Košava (wind)

Košava (Serbian Cyrillic: Кошава, pronounced [kɔ̌ʃaʋa]) is a cold, very squally southeastern wind found in Serbia and some nearby countries. It starts in the Carpathian Mountains and follows the Danube northwest through the Iron Gate region where it gains a jet effect, then continues to Belgrade. It can spread as far north as Hungary and as far south as Niš.[1]

In the winter, it can cause temperatures to drop to around −30 °C (−22 °F). In the summer, it is cool and dusty. It varies diurnally, and is strongest between 5:00 and 10:00 in the morning. Košava is usually caused by a low pressure zone over the Adriatic Sea and a corresponding high pressure zone in southern Russia.[1]

The name is also used traditionally in northwestern Bulgaria to mean a southeastern or eastern wind.[2][3] There is a saying that goes: "When košava blows, the Nišava freezes".[4]

The speed and occurrence of the Košava wind declined from 1949 to 2010.[5] The same study showed that Košava usually lasts for two or three days, one-day events being very rare.

Košava wind blows when there is a high air pressure (an anticyclone) over eastern Europe and/or west Asia and a low pressure (a cyclone) over the middle and/or western Mediterranean region.[6] The strong anticyclone, however, is the main trigger for the Košava wind. Košava is also a gap flow windstorm.[7] Košava's occurrence can be successfully forecast using the across-mountain mean sea level pressure and potential temperature differences.[8]