10B.1 Impact of WSR-88D Intra-volume Low-level Scans on Tornado Warning Performance Parsed by Storm Type

Wednesday, 30 August 2023: 10:30 AM
Great Lakes A (Hyatt Regency Minneapolis)
John Y. Cho, MIT, Lexington, MA; and J. M. Kurdzo, B. J. Bennett, and A. Anderson-Frey

The National Weather Service (NWS) Radar Operations Center (ROC) continues to develop new Volume Coverage Pattern (VCP) options for the operational Weather Surveillance Radar 1988-Doppler (WSR-88D) network to better meet the needs of forecasters and forecast models. The supplemental adaptive intra-volume low-level scan (SAILS) VCP option was introduced in 2014, followed by the multiple elevation scan option for SAILS (MESO-SAILS). In order to quantify the impact of these new VCP options on NWS severe weather warning performance, Cho et al. (2022) analyzed historical statistical relationships between (MESO-)SAILS usage and warning performance. Results yielded statistically meaningful improvement in severe thunderstorm, flash flood, and tornado warning performance with (MESO-)SAILS usage.

In this follow-on study, statistical relationships between (MESO-)SAILS and tornado warning performance are parsed by storm type. This effort was motivated by questions like whether the overall statistical results might have been biased by lower (MESO)-SAILS usage for storm types that tend to have lower tornado warning performance, and whether most of the apparent (MESO)-SAILS benefit is concentrated in just a few storm types. The results show that SAILS usage is associated with statistically meaningful improvement in detection probability for the majority of storm categories, and that progressively higher MESO-SAILS tiers (more frequent base scan updates) are associated with higher detection probability in a smaller subset of storm types. As with the previous overall tornado warning results, statistically meaningful impact of (MESO)-SAILS usage on lead time was generally not observed among the different storm types.

Reference:

Cho, J. Y. N., J. M. Kurdzo, B. J. Bennett, M. E. Weber, J. W. Dellicarpini, A. Loconto, and H. Frank, 2022: Impact of WSR-88D intra-volume low-level scans on severe weather warning performance. Wea. Forecasting, 37, 1169-1189, https://doi.org/10.1175/WAF-D-21-0152.1.

DISTRIBUTION STATEMENT A. Approved for public release: distribution unlimited. This material is based upon work supported by the National Oceanic and Atmospheric Administration under Air Force Contract No. FA8702-15-D-0001. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration.

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