Weather Outside Your Window: Steadfast Sam to make run at top 5 list of long-duration major Atlantic hurricanes

By Alex Sosnowski, AccuWeather senior meteorologist

Updated Sep. 30, 2021 11:03 PM EDT

Mighty Sam has maintained its major hurricane force, meaning a cyclone of Category 3 strength or greater, since 11 a.m. EDT on Saturday, Sept. 25, while churning over the open waters of the Atlantic Ocean. AccuWeather meteorologists believe that Sam could remain a powerful major hurricane into this weekend as it passes a couple hundred miles to the east of Bermuda. And in doing so, it could make a run at the top-five list for long-duration major hurricanes in the basin.

As of Thursday evening, Category 4 Hurricane Sam continued to pack 145-mph maximum sustained winds, which is 12 mph shy of Category 5 strength. Sam was churning over the Atlantic Ocean about 550 miles to the south-southeast of Bermuda and was moving toward the north-northwest at 16 mph.

The relatively small but intense hurricane is forecast to take a similar path east of Bermuda as Larry did just weeks ago.

As a precaution due to the approach of Sam, the Bermuda Weather Service issued a tropical storm watch for Bermuda, but AccuWeather meteorologists believe that significant impacts on the islands will be limited to rough seas and surf.

Larry passed about 170 miles east of the islands on Sept. 9, but at the time, tropical storm-force winds extended up to 220 miles outward from Larry's center with hurricane-force winds reaching out 90 miles from its center. Bermuda experienced some rain and almost tropical storm-force wind gusts from Larry as it moved east of the islands.

In comparison, Sam is much smaller in size than Larry. As of Thursday evening, hurricane-force winds extended 60 miles outward from its center with tropical storm-force winds extending outward up to 150 miles.

"Sam is likely to still be a major hurricane as it passes by about 225 miles to the east of Bermuda early this weekend," AccuWeather Senior Meteorologist Adam Douty said.

There is a chance that Sam will hold onto maximum sustained winds of 111 mph or greater, which is the minimum threshold for a major Category 3 hurricane, well into this weekend. If the hurricane sustains this intensity into Sunday morning, Sam could eclipse Edouard from 1996 and take the title of fifth longest-lasting major hurricane to ever churn in the Atlantic. Edouard spent 186 straight hours, or seven and three-quarter days, as a major hurricane. As of Thursday midday, Sam had maintained major hurricane status for 120 straight hours or five days.

There are some notorious hurricanes on the same top-five list, according to Philip Klotzbach, Colorado State University meteorologist. These include Isabel from 2003 at 192 hours (eight days), Irma from 2017 at 210 hours (eight and three-quarter days) and Ivan from 2004 at 240 hours (10 days). Fabian from 2003, which struck Bermuda head-on, sits at number seven on the list at 174 hours or seven and one-quarter days.

CLICK HERE FOR THE FREE ACCUWEATHER APP

"Sam's small size and distance from Bermuda will minimize impacts, but showers and gusty winds, along with dangerous surf, will affect the islands on Friday and Saturday," Douty said.

Hurricane Sam, northeast of the Leeward Islands, is shown on the AccuWeather RealVue™ Satellite on the afternoon of Sept. 30, 2021. Check out our photo gallery for more amazing photos of Hurricane Sam.

Even though Sam is much smaller than Larry was when it cruised the central Atlantic, swells generated by Sam will reach outward. An increase in wave and rip currents is forecast along the shores of the United States east coast into this weekend. Waves and rip currents can be strong enough to pose dangers to bathers from northeastern Florida to New England this weekend.

The heaviest seas will generally remain east of Bermuda into this weekend but will build north of Bermuda during the weekend and into early next week, due to Sam's forecast track and the fact that the storm is expected to grow in size.

At the same time, as Sam shifts to the northeast of Bermuda, the hurricane will gradually encounter progressively cooler waters and begin to weaken.

Sam will interact with a non-tropical system, and that can cause rain and wind to expand over Atlantic Canada early next week, even if the center of Sam stays a couple hundred miles to the east. During that time, Sam itself is likely to be transitioning to or will have already transitioned to a non-tropical system.

"Direct impacts to Atlantic Canada look minor and perhaps on par with that of Bermuda, but a track farther west would bring some rain and strong wind gusts to the island of Newfoundland early next week," Douty said.

Elsewhere in the Atlantic, Tropical Storm Victor is moving to the west-northwest through the Atlantic Ocean. Victor is the 20th named tropical storm this year, and there is only one more name, Wanda, on the designated list for this season.

AccuWeather is expecting up to 25 named storms, so a supplemental list of names set forth by the World Meteorological Organization last spring is likely to be utilized for the first time.

Already AccuWeather meteorologists are eyeing the next trouble spot to emerge in the basin. Forecasters are expecting a broad area of unsettled weather to develop over the central Caribbean to the Bahamas and over waters near the southern Atlantic coast. There will be potential for tropical development to take place starting next week and lasting through next weekend.

It may be possible for more than one system to brew in this zone, but not all of the systems may be fully tropical in nature. It's possible that a sub-tropical system, which has both tropical and non-tropical characteristics, could develop.

The last subtropical storm, Teresa, formed just under a week ago to the north of Bermuda.

Whether any tropical or sub-tropical systems take shape or not, the pattern along much of the eastern third of the U.S. and coastal waters has the potential to be unsettled with vast areas of clouds and rain much of next week.

MORE WEATHER NEWS: