Verification of the Origins of Rotation in Tornadoes Experiment

Project Description
The Verification of the Origins of Rotation in Tornadoes
EXperiment (VORTEX) will be held in the central and southern
Plains during the spring seasons of 1994 and 1995. Broadly
stated, this experiment is designed to address current research
questions relating to tornadogenesis and tornado dynamics. It
will be hosted by the National Severe Storms Laboratory, and
will involve the collaboration of the University of Oklahoma and
the Center for the Analysis and Prediction of Storms (CAPS),
Texas A&M University, the University of Illinois, Texas Tech
University, New Mexico Tech, the University of West Virginia,
the University of Alabama at Huntsville, the University of
California at Los Angeles (UCLA), the National Center for
Atmospheric Research (NCAR), the National Science Foundation
(NSF), NOAA/NWS (National Oceanic and Atmospheric
Administration/National Weather Service), and Atmosphere
Environment Service (AES; Canada).

The primary benefit of VORTEX will be the new knowledge
generated through careful analysis of the data sets obtained
during the field experiments. This new knowledge should lead to
some very practical benefits.

This experiment is being executed with a set of specific
scientific hypotheses in mind, as documented elsewhere ( "
Scientific Objectives" ), but the general sense of the
experiment is to increase understanding of tornadogenesis,
thereby enhancing the ability to anticipate tornado
development. Many of the scientific objectives are closely tied
to the mission statement of SELS (soon to become SPC). With the
deployment of Doppler radars around the nation, it is becoming
increasingly obvious that (1) even this exciting new tool has
some limits in its tornado detection capability, as do all
weather radars, and (2) not all mesocyclonic circulations
detectable by a Doppler radar will become tornadic. Since not
all detectable mesocyclones go on to produce tornadoes, it is
quite crucial to tornado warning operations at the WFO level
(in the reorganized NWS) that we have some means to distinguish
tornadic from non-tornadic circulations (as seen on a
WSR-88D). Otherwise, excessive fal! se alarms could damage NWS
credibility. Tornadoes produced from non-mesocyclonic storms,
about which we hope to learn in VORTEX, are another challenge
with direct application to operations.

In the warning process, it is not only important to know if a
tornado is about to form, but also to be able to predict when
the tornado will dissipate. VORTEX is designed to acquire new
information that may allow users of WSR-88D data to interpret
radar signatures to diagnose tornado dissipation, and to predict
the formation of additional tornadoes in cyclic storms.

In the process, an important issue becomes the interaction
between the potentially tornadic storm and its
environment. Modelling work (numerical and mathematical) and
some limited observational studies have suggested some ways to
distinguish tornado-prone environments from those that are not,
but these concepts have yet to be given an adequate test. Given
that the detection of a potentially tornadic storm is more
likely when the forecasters have anticipated such a possibility
than when they have not, the VORTEX operating plan also includes
some experimental forecasting techniques that may become
prototypes for how operational tornado forecasting will be done
in the future. Preventing false alarms is just as important as
not missing important events. Many of the hypotheses being
investigated in VORTEX are designed to resolve these important
issues and explore new methods for dealing with the tornado

Especially exciting will be the incorporation of some
experimental numerical modelling on the mesoscale and the storm
scale, with the participation of CAPS (Center for the Analysis
and Prediction of Storms, affiliated with the University of
Oklahoma). Operational implementation of such numerical models
is in its infancy, but it appears quite likely that mesoscale
and storm scale models will eventually have some role in
operations. By participating in VORTEX, a number of NWS
forecasters from the NOC and the SPC will have a chance to
experiment with using such forecasting input. This gives those
individuals an opportunity to have input on how such models
will be implemented in the future, based on their
experiences. A continuing problem with introduction of new
technology is that forecasters often have so little experience
with the new systems that they have no chance to influence the
acquisition and evolution of the new technological tools until
very late in the game. By bein! g involved with VORTEX, the
participating forecasters (and their associated agencies) have
a real chance to affect the implementation of new forecasting
techniques and technology.

Similar benefits accrue for the participating forecasters (and,
their associated agencies within the NWS) as a result of
interacting with the principal scientific investigators. This is
especially important for the OUN NOC by virtue of their combined
research-operations mission. By their involvement, contact by
the NWS with the leading scientists in the area gives the NWS an
opportunity to (a) learn about what the research community is
doing in this topic area, and (b) offer their insights about
what problems the NWS is encountering. This experiment is an
ideal venue for encouraging research-operations interaction that
can only benefit all of the agencies involved.

Finally, the new knowledge we hope to gain through VORTEX
tornado dynamics studies should enable structural engineers to
establish improved design standards to mitigate tornado damage.

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