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tions were experienced in Halifax; first a warm day followed by one 

 which was cool. 



An unusually deep atmospheric depression was observed on the 

 meteorological chart for the morning of May 9. The lowest barome- 

 ter reading was recorded in Nebraska but the attending low-pressure 

 system spread over a relatively large area of the central United States. 

 This "low" moved eastward very slowly and assumed various shapes 



Fig. 7.— May weather diagram 



and positions but remained at all times over the continent. The 

 period May 11 to 20, consequently, was characterized by general low 

 atmospheric pressure over the United States east of the Mississippi 

 River Valley and extended eastward over the Maritime Provinces and 

 Newfoundland. (Fig. 9.) These summer-time conditions brought 

 southerly winds, rain, and a protracted spell of wet weather to the 

 northeastern part of the country, and the ice regions coming again 

 under prevailing southwesterly winds received the first prolonged 

 period of fog for the season. We had almost continuous fog and low 



