Mediterranean Local Wind Names

The Mediterranean Sea has various local areas with different topographical features, such as coastal shapes, valleys, and mountains. Air movements between high and low pressure areas in these local areas create special local winds called “katabatic winds.” Understanding the winds in the Mediterranean will not only be useful for the safety of our voyages but will also enable us to determine appropriate navigation routes. Catabatic winds are divided into two groups.

1. Cold katabatic winds: These are cold winds blowing from high-pressure areas with cold characteristics (systems with a central pressure greater than 1030 mb) toward the low-pressure area at their base. Coastal elevation can affect wind speed, potentially causing storms or severe storms. Different local names are given depending on the region where they blow.

For example, the “split rock storm” refers to winds blowing from the high-pressure area over the Eastern Taurus Mountains toward the Eastern Mediterranean, with directions ranging from north (N) to northeast (NNE) and east-northeast (NE), reaching up to 9-10 on the Beaufort scale in the Iskenderun Bay.

2. Warm katabatic winds: These are warm and dry winds blowing down from mountain peaks toward valleys or the sea. Their speeds range from 3 to 8 on the Beaufort scale. They are more effective in winter. As cold air from the high-pressure area on the backside of the mountain rises, it loses moisture, compresses as it flows over the mountain peak to other regions, and gains heat (adiabatic heating). These winds are called Föhn winds because they blow warm and hot air like a hair dryer. The most effective region for Föhn winds is the foothills of the Swiss Alps. In our country, they are effective in the Eastern Black Sea region.

Local winds are also classified into two groups based on their cyclical periods: daily and annual periods. Daily-period local winds are katabatic winds that blow in opposite directions during the day due to changes in air pressure resulting from the difference in temperature between night and day in an area, where land and sea or valleys heat up at different rates due to elevation and topography. The best example is the Meltem wind that blows in many local areas of the Aegean Sea. The other group consists of annual-period winds, which are similarly catabatic winds formed as a result of seasonal temperature changes over broader areas.

We have listed the local winds of the Mediterranean Sea starting from the Strait of Gibraltar and moving eastward.

Levanter and Vendavel (Vendaval)

Levanter is a local prevailing wind that blows from the south of France to the Strait of Gibraltar along the coast and inland, generally from the east or northeast, with a force of 5-7, usually between February and May and October and December.

The wind originates from slow-moving low-pressure systems between France and Algeria. It does not form in January due to the dominance of the Iberian anticyclone and is rare and light during the summer months. Levanter is a wind with high humidity that causes rainfall. It can lead to floods in mountainous areas.

Vendavel is a stormy, thunderous, and rain-bearing SW wind that blows in the opposite direction of the Levanter, caused by low-pressure systems entering the Mediterranean from the west across the ocean. It often blows at storm levels during the rainy winter season from November to April.

The Vendavel follows the Levanter and blows before the cold front passage of the Poniente (west wind). Sometimes, when a moderate Vendavel blows, a rotor (vortex) cloud can form east of the Rock of Gibraltar due to the moisture carried by the SW wind. This situation can be a harbinger of winter and approaching harsh weather conditions. The cloud is locally known as La Carlota.

Mistral

In France’s Bay of Biscay, it is a dominant local wind that blows cold, dry, and strong from the N and NW directions in winter due to the katabatic effect of the Alps, reaching 8-9 on the Beaufort scale. It is extremely cold as it originates from the north, passing over the snow-covered high mountains of the Massif Central. In summer, it blows gently and mildly.

The Mistral is most intense in the Rhône Valley, where its strength increases as it reaches the sea. The wind affects the southern coasts of France. It has been determined that Mistral wind periods last 3, 6, or 9 days. The Mistral typically forms when there is high pressure or an anticyclone in the Bay of Biscay and low pressure or a cyclone in the Gulf of Genoa.

The wind can affect a wide area between Spain and the island of Sardinia, from southern France to Algeria, especially in winter. When the Mistral creates strong and high waves, boats heading to southern France follow a route around the northern tip of the island of Corsica in the Tyrrhenian Sea or a route close to the coast of Spain, following the Barcelona coastal route. When the Mistral loses its effect and creates a dead sea, boats follow a route that circles the Gulf of Roses north of Barcelona. Boats traveling between Sicily and Gibraltar in both directions sail close to the coasts of Algeria and Tunisia. When the wind is strong, the Bon Cape of Tunisia and the southern coast of Spain are suitable shelters along the route.

