According to their model, so far global warming hasn't had much of an effect on moderate precipitation events. However, if global warming increases to 2o C we can expect the number of moderately heavy precipitation events to increase by about 65%.
The effect of global warming on moderate heat waves, however, is much worse. Already, the 0.85o C rise in global temperatures since pre-industrial times has increased the number of moderately hot days by about 5-fold. If global warming rises to 2o C we can expect another 5-fold increase in hot days.
Of course, predictions about the future are based on climate models; models that are developed based on past experience. Predictions may or may not come to pass. But climate models are getting better every year; we ignore them at our peril.