WW2010
University of Illinois

WW2010
 
welcome
 
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educational cd-rom
 
current weather
 
about ww2010
 
index

Online Guides
 
introduction
 
meteorology
 
remote sensing
 
reading maps
 
projects, activities

Meteorology
 
introduction
 
air masses, fronts
 
clouds, precipitation
 
el nino
 
forces, winds
 
hurricanes
 
hydrologic cycle
 
light, optics
 
midlatitude cyclones
 
severe storms
 
weather forecasting

Severe Storms
 
introduction
 
dangers of t-storms
 
types of t-storms
 
tstorm components
 
tornadoes
 
modeling

Tornadoes
 
introduction
 
useful diagrams
 
union city storm
 
low-level flow
 
evolution (photos)
 
cyclic storms

User Interface
 
graphics
text

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Union City Tornado of 1973
low level air flow highlighted

The first of three photos of the Union City, Oklahoma, tornado of 1973 has warm inflow and cool rear flank downdraft (RFD) outflow arrows superimposed to help clarify the low-level airflow around a tornado.

[Image: tornado with low level inflow highlighted (63K)]
Photograph by: Tegtmeier

Note inflow wrapping into the tornado from the southeast, east, and northeast. We are looking west-northwest from about 10 miles. A clear slot is becoming visible behind the subtle outflow lowering.

[Image: mature tornado (69K)]
Photograph by: Tegtmeier

A few minutes later, the clear slot becomes more obvious, as does the weak shelf-like outflow cloud at the base of the flanking line. This is during the tornado's mature stage, and the twister's warm inflow is about to be cut off by the left-to-right advancing cold RFD outflow.

[Image: dissipating stage (55K)]
Photograph by: Tegtmeier

Near the end of the mature stage, we have a spectacular view of the clear slot wrapping around the east side of the tornado. The gust front continues to advance and virtually has isolated the tornado from the rest of the storm. The Union City storm was not cyclic, and it weakened rapidly when the tornado dissipated about 10 minutes after this photograph was taken.


Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.