Modulation of the diurnal cycle of warm-season precipitation by short-wave troughs

To date, relatively few studies have formally documented the climatology of short waves and their relationship to the diurnal heating cycle, the topography, and the diurnal cycle of precipitation. Those that did had to rely on low-resolution global analyses and often could not track short waves across mountain barriers.

In this study, 10 yr of the (32 km) NCEP North American Regional Reanalysis (NARR) are used to objectively identify and track short waves in the North American domain. Statistics of short-wave span, duration, phase speed, latitudinal extent, and locations of preferred intensification/decay are presented. Some of the key findings from the climatology include that the lee (windward) of mountain barriers are preferred regions of intensification (decay) and short waves show little evidence of a diurnal cycle and can pass a given point at any time of the day.