Formation of altocumulus clouds due to a strong jet streak in the vicinity of the Maltese Islands. Such jet streaks cause instability to develop over the area despite limited CAPE hence such clouds. The jet stream itself was caused due to the contrast of hot airmass over Africa and cooler air to the northwest. This jet streak is indicated by a solid black line on the surface pressure chart which also corresponds with a line of altocumulus clouds as seen in the visible satellite imagery. The first thumbnail is another view of the cloud cover indicating also undulations in the cloud cover due to wind shear.