Radar analyzed quasi-linear convective system mesovortices during the Propagation, Evolution, and Rotation in Linear Storms (PERiLS) Project



This is a collection of 31 quasi-linear convective system (QLCS) mesovortices (MVs) that were manually identified and analyzed using the lowest elevation scan of the nearest relevant Weather Surveillance Radar–1988 Doppler (WSR-88D) during the two years (springs of 2022 and 2023) of the Propagation, Evolution, and Rotation in Linear Storms (PERiLS) field campaign. Throughout the two years of PERiLS, a total of nine intensive observing periods (IOPs) occurred (see https://catalog.eol.ucar.edu/perils_2022/missions and https://catalog.eol.ucar.edu/perils_2023/missions for exact IOP dates/times). However, only six of these IOPs (specifically, IOPs 2, 3, and 4 from both years) are included in this dataset. The inclusion criteria were based on the presence of strictly QLCS MVs within the C-band On Wheels (COW) domain, one of the research radars deployed in the field for the PERiLS project. Further details on how MVs were identified are provided below. This analysis was completed using the Gibson Ridge radar-viewing software (GR2Analyst).

Each MV had to be produced by a QLCS, defined as a continuous area of 35 dBZ radar reflectivity over at least 100 km when viewed from the lowest elevation scan. The MVs analyzed also had to pass through/near the COW’s domain at some point during their lifetimes to allow for additional analysis using the COW data. Tornadic (TOR), wind-damaging (WD), and non-damaging (ND) MVs were analyzed. ND MVs were ones that usually had a tornado warning placed on them but did not produce any damage and persisted for five or more radar scans; this was done to target the strongest MVs that forecasters thought could be tornadic.

The QLCS MVs were identified using objective criteria, which included the existence of a circulation with a maximum differential velocity (dV; i.e., the difference between the maximum outbound and minimum inbound velocities at a constant range) of at least 20 kt over a distance ≤ 7 km. The following radar-based characteristics were catalogued for each QLCS MV at the lowest elevation angle of the nearest WSR-88D: latitude and longitude locations of the MV, the genesis to decay time of the MV, the maximum dV across the MV, the maximum rotational velocity (Vrot; i.e., dV divided by two), diameter of the MV, the range from the radar of the MV center, and the height above radar level of the MV center.

In the Excel sheet, there are a total of 37 sheets. 32 of the 37 sheets are for each MV that was examined. One of those MVs (sheet titled 'EFU_tor_iop3') was not included in the final count of MVs (31). This MV produced an EFU tornado and only tornadoes that were given ratings were used to calculate MV statistics. The 31 MV sheets that were used to calculate MV statistics are labeled following the convention 'mv#_iop#_qlcs'. ‘mv#’ is the unique number that was assigned to each MV for clear identification, 'iop#' is the IOP in which the MV occurred, 'qlcs' denotes that the MV was produced by a QLCS, and the 2023 IOPs are denoted by ‘_2023’ after ‘qlcs’ in the sheet name. In these sheets, there are notes on what was visually seen in the radar data, damage associated with each MV (using the National Centers for Environmental Information (NCEI) database), and the characteristics of the MV at each time step of its lifetime. The yellow rows in each of the sheets indicate the last row of data included in the pretornadic, predamaging (wind damage), and pre-nondamaging statistics. The orange boxes in the notes column indicate any reports that were in NCEI but not in GR2Analyst.

There are also sheets that examine pretornadic and predamaging diameter trends, box and whisker plot statistics of the overall characteristics of the different types of MVs, and the overall characteristics of each MV, with one Excel sheet (‘combined_qlcs_mvs’) examining the characteristics of each MV over its entire lifetime and one Excel sheet (‘combined_qlcs_mvs_before_report’) examining the characteristics of each MV before it first produced damage or had a tornado warning placed on it.
Date made availableJan 4 2024
PublisherUniversity of Illinois Urbana-Champaign


  • C-band On Wheels
  • nontornadic
  • quasi-linear convective system
  • tornado
  • tornadic
  • PERiLS
  • tornado warning
  • QLCS
  • radar
  • low-level rotation
  • wind-damaging
  • mesovortex
  • Propagation, Evolution, and Rotation in Linear Storms

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