PROBLEMS AND METHODS OF RAINFALL INVESTIGATION 
the precipitation intensity would pick up again 
at the rear edge of it. 
Some years later I was able to confirm this 
assumption or ‘forecast’ as seen in Figure 3, 
which shows the distribution of rainfall during 
one hour from this very convective system. At 
the leading edge there is a rainfall intensity of 
up to two inches per hour. In the interior of the 
convective system the rain intensity goes down 
to zero over considerable areas, and further west 
it reaches values of at least one tenth inch per 
hour, proving the expected increase at the rear 
RWERRS 
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11 
edge of the system. This whole mechanism 
moved across the eastern part of the United 
States, giving from one to eight inches of rain 
within a few hours. Seemingly, this kind of 
mechanism is the main rain-spender during the 
summer-half of the year in the Middle West. 
Thus, the convective system is a most important 
mechanism, worthy of all those very minute and 
ingenious investigations that Dr. Fusrra has 
made; and also, of course, of being tackled by 
many more investigators. 
From Dr. M. Tepper I got data on the ‘pres- 
IK=O Cloudless 
Pressure-jump line 
3-hourly isallobar Ground 
Fictitious isobar >24kmalt 
Pseudo-coldfront (and isobar) 
Precip. area at synoptic hour 
> Isohyetal 00 s within 
eo 
2:5 ae 
central 
region 
Fig. 5b—Convective system, June 2, 1951, 09h 30m 
