Questions and Answers about Mediterranean Cyclones

Dr. writes. Nikos Mazarakis

On the occasion of the passage of the Mediterranean Cyclone "Zorba", we will try, through questions and answers, to provide a more detailed picture of this phenomenon.

1) What is a Mediterranean Cyclone?

The Mediterranean Cyclone is a low that forms over the Mediterranean Sea, usually in Autumn and Winter. Its morphological characteristics are similar to those of tropical cyclones, i.e. lows that form at latitudes 3-8 degrees north and south of the equator. Thus, a Mediterranean cyclone has at its center the characteristic eye, i.e. a small-diameter area with a cloudless or slightly cloudy sky and weak to moderate winds. Also, the Mediterranean Cyclone is not accompanied by fronts but is a circular disturbance that swirls around the eye.

2) Is a Mediterranean cyclone as strong as a tropical cyclone?

The answer is clearly no. A tropical cyclone (typhoon as it is called in East Asia or Hurricane as it is called in America) is much larger in diameter (for example, Katrina in 2005 reached a diameter of 600 km). The winds that accompany it have an intensity of more than 64 knots (12 Beaufort) and the rainfall can exceed even 800 mm in a 24-hour period (an amount equivalent to the rain that falls in Attica in 1.5 years). However, the Mediterranean Cyclone is a quite dangerous phenomenon, as the winds around the eye can reach even 60 knots.

3) How often do Mediterranean Cyclones occur?

The frequency of occurrence is 1-2 per year. They usually move over the Mediterranean Sea but sometimes, as is the case with “Zorba”, they pass over land where they weaken.

4) Is their appearance related to climate change?

No one can answer with certainty. However, the increase in sea temperature certainly has an impact on the frequency of occurrence. Warmer waters mean more favorable conditions for their creation but also more intense phenomena.

5) Why is their trajectory difficult to predict?

Mediterranean Cyclones are small-scale phenomena, compared to classic cyclones (lows) which are accompanied by fronts and occupy a much larger geographical area. Thus, meteorological models often fail to predict their trajectory accurately.