Higher evaporation and a higher water absorption capacity of the warmer air can lead to increased and heavier precipitation.

For the weather forecast, the German Weather Service (DWD) has set the warning criteria for heavy precipitation as follows: 25 mm in 1 hour and 35 mm in 6 hours.

https://www.eea.europa.eu/data-and-maps/figures/projected-changes-in-20-year-2

Global warming is projected to lead to a higher intensity of precipitation and longer dry periods in Europe (IPCC, 2012; Hov et al., 2013). Projections show an increase in heavy daily precipitation in most parts of Europe in winter, by up to 35 % during the 21st century. Heavy precipitation in winter is projected to increase over most of Europe, with increases of up to 30 % in northeastern Europe (Map 3.10, left). In summer, an increase is also projected in most parts of Europe, but decreases are projected for some regions in southern and south‑western Europe (Map 3.10, right) (Jacob et al., 2014). Similar patterns were found for other heavy precipitation indices (Rajczak et al., 2013; Sillmann et al., 2013; Giorgi, Coppola and Raffaele, 2014).

https://www.eea.europa.eu/publications/climate-change-impacts-and-vulnerability-2016