Air Mass Origin and Fine Scale Radar and Thermodynamic Structure of a Warm Front over the Midwestern United States

From 0000 UTC 29 January 2010 to 1200 UTC January 30 2010, a Gulf Coast cyclone moved across the Tennessee Valley. A research flight was conducted during the Profiling of Winter Storms (PLOWS) project across a warm front using the NCAR/NSF C-130 aircraft which had onboard the Wyoming Cloud Radar. PLOWS, organized by the University of Illinois, was aimed at understanding the dynamic and microphysical processes that govern winter precipitation of extratropical cyclones . A single, straight flight path was organized across the warm front at an altitude of 4.5 km, altered to 6 km later in the flight path. A combination of Wyoming Cloud Radar (15m resolution) and RUC thermodynamic analyses were applied to analyze the fine scale structure of the warm front while HYSPLIT modeled the backward trajectories of the warm front's various sectors. The trajectory analysis showed that there were three major air mass sources: Canada, the Gulf of Mexico, and the mountains of Baja California. With the Wyoming Cloud Radar, several regions of convective generating cells were observed, as well as a bounding layer of cirrus. Utilizing the NCAR Command Language (NCL), the RUC thermodynamic analyses showed a distinct boundary between the warm frontal shield and both the cold air mass and the dry slot. Furthermore, precipitation evaporation below the cirrus shield was observed via the Wyoming Cloud Radar.