Occurrence of Nocturnal Warming Events at Prototype Sites of Mississippi Mesonet

Dramatic short time scale warming events have been observed on many nights since installation of the first station of the Mississippi Mesonet. Often accompanied by dramatic drops in dewpoint, it is hypothesized that most events are probably associated with mixing of relatively warm dry air downward under thermally stable conditions. In many cases, this appears to be induced by relatively subtle increases in surface wind speed. Data from the developing mesonet will be used to develop an initial description of the seasonal, synoptic, and case-to-case variability among nocturnal warming events. Typically the events are not unambiguously detectable using standard hourly surface observations. Although a fairly benign phenomenon, there are potential implications for daily minimum temperature forecasts and surface radiation fog development/dispersal.