Medicane. Mediterranean tropical-like cyclones. Websites and social media are full of these headlines – but are these systems something new? Mediterranean tropical-like cyclones are interesting severe weather events but nothing new, and they have been observed in the past. Here is some of what we know about them.
Tropical-like storms or cyclones in the Mediterranean, also known by their popular name medicanes, are cyclones with subtropical and tropical characteristics that form in the Mediterranean.
They can produce severe winds and torrential rainfall. Similar to tropical cyclones, medicanes are warm core systems; they often closely resemble tropical cyclones in satellite images. Well-developed medicanes have tropical characteristics, with clear circular eyes, surrounded by an eyewall and (axisymmetric) cloud pattern.
Medicane Leucosia tracking north of Libya on January 26th, 1982. Image: NASA.
Medicanes typically reach gale to storm force strength. However, the strongest have even reached hurricane strength and thus pose a very significant severe wind threat. They also result in torrential rainfall, producing major floods in affected areas.
Tropical-like storms or cyclones / medicanes are an annual occurrence, appearing on average 1-2 times yearly.
Medicane in December 2005. Image: NOAA.
What is a Medicane, and how does it form?
Unlike tropical cyclones, medicanes can form with sea surface temperatures below 26 °C. They form throughout the year but are by far most likely to form between September and January. Medicanes typically form under troughs or cutoff upper lows, characterized by very cold airmass aloft and resulting in instability over the warm Mediterranean Sea.
As in tropical cyclones, low wind shear is required by medicanes to form. Two preferred areas of occurrence have been noted: the Ionian Sea and the Balearic Islands. The strength and size of medicanes are constrained by the enclosed environment of the Mediterranean Sea; the largest medicanes can reach a size of about 300 km.
Mediterranean tropical-like cyclones typically persist between 12 hours and 5 days.
Mediterranean tropical-like cyclones undergo three phases in their lifetime:
- 1. Pre-eye: with vigorous convective activity occupying most of the cyclone.
- 2. Stationary phase: an eye forms, surrounded by an axisymmetric structure to the cyclone. Strong winds and heavy rainfall occur. Lightning rates drop as an enclosed warm core forms.
- 3. Itinerant phase: is characterized by fast, directional motion of the medicane. There is less rainfall but the strongest, most severe winds.
Tropical-like cyclones or medicanes may approach or even reach hurricane intensity; they are considered potentially dangerous due to the dense population of coastal regions in the Mediterranean. The peak attainable strength of medicanes is estimated to be equivalent to a Category 1 hurricane on the Saffir-Simpson scale.
Notable significant medicane events in the past
While many medicanes do not become significant, severe systems, some do.
Deadly medicane at the end of September 1969
An unusually severe medicane developed on the 23rd of September, 1969, southeast of Malta, producing severe flooding. The storm left 600 dead and 250.000 homeless in Algeria and Tunisia.
Medicane Celeno, January 1995
Medicane Celeno emerged from the Libyan coast and moved toward the Ionian shoreline of Greece on the 13th of January as a compact low-pressure area.
The storm maintained winds reaching up to 108 km/h (67 mph) as it crossed the Ionian Sea, while the German research ship Meteor recorded wind gusts of 135 km/h (84 mph).
Medicane Cornelia, October 1996
In October 1996, medicane Cornelia formed in the Tyrrhenian Sea, north of Algeria. Cornelia strengthened while sweeping between the Balearic Islands and Sardinia, with an eye-like feature prominent on satellite.
It produced 90 km/h winds as far as 100 km from the center and extreme damage in the Aeolian Islands.
Medicane Qendresa, November 2014
On 6 November 2014, the low-level circulation center of Qendresa formed near Kerkennah Islands, Tunisia, and tracked towards Malta, where it directly hit the island on Nov 7th. Qendresa was a well-developed storm with a distinct eye: 10-minute sustained winds reached 111 km/h and peak gusts 154 km/h.
The minimum central pressure was 978 mbar at its peak intensity.
Medicane Numa, November 2017
Medicane Numa emerged in the southern Adriatic Sea and gradually moved into the Ionian Sea and western Greece from Nov 14th to 17th, 2017.
Numa produced a hurricane-like structure, including some upper-level outflow cirrus shield visible on the satellite.
Numa made landfall in Greece, with a station at Kefalonia reporting peak winds of 110 km/h (69 mph). The minimum pressure reported was 998 hPa.
Medicane Zorbas, September 2018
A medicane Zorbas emerged over the Aegean Sea and hit southwest Greece. It produced peak wind gusts up to 120 km/h when it made landfall west of Kalamata, Peloponnese, on Sept 29th, 2018. Zorbas produces significant wave heights and a 1-1.5 m storm surge.
The minimum central pressure was 987 mbar.
The medicane satellite view displays vigorous convection with a nearly complete eyewall, a distinct eyewall, and some dense cirrus overcast.
Medicane Zorba also produced multiple waterspouts and caused significant flash floods in part of Greece and Turkey as it tracked across the Aegean Sea on October 1st and 2nd, 2018. Zorbas was estimated to have caused millions of US dollars in damage.
Medicane Ianos, September 2020
Medicane Ianos impacted the eastern Mediterranean, especially Greece, on September 17 and 18, 2020. Soon after forming over the Gulf of Sidra, Libya, Ianos gradually intensified while tracking towards the Aegean Sea, acquiring an eye-like feature.
Ianos made a significant landfall on Greece with peak intensity on 03:00 UTC on 18 September, the minimum central pressure was estimated at 984.3 mbar. Ianos’ peak winds were up to 160 km/h (99 mph). This is equivalent to a minimal Category 2 hurricane.
Additionally, as Ianos passed to the south of Italy on Sept 16th, it produced heavy rain across the southern part of the country and in Sicily. Reggio Calabria reported as much as 35 mm of rain, more than the city’s normal monthly rainfall.
Ianos left four dead people and one missing, in addition to strong tides in Ionian islands such as Kefalonia, Zakynthos, Ithaca, and Lefkada. Wind gusts up to 120 km/h (75 mph) were reported at Karditsa, which brought down trees and power lines and caused landslides.
More discussion on recent medicanes:
- Medicane Detlef in the western Mediterranean, heads for landfall in northern Algeria – Nov 2019
- Medicane Numa heads for landfall along the west coast of Greece – Nov 2017
- Extremely dangerous medicane Ianos heads for Greece – Sept 2020
- Severe Weather Outlook for Medicane Ianos – Sept 17-19th, 2020
- A medicane Apollo formed south of Italy, with a Red Alert warning for Sicily, Malta, and Libya – Oct 2021