244 ANNUAL REPORT SMITHSONIAN INSTITUTION, 194 5 



surprising observation was the strong and persistent descent of air 

 observed at a height of a mile in the southwest quadrant of the storm 

 near the outer limits of the rain area. This was evidently in partial 

 compensation for the terrific ascent of large volumes of air around 

 the central core. 



FORCE AND EFFECTS OF THE HURRICANE 



During the 14th, peak winds at the surface were generally 75 to 90 

 miles an hour and showed little evidence of weakening. Variations 

 between different points could not be related to changes in the strength 

 of the storm as a whole, because of differences of exposure and distance 

 from center. The highest wind velocity recorded was 134 miles an 

 hour at 12 : 20 p. m. on September 14 at Cape Henry, Va. Maximum 

 (5 minutes) wind velocities equaled or exceeded all previous records 

 at Hatteras, Cape Henry, Atlantic City, New York, and Block Island. 



However, the wind on the left of the storm when it reached New 

 England was appreciably less than had been expected, as a result of 

 friction over the rough terrain, the greater proportion of land air in 

 the circulation, the cushioning effect of the cooler night air, and the 

 more rapid advance of the center. These effects were slightly reduced 

 by the increase in energy due to the greater contrast between the 

 density of the cooler air over the land and that of the warmer air over 

 the ocean. The wind on the right, however, retained practically 

 its full force, since it came straight in from the sea. The increasing 

 southeast-northwest general pressure gradient added somewhat to the 

 wind on the right of the vortex and offset to a certain extent the ten- 

 dency of the wind to decrease as the cyclone weakened. 



Between its emergence from the Tropics and its arrival in New Eng- 

 land the storm lost some of its original force. This was not true of 

 the hurricane of 1938, because then the much greater difference in the 

 temperature on the east and west sides (the land air was much cooler) 

 created potential energy that compensated in large measure for the loss 

 in latent heat, 10 and the storm, being well out to sea, did not lose so 

 much energy by friction with the land en route. The east-west 

 diameter of the storm at the surface (inside the isobar of 1,005 milli- 

 bars) was 520 miles on the 14th, and 420 miles on the 15th. 



A further weakening, between the time when the storm entered 

 New England and that when it reached the Gulf of St. Lawrence, 

 is shown by the record of lowest pressures: 28.34 inches at Block 

 Island and 28.31 at Point Judith, R. I. ; and 29.19 at Summerside and 

 29.18 at Charlottetown, Prince Edward Island. 



The tropical air that preceded the storm brought the first of the 

 heavy rains to New England on the night of the 12th. These were 



1# Pierce, C. H., The meteorological history of the New England hurricane of September 

 21, 1938, Month. Weather Rev., vol. 67, pp. 237-285, 1939. 



