Hurricane Lorenzo exploded into a Category 5 hurricane over the weekend. Why that’s raising more concerns about climate change.

Hurricane Lorenzo grew to an explosive Category 5 storm over the weekend, and while its winds have since slowed, the unusual tropical cyclone is making history.

And raising climate change concerns.

At 10:10 p.m. Saturday, the National Hurricane Center issued a special advisory noting Lorenzo was an “extremely dangerous Category 5 hurricane with winds reaching 160 mph.”

That was just 11 hours after forecasters had predicted a slow weakening of what was then a 115-mph Category 3 storm.

“Instead, Lorenzo took advantage of well-above-average sea-surface temperatures (up to 1 deg C or 1.8 deg F warmer than usual for this time of year), as well as a window for strengthening made possible by the completion of an eyewall replacement cycle and the ‘new’ eye that resulted,” said Weather Underground meteorologist and writer Bob Henson in a column.

Lorenzo is unparalleled in Atlantic basin history. It is the farthest east Category 5 hurricane on record, reaching its pinnacle of intensity around 45 degrees West, according to Colorado State University researcher Phil Klotzbach.

It has generated the most accumulated cyclone energy – a measure of storm strength and longevity – of any storm in its location.

It also marks 2019 as only the seventh Atlantic hurricane season with at least two Category 5 hurricanes.

“The bottom line is that Category 5 storms are already rare, and Hurricane Lorenzo is unprecedented in the record-keeping era,” said Marshall Shepherd, a University of Georgia atmospheric sciences professor, in a post he wrote for Forbes. “We just don’t see hurricanes at this intensity so far east and north because water temperatures are typically too cold and wind shear conditions can also be restrictive.”

Only about 2 percent of Atlantic basin hurricanes become Cat 5 storms, notes Brian McNoldy, a senior research associate at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science.

In the past four years, 20 percent of the 30 hurricanes have reached Cat 5 strength.

Lorenzo strengthened as it moved over unusually warm ocean temperatures for the Central Atlantic of about 82.4 degrees, McNoldy noted.

Weather models had been predicting Lorenzo would form even before it left Africa as a tropical wave.

It was just south of the Cabo Verde Islands when it became a tropical storm.

“The water temperatures have been warmer than normal, but not a lot warmer,” Klotzbach said. “To me, it was more about the wind shear, which has been quite low since late August.”

As of Monday afternoon, Lorenzo was a Category 2 hurricane with 105 mph winds and a minimum central pressure of 962. It was moving north-northeast at 15 mph.

A hurricane warning was in effect for parts of the Azores, including Flores, Corvo, Faial, Pico, Sao Jorge, Graciosa and Terceira.

Lorenzo is expected to maintain hurricane strength through Thursday as it approaches Ireland. The storm is expected to miss Ireland to the west and weaken to a tropical storm Friday.

Scientists are careful not to link a single storm to climate change, but say signals, such as those that helped Lorenzo go supersonic are increasingly seen in tropical cyclone behavior.

This year marks the first time in recorded history where Cat 5s have formed four years in a row. Two made landfall retaining the lofty crowns: 2018’s Hurricane Michael and this season’s Hurricane Dorian.

NOAA’s Geophysical Fluid Dynamics Laboratory recently issued a 20-page synopsis of current research results about global warming and hurricanes.

In summary, it says sea level rise will cause higher storm surge that reaches farther inland, rainfall rates will increase 10 percent to 15 percent within 60 miles of a storm, and hurricane intensities will increase on average by 1 to 10 percent.

The global proportion of tropical cyclones that reach very intense Category 4 and 5 levels also is likely to increase because of human-caused warming over the 21st century, according to the NOAA report.

“This change would imply an even larger percentage increase in the destructive potential per storm, assuming no reduction in storm size,” notes the report, titled “Global Warming and Hurricanes, An Overview of Current Research Results,” which was last revised Aug. 15.