Hurricane Epsilon rapidly intensified Tuesday and Wednesday, unexpectedly becoming a major Category 3 hurricane and claiming two records as it cruised northwest over the open Atlantic. Bermuda will be sideswiped by the storm Thursday before it becomes a powerful mid-latitude storm and races east across the ocean.

On Tuesday morning, Epsilon was a 45 mph tropical storm; by early Wednesday, it had morphed into a Category 1 hurricane with 90 mph winds. It surprised meteorologists when it intensified into Category 3 major hurricane with 115 mph winds on Wednesday afternoon.

That significantly exceeds the criterion for “rapid intensification” of 35 mph or more in 24 hours. Epsilon jumped at least 50 mph in that same time frame.

According to Sam Lillo, a postdoctoral researcher with the National Oceanic and Atmospheric Administration, no other storms on record have even approached that rate of intensification or reached Epsilon’s strength near its current position so late in the season.

Epsilon joins Laura, Teddy, and Delta as the fourth major hurricane of 2020 in the Atlantic. Only Laura impacted land at major hurricane strength.

The unsettling achievements mark the latest toppled records in what can only be described as a rambunctious hurricane season. Epsilon is the 26th named storm to form in the 2020 season, which has outpaced every other hurricane season to date. An ordinary season averages just over a dozen named storms in the Atlantic. If one more named storm forms in 2020, it will tie the mark for most storms in any Atlantic hurricane season on record, set in 2005.

Rapid intensification occurs when atmospheric and ocean conditions foster a period of explosive development within a tropical storm or hurricane. Weak upper-level winds allow the storm to mature in its vertical structure, while warm sea surface temperatures provide the fuel to support its organization.

Epsilon is the seventh named storm to rapidly intensify in the Atlantic in 2020. This month, Delta intensified from a tropical depression with 35 mph winds to a Category 4 with 145 mph winds — faster than any previous storm on record. It weakened to a Category 2 storm before lashing Mexico’s Yucatán Peninsula, including Cancun, and then southwest Louisiana.

Rapid intensification is probably a product of warming waters in the face of climate change. And more storms are likely to undergo rapid intensification in the future, presenting predictive challenges to meteorologists.

In mid-September, Hurricane Sally intensified leading up to its landfall in southern Alabama as a 105 mph Category 2.

On Monday, Epsilon was struggling against wind shear — a change of wind speed and/or direction with height. That worked to tear apart the system, displacing the bulk of any shower and thunderstorm activity to the east of the exposed low-level center of circulation.

But on Tuesday, Epsilon got its act together with thunderstorms blossoming over the core. A well-formed eye emerged Tuesday night.

Satellite imagery showed a spiraling arc of thunderstorms feeding into the system Wednesday, with a narrow core only about 125 miles across. It was wrapped up in the middle of a larger zone of low pressure at high-altitudes.

In the coming days, Epsilon, which was 340 miles east-southeast of Bermuda late Wednesday afternoon, will skirt Bermuda with tropical storm conditions. The British territory was under a tropical storm warning, with squall-like showers and some 40 mph wind gusts possible late Wednesday into Thursday.

After slipping east of Bermuda on Thursday, Epsilon should charge north and transition into a high-latitude storm. Over the weekend, it is expected to become a very powerful ocean storm and stir up the seas of the North Atlantic near Iceland.