Severe Weather Warnings for Sofia, Bulgaria: May – September 2010–2019

Abstract

Severe weather monitoring and forecasting is the prime task of the National Meteorological Services according to World Meteorological Organization Guidelines (WMO). Since 2009 Bulgarian National Institute of Meteorology and Hydrology (NIMH) issues 48 h ahead severe weather warnings as a contribution to the European warning system (METEOALARM). A total of 243 days with warnings for heat, thunderstorms and intense rain were issued for the period May-September 2010–2019. The monthly maximum for heat is 42 days in July, for thunderstorms it is 26 days in June, and for intense rain it is 27 days in June. Objective circulation classification is conducted which shows that the majority of heat warnings are associated with Anticyclonic and West flow circulation types. About 40% of thunderstorm warnings are of Cyclone type followed by 28.6% of Cyclonic Directional types. For rain warnings, most of the days are with Cyclone type (46.2%) and Cyclonic Directional types (27.5%). Analysis of Global Navigation Satellite Systems (GNSS) derived Integrated Water Vapour (IWV), from the Bulgarian station in Sofia, shows consistently higher values for the days with METEOALARM warnings for heat, thunderstorm and rain.