Will Hurricane Lee winds exceed Category 5? Can there be a Cat 6 hurricane?

Hurricane Lee powered up dramatically quickly Friday morning, doubling its wind speeds to 155 mph in just 24 hours. It peaked overnight as a Category 5 hurricane with winds up to 165 mph, but dropped back to Category 4 before dawn.

Lee was previously forecast to reach wind speeds of up to 180 mph and the National Hurricane Center (NHC) said its new Hurricane Forecast and Analysis System had runs projecting peak intensity of 195-207 mph, but the official forecast calls for Lee to stay just under Cat 5 level through Saturday and then start to weaken and slow down.

Had Lee kept strengthening, would Category 5 have been enough to describe it? Winds of 180 mph are 23 mph more than the threshold for Category 5, which is 157 mph. Do we need to add a Category 6?

Don't expect to see one any time soon.

What are the hurricane categories?

According to the NHC, the Saffir-Simpson Hurricane Wind Scale, developed in 1971 by civil engineer Herbert Saffir and meteorologist Robert Homer Simpson, is a rating of 1 to 5 based on a hurricane's sustained wind speed.

The scale is designed to measure the potential for significant loss of life and damage. Hurricanes designated Category 3 and above are considered by the NHC to be major. The categories are:

• Category 1 hurricane: Sustained winds are 74 mph to 95 mph.Very dangerous winds would produce some damage — to roofs, shingles and gutters; toppling trees; damaging power lines; and likely creating power outages.

• Category 2 hurricane: Sustained winds are 96 mph to 110 mph. Extremely dangerous winds would cause extensive damage — major roof damage, toppled trees, uprooted trees, damaged power lines and likely power outages.

• Category 3 (major) hurricane: Sustained winds are 111 mph to 129 mph. Devastating damage will occur — extensive roof damage, toppled and uprooted trees, power outages and water shortages.

• Category 4 (major) hurricane: Sustained winds are 130 mph to 156 mph. Catastrophic damage will occur — severe damage to roofs, exterior walls, toppled trees, downed power poles, power outages, water shortages.

• Category 5 (major) hurricane: Sustained winds are 157 mph and higher. Catastrophic damage will occur — a high percentage of homes will be destroyed, with total roof failure and wall collapse; fallen trees; downed power poles; power outages; water shortages.

Since categories run in roughly 20 mph increments, why does it stop at "157 mph and higher"'"?

Will there be a Category 6 hurricane?

Despite the predictions of a "time traveler" in a viral TikTok video, we aren't likely to see Category 6 storms described in the news any time soon. But the idea has come up before.

In 2006, ABC News reported that some scientists believed a Category 6 could define storms with winds over 175 or 180 mph. Climate scientists in New Zealand brought up the idea in 2018 to reflect the increasing severity of tropical cyclones due to climate change and warming sea temperatures.

“Scientifically, [six] would be a better description of the strength of 200mph (320km/h) storms, and it would also better communicate the well-established finding now that climate change is making the strongest storms even stronger,” climatologist Michael Mann, the director of the Penn Center for Science, Sustainability and the Media said at the time. He pointed out that since the scale was used in a scientific context as much as for damage assessment, it made sense to introduce a new category to describe the massively powerful storms seen over the last few years.

Scientists in 2017 reportedly revisited the idea after Hurricane Irma, a Category 5 storm whose highest winds reached as high as 185, formed on Aug. 10 that year.

Former NOAA Hurricane Hunter and co-founder of Weather Underground Jeff Masters suggested to Scientific American in 2019 that Hurrican Dorian should have gotten a Category 6 rating, and there should even be a Category 7 for storms over 210 mph to account for Hurricane Patricia, which peaked with 215 mph sustained winds in the Pacific Ocean in 2015. For years Masters co-authored a blog on Weather Underground called Category 6.

"It makes sense from a climate change communication point of view to expand the Saffir-Simpson scale to include a category 6 — and category 7 — to call attention to this new breed of ultra-intense catastrophic hurricanes that will likely grow increasingly common in the coming decades," Masters wrote, although he admitted there was little support from the NHC to increase the scale since a Category 5 is already considered catastrophic.

Add a Category 6 to the Saffir-Simpson scale? Simpson doesn't think so

In 1991, tropical weather specialist Debi Iacovelli asked Simpson directly if he didn't think a new category should be added to his open-ended scale.

“I think it's immaterial,” Simpson said. “Because when you get up into winds in excess of 155 miles per hour you have enough damage if that extreme wind sustains itself for as much as six seconds on a building it's going to cause rupturing damages that are serious no matter how well it's engineered. It may only blow the windows out, but on the other hand, it can actually rupture the stairwells, the elevator wells and twist them, and it's happened in many buildings so that you can't even use the elevators after they've experienced this.

"So I think that it's immaterial what will happen with winds stronger than 156 miles per hour. That's the reason why we didn't try to go any higher than that anyway.”

How many Category 5 hurricanes have there been in the Atlantic?

Only 40 hurricanes, including Lee, have reached Category 5 strength since 1924, according to the NOAA's hurricane database. That's about 2% of the Atlantic storms in that time period.

But it's becoming more common: 20% of those Cat 5 storms have been in the last seven years. Lee is the 8th Category 5 hurricane since 2016.

What was the strongest Atlantic hurricane?

Hurricane Allen in 1980 reached maximum sustained winds of 190 mph. The "Labor Day" hurricane, in 1935, Hurricane Gilbert, in 1988, Hurricane Dorian in 2019, and Hurricane Wilma in 2005 all reached maximum sustained winds of 185 mph.

Mitch (1998), Rita (2005) and Irma (2017) all hit 180.

However, hurricane strength is measured by wind speed and lowest barometric pressure, and by that measurement Hurricane Wilma in 2005 (882 mbar) is the strongest Atlantic hurricane ever recorded, so far.

This article originally appeared on The Daytona Beach News-Journal: Hurricane Lee path and strength Should a Category 6 storm be added?