A detailed analysis was performed of precipitation data from the years 2011-2013 collected from 17 stations in the city of Łódź over six days with the highest six-hour precipitation periods. Each day was analyzed in respect of the synoptic conditions affecting the weather, with particular emphasis placed on moisture conditions. The highest precipitation was recorded during the May to August period. The convergence of thermally contrasting air masses and significant amounts of water vapor transported to the area of Central Europewere the main cause of extreme precipitation in the area of Łódź. During the advection of warm air masses, the significant amount of water vapor in the air originated not only from the warm sea basins, but also from evapotranspiration during the air masses travelling over hot land areas. A high content of precipitable water during heavy precipitation events was reported in the area of Poland and its neighborhood.
Piotr Piotrowski, Department of Meteorology and Climatology, University of Łódź Narutowicza 88, 90-139 Łódź, Poland