https://maltaclouds.net/wp-content/uploads/2018/09/Cu-mediocris-homogenitus.jpg?v=156991994714003065adminhttp://maltaclouds.net/wp-content/uploads/2018/10/logo-1-300x138.pngadmin2017-05-22 18:34:152018-10-30 18:38:23Cu mediocris homo
This photo is a rare cumulus congestus cloud of the variety radiatus and praecipitatio. Mid-July rainfall in Malta is almost unheard of hence a very rare cloud formation for a Maltese July. In short, this weather was caused by a very rare Summer mid-latitude cyclone that passed over Southern Italy bringing fresh mistral currents from the North which contrasted with the warm land and sea generating a degree of instability. The exact trigger for this cloud formation was the clash between the Mistral and a NE current as the low pressure continued in its trajectory eastwards. This generated a weak squall line which passed over the Maltese Islands bringing isolated rain showers. Perhaps due to the time of day or more stable conditions higher up, this did not generate any thunderstorm activity. This explanation is illustrated through the SLP chart on the seventh thumbnail, the surface wind field on the fifth thumbnail depicting this surface wind clash and the satellite imagery on the sixth thumbnail showing exactly the photographed cloud band which headed southwards and thereafter dissipating. The clashing airmasses forced the air to rise upwards along a rather large line forming cumulus congestus clouds towards the north and northeast side of Malta as per the second and third thumbnails hence also acquiring the radiatus variety and the praecipitatio as rain was clearly seen falling at its base. The first thumbnail is a panoramic photo of the main single shot cumuliform cloud showing its large extent covering a very large horizon of the sky. Future Summers might witness more of such cloud formation as the Hadley cell becomes more activated with alternating periods of strong heat from the North African anticyclone followed by disturbed Atlantic currents as the traditional Azores High weakens over the Mediterranean.