Tramontana

Tramontana is the local name given to the N and NE winds that blow almost constantly in winter along the western coast of Italy and off the coast of Corsica. This wind never reaches storm force but creates a comfortable and pleasant atmosphere in the area where it blows. When the synoptic conditions during these winds are examined, it is observed that there is a low-pressure center over the Adriatic Sea and a high-pressure center further west. The wind brings cold air and lowers temperatures.

Gregale

Gregale is a local wind that blows in the central Mediterranean, especially around the island of Malta, during the winter months, reaching a speed of 8 on the Beaufort scale, and is stronger than the Levante wind, blowing from the northeast. It is caused by high pressure over Central Europe or the Balkans and low pressure over Libya, and can last for up to five days. Sometimes, if the wind shifts to the south or southeast, it lasts for one or two days. It is more common in winter. Weather conditions vary depending on the type of pressure distribution and whether the wind blows toward land or open sea. The wind typically carries cool, dry air blowing from the sea toward land. In Malta, Gregale often creates dangerous seas in the harbor.

Gregale sometimes manifests itself in conjunction with low pressure settling over southern Malta. It is effective between southern Greece and southern Italy. It blows strongly in the summer months, and the island of Malta provides a suitable shelter from this wind.

Another type of wind is the Grégal of the Côte d’Azur (French Mediterranean coast), which is moist and rainy because it is a wind that comes from the Mediterranean and veers off the Alps (the Roussillon region). Generally, this wind occurs in the summer in the Provençal and Languedoc regions (southern France), where it is called Gregau, in Spain and Minorca where it is called Guergal, and in Corsica where it is called Grécale. The Gregale wind that blows in the spring is cold and dry, causing spring frosts. In the summer, it causes powdery mildew disease on vines on land.

Bora

Bora is a strong and cold wind that blows from the northeast over the Adriatic Sea, generally from November to March. The wind can quickly reach force 9 due to the north-east pressure gradient created by the katabatic effect on the Balkan plateau. It is most commonly observed along the eastern Adriatic coast. Its most distinctive feature is that it blows as a squall wind. While blowing, it produces shallow, short waves that make steering a boat extremely difficult, lifts the sea, and creates a spray of water suspended in the air. This reduces visibility.

The area most heavily affected by the Bora is generally the coast of Croatia. The affected coasts are the Velebit Channel (Pag), Kvarner Bay (Krk, Cres, Rab, Goli Otok), and the Makarska Riviera region. The effect of the Bora decreases as one moves south.

Meltem

Meltem winds are known by their Latin name Etesiae or Etesian. They are strong, dry, northerly summer winds that blow in the eastern Mediterranean, particularly over the Aegean Sea, during the summer months. Well known in the ancient Hellenic city-states, the Etesian winds were described as “winds that blow for 40 days starting from the rising of the Dog Star, Sirius.”

Meltem (Meltemi) winds are formed by the collision of high pressure over the Balkans and low pressure over Turkey. From a seafarer’s perspective, the sudden onset of the wind, its rapid acceleration to high speeds, and waves reaching up to four meters can create dangerous situations.

According to meteorological records in our country, the wind begins to blow in mid-May, reaches its peak frequency in July and August, and subsides by mid-October. The wind speed can reach up to 7-8 on the Beaufort scale, sometimes reaching 10. These generally dry winds gain moisture as they cross the Mediterranean, causing fog and mist along the coasts of Algeria and Tunisia, and slightly lowering temperatures along the North African coast.

Meltem winds are also defined and classified as winds formed between different pressure belts caused by daily temperature differences. Meltem blows in opposite directions from different locations in the local area during the day and night.

According to the classification made:

• Valley breezes (Anabatic4)

   

• Mountain breezes (Catabatic)

   

• Land breezes

   

• Sea breezes are divided into four groups.

1 Adiabatic heating: the change in temperature of an air mass as it rises or descends from its location without exchanging heat with its surroundings. Descending air masses heat up as air molecules compress, while rising air masses cool down as molecules expand.

2 Synoptic conditions: Atmospheric conditions existing over a wide area at a specific time.

3 Pressure gradient formation: The formation of a force that affects the direction and speed of air movement due to the pressure difference between two specific points. When air movement is considered as a vector, the effect of the pressure gradient force on moving air is from the side with higher pressure to the side with lower pressure.

4 Anabatic wind: A local wind that blows upward from a slope as a result of one side of a hill or mountain being strongly heated by the sun. It is generally a wind that blows toward a hill or mountain as a result of local surface heating and is separate from the effects of larger-scale circulation.

With contributions from Nalan Yüksel…