673A Wisconsin’s Record Tornado: Thought Process of a Warning Forecaster during the 134-km (83 mi) Long-Track Tornado

Tuesday, 8 January 2019
Hall 4 (Phoenix Convention Center - West and North Buildings)
Jacob R., Beitlich, NOAA/NWS Forecast Office, Chanhassen, MN

On 16 May 2017 a long-track tornado traveled 134 km (83 mi) across western Wisconsin, setting the state record for a continuous damage track by a single tornado. At its peak intensity, the tornado was rated EF-3, with a maximum estimated wind speed of 63 ms-1 (140 mph). This poster will discuss the warning forecaster’s train of thought during the tornado warning decision process from the onset of the storm to its conclusion. Despite the continuous damage track, there were no reports of damage for nearly one hour after touchdown. This caused the warning forecaster to lose confidence and consider holding off on issuing downstream warnings despite compelling radar signatures and a favorable near-storm environment. In this poster, radar imagery and NOAA/CIMSS ProbTor Model output are shown, along with local storm reports to aid in illustrating the thought process of the warning forecaster. The goal of this presentation is to demonstrate the complexity of the warning decision process and showcase the importance of timely spotter reports to enhance severe weather messaging and communication.
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