MESOSCALE CONVECTIVE COMPLEX (MCC)

This might be regarded as the 'super' version of an MCS. It is strictly defined in terms of areal extent of coldest tops of the cloud sensed by IR imagery (typically over 300 km), and must last at least 6 hr, with many active systems lingering for upwards of 12hr. Would be regarded as extremely rare for NW Europe - more a feature of central and eastern Europe with average annual frequency around 5.