30 DISCUSSION 
from the southwest that spender clouds could 
easily form. Then, many of them, perhaps, were 
simply convective formations at favored spots. 
We know little about them; but there are cer- 
tainly such favored spots, and the convective 
systems probably moved as Dr. Newton said, up 
the Ohio Valley, maybe because their formation 
was favored by the lee-side convergence I men- 
tioned before. That would be my way of sum- 
ming up what has been said. Perhaps you do not 
agree, though. 
Mr. Namias—I am inclined to think that the 
orography must play a role. There undoubtedly 
is some mountain effect, but how much remains 
to be shown. 
Dy. Bergeron—l agree with Mr. Namias. I 
am quite aware of these facts. What I wanted 
to point out is that the bulk of the precipitation 
is formed within the Gulf air; I am opposed to 
the view that it was formed at a stationary front. 
No, it originated within the Gulf air, convective 
systems forming there; and a preferred locality 
is the Ohio Valley because of the reasons we both 
mentioned. As to the convective systems, I am 
sorry to say, Dr. Fujita, that you do not need a 
mesoscale network to find them. They may be 
very well located with the network that we have 
had in Europe for 50 years and even in the net- 
work of the United States, although that is much 
looser; but in order to find the finest details of 
the convective systems, one needs the time sec- 
tions that Dr. Fujita has utilized so ingeniously, 
and one also needs the densest network possible. 
