628 Assessing MCS Predictability with the NSSL Experimental Warn-on-Forecast System for ensembles

Tuesday, 24 January 2017
4E (Washington State Convention Center )
Kent H. Knopfmeier, CIMMS/Univ. of Oklahoma and NOAA/OAR/NSSL, Norman, OK; and D. M. Wheatley, P. S. Skinner, D. C. Dowell, T. Ladwig, C. R. Alexander, and G. J. Creager

The NOAA Warn-on-Forecast (WoF) project is tasked with the development of a regional storm-scale prediction system capable of simulating all convective modes, and their attendant hazards.  WoF-based research to this point has focused on the ability of a prototype system, the NSSL Experimental Warn-on-Forecast System for ensembles (NEWS-e), to accurately forecast mid- and low-level rotation within supercell thunderstorms over short (i.e. 90-min) periods.  Yet undetermined is the capability of the NEWS-e to reproduce the salient features of severe mesoscale convective systems (MCSs), including mesovortices, which can generate localized swaths of significant wind damage and occasionally tornadoes.

Utilizing the NEWS-e configuration employed during the 2016 NOAA Hazardous Weather Testbed Spring Forecast Experiment, this study explores two severe MCS events that occurred during April 2016.  Initial experiments will examine the ability of 3-km NEWS-e simulations to predict MCS evolution on time-scales of up to three hours and produce system-scale features, including damaging surface winds, observed in these cases.  Due to the small-scale, transient nature of mesovortices, grid spacing of 3-km will likely be too large to accurately capture their structure and evolution.  Therefore, higher resolution (smaller grid spacings; i.e., 1-km) forecasts will also be completed in order to examine in greater detail the development of the mesovortex structures and the accompanying severe hazards present in these MCS events.

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