Delayed Tornadogenesis Within New York State Severe Storms Journal of Operational Meteorology

Past observational research into tornadoes in the northeast United States (NEUS) has focused on integrated case studies of storm evolution or common supportive environmental conditions. A repeated theme in the former studies is the influence that the Hudson and Mohawk Valleys in New York State (NYS) may have on conditions supportive of tornado formation. Recent work regarding the latter has provided evidence that environments in these locations may indeed be more supportive of tornadoes than elsewhere in the NEUS. In this study, Weather Surveillance Radar–1988 Doppler data from 2008 to 2017 are used to investigate severe storm life cycles in NYS. Observed tornadic and non-tornadic severe cases were analyzed and compared to determine spatial and temporal differences in convective initiation (CI) points and severe event occurrence objectively within the storm paths. We find additional observational evidence supporting the hypothesis the Mohawk and Hudson Valley regions in NYS favor the occurrence of tornadogenesis: the substantially longer time it takes for storms that initiate in western NYS and Pennsylvania to become tornadic compared to storms that initiate in either central or eastern NYS. An analysis of approximate near-storm environments using the 13-km Rapid Refresh (RAP) is used to confirm that the long-lived storms encounter more tornado-favorable conditions leading up to tornadogenesis in the NYS valley regions.