831 Microphysical and Near-Storm Environmental Control on the Maintenance of the 15 July 2015 MCS

Tuesday, 9 January 2018
Exhibit Hall 3 (ACC) (Austin, Texas)
Tam Iat Hin, National Taiwan Univ., Taipei, Taiwan; and M. J. Yang and W. C. Lee

Handout (1.6 MB)

A ground-based, self-sustained convective line was sampled by a mixture of high-frequency ground-based observational instruments in Brewster, KS for the Plains Elevated Convection at Night (PECAN) field experiment on 15th July, 2015.

A synthesis of observational datasets, including 1) high temporal frequency radiosonde and surface observation, 2) dual-polarization parameter data from the Goodland (KGLD) WSR-88D, 3) 449 MHz Profiler and 4) Wyoming King Air leg data is utilized to document the pre-convective line environmental change and the convective line structural deterioration while the convective line moved rapidly across northwestern Kansas.

The processes contributed to the initial weakening of the convective line included: 1) the stabilizing effect of compensating subsidence and surface radiative cooling after sunset in the pre-convective line region, 2) upshear-tilted updraft associated with strong cold pool. Dual-polarization observation reveals the importance of the weak convection in the weakening convective region in strengthening the cold pool due to a more robust evaporation process, while the larger droplet size and fall speed in the stratiform region limited its contribution to cold pool accumulation. Possible processes that are responsible for the wave-like cell initiation in the dissipated convective region will also be discussed.

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