Schematic of Funnel StageLecture #20
Tornadoes, Climatology, Non-Supercell Tornadoes, Hodographs
Wednesday, 7 March 2001
Text Reading for Lecture
#20
Tornadoes (403-413)
Supplemental Reading Materials Given Below
Stages or Life Cycle of a Tornado
Supplemental Reading HERE
Large tornadoes typically proceed through a
distinct 3-stage life-cycle:
Schematic of Funnel Stage
Photo of Funnel Stage (Courtesy Bob Houze, U of
Washington)
Schematic of Mature Stage
Photo of Mature Stage
Schematic of Rope Stage
Photo of Rope Stage (Courtesy Bob Houze, U of
Washington)
Other tornado photos HERE
Multi-Vortex Tornadoes (page 406
in text)
Schematic of multi-vortex tornado
Photograph of multi-vortex tornado
Photograph of scratch marks made by a multi-vortex tornado.
The Swirl Ratio, or ratio of rotational wind speed to updraft
speed, is a critical factor in vortex structure. If the swirling
componenet of the flow exceeds the updraft, then multiple
vortices tend to form.
Non-Supercell Tornadogenesis
Tornadoes can form from lines of relatively weak
clouds that are growing above a surface
wind-shift line (along which vertical rotation
exists and can be stretched to intensify the
vortex, leading sometimes to weak tornadoes
often referred to as "land spouts").
Life cycle of non-supercell tornadoes
(Wakimoto and
Wilson, MWR, 1989).
Movies of non-supercell tornadoes
via numerical simulation
The Tornado Project Online
- A Good Source of
Information for the Curious
The OU Doppler on Wheels Radar
Climatology of Tornadoes (page 404 in
text)
Courtesy Harold
Brooks, NSSL
Courtesy Harold
Brooks, NSSL
Courtesy Harold
Brooks, NSSL
Courtesy Harold
Brooks, NSSL
Other severe storm climatology information
can be found HERE.
See USAF Handout
See Handout by Weisman and Klemp
Click HERE for powerpoint file
A real hodograph:
ADIABATIC CHARTS/THERMODYNAMIC
DIAGRAMS (text reading pages 174-175; review
pages 161-171)
To come: Use of soundings and hodographs
to determine storm type, motion, and
other characteristics.
