The Airflow Within the Weak Echo Region of an Alberta Hailstorm

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  • a Dept. of Meteorology, McGill University, Montreal, Quebec, Canada
  • | b Desert Research Institute, University of Nevada, Reno
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Abstract

A severe hailstorm having many of the characteristics of Browning's right-moving severe local storms occurred in Alberta on 28 July 1969. This storm was systematically scanned by the Alberta Hail Studies high-resolution 10-cm radar and by the 3-cm radar in the Desert Research Institute's B-26 research aircraft. The former obtained reflectivity factor data throughout the volume of the storm while the latter obtained ground-reference PPI radar contours at flight levels varying from cloud base (7000 ft MSL) to 16,000 ft, and updraft measurements on the southern side of the storm in the Weak Echo Region (WER). Updrafts were smooth and reached a speed of 3500 ft min−1 (18 m sec−1). The width of the WER narrowed from ∼4 mi near cloud base to 2 mi at 16,000 ft. The radar echo was found to tilt approximately 40° from the vertical toward the right of the mean environmental winds. The echo intensity reached 30 dBZ at 25,000 ft directly above the WER.

Abstract

A severe hailstorm having many of the characteristics of Browning's right-moving severe local storms occurred in Alberta on 28 July 1969. This storm was systematically scanned by the Alberta Hail Studies high-resolution 10-cm radar and by the 3-cm radar in the Desert Research Institute's B-26 research aircraft. The former obtained reflectivity factor data throughout the volume of the storm while the latter obtained ground-reference PPI radar contours at flight levels varying from cloud base (7000 ft MSL) to 16,000 ft, and updraft measurements on the southern side of the storm in the Weak Echo Region (WER). Updrafts were smooth and reached a speed of 3500 ft min−1 (18 m sec−1). The width of the WER narrowed from ∼4 mi near cloud base to 2 mi at 16,000 ft. The radar echo was found to tilt approximately 40° from the vertical toward the right of the mean environmental winds. The echo intensity reached 30 dBZ at 25,000 ft directly above the WER.

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