Convergence zones over the Greek peninsula and associated thunderstorm activity

Abstract

AbstractIn the frame of this study, the initiation of summer storm activity over the Greek peninsula during a prevailing weak synoptic flow is investigated using the Colorado State University‐Regional Atmospheric Modelling System. On 10 July 1994, thunderstorm activity was observed along a convergence zone which had developed following the main axis of the peninsula. the convergence zone first deepened the moist layer locally, providing a region potentially favourable to deep convection, while terrain variability and diurnal differential‐heating‐forced vertical motions. the cold air intrusion aloft, associated with the low‐level convergence, resulted in deep convection and significant storm activity. the origin of the moist air masses which fed this activity has been investigated through simulations with a Lagrangian particle dispersion model. Moist air masses, which originated from marine boundary‐layer of the Ionian Sea on the west, and north Aegean Sea on the east of the Greek peninsula, were transported over the land through the sea‐breeze mechanism and later, at the time of the storm activity, were deeply injected into the troposphere over the convergence line, at heights up to 5 km.