Orographic roll clouds south of the Alpine ridge

Orographic roll clouds south of the Alpine ridge

09 March 2019 14:10–15:10 UTC

Orographic roll clouds south of the Alpine ridge
Orographic roll clouds south of the Alpine ridge

Meteosat-10 captured imagery of orographic roll clouds south of the Alpine ridge on 9 March 2019.

Last Updated

18 February 2021

Published on

09 March 2019

By HansPeter Roesli (Switzerland)

As shown by the profile over the gridpoint 46.2°N/8.8°E of Locarno forecast for 15:00 UTC, a strong vertical velocity shear was present in the west-northwesterly winds above 700 hPa.

The wind shear explains the presence of the orographic roll clouds observed from the ground (Figure 1), and by the Meteosat-10 high resolution visible channel in the rapid scanning mode (every 5 minutes) (Figure 2). The photograph was looking east-northeast.

 Photo from the ground, 09 March, 14:40 UTC
Figure 1: Photo from the ground, 09 March, 14:40 UTC. Credit: HansPeter Roesli.
 
 Met-10 HRV, 09 March, 14:40 UTC
Figure 2: Met-10 HRV, 09 March, 14:40 UTC

The rapid evolution of the waves, partially hidden under a cirrus deck, may be followed in the animated High Resolution Visible HRV sequence between 14:10 UTC and 15:10 UTC (Figure 3).

Figure 3: Meteosat-10 HRV animation, 9 March 14:10 UTC–15:10 UTC