A Conceptual Model of the Severe-Storm Environment for Inclusion into Air Weather Service Severe-Storm Analysis and Forecast Procedures.
Scientific interim rept. Jan-Sep 84,
AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA
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A severe-storm conceptual model first proposed by Carlson and Ludlam is described, and its relevance to identifying potential areas for severe thunderstorms is discussed. The theory complements that of Fawbush and Miller, but revises some ideas concerning large-scale atmospheric structure preceding the outbreak of severe storms, particularly the presence of a capping inversion or lid in the pre-storm environment. The processes that produce the lid are then discussed along with methods for identifying the lid on both convectional pressure charts and Skew T-Log P diagrams. The diagrams are used to define a new stability index that considers the strength of the restraining inversion. Two detailed case studies are presented that illustrate the role of the lid in determining the location of severe weather and the analysis techniques used to identify the lid, and that incorporate the lid concept into the operational severe-storm analysis and forecast procedures used by the Air Weather Service. Originator-supplied keywords Severe-storm conceptual model, Fawbush-Miller theory, Carlson-Ludlam theory, Elevated mixed-layer inversionlid, Lid strength index, Severe-storm forecasting.