NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
A concentrated outbreak of tornadoes, downbursts and microbursts, and implications regarding vortex classificationA remarkable case of severe weather occurred near Springfield, Illinois on 6 August 1977. Aerial and ground surveys revealed that 17 cyclonic vortices, an anticyclonic vortex, 10 downbursts and 19 microbursts occurred in a limited (20 km x 40 km) area, associated with a bow-shaped radar echo. About half of the vortices appeared to have occurred along a gust front. Some of the others appear to have occurred within the circulation of a mesocyclone accompanying the bow echo, but these vortices seem to have developed specifically in response to localized boundary-layer vorticity generation associated with horizontal and vertical wind shears on the periphery of microbursts. Some of these vortices, and other destructive vortices in the literature, do not qualify as tornadoes as defined in the Glossary of Meteorology. A more pragmatic definition of a tornado is suggested.
Document ID
19830044175
Document Type
Reprint (Version printed in journal)
Authors
Forbes, G. S. (Pennsylvania State University University Park, PA, United States)
Wakimoto, R. M. (Chicago, University Chicago, IL, United States)
Date Acquired
August 11, 2013
Publication Date
January 1, 1983
Publication Information
Publication: Monthly Weather Review
Volume: 111
Subject Category
METEOROLOGY AND CLIMATOLOGY
Funding Number(s)
CONTRACT_GRANT: NOAA-NA-80AAD00001
CONTRACT_GRANT: NGR-14-001-008
CONTRACT_GRANT: NRC-04-74-239
Distribution Limits
Public
Copyright
Other