A New Approach for Mesoscale Surface Analysis: the Space-time Mesoscale Analysis System (stmas)

The importance of narrow zones of boundary layer convergence (or boundaries) for thunderstorm development and evolution has been recognized since the days of the Thunderstorm Project. Boundary detection and characterization are primary objectives of automated nowcasting systems, which employ surface data, radar and satellite observations of current storms and trends in their intensity to forecast thunderstorm initiation, growth, and dissipation (Golding 1998; Pierce and Hardaker 2000; Boldi et al. 2002). The National Center for Atmospheric Research (NCAR) Auto-Nowcast System, or ANCS (Mueller et al. 2003), utilizes a numerical model of the boundary layer and its adjoint, in addition to meteorological observations, to forecast the evolution of boundaries. Conceptual models for using boundaries to nowcast thunderstorms presented by Wilson and Mueller (1993) form the basis for the ANCS.