An extreme cold surge over the Greek peninsula

This paper is devoted to the detailed description of an extreme cold surge that occurred 3-13 March 1987, over Greece. This event has been rated as the worst snowfall over the last 100 years and, due to its severity and persistence, it paralysed the economic and communal life of Greece for several days. Emphasis is given to the initiation phase of this event. The structural evolution of the cold surge is analysed using both observations and model results. Model simulations, performed with the Colorado State University-Regional Atmospheric Modelling System, provided the necessary data to diagnose the mesoscale structure of the cold outbreak. Different mechanisms involved in the structural evolution of the cold surge are investigated. The gustiness of the observed winds and their significant departure from geostrophy are related to the role of an important isallobaric wind. The progression of this surge presented characteristics of a density current, while near the eastern slopes of the mountain barriers of continental Greece cold-air damming occurred, leading to an accelerated flow parallel to the mountains.