There are no two ways about it — the storm known as Leslie was a weirdo, the strangest to develop in the Atlantic Ocean this year, if not in many years.
The storm finally crashed into Europe’s Iberian Peninsula over the weekend, creating all sorts of havoc, after meandering over the open Atlantic Ocean for 19 days, where it took on many forms.
Previously a hurricane, Leslie arrived in Europe as an intense extratropical or mid-latitude storm, having lost its tropical characteristics. While not a hurricane in name at landfall, it was just as powerful, battering the Iberian Peninsula at virtually unprecedented strength.
The unusually strong winds were due in part to a sting jet, a potent but narrow surge of exceptional winds caused when evaporative cooling within the storm drags the jet stream to the surface.
Leslie became the first tropically borne system to directly impact Spain since Vince in 2005 and was far more powerful. The BBC said winds gusted over 60 mph in the city of Zamora.
Farther north, devastating floods engulfed France as Leslie’s tropical connection drenched southern areas with heavy rainfall. At least 10 deaths were blamed on the floods.
Meteo-France reported the following rainfall totals in the south of France:
- 11.6 inches (296 mm) fell in eight hours near Carcassonne, 9.6 inches (244 mm) fell in six hours and 4.4 inches (111 mm) in two hours.
- 14.3 inches (364 mm) fell in 24 hours in the Haut-Languedoc region.
As of Tuesday, Leslie’s remnant circulation had merged with the remnants of Hurricane Michael, both entities substantially weakened.
Leslie’s long and remarkable history
Leslie first got its name on Sept. 23 as a subtropical storm in the middle of nowhere in the open Atlantic. Spinning absentmindedly in the central North Atlantic, the prospects for Leslie’s development weren’t good. In its first advisory, the National Hurricane Center ironically said it was “forecast to be a short-lived cyclone.”
Nobody knew Leslie would become the 11th-longest-lived Atlantic cyclone on record, fluctuating between tropical storm and Category 1 strength for at least 19 days.
But Leslie defied the odds, stubbornly dodging systems that could harvest its energy and strengthening when all signs suggested it shouldn’t. The National Hurricane Center first stated that Leslie was “forecast to become absorbed by a larger non-tropical low” within two or three days.
On Sept. 25, Leslie fell apart into a subtropical depression right on schedule. All done. Or so we thought.
Leslie’s brief falter didn’t last long, and the capricious storm rose from the dead two days later. The “zombie cyclone” took on the characteristics of a mid-latitude nor’easter-type storm instead, stirring up the seas with powerful hurricane-force winds on Sept. 27. Meteorologists refer to this type of storm as extratropical. Despite gusts exceeding the 74 mph criterion, however, Leslie’s cold-core nature did not fit the bill for it to be classified as a hurricane.
That’s when Leslie decided to switch things up. The post-tropical cyclone swirled in some warmer air on the 28th and became subtropical — a wacky hybrid combination of a tropical cyclone and a mid-latitude low — again.
Until this point, Leslie was never “officially” a tropical cyclone or hurricane. Only at 11 p.m. Atlantic time on Sept. 29 did the hurricane center finally award a tropical designation to Leslie. By then, the 50 mph storm was quickly acquiring the textbook hurricane shape and at last matured into a Category 1 hurricane with 80 mph winds on Oct. 3.
All the while, Leslie didn’t bother anybody but mariners. The storm went through an entire cycle again between different structures, wandering over the open ocean. Leslie began to peter out around Oct. 7 but then got feisty on the 8th. By Oct. 10, Leslie was mean — baring its teeth with winds of 90 mph tightly packed around a symmetric clouded-in center.
Part of Leslie’s perceived longevity is due to the wide arsenal of satellite imagery currently at the disposal of Hurricane Center meteorologists. Nowadays, forecasters can utilize remote sensing to better understand the internal organization of storms. A mere three or four decades ago, these tools existed in a much more rudimentary form — and Leslie probably would not have been named until it actually looked like a tropical cyclone in early October.
The takeaway? Leslie’s life span is certainly unusually long, but by no means unheard of. The San Ciriaco hurricane of 1899 persisted a whopping 27 days, and in the Pacific, cyclones have stuck around even longer. John clocked in at a staggering 30 days in 1994.