Weather Events

Parameter Description
Wind, Wind gusts
  • strong to gale force mean wind (hourly mean wind speed can exceed 20 m/s)
  • hurricane speed gusts (up to 65 m/s) due to which roads along the coast can be closed to traffic
  • in deep-layer bora cases, gale force wind also in the upper layers.
  • turbulence
  • temperature drops on the coast due to strong cold advection from the upwind side
  • relatively dry air descends to the sea level
  • high sea waves close to the coastline with sea spray due to gusts cause serious problems to marine traffic

10 min maximum wind speeds (m/s) measured at some stations during one of the most severe bora episodes in March 2015.
Locations of the measurement stations.

Because of the wavy structure that can often occur during bora events, clouds appear at different heights, with different cloud phases, temperatures and microphysics. Therefore, different SAFs can be useful for detecting these features.

Cloud Phase product from 05 February 2020, 12 UTC.

The Cloud Phase product discriminates between liquid and ice phases. In combination with the Cloud Top Height product, the three-dimensional structure of the waves can be clearly visualized.

The Cloud Optical Thickness product provides information about the density and transmissivity of the cloud layer. It shows that clouds are thicker at the wave crests (red stripes) than at the wave troughs (between red stripes).


Cloud Top Height product (left) and Cloud Optical Thickness product (right) from February 5 2020, 12 UTC.