reasonably confident that required sea conditions would be met and that 

 they would be predicted with acceptable accuracy. In addition, it was felt 

 that acceptable ceiling and visibility could be predicted. 



There remained only one problem with which the forecasting personnel 

 could not cope; this was concerned with the requirement that the illumii^ation 

 level be sufficiently high to carry out the aJerial photography. This require- 

 ment limits the operation to a daylight period of approximately six hours; 

 and the sequence of increasing visibility, rising ceiling, with little or no de= 

 crease in wave height must necessarily occur during that time. Fortunately, 

 these conditions did occur during daylight hours, with a decrease in wave 

 height very shortly after the photography was accomplished. The careful 

 prelim.lnary planning, with, consequent accurate timing, made possible the 

 accomplishment of Operation SWOP. 



Analysis of Mfteorologlcal ConditionjB''' 



The first significant wave height of over 5 1/2 feet was observed on 

 October 20th at 1100 Z, at which time the R. V, ATLANTIS was on station 

 near 38°N 68°W, On the synoptic surface chart of 1230 Z of October 18th, 

 there was a quasi^stationary front oriented NNE=SS'W and extending from. 

 Labrador to the Bahamas, A wave developed on this front during the 19th. 

 By the 20th at 1230Z (fig, 5,1a) this wave was centered near 370N 67.5°W 



♦Extracted from "Observationg of the Growth and Decay of a Wave 

 Spectrtun" by Wilbur Marks and Joseph Chase, Woods Hole Oceano- 

 graphic Institution, Woods Hole, Mass. 



34 



