Extended Abstract (520K)17.8
Convective contamination and the poor forecasts that follow
James Correia Jr., Iowa State University, Ames, IA; and R. W. Arritt, W. Gallus, and I. Jankov
Eta model initializations are frequently used to initialize other mesoscale models such as MM5 and WRF. In an investigation of one bow echo, we discovered that convection present in the model first guess fields contaminated the initial conditions to favor development of one MCS and completely misforecast development of a second MCS. Poorly forecast MCS cases were used to search for the signature of a poor initial condition. This signature was not readily apparent in model basic state fields but was more readily discerned in the divergence field. The divergence signature often resulted from convection triggered in the model first guess field. Implications for case studies of deep convection will be discussed at the conference.
Session 17, Use of Mesoscale Numerical Modeling in Severe Local Storms Forecasting
Friday, 8 October 2004, 10:30 AM-12:30 PM
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