37 



haps it will be of interest and instruction to describe the paths of 

 some of the cyclones, rate of motion, and sequence in the procession 

 which was observed. 



MARCH 



The weather conditions on March 25, our sailing day from Boston, 

 consisted of a trough of low pressure stretched along the Ohio and 

 St. Lawrence River Valleys and embracing a well marked center 

 \V'^hich was progressing northeastward. It was rather interesting to 

 watch the path of this disturbance which has been plotted on Figure 5, 

 page 38, as track A. The center, during the night of March 26, 

 curved to the right and followed a southeasterly path to the vicinity 

 of Sable Island. At 8 a. m. on the 27th it was located again on the 

 weather map off Sydney, Cape Breton, and thence it moved in the 

 more frequently traveled route toward the northeast. The excursion 

 to the southward of the usual cyclone path was attributed in this 

 case to the presence of a deficiency of pressure over the Carolinas 

 combined with the blocking influence of a high pressure area to the 

 northward. The subsequent behavior of this disturbance is worth a 

 word or two. It can be seen by Figure 5, page 38, that the center 

 moved northeastward for two days when somewhere east of New- 

 foundland it deepened and thus intensifying the gradient gave to the 

 Grand Banks region strong westerly winds for several days. On 

 March 31 an excess of air accumulated to the westward over the United 

 States in sufficient proportions finally to remove all effects of our 

 storm offshore into the ocean. (For a daily record of winds, pres- 

 sures, and fog, reference may be made to the weather diagram, 

 fig. 1, p. 33.) 



APRIL 



During the early part of the ice season the atmospheric envelope 

 we repeat for emphasis, is usually in violent agitation; rocked inter- 

 mittently, so to speak, as successive cyclonic vortices disturb the 

 prevailing atmospheric pressure distribution. The normal pressure 

 character for this time of year is one to which we have previously 

 referred as wintertime, and is clearly identified by a dominating excess 

 of pressure lying over the cold continental area as compared with the 

 air mass over the warmer ocean. No sooner had March 31 marked 

 the disappearance to the eastward of the storm center described 

 above than it also ushered in a similar vortex in the troposphere, first 

 noticed on our map for the eastern United States just south of Chicago, 

 111. The career of this cyclone across the country and out to sea, 

 March 31 to April 3, has been traced as track B, Figure 5, page 38, 

 The effect of its approach was first detected when at a distance of 

 500 miles from the ice patrol ship, the barometric pressure began to 

 fall the afternoon of April 1. The northwesterly winds which had 

 been blowing with great intensity and duration ceased about this 



