An updated tornado climatology and associated meteorological environments in Greece

Tornadoes are common in Greece, as they have been reported in many parts of the country, including continental and maritime areas. Systematic records of tornado occurrences have been collected in the last 23 years, offering to the development of the Greek tornado database and the establishment of relevant climatologies for Greece and Eastern Mediterranean. The 23-year data of the Greek tornado database (2000-22) includes a total of 1435 days with 2086 tornado events. The vast majority of the database, a total of 1485 events, are tornadoes over the sea, the so-called waterspouts, 365 are land tornadoes and 236 are funnel clouds.

An updated tornado climatology is presented for Greece based on the geographical spatiotemporal analysis of tornado, waterspout and funnel cloud occurrences with mapping of the events and investigation of frequency distributions. Further climatological aspects are highlighted, including tornado prone areas, tornado intensity, path scales, damage characteristics and remarkable cases with outbreaks in sequence of days and number of events. Climatological analyses identified western Greece, the Ionian Sea and lowland prairies and coastal areas as most prone to tornado activity. In the Aegean Sea, waterspouts are reported from many places, with a maximum frequency from the north coast of Crete. Strong damaging tornadoes are mostly products of warm season severe thunderstorms, occasionally with supercell characteristics and also by mesoscale convective systems associated with frontal activity.

Synoptic circulation patterns associated with tornado occurrence are identified and categorized into six specific upper-air synoptic flow types, namely: southwest flow (SW), northwest flow (NW), closed-low system (CLOSED), cut-off low (CUT), shortwave trough (SWT) and longwave trough (LW). Mesoscale environments are also investigated based on thermodynamic, dynamic, wind parameters and convective instability indices.

The results help improves a forecasters’ ability to identify and anticipate such extreme weather events, by providing critical background information to the operational forecasting. Establishing synoptic climatologies can be useful in identifying weather conditions associated with tornadoes, possibly not the same as in the USA or other parts of the world with significant tornadic activity. Furthermore, it is important to improve our knowledge about meteorological environments favoring tornado occurrence in the view of the climate change that possibly has a large influence on such extreme weather phenomena.