Deadly cyclone Freddy has become Earth’s longest-lived tropical storm

“At this time, it does appear to be a new record holder for ‘longest-lasting’ recorded tropical cyclone … but we are continuing to monitor the situation,” said Randall Cerveny, the World Meteorological Organization’s rapporteur for weather and climate extremes, in a news release.

Over its lifetime, Freddy has tracked more than 5,000 miles since it developed between Western Australia and Indonesia and even attained the strength of a Category 5 hurricane. It’s presently crossing the Mozambique Channel for a third time.

Remarkably, the storm has rapidly intensified six times.

Rapid intensification describes an uptick in winds of 35 mph or greater in 24 hours. Research has shown rapid intensification increasing in frequency in many ocean basins because of rising ocean temperatures linked to human-caused climate change.

Before Freddy, no previous storm in the Southern Hemisphere had rapidly intensified more than three times. In the Northern Hemisphere, it appears that only three storms (Norman ’18, Emily ’05 and John ’94) have undergone four bouts of rapid intensification.

Freddy is continuing to strengthen now, coming off its sixth spate of swift strengthening. Just 24 hours ago, it was a tropical storm with sustained winds of 65 mph. Now it’s the equivalent of a Category 2 hurricane with maximum sustained winds just shy of 100 mph.

Forecasts call for continued strengthening, likely to Category 3 intensity, in the next 72 hours. In Mozambique, preparations are underway for the storm’s return visit after its first landfall there on Feb. 24. Ten people died, 8,000 people were displaced and 28,300 homes were destroyed. Over the past seven days, the storm unloaded up to 20 inches (500 millimeters) of rain on southern portions of the country, according to the WMO.

Freddy will probably be stronger when it hits Mozambique for a second time, though displaced somewhat to the north.

Freddy now

As of midmorning Eastern time on Tuesday, Freddy was located just west of Toliara in southwest Madagascar, where the storm was producing heavy rainfall. It had winds of between 95 and 100 mph and was moving northwest at 6 mph.

On satellite, Freddy had a pinhole eye six miles wide that recently emerged from a central dense overcast region.

At the high altitudes, counterclockwise-spinning high pressure is present, shunting the jet stream to the south. That’s allowing for “exhaust” air exiting above Freddy to fan radially outward, especially to the north. The easier it is for “outflow” air to escape away from a system, the more efficiently a storm can ingest warm, humid air in contact with the toasty ocean waters below.

Freddy’s next move

High-resolution weather models indicate Freddy will continue northwest though the Mozambique Channel while intensifying. By late in the workweek though, its forward progress will slow, and there are some models that hint at Freddy stalling over the channel — or perhaps even wobbling back eastward.

For now, however, the Joint Typhoon Warning Center is calling for Freddy to make landfall in Mozambique Friday night into Saturday morning with winds of just over 100 mph. The most likely landfall location would be near the mouth of the Zambezi River.

Historic longevity

Freddy has already lived a historic life as a hurricane. It peaked at Category 5-equivalent status on Feb. 18-19 with winds of 165 mph. While the WMO says it will probably set up a committee to confirm the matter, the storm appears to have surpassed the 31-day life of 1994′s Hurricane-Typhoon John, which traveled from the eastern to western Pacific, passing south of Hawaii, before turning north and dissipating south of the Aleutians.

Equally impressive is how much ACE, or Accumulated Cyclone Energy, Freddy has generated. ACE is a product of wind speed and storm duration, and it attempts to quantify how much energy a storm extracts from warm ocean waters. Freddy has already set the southern hemisphere’s record, and could nab a record worldwide.

“Freddy has just surpassed several storms for ACE including Paka (1997), Ivan (2004) and John (1994),” wrote Philip Klotzbach, a hurricane researcher at Colorado State University, in an email. “It currently stands in 2nd place behind Ioke (2006) for most ACE for a single tropical cyclone since 1980. Prior to that time, data in the Southern Hemisphere gets really sketchy!”

Klotzbach said that Freddy has currently racked up 74.5 ACE units, and could keep harvesting energy. Some experts say it may fall just shy of Ioke’s 85 ACE units, but some say Freddy has a chance.

It’s important to note that, while Freddy has been listed on weather maps for a month, it did spend several days as a tropical depression — technically a tropical cyclone but not strong enough to warrant a name. Once a named storm weakens into a depression, however, it retains its name in case it comes back to life — as was the case with Freddy.

No matter how you slice it, Freddy has been around for a long time and has certainly overstayed its welcome. Unfortunately, its destructive journey is far from over.