Since the spring of 2002, tornadoes were sampled on nine occasions using Hardened In-Situ Tornado Pressure Recorder probes, video probes, and mobile mesonet instrumentation. This study describes pressure and, in some cases, velocity data obtained from these intercepts. In seven of these events, the intercepted tornadoes were within the radar-indicated or visually identified location of the supercell low-level mesocyclone. In the remaining two cases, the intercepted tornadoes occurred outside of this region and were located along either the rear-flank downdraft gust front or an internal rear-flank downdraft surge boundary. The pressure traces, sometimes augmented with videography, suggest that vortex structures ranged from single-cell to two-cell, quite similar to the swirl-ratio-dependent continuum of vortex structures shown in laboratory and numerical simulations. Although near-ground tornado observations are quite rare, the number of contemporary tornado measurements now available permits a comparative range of observed pressure deficits for a wide variety of tornado sizes and intensities to be presented. ABSTRACTSince the spring of 2002, tornadoes were sampled on nine occasions using Hardened In-Situ Tornado Pressure Recorder probes, video probes, and mobile mesonet instrumentation. This study describes pressure and, in some cases, velocity data obtained from these intercepts. In seven of these events, the intercepted tornadoes were within the radar-indicated or visually identified location of the supercell low-level mesocyclone. In the remaining two cases, the intercepted tornadoes occurred outside of this region and were located along either the rear-flank downdraft gust front or an internal rear-flank downdraft surge boundary.The pressure traces, sometimes augmented with videography, suggest that vortex structures ranged from single-cell to two-cell, quite similar to the swirl-ratio-dependent continuum of vortex structures shown in laboratory and numerical simulations. Although near-ground tornado observations are quite rare, the number of contemporary tornado measurements now available permits a comparative range of observed pressure deficits for a wide variety of tornado sizes and intensities to be presented.

Data collected by a mesonet within the near-tornado environment and in the Tipton tornado on 29 May 2008 provided a rare opportunity to analyze rear-flank downdraft (RFD) outflow properties closely bounding a tornado and to characterize parcel thermodynamics being ingested into a tornado from the rear-flank downdraft. Parcels moving into the tornado on its right flank had very small negative buoyancy and considerable potential buoyancy. Measurements within and very near the tornado showed similar buoyancy characteristics to the storm inflow. Analyzed surface divergence and videographic evidence indicated that the RFD outflow just to the right and wrapping in front of the tornado was supported by parcels moving out of a narrow downdraft bordering the right flank of the tornado. Surface flow field analysis showed that parcels moved out of the downdraft-associated divergence region and into the right side of, as well as in front of, the tornado. An internal RFD surge boundary was positioned roughly 0.5 km in front of the eastern edge of the analyzed divergence region and implied downdraft.The broader RFD outflow thermodynamic characteristics were consistent with recent research with only small negative buoyancy and substantial potential buoyancy; however, convective inhibition was considerably higher than typically found in other tornadic cases. This latter characteristic was emblematic of the broader storm environment on this day. Parcels making up the RFD outflow originated from low-levels, consistent with recent findings for tornadic rear-flank downdrafts and in contrast to past historical indications for the rear-flank downdraft source region.

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