of rip currents along Puerto Rico’s southern beaches, and a moderate risk on the north shore of the island. Rip currents will reman dangerous through Tuesday, and care should be taken to avoid the water. Swimming is not recommended.
The center of Fiona may cross the Mona Passage between western Puerto Rico and the eastern Dominican Republic late Sunday night into early Monday. That could bring the eyewall close to Punta Cana during the predawn hours Monday. By then, Fiona will probably be a hurricane. Four to 8 inches of rain, with localized totals up to a foot, are projected for the eastern Dominican Republic.
From there, Fiona’s evolution closely hinges on its path. If it continues hewing on the southern edge of the envelope of predictions, it may have a closer brush with the Dominican Republic’s mountains than models are simulating. That could disrupt the storm’s core circulation and prompt a reorganization that could temporarily weaken it. Conversely, if Fiona skirts the mountains to the east, it will remain intact and able to continue strengthening.
As Fiona has intensified, it has grown taller, meaning it can “feel” southerly winds at the high altitudes. That has been responsible for its slight northward turn in the past 12 hours, and will continue tugging Fiona north over the next several days.
A tropical storm watch is up for Turks and Caicos as well as the southeastern Bahamas, although current projections suggest Fiona may pass to the east of most inhabited land masses.
Eventually, an approaching trough, or dip in the jet stream, will scoot eastward over the U.S. East Coast and out to sea, dragging Fiona with it. That is good news for mainland U.S. residents, but could bring Fiona precariously close to Bermuda late Thursday into Friday as a high-end Category 2 hurricane approaching major hurricane status.
There is a chance the Canadian Maritimes and Newfoundland could be in line for eventual impacts toward next weekend, but confidence remains low.