Predictability of the Location and Amount of Winter Storm Precipitation

A pair of new diagnostic equations is derived for the verification of ensemble forecasts of the location of precipitation events by combining conventional diagnostic equations of meteorology with techniques of digital image processing. The resulting diagnostics are applied to operational ensemble forecasts of the named winter storms of the United States from the 2014/2015 and 2015/2016 winter storm season. The results suggest that the ensemble forecasts predict the uncertainty in the location of the precipitation systems of the storms accurately for the first 15 forecast days. In contrast, the same forecasts grossly underestimate the uncertainty in the amount of the precipitation at the shorter than 5-day forecast times.