S17 Verifying model forecasts of arctic fronts in advance of winter storms in the southern Plains

Sunday, 23 January 2011
William E. Leatham IV, University of Massachusetts Lowell, Lowell, MA; and P. Burke and A. A. Taylor

Arctic fronts and associated freezing line positions are of concern in winter storm forecasting. In the southern Great Plains of the United States the arrival of shallow arctic air plays a major role in the development of severe ice storms. At other times, the cold air becomes deep enough to support snowstorms and even blizzard conditions. Forecasters' providing at least twelve to twenty-four hour advanced warning allows the public and other groups time to prepare for these potentially dangerous events. Therefore, determining how operational forecast models perform in these situations is crucial to improving forecast accuracy and increasing our understanding of shallow cold air. This paper compares the observed surface freezing line and cold front location with model forecasts of both these features during the twenty-four hour period leading up to the onset of four winter storms. The model forecasts tend to move arctic fronts southward much too slowly. This has strong implications for the southward extent of winter storm warnings based on model forecasts, and their associated lead time.
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