Areal Coverage of Precipitation in Northwestern Utah

Abstract

Areal coverage of precipitation over a subsynoptic-scale and a mesoscale network of stations in north-western Utah for the four seasons is discussed. As would he expected, 100% areal coverage is rare in summer, but, surprisingly, also infrequent in winter. The scattered nature of precipitation in this area is shown to have a pronounced effect on Brier scores for forecasts of probability of precipitation (PoP). This effect, in turn, limits the predictability of precipitation in the area, which is defined as the maximum improvement over climatology that can be achieved by PoP forecasts.