Early on October 16, a non-tropical low pressure system formed over the central tropical Atlantic, well to the east-southeast of Bermuda. The system moved little over the next few days, but gradually deepened. By October 19, thunderstorm activity had increased near the center. Advisories were initiated on Tropical Depression Twenty-Seven that morning. Initially, the center was exposed due to westerly shear, but conditions soon improved and the system strengthened. It was named Tropical Storm Epsilon a few hours later. Epsilon was the 26th named storm of 2020. 2005 was the only other year to see a 26th named storm (Delta, which formed on November 22 of that year). The name "Epsilon" was also used that year, for a cyclone which was named on November 29th.
Initially, the cyclone moved little, but early on October 20 a ridge built in and began pushing Epsilon northwest. The storm sat in a decidedly mixed environment: water temperatures where warm and there was plentiful atmospheric instability, but wind shear was still affecting the storm, and there were pockets of dry air in the circulation. Nevertheless, it fared well; a central dense overcast developed that morning, and an eye feature appeared intermittently later in the day. Accompanying these structural improvements was a corresponding increase in winds, and Epsilon rapidly intensified into a hurricane that evening.
The storm turned toward the west overnight and continued its intensification trend. The eye cleared out further and cloud tops in the small eyewall cooled. Aircraft reconaissance arriving during the afternoon of October 21 found that Epsilon was remarkably on the verge of major hurricane strength. A few hours later, it reached category 3 intensity, with peak winds of 115 mph and a central pressure of 951 mb. After a wobble, the center then assumed a north-northwest heading. The hurricane was running out of warm waters to traverse as it gained latitude, and, inevitably, began to decay. On October 22 it dropped back to category 1 intensity, though its satellite presentation was still impressive. Epsilon made its closest approach to Bermuda that afternoon, but was almost 200 miles east; gale force winds impacted the island, but little rain.
The hurricane followed a typical trajectory as it moved further into the mid-latitudes, recurving north and east and accelerating as it went. It underwent some normal structural changes too: the windfield broadened, the core became less compact, and the cyclone as a whole became asymmetric. Nevertheless, Epsilon maintained category 1 hurricane status through for the next few days. High surf and rip currents affected the northeast United States and Atlantic Canada. On October 25, the storm reached a forward speed of over 40 mph; by that time, it was north of 45 ° N, and the circulation was elongating. Satellite estimates indicated that Epsilon weakened to a tropical storm. Nevertheless, it maintained enough deep convection to be classified as tropical through the evening, when it finally completed extratropical transition. The next day, the remnants were absorbed by another powerful low.
The above image shows Epsilon near peak intensity over the open Atlantic. The storm exhibited a relatively small core inside a large mesoscale circulation; this structure is common for hurricanes in the subtropics.
Epsilon's path took it past the island of Bermuda well to the east, so it caused only minor land imapcts.
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