Three-Dimensional Storm Structure and Low-Level Boundaries at Different Stages of Cyclic Mesocyclone Evolution in a High-Precipitation Tornadic Supercell

Figure 3

Storm-relative streamlines at an altitude of 250 m (a, c, e) at 2358 UTC (a), 0011 UTC (c), and 0022 UTC (e) with the asymptotic contraction rate overlaid in color in units of 10⁻³ s⁻¹ according to the color scale. Near-surface boundaries are drawn with the primary rear-flank gust front (RFGF) in red, the secondary rear-flank gust front (SRFGF) in light blue, the previous mesocyclone cycle’s secondary rear-flank gust front in dark blue, and the forward flank convergence boundary (FFCB) in green. Reflectivity greater than 40 dBZ is shaded in grey. Vertical vorticity maxima are annotated with magenta contours at −5 (dashed), 10, and 30 (solid) 10⁻³ s⁻¹. Horizontal cross-sections at 1 km altitude (b, d, f) for the 2358 UTC (b), 0011 UTC (d), and 0022 UTC (f) analysis of vertical velocity (in m s⁻¹, according to the color scale), radar reflectivity greater than 20 dBZ (contoured every 10 dB with 20 dBZ dashed and higher values solid). Vertical vorticity maxima are annotated in magenta at −5 (dashed), 10, and 30 (solid) (×10⁻³ s⁻¹).

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