Symposium on the Challenges of Severe Convective Storms


The Connection Between a Cold Front Aloft and the Extensive Squall Line of 2930 October 2004

Mark Stoelinga, Univ. of Washington, Seattle, WA; and J. D. Locatelli

On 29-30 October 2004, an extensive squall line swept across the central United States, resulting in numerous reports of severe weather over a nine-state area. This squall line was characterized by a narrow, continuous, arc-shaped band of convective radar echoes over 2,000 km in length, and it occurred 150-250 km ahead of a synoptic-scale surface cold front analyzed on operational surface charts. These are the hallmarks of a squall line associated with a cold front aloft (CFA). Analysis of VAD wind profiles from the Lincoln, IL, NEXRAD radar, including thermal wind-based retrieval of temperature gradients and advection aloft, identify the structure of a CFA and its collocation with the squall line. Comparisons with an NCAR real-time WRF model forecast confirm and supplement the results from the VAD retrieval. The model forecast is also used to illustrate the dynamical connection between the CFA and the squall line, and to investigate the roles of the spatial distributions of evaporative cooling and surface heating in the behaviors of the frontal structure and squall line.

Poster Session 1, The Observation, Modeling, Theory, and Prediction of Severe Convective Storms and Their Attendant Hazards
Wednesday, 1 February 2006, 2:30 PM-4:00 PM, Exhibit Hall A2

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