Hurricane Fiona May Strike Nova Scotia as Strongest Regional Storm on Record

ON 10/06/2022 AT 03:16 AM

On the morning of September 24, the same hurricane which just pummeled Puerto Rico and the Dominican Republic may make history. After making an abrupt northwards turn, it is expected to make landfall on Nova Scotia with record wind gusts, storm surges, and what could be the lowest air pressure ever recorded in Canada.

Project path of Hurricane Fiona.

A projected path of Hurricane Fiona as of early morning September 23, 2022, Atlantic Daylight Time. The areas outlined in red already have been put on Hurricane Warning status. Those outlined in blue are on Tropic Storm Warning status. Photo: National Oceanographic and Atmospheric Administration (NOAA), Hurricane Tracker Maps

As perfect storms go, this one — at least by the time it hits the province of Nova Scotia for its last landfall — will have found  energy and focus through a combination of unusual meteorological events.

The launching pad for Fiona took shape when the storm formed of the coast of Africa, as most Atlantic hurricanes do. As it traveled westwards over the warm Caribbean, it gained energy quickly. It made landfall on Puerto Rico as a Category 1 storm, with maximum sustained winds of 85 mph, early morning on September 19, local time.

Though the winds were mild compared to other hurricanes which have leveled the island, this one delivered heavy rains peaking as high as 2 feet in some sections of the island. Lagos Cerrillo, in south-central Puerto Rico, had the highest recorded rainfall there, at 27 inches.

The resultant flooding created landslides, forced rivers over their banks, and wiped out bridges such as one in the central mountain town of Utuado which was built by the National Guard after Hurricane Maria hit in 2017. As asphalt cracked from rushing waters and rain-swollen ground underneath, roadways shattered. Rising rivers and lakes forced hundreds out of their homes, submerged cars, and flooded many first floor areas throughout the island. The soaked ground and Hurricane Level 1 winds were enough to yank power poles from the ground and cause a near-total blackout.

The destruction was so severe that earlier this week the president authorized emergency FEMA funds to begin picking up the pieces and rebuilding again after yet another brutal storm landing.

Fiona next passed through the Dominican Republic and pushed up through Turks and Caicos, creating similar damage to what happened to Puerto Rico.

A high-pressure system then drove Fiona northwards from its original path, sparing Florida in its attack.

Fiona strengthened as it moved on over a larger expanse of warm waters. As of yesterday morning, it had peak sustained winds of 130 mph, making it officially a Category 4 hurricane. It was heading toward Bermuda at a rate of 13 mph. It is being pushed roughly parallel to the east coast of North America via stronger-than-normal upper-level winds.

Fiona is the first Category 4 storm of this year's Atlantic Hurricane season.

As of this writing, the hurricane will make landfall at the edges of Bermuda early morning Eastern Time on September 23.

Under normal circumstances, after making it this far the storm would continue northwards in the open ocean, far off the United States east coast. It would weaken in power to become at best a moderately blustery storm with occasionally high winds and seasonally heavy rainfall, where it would move just off the coast of Atlantic Canada.

This time things are going to be different. They start with that Hurricane Fiona will be making its trek northwards beyond Bermuda already as a strong hurricane. But this time, instead of passing across cooler waters it will be greeted with a much hotter-than-usual ocean, turbocharged by a summer of extended heat waves which have helped keep the Atlantic hot.

Atlantic Ocean Surface Temperatures

Atlantic Ocean surface temperature map as of September 21, 2022. Photo: National Oceanographic and Atmospheric Administration (NOAA)

Fiona is going to stay stronger longer than any other previous hurricane heading to Canada first because air pressure systems are keeping it positioned over some of the warmest seas in the Atlantic, as the above satellite image shows. A second reason is the unseasonably high surface temperatures which are being maintained particularly in the northern part of that ocean, just off the east coast of the U.S.

