67 

 WEATHER 



Throughout the 1929 ice-patrol season the vessels actually on 

 patrol remained within 120 nautical miles of 42° 30' N., 49° 30' W. 

 That position, therefore, can be taken for all practical purposes as 

 the place where the observations, which are described below, month 

 by month, were made. But too much stress should not be placed 

 on this position, for the weather experienced by the ice-patrol vessels 

 depends to a very great extent on their location in the ice-patrol 

 area. The northern part of the area cruised in is often cold and foggy 

 because of Labrador Current water, while, at the same time, the 

 near-by southern part of the ice-patrol area is warm and sunny be- 

 cause of Gulf Stream influence. In comparing figures like average 

 air temperatures and fog percentages of any one month with those 

 of the corresponding month in previous years, or of other months of 

 the same year, the fact should not be lost sight of that warmer and 

 clearer conditions recorded may be due not so much to actually dif- 

 ferent conditions in the region as a whole as to whether or not the 

 patrol vessels remained in the colder or warmer parts of the ice area 

 during the greater part of the time under consideration. 



The weather diagrams for each month of the active patrol season 



show graphically the wind directions and forces averaged for each 12 



hours, the barometric curve, and the time and duration of fog and 



low visibility. In addition, the maximum, minimum, and average 



AIT temperatures, as well as percentages of the time that bad and 



poor visibility prevailed, have been given for each patrol month. 



As these figures were obtained in exactly the same manner as the 



corresponding ones for last year, the remarks made regarding them 



on page 50 of the 1928 Ice Patrol Bulletin apply with equal force 



to this season's values. 



APRIL 



Maximum air temperature, 57° F. 



Minimum air temperature, 30° F. 



Average air temperature, 40° F. 



Visibility was less than 4 miles 35 per cent of the time. 



Visibility was less than 2 miles 26 per cent of the time. 



The first ship to go out on the- 1929 ice patrol left Boston, Mass., 

 for the eastward on April 1 during the early stages of one of the 

 four deep barometric depressions of the month. Winds of gale force 

 were experienced on the second day out, but, fortunately for progress 

 and fuel consumption, they came from a following direction. The 

 temperature and fog figures given above are those from noon of the 

 3d to the end of the month. The values for the first two and a half 

 days of April were disregarded because the patrol vessel did not get 

 out into the real ice-patrol area conditions of weather until after 

 that time. 



