A study of a heavy rainfall event and a tornado outbreak during the passage of a squall line over Catalonia.

Abstract During the 13 September 2006 a squall line crossed the coastal areas of Catalonia (NE of Spain) causing heavy rainfall and a tornado outbreak. In the south and central coast of Catalonia some waterspouts and tornadoes were observed. There was damage on roofs, walls and cars. Some cars were observed totally overturned and at least two trucks were diverted from their way. A description of the event is presented in this work. The synoptic and mesoscale patterns and possible tornadogenetic mechanisms are analyzed. The aim of this work is to document in detail this squall line event and to improve our understanding of convergence lines in this area. In the study satellite and radar images, rawinsonde data and automatic weather station observations of the Catalan Meteorological Service were examined to document and discuss the main features of this event.