8 



snow, will arrive and when high winds may be expected. The patrol 

 vessel must at these times be in the vicinity of the southernmost or 

 most dangerous iceberg and not 50 or 100 miles away and miable to 

 return because of weather conditions. Long periods of strong wmds 

 or gales effect the drift of icebergs considerably and the areas of these 

 high winds are sometimes restricted and the wind force and direction 

 may vary greatly from place to place over the area. These differences 

 show up on the weather maps. It is necessary to have a complete 

 synoptic picture m order to give accurate and detailed mformation 

 concerning present conditions in any particular area or coming weather 

 for any general area. 



It must be borne in mind in interpreting the average temperatures 

 given below that the Ice-Patrol area is a region of sharp contrasts 

 due to the juxtaposition of the warm waters of the Gulf Stream and 

 the cold waters of the Labrador Current. Also the region Hes in the 

 average track of all North Atlantic storms and the weather is there- 

 fore excessively boisterous. The patrol vessel, itself, constantly on 

 the move as it is, passes from cold water to warm and vice versa 

 with consequent rapid changes in temperature; and from cold fog to 

 warm clear weather, and its average position varies considerably from 

 year to year depending on the distribution of the ice. For these 

 reasons the data are of little use from a clhnatological point of view 

 but are interesting as a picture of the type and variations in weather 

 that may be expected in this region. The weather conditions experi- 

 enced by the patrol vessel are discussed below by months, in general, 

 and figs. 7 to 18 give the observed weather data in detail. 



MARCH 

 The weather during the last of March in the vicinity of the Grand 

 Banks was governed in large measure by a deep trough which remamed 

 almost stationary over the ocean about 750 miles east of Newfound- 

 land. This gave the Grand Banks region prevaiHng fresh to strong 

 northerly winds at tmies approaching gale force. This excess of 

 polar ah- resulted in cold weather and freedom from fog. No disturb- 

 ance of marked intensity passed directly over the area. The average 

 temperature was 37.7° F. and the percentage of fog, visibihty less 

 than 2 miles, was 0.095 percent. (See figs. 7 and 8.) 



APRIL 

 The rather stationary conditions existing over the northwestern 

 Atlantic in the last days of March were ended early m April, April 8 

 and 9 by the passage of a migratory cyclone of marked intensity. 

 This disturbance brought winds of gale force for 18 hours, reacliing a 

 max-imum, force 11, from the north-northwest at 0100, April 9, 4 hours 

 after the cold front passage. Lowest barometer reading was 28.87 

 inches. (See fig. 9.) On April 13 and 14 an unusually long period of 



