3.7 Structure and Dynamics of an Intense Rear-Inflow Jet Observed on 20 June 2015 during PECAN

Tuesday, 9 January 2018: 3:00 PM
Room 6A (ACC) (Austin, Texas)
Michael M. Bell, Colorado State Univ., Fort Collins, CO; and J. Martinez, D. M. Stechman, R. M. Rauber, G. M. McFarquhar, and A. Marchi

A rear-inflow jet (RIJ) in a mesoscale convective system (MCS) can play a significant role in the system evolution and maintenance and is often associated with damaging winds, but detailed three-dimensional observations of this phenomena are limited. Airborne radar observations of an intense RIJ were obtained during the Plains Elevated Convection at Night (PECAN) field experiment on 20 June 2015. The MCS was observed by the NOAA P3 aircraft during an unofficial field operation (UFO4) in South Dakota within view of two NEXRAD radars. The multi-Doppler observations provide a unique opportunity to investigate the three-dimensional kinematic and retrieved thermodynamic structure of an intense RIJ during the bow-echo stage of the MCS life cycle. The RIJ was quite strong compared to previous observational and numerical simulation studies, with rear-to-front flow occurring over a very deep layer and exceeding 40 m s−1 at low-levels. The RIJ was flanked by cyclonic and anticyclonic bookend vortices to the north and south, with strong cyclonic vorticity at the leading edge of the convective line. Microphysical data from spiral ascents and descents in the stratiform region of the line were also obtained to provide further insight into the physical mechanisms that produced the intense RIJ. An analysis of the observed structure of the RIJ and its potential implications for straight-line wind damage and MCS longevity will be presented.
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