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Josué U. Chamberlain
,
Matthew D. Flournoy
,
Makenzie J. Krocak
,
Harold E. Brooks
, and
Alexandra K. Anderson-Frey

radar-based storm objects with 3991 tornado reports. The reports were associated with a mix of storm modes, including both supercells and QLCSs. This pairing was done by assigning each storm object a number (e.g., 1, 2, 3, etc.) that was then associated with each tornado that each storm produced. Some examples of this process are shown in appendix B . Individual storms were numbered based on the order of initial tornadogenesis for each storm (e.g., the first tornado in time was paired with Storm 1

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Brian A. Klimowski
,
Mark R. Hjelmfelt
, and
Matthew J. Bunkers

– 79 . 10.1175/1520-0434(2000)015<0061:PSMUAN>2.0.CO;2 Burgess, D. W. , and Smull B. F. , 1990 : Doppler radar observations of a bow echo associated with a long-track severe windstorm. Preprints, 16th Conf. on Severe Local Storms, Kananaskis Park, AB, Canada, Amer. Meteor. Soc., 203–208 . Conway, J. W. , Brooks H. E. , and Hondl K. D. , 1996 : The 17 August 1994 Lahoma, OK supercell: Issues of tornadogenesis and bow echo formation. Preprints, 18th Conf. on Severe Local Storms

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Jerald A. Brotzge
,
Steven E. Nelson
,
Richard L. Thompson
, and
Bryan T. Smith

, Mississippi, and Louisiana). Another 19.4% occurred across the southern plains (Texas, Oklahoma, and Arkansas). One reason for the difference in lead times between supercell and nonsupercell storms is that nonsupercell storm tornado warnings contained a higher fraction of zero and negative warnings. Negative lead times (when the warning was issued after tornadogenesis) with nonsupercell morphologies occurred at over 3 times the rate of supercells (17.8% vs 5.2%, respectively). The percentage of warnings

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Russell L. Pfost
and
Alan E. Gerard

tornadogenesis (the exact time of the beginning of the first tornado is unknown, but it was likely around 1941 UTC from radar and eyewitness accounts). From 1941 to 2002 UTC, the core diameter remained around 6 km, and the base of the circulation continued at the lowest detectable height ( Figs. 12c–f ). During this period (1941 to 2002 UTC), tornadoes were occurring on the southeast side of the comma head, behind the bowing line. This apparently occurred due to increased shear as the rear inflow jet (RIJ

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Darrel M. Kingfield
and
Joseph C. Picca

-relative wind vector over the depth of the precipitation shaft above the layer containing the signature. Thus, as the magnitude and shape of the signature are correlated with the strength and direction of the storm-relative wind field, this signature can reveal critical information regarding the near-storm environment—specifically, the likely presence of storm-relative helicity favorable for low-level mesocyclogenesis. While such a capability does not offer explicit prediction of tornadogenesis, it can

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Nusrat Yussouf
,
John S. Kain
, and
Adam J. Clark

the 5-min-update radar experiment to reproduce low- and midlevel rotations associated with the El Reno supercell thunderstorm are evaluated using the ensemble probabilistic forecasts initialized from the storm-scale analyses every 30 min during the 1-h period preceding tornadogenesis ( Fig. 6 ). The forecast probability swath of vertical vorticity greater than 0.003 s −1 at 1 km AGL is used to represent low-level rotation, while the forecast probability swath of 2–5-km updraft helicity (UH; Kain

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Levi T. Lovell
and
Matthew D. Parker

perturbations and sub-tornadic centers of vorticity on vortex intensification. Additionally, a focused analysis on an ensemble of idealized simulations with perturbed hodographs may be insightful for determining the degree to which stochasticity of storm-scale processes affects tornadogenesis. A radar emulator applied to high-resolution model output may help diagnose potential precursors leading up to vortex genesis. Observational studies with high spatial and temporal resolution would also be useful to

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John Y. N. Cho
,
James M. Kurdzo
,
Betty J. Bennett
,
Mark E. Weber
,
Joseph W. Dellicarpini
,
Andrew Loconto
, and
Hayden Frank

TOR warning performance further. This agrees, at least conceptually, with the multitude of studies utilizing experimental mobile rapid-scan radar systems for observations of tornadoes and tornadogenesis (e.g., Bluestein et al. 2007 ; Wurman et al. 2007 ; Kosiba et al. 2013 ; Kurdzo et al. 2017 ). The incredibly rapid changes that can occur in the low-level mesocyclone, the rear-flank downdraft, and the surrounding wind field seen in several rapid-scan radar studies suggests that ∼90-s updates

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Jonathan M. Garner
,
William C. Iwasko
,
Tyler D. Jewel
,
Richard L. Thompson
, and
Bryan T. Smith

; Markowski and Richardson 2014 ; Brown and Nowotarski 2019 ). Supercells that fail to experience significant tornadogenesis due to excessive outflow often occur in environments with high MLLCL heights ( Thompson et al. 2003 ; Murdzek et al. 2020 ). Despite evidence that wider, longer-lived, and longer-tracked tornadoes are responsible for greater societal impacts ( Ashley and Strader 2016 ), few efforts exist in literature to directly relate these attributes to their radar signatures, near

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Bryan T. Smith
,
Richard L. Thompson
,
Douglas A. Speheger
,
Andrew R. Dean
,
Christopher D. Karstens
, and
Alexandra K. Anderson-Frey

speed (a function of V rot strength and diameter) and mesocyclone depth several volume scans (~10–20 min) prior to tornadogenesis, to provide lead time on tornado warnings for significant (EF2+) tornadoes. However, Gibbs and Bowers (2019) did not consider tornado intensity variations beyond the onset of EF2+ damage. An information gap still exists within the context of tornado warnings that can be addressed by V rot derived from WSR-88D data, which enables diagnostic estimates of peak damage

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