Warm Season Nocturnal Precipitation in the Great Plains of the United States

Abstract

This paper identifies temporal and spatial patterns in the diurnal cycle of hourly warm season precipitation events over the Great Plains of the United States. Results from 30 years of hourly precipitation records from 515 stations indicate that over 60% of all warm season rainfall (≥0.25 mm) occurs at night from southern Nebraska to panhandle Oklahoma and portions of northern Texas. The larger precipitation events (≥2.54 mm) display a much larger region where 60% of the warm season precipitation occurs at night. Harmonic analysis reveals a remarkably uniform longitudinal gradient in the timing of maximum rainfall frequencies across much of the Great Plains. The more precise identification of these spatial and temporal patterns should be particularly useful in 1) assessing the many theories of nocturnal precipitation in the central United States, 2) verifying numerical precipitation models for the region, and 3) generating rainfall forecasts for various times of the day.