4.4 MIPS Observations of Bow Echoes during BAMEX

Tuesday, 5 October 2004: 9:00 AM
Dustin Phillips, University of Alabama, Huntsville, AL; and K. Knupp

The UAH Mobile Integrated Profiling System (MIPS) played a key role in the Bow Echo and MCV Experiment during 20 May to 7 July 2003. This paper will summarize MIPS measurements from two nocturnal bow echoes observed on 24 June (90 km NW of Des Moines) and 3 July (50 km NW of Minneapolis). These measurements include 915 MHz profiler, 12-channel microwave profiling radiometer, ceilometer, Doppler sodar, electric field mill, disdrometer, and surface measurements. In addition, the ground-based component of BAMEX included two mobile NCAR GLASS sounding units, and a third at the MIPS.

Around 0650 UTC on 24 June, the MIPS acquired an excellent data set on a surging bow echo, near the time of maximum radial velocity (exceeding 30 m s-1 from the DMX WSR-88D) over a large region centered at the MIPS deployment site. A dissipating gravity wave was measured 10 min prior to the arrival of the bow echo gust front, which produced updraft speeds of 10 m s-1. The peak updraft within deep convection, ~20 m s-1, occurred about 10 min after the gust front arrival. The maximum surface wind gust of 24 m s-1 was measured about 15 min after gust front arrival, well behind the leading edge within relatively heavy precipitation.

Around 0600 on 3 July, the MIPS acquired measurements of a maturing bow echo whose outflow attained maximum intensity after passage over the MIPS. In this case, the maximum wind gust at the MIPS location was 21 m s-1, and the primary updraft of ~20 m s-1 magnitude was closely tied to the surface gust front.

In both cases, analysis of analyses of MIPS data will include a definition of the environment preceding the bow echo (GLASS soundings and the MPR), and the environment in the wake of the bow echo. Internal storm structure will be described from analyses of MIPS 915 MHz profiler and electric field mill measurements, supplemented with Doppler analyses from WSR-88D and Eldora Doppler radar that was available for each case.

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