Cold air channelling traced by Cumulus cloud movement

Tracing cold air channelling

20 April 2016 05:00–17:00 UTC

Cold air channelling traced by Cumulus cloud movement
Cold air channelling traced by Cumulus cloud movement

Cold air that moved north of the synoptic ridge was channelling between the Alps and the Western Carpathians, swirling behind the mountains in the lower levels.

Last Updated

10 October 2022

Published on

20 April 2016

By Ivan Smiljanic (DHMZ)

The movement of the cold air, south east of the ‘channelling gates’, can be clearly identified on the High Resolution Visible animation (Figure 1), by following the movement of the small cumulus clouds in that area.

 Meteosat-10 High Resolution Visible animated gif, 05:00–17:00 UTC
Figure 1: Meteosat-10 High Resolution Visible, 20 April 05:00–17:00 UTC

Looking at the synoptic situation on the Airmass RGB image (Figure 2), it is obvious that the cold air (blue shades in this RGB combination) was moving from the north west towards the region between the Alps and the Western Carpathians, and further to south eastern parts of Europe.

Cold advection channelling and swirling behind the mountains (especially the Alps) happened in the lower levels of atmosphere.

This anticyclonic leeward movement behind the Alps was also picked up by the NWP model. On the zoomed Airmass image (Figure 3), the green arrows show the wind vectors at the pressure level of 850hPa (approximately 1500m high).

 Met-10, 20 April 2015, 12:00 UTC
Figure 2: Meteosat-10 Airmass RGB with 850hPa winds overlaid, 20 April 12:00 UTC
 
 Met-10, 20 April 2015, 12:00 UTC
Figure 3: Meteosat-10 Airmass RGB with 850hPa winds overlaid (zoomed in), 20 April 12:00 UTC