25th Conference on Severe Local Storms


A comparison of the structural evolution and microphysical state of a forecasted MCS using a single and two-moment microphysics scheme

Bryan J. Putnam, CAPS/Univ. of Oklahoma, Norman, OK; and M. Xue, G. Zhang, Y. Jung, N. Snook, and A. D. Schenkman

A mesoscale convective system (MCS) developed over western Oklahoma early on May 9 2007. The MCS, as well as an associated line end vortex (LEV), were observed by KOUN, a dual-polarimetric WSR-88D in Norman, OK. Four three hour forecasts of this MCS were made using the Advanced Regional Prediction System (ARPS) atmospheric model. The forecasts were separated into two groups with each group containing a forecast initialized with previously completed EnKF and 3DVAR method analyses. The first two forecasts utilized a single moment (SM) Lin Ice microphysics scheme while the second two were made using a Milbrandt and Yau two- moment (DM) microphysics scheme. The structural evolution of the forecasted MCV using the two different microphysics schemes will be evaluated compared to observations. Additionally, a polarimetric emulator included in the ARPS package was used to simulate the polarimetric variable fields as would be observed by a weather radar such as KOUN. Recent studies using the 3DVAR and EnKF methods employing a SM microphysics scheme showed a good fit of analyzed reflectivity to observations and produced highly accurate forecasts. In this study, the microphysical state estimates of the two analyses will be further investigated using KOUN data. The values and qualitative trends of the simulated variables from the SM and DM microphysics scheme forecasts will be compared to KOUN observations as well.

extended abstract  Extended Abstract (1.8M)

Poster Session 7, Numerical Weather Prediction Posters
Wednesday, 13 October 2010, 3:15 PM-5:00 PM, Grand Mesa Ballroom ABC

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