Dangerous weather phenomena in Europe in the year 2000 and their dependence on circulation

In the paper the influence of atmospheric circulation on selected dangerous weather phenomena in Europę in the year 2000 has been presented. Dangerous weather phenomena include: 30 days with thunderstorms in Poland and 26 examples of such phenomena in Europę (tornados, strong winds, thunderstorms, torrential rains, floods, etc.). The NAO index (North Atlantic Oscillation) served to determine the character of the circulation that influenced the occurrence of catastrophic phenomena in Western, Central and Southern Europę. The J. Lityński classification of circulation types was used to thunderstorms occurring in Poland only. Most catastrophic phenomena during the positive NAO phase (predominance of zonal circulation) happened in Western and Central Europę. During the negative NAO phase (predominance of meridional circulation) the regions of the Mediterranean Basin were more freąuently affected. In the case of thunderstorms in Poland in the year under investigation (2000) their occurrence was related to the inflow of air masses from the northern sector.