Around the Sound, west-northwesterly winds prevail in winter with 

 the wind blowing from west to north 52 percent of the time, the most persist- 

 ent wind of any season. Mean speeds averaged over all directions range from 

 8 to 12 knots (9.2 to 13.8 mph), but the strongest winds are northwesterly, 

 averaging between 11 and 16 knots (12,7 to 18.4 mph) over the entire season. 



Spring is a time of variable wind with frequent changes in weather 

 control. Northwesterly winds prevail in western portions of the region, but 

 southwesterl ies begin to assert themselves gradually in more easterly sections. 

 The mean wind speed for the season ranges from 9 to 1 1 knots (10.3 to 12.7 

 mph) but strongest winds range from 11 to ]k knots (12.7 to 16.1 mph) and are 

 from the northwest. 



Southwesterly winds prevail in the summer as the flow is most 

 frequently dominated by the high pressure area which extends into the south- 

 eastern United States from the Atlantic Ocean. Southwesterly winds occur 

 from ]h to 20 percent of the time although there is considerable alternation 

 from south to west-southwest and sometimes east. Mean wind speeds over all 

 directions range from 7 to 9 knots (8.1 to 10.3 mph). 



Winds in the autumn reflect the transition from summer to winter 

 in both speed and direction. Cyclonic activity begins to increase and pre- 

 vailing winds gradually shift from southwesterly to northerly directions, 

 ranging between northwest and northeast except in extreme easterly sections 

 where the southwesterly winds continue longer into the season. Mean speeds 

 averaged over all directions range from 7 to 10 knots (8.1 to 11.5 mph) and 

 show a gradual increase through the season. 



In general the Sound and Atlantic Ocean have a dampening effect 

 on hot summer winds and the Sound has an accelerating effect on cold winds 

 from the mainland in winter. When anticyclonic conditions prevail on the 

 mainland in winter, the wind frequently reaches the northern shore of Long 

 Island with much higher velocities than occur over Connecticut. Since the 

 Long Island Sound Region lies well south of the northern storm track and 

 north of the path usually followed by the southern storms, wind movement is 

 not as great as it is in these areas. Winds of gale force are seldom expe- 

 rienced. Many times when areas east of the region are lashed by violent 

 coastal storms, only moderately high winds are experienced. Occasionally, 

 however, when a storm or hurricane moves up the coast or when a storm from 

 the Great Lakes moves southeastward, destructive winds occur throughout the 

 Long Island Sound Region. 



In designing large structures, it is necessary to take wind pres- 

 sure into account. Estimates of the distribution of extreme wind speeds 

 likely to be experienced once in 50 years and once in 100 years have been 

 prepared for the entire United States by H. C. S. Thorn (35) . These estimates 

 are based on winds 30 feet above the ground, but can readily be adjusted to 

 other elevations. For the 50-year return period, values of 65 to 80 mph are 

 estimated for Connecticut, increasing from the northwest toward the south- 

 eastern coast. The extreme wind speed to be expected once in 100 years ranges 

 from 80 to 90 mph in the interior and along the southwestern coast to close 

 to 100 mph in the extreme southeast. 



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