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PROBLEMS AND METHODS OF RAINFALL INVESTIGATION 
aa iN 
BN) 
10 APRIL IQd7 
18530 C.S.T. 
Vip Slight —moderate rain Rising pressure Imb/3" 
YU; Heavy rain Falling pressure 5mb/3° 
rr Pseudo-coldfront Isohypse of 300m 
ab. s.-l. 
--~-0 Isallobar Omb/3" 
Fic. 2—Weather map with convective system over eastern U. 8., April 10, 1947, 18h 30m CST 
