Short Version


Bora (locally called BURA) is a gusty northeasterly downslope windstorm often occurring along the eastern coast of the Adriatic Sea, at the leeward side of the Dinaric Alps (Velebit, Dinara and Biokovo mountains). In strong bora episodes hourly mean wind speed often surpasses 20 m/s with gusts reaching up to 50 or even 65 m/s. Severe bora with maximum gusts may appear along the entire Adriatic coast, but its duration and frequency generally decrease from north to south.

Depending on the synoptic situation, bora sometimes occurs with clouds gathering on the hilltops and moving towards the sea with rain or snow. This type of bora is usually reffered to as a "dark bora". On the other hand, a "clear bora" is a bora with clear skies, which is the more frequent case.

The effects of bora on cloud formation.
"Dark bora": 08 April 2015/09.45 UTC Modis TERRA RGB image (0.65 µm, 0.55 µm, 0.46 µm)
"Clear bora": 09 April 2015/06.15 UTC Meteosat 10 RGB image (HRV, 10.8, 10.8)

Key Parameters

Mean sea level pressure
Anticyclonic/clear bora Cyclonic/dark bora
AT 500 hPa
Anticyclonic/clear bora Cyclonic/dark bora
Wind Isotachs 300 hPa

Vertical Cross Sections

Location of the cross section