The diurnal variation of precipitation in California and Nevada

Abstract

The diurnal variation has been studied by means of a harmonic analysis of 35 years of hourly precipitation data for 347 stations. Results are shown for the cool (November-April) and warm (May-October) seasons. For all measurable (>0.25 mm) precipitation events, the phase of the cool season diurnal cycle tends to peak between 0300-0900 LST along the coast, between 1000-1300 LST in the coastal mountains and the Sierra Nevada and in the Sacramento and San Joaquin valleys and between 0800-1200 LST in most of Nevada. During the warm season, precipitation tends to maximize between 1400-2200 LST at most interior locations and in portions of the coastal mountains in phase with the diurnal heating cycle. Coastal areas from Santa Barbara to San Diego retain a 0300-0700 LST precipitation maximum for the lighter precipitation amounts, characteristic of the well-known coastal summer stratus regime. -from Authors