ARPA-FVG OSMER (Regional Meteorological Observatory) - Italy
Friuli Venezia Giulia is a small region (7800 km2) in the Northeast of Italy, bordered to the North by the Carnic and Julian Alps and to the South by the Adriatic Sea, with the lagoons of Grado and Marano. Due to its orography and geographical position, this region hosts several kinds of local severe weather phenomena (heavy rain, tornadoes, downbursts, hail, etc.). In this region, since 1999, a campaign of observations of local severe weather events is carried out. The goal of this campaign is to collect standardized information obtained by the visual observers of the events, to be further inserted in the frame of the meteorological data managed by the Regional Meteorological Observatory.
In the three years from 1999 to 2001, 17 events, classified as "severe weather events" according to a definition locally adopted were observed and reported by people. In this work they are presented and displayed on a map of Friuli Venezia Giulia, distinguishing them in the categories of "tornadoes", "downbursts-microbursts" and "uncertain cases". Moreover, for each one of these classes, a stratification of the cases according to the synoptic situation is presented, together with a simple description of the event and of its effects.
Even if the sample is too short for any kind of quantitative consideration, up to now the "severe weather events" are not uniformly distributed in the region, but their frequency seems to be higher in a specific area. A future development of this work, in the frame of the ATTILA project (Analysis of Thunderstorm Triggers in an Italian Limited Area), will be the creation of a group of trained voluntary people for the systematic collection of the field information.