To explain further, the storm track which brought Fiona across from the coast of Africa to Puerto Rico and the Dominican Republic earlier this week show temperatures of about 29° C (84° C). That warmth is where thermals forced upwards from the ocean floor gave rise to Fiona’s initial growth. It is hot but not abnormal.

Looking northwards the situation is decidedly abnormal. Water ocean temperatures hovering close to 30° C (86° F) up through Bermuda and into the central Atlantic coast are keeping Fiona fully charged with moist hot circulating clouds. As the storm moves even further north, still driven by higher-velocity upper atmospheric winds, the ocean waters do cool slightly but nowhere near what is normal. For much of the journey up to Canada, ocean temperatures will stay in excess of 25° C (77° F), dropping significantly only as they reach the coast of Nova Scotia.

Rather than moving further east out to sea, the storm is being pulled westwards by a trough of low pressure coming from the U.S. east coast. That is what is setting the path more directly on Nova Scotia.

There the cooler temperatures will serve to restructure some of the form of Hurricane Fiona and weaken it back down, more to what it was like when it hit Puerto Rico. That, unfortunately for the region, still constitutes a storm with serious hurricane force winds.

Hurricane Fiona Approaches Nova Scotia on September 22, 2022.

Projected path of Hurricane Fiona as of 9 PM on September 22, 2022. Photo: Environment Canada Canadian Hurricane Center (ECCC)

The projected storm track, reported as of 9 pm Atlantic Daylight Time on September 22 by the Environment Canada Canadian Hurricane Center (ECCC), projects Fiona now to make landfall on the Nova Scotia southern coast at 9 AM ADT Saturday.

Prince Edward Island and western Newfoundland are also included in the Hurricane Warning alert. Because of the wide swath of the storm and the possibility of wind shifts in the upper atmosphere which could steer the storm, residents of all three provinces are recommended to make immediate preparations to protect themselves.

It will strike with sustained winds of 155 km/h (96 mph) as a full-fledged hurricane and at the low end of Category 2 hurricane winds, which run from 155 to 177 km/h  (96 to 110 mph). Maximum wind gusts are projected to run much higher and should exceed 230 km/h (145 mph).

Because of its path from the tropics northward, when it hits Canada it will exhibit an unusual combination of high-latitude and tropical storm features.

“We call this a deep hybrid low pressure system, possessing north tropical and intense winter storm properties with very heavy rainfall and severe winds,” wrote Environment Canada, the Canadian equivalent of the U.S. National Weather Service, as the forces shaping Fiona’s final journey took shape. “Most regions will experience some hurricane force winds. Similar cyclones of this nature have produced structural damage to buildings.”

As Fiona gets closer to its landfall currently projected for Saturday morning, it will be drawn in by an atmospheric structure known as a “pressure dipole”. Because of an unusual high pressure dome which has formed southeast of Greenland, that dipole will subject the storm to vastly different air pressure ranges occurring over relatively short distances. What that means for the province as landfall nears and beyond is that the steep air pressure gradient will tend to push very powerful winds towards the extremely low pressure eye of the storm.

Because of the pressure dipole and the setup for the storm as it approaches the Canadian coast, the area could end up experiencing the lowest pressure ever recorded in Canada.  Current meteorological models project the eye to show the minimum atmospheric pressure levels running between 930 and 935 millibars. The current lowest air pressure in Canada was 940.2 millibars, set on January 20, 1977, at St. Anthony, Newfoundland.

Wind gusts as the storm passes will run over 100 mph. They will bring with them a storm surge of 5 to 8 feet. Off the coast, in the open ocean nearby, waves could reach 24 meters (80 feet) in height routinely, with some as high as 31 meters (100 feet).

Fiona could also dump rainfall of between 10 and 15 centimeters (4 to 6 inches) over much of the province before it moves on.

Canada’s Sable Island National Park Reserve, located 285 km (177 mi) east of Halifax, Nova Scotia, will likely bear much of the brunt of the storm as it hits. Sable Island is referred to as the "Graveyard of the Atlantic" with hundreds of ship wrecks.