Real-data and idealized simulations of the 4 July 2004 bow echo event

During the morning hours of 4 July 2004, an intense, long-lived bow echo produced a swath of straight-line wind damage and an F1 tornado along its path from southeastern Kansas through northern Alabama. Level II radar observations from the Springfield, MO (KSGF) Doppler Radar revealed that the system contained a strong rear-inflow jet and a low-level mesovortex. These observations also captured the interaction between the bow echo and an externally produced outflow boundary. The dynamics of this interaction are of particular interest, and are examined using the Weather Research and Forecasting (WRF) model in both a real-data and idealized framework.

The real-data WRF simulation successfully represents the formation of the bow echo as well as the external outflow boundary. An interaction is also simulated, as is a modest low-level mesovortex. The extent with which these two processes are related is analyzed in two different ways. The first is through traditional diagnoses of the real-data WRF output. The second is through an idealized WRF simulation, which is based on a pre-convective sounding extracted from the real-data simulation.