A cold front was predicted to pass through the north part of catchment Tisza (Sajó-Hernád and Bodrog rivers) by the weather forecast released on Monday, 3 September 2007. According to the quantitative precipitation forecasts (QPF), a high amount of precipitation was predicted over the area for the middle of the week (Table 1).
Using the above weather forecasts, the National Hydrological Forecast Service of Hungary forecasted high water levels for the end of the week and the beginning of the following week. Exceeding of the
highest alarm level was predicted on both rivers.
As the centre of the cyclone happened to be more in the north than it was predicted, temporal and spatial distributions of the precipitation over the two catchments were different from expected. On the second day of the period the observed precipitation was higher, on the third and forth day it was much lower (see Table 2). Thus, the total amount of observed precipitation in the whole period remained under the forecasted value.
Compared to the forecasts, the observed precipitation caused significantly smaller flood waves. Moreover, the flood waves were likely diminished by the operation of the Slovakian reservoirs situated by the rivers. Consequently, water levels did not exceed even the first alarm level.