P4M.1 Analysis of the development and evolution of the 15–16 June 2002 Southern Plains severe MCS through high–resolution numerical forecasts

Tuesday, 25 October 2005
Alvarado F and Atria (Hotel Albuquerque at Old Town)
Daniel T. Dawson II, CAPS/Univ. of Oklahoma, Norman, OK; and M. Xue

A set of high-resolution (3 km) numerical forecasts of the 15-16 June 2002 Southern Plains severe MCS are presented. The case was forecasted using the Advanced Regional Prediction System (ARPS) developed at the Center for Analysis and Prediction of Storms (CAPS) at the University of Oklahoma. Initial conditions for the forecasts were produced using the ARPS Data Analysis System (ADAS), including a complex cloud analysis using WSR-88D level II radar reflectivity data that can be used to adjust the thermal fields in cloudy areas to better represent buoyant convective updrafts in the initial state of the model. An analysis of the initial development of the MCS over southern KS during the afternoon of 15 June 2002 by examining the model forecasts as compared to observations, in which several discrete thunderstorm cells and short lines of cells merged to form an east-west oriented squall line. This line subsequently formed into a bow-echo around 0000 UTC 16 June 2002 over northwest Oklahoma and accelerated southward over Oklahoma and Texas, reaching the Texas Gulf Coast by 1200 UTC 16 June 2002, producing a swath of wind damage. Both the initial development stages of the MCS, and its subsequent evolution into a severe bow echo, are remarkably well reproduced by the ARPS model, especially when radar data are assimilated into the initial conditions via the cloud analysis procedure. A discussion of the physical processes responsible for this development and evolution on scales ranging from the storm scale to the synoptic scale, as revealed from the model output, will be presented and compared to the observations and previous numerical studies of bow echoes.
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