Pressure Measurements and Video Observations near and inside Three EF2 Tornadoes
Lanny E. Dean, David R. Moran, Randy D. Hicks, Pat T. Winn
ABSTRACT
From the spring of 2016 through the spring of 2019, three EF2-rated tornadoes were sampled with in-situ tornado probes as part of the Pressure Acoustics Recordings Inside Tornadoes Experiment. The probe meteorological instrumentation resolved the temperature, humidity, and pressure-deficit characteristics near or inside all three tornadoes. Probe recorded pressure and visual observations during each tornado event show unique attributes, including multiple strong pressure irregularities before and just after the first EF2 tornado, a rotating bowl-shaped cloud feature located some distance ahead of the second EF2 tornado, independent of the tornado core and immediate inflow layer. Pressure measurements of the bowl feature reveal a brief pressure perturbation lasting roughly 4 s as it passed near or directly over the research team before the documentation of a 41 hPa pressure deficit. During the third EF2 near in-situ deployment, pressure trace observations also reveal pressure fluctuations ahead of the tornado core lasting some 65 s before the documentation of a 13 hPa pressure deficit. These pressure measurements and video observations are consistent in location with recent ultra-high-resolution simulations of the Streamwise Vorticity Current (SVC), or more precisely, the related Vertical Vorticity Sheet (VVS) and Pressure Deficit Lobe (PDL) regions. This paper describes the measured pressure deficit traces during three EF2 tornadoes near and in situ, augmented with brief, one-of-a-kind, near and in-situ video observations of a unique bowl feature, tornado inflow, corner-flow, and tornado core regions. The recorded data and instrumentation were analyzed; results are presented and discussed.
Citation: Dean, L. E., D. R. Moran, R. D. Hicks, and P. T. Winn, 2024: pressure measurements and video observations near and inside three EF2 tornadoes. Electronic J. Severe Storms Meteor.,19(2), 1–45.