Analyzing the Accuracy of the National Weather Service Central Region Tornado Events in Storm Data and Developing Techniques for Database Improvements

The National Weather Service (NWS) Central Region (CR) Tornado Warning Improvement Project (TWIP) team conducted a review of the CR 2014-15 unwarned tornadoes. Numerous errors in Storm Data were found by the team while conducting the review. Of the 457 unwarned tornadoes reviewed, 65 or 14 percent contained errors, including 29 warned tornadoes that were counted as unwarned due to timing and placement errors. As a result of the errors found in the 2014-15 Storm Data, the TWIP team reviewed the entire CR tornado Storm Data database of 547 tornadoes for 2018. An error rate near 14 percent was again identified with many of the same errors as the 2014-2015 database. Common errors included timing and placement errors. Other errors included tornadic debris signatures prior to the tornado entry start time and satellite data revealing larger tornado tracks than what are listed in Storm Data. These errors had negative impacts on the Government Performance and Results Act (GPRA) metrics for tornadoes, as well as negative impacts to scientific research. In an effort to minimize future errors, the CR TWIP team has developed a Storm Data Best Practice guidelines to enhance the quality control process.