Observations of the 24 June 2003 Bow Echo Case during BAMEX

This presentation will summarize profiler and radar measurements of a nocturnal bow echo observed on 24 June 2003, 90 km NW of Des Moines, IA (DMX). The MIPS measurements include 915 MHz profiler, 12-channel microwave profiling radiometer (MPR), ceilometer, electric field mill, disdrometer, and surface measurements. In addition, analysis of data acquired by the DMX WSR-88D radar, the NCAR Eldora Radar and the two mobile NCAR GLASS sounding units are analyzed.

Between 0530 and 0800 UTC on 24 June, the MIPS acquired an excellent data set on the environment in advance of a surging bow echo, and the internal structure of the 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 1 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 near 0652 UTC, well behind the leading edge within relatively heavy precipitation.

In this case, an 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 also 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 this case.