STRUCTURE OF CONVECTIVE STORMS 
65 
R 
METER 
200 
40 
(3) 
S 150 ~N 
a 
a 
ita 
LAMINAR FLOW 
100 
TURBULENT 
44 
en 
a 30 20 
10 M/S 
1827¢ 1828 1829 1830C JUN 2057 
Fie. 6—Tangential wind speed shown as a function of time and radius of 
the funnel; the dashed line indicates the radius of the rounded bottom 
funnel 
Fie. 7—The nonadiabatic process taking place beneath a tornado funnel after it is rounded; note 
that the edge of the rounded funnel no longer represents a surface of condensation pressure 
and condensation pressure in the parcel method 
shows reasonable values. However, as soon as the 
funnel reaches a certain diameter, large enough 
to provide a long spiral inflow path of the parcels 
near the ground, the lower portion of the funnel 
is rounded. At this stage the bottom of the funnel 
no longer maintains the same condensation pres- 
sure. A dry adiabatic irreversible process asso- 
ciated with the near ground inflow was found to 
be one of the explanations for this. 
Acknowledgment—The research reported in 
this paper has been sponsored by the U. S. 
Weather Bureau under Contract Cwb 9530. 
