10A.2
Comparison of radar-observed and WRF-modeled structures of two STEPS storms
L. Jay Miller, NCAR, Boulder, CO; and M. L. Weisman
We will compare the radar-observed and WRF-modeled structures of two storms observed in the summer of 2000 during the Severe Thunderstorm Electrification and Precipitation Study (STEPS). The broad goal of STEPS is to achieve a better understanding of the interactions between kinematics, precipitation production, and electrification in severe thunderstorms on the High Plains. The radar network for STEPS consisted of two research 10-cm polarimetric radars, CSU-CHILL from Colorado State University and S-Pol from the National Center for Atmospheric Research (NCAR), and the National Weather Service (NWS) radar at Goodland Kansas. The radars covered about 300 x 300 square kilometers centered about 40 km northwest of Goodland and included the climatological position of the north-south oriented dryline.
The two storms that will be discussed represent a range of supercells from the low-precipitation (LP) end on July 5 to the more high-precipitation (HP) end on June 29. Typical Doppler-synthesized updrafts in these two storms ranged around 35-45 m/s, with the July 5 case reaching a maximum of about 65 m/s during its mature phase. Both storms exhibited localized areas of strong vorticity, and the June 29 case produced a small, but intense tornado that was on the ground for about 20 min. We will emphasize the ability (or inability) of the Weather Research and Forecasting (WRF) model with its current parameterized microphysics scheme to produce a storm with realistic precipitation, cold pool, and kinematic structures as compared to the observed features. Preliminary results suggest that the WRF model did reasonably well on the July 5 LP storm, but it has done less well on the June 29 HP storm pointing to the possible importance of the microphysics scheme in replicating the observed storm.
Session 10A, Results from the Severe Thunderstorm Electrification and Precipitation Study (STEPS) Experiment
Wednesday, 14 August 2002, 1:30 PM-3:00 PM
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