Summer rain fall duration and its diurnal cycle over the US Great Plains



By diagnosing the hourly station rain gauge data set for the 1981–1999 periods, it is found that the rainfall diurnal cycle is closely related to its duration during summer (June–August) over the Great Plains [(GP), 100–90°W, 35–45°N]. Short-duration rainfall events (an event of 1 h in duration) occur more frequently in summer, and they tend to have two diurnal maxima over the GP, with one in the early morning [0400–0600 local solar time, (LST)] and the other in the afternoon (1500–1700 LST). Long-duration rainfall events (an event that lasts longer than 3 h) contribute more to the precipitation amount, and they tend to peak from the midnight to early morning (000–0600 LST). This contrast in the diurnal cycle of different classifications of precipitation events over the GP reflects the differences in the convective processes at night and during late afternoon. Copyright © 2008 Royal Meteorological Society