Moving northward, Ophelia regained tropical storm status early on September 28, and rapidly deepened to attain its peak intensity with maximum sustained winds of 140 mph (230 km/h) several days later.

Following Ophelia's transition into an extratropical cyclone, residents across Europe were urged to prepare for strong winds in excess of 75 mph (121 km/h) in some locations, as well as rainfall accumulations up to 4 in (100 mm).

In northern Ireland, a combination of moisture and significantly cooler weather produced several inches of snow across the region, cutting electricity to hundreds.

Deep shower and thunderstorm activity continued to fire as the disturbance moved in a general westward motion, and it was assessed with a high chance of development by early on September 19.

Despite the poor presentation on satellite imagery, data from a nearby buoy revealed that the system was stronger than previously thought, with maximum sustained winds of 65 mph (105 km/h) on September 22.

As the upper-level low moved closer to Ophelia, inducing increasingly unfavorable shear on the storm, it caused the low-pressure area to become completely void of thunderstorms.

The low-level center became exposed once again during the pre-dawn hours of September 25, and without the return of organized shower and thunderstorm activity, led to the NHC declaring Ophelia as a remnant area of low pressure, while situated 180 mi (290 km) east of the northern Leeward Islands.

[8] Upper-level outflow expanded in all four quadrants of the cyclone by the afternoon hours of September 29,[9] and satellite intensity estimates continued to rise, prompting the NHC to upgrade Ophelia to a Category 1 hurricane by 1800 UTC that day.

Ophelia intensified into a Category 4 hurricane at 0000 UTC on October 2 and simultaneously attained its peak intensity with maximum sustained winds of 140 mph (230 km/h) and a minimum barometric pressure of 940 mbar (940 hPa; 28 inHg) as it passed east of Bermuda.

[13] As Ophelia made its closest approach to the region, heavy rainfall submerged Canefield Airport, and numerous roads, buildings and farms were damaged, leaving residents trapped.

[15] Over the following days, the threat of damaging winds gradually decreased as the storm's forecast track took it far enough east of the territory to spare the region of a direct hit.

[17] Passing roughly 140 mi (230 km) east of Bermuda, the outer bands of Ophelia produced 0.38 in (9.7 mm) of rain and wind gusts up to 35 mph (56 km/h) across the islands.

[22] In the midst of a record-breaking heat wave, with temperatures reaching an all-time monthly record high of 86 °F (30 °C), the storm was expected to bring much cooler weather across the region.