Heat waves in the south Moravian region during the period 1961-1995

Heat waves (periods of extremely hot summer weather) in the region of south Moravia are in the focus of this study. The introduced definition consists of three requirements imposed on the period that is considered a heat wave: at least three days with T-MAX greater than or equal to 30.0 degrees C must be observed; the mean T-MAX over the whole period is at least 30.0 degrees C and T-MAX must not drop below 25.0 degrees C. To compare the severity, of the individual hear waves, various characteristics (duration, number of tropical days, peak temperature, cumulative temperature excess, precipitation amount) are examined. The hear wave index HWI is defined to express the severity of heat waves in the most comprehensive way. An extraordinary heat wave occurred in July and August 1994, it lasted more than a month at several stations, while the duration of a typical hear wave is only 4 - 7 days. The extremely, lor2g unbroken period of tropical days, and even of days with T-MAX greater than or equal to 32.0 degrees C, represents the most distinct feature of the severe 1994 heat wave. with regard to heat wave characteristics, the summer temperature exceptionality of the early 1990s is indubitable.