measurements provide a very detailed description of the conditions; NWS col- 

 lects wind data every hour and averages three successive observations to 

 create data summaries every 3 hours, which appears to be the optimum meteoro- 

 logical sampling plan. However, the author's review of the continuous analog 

 chart records confirmed that for all but a very few exceptions the 6-hour data 

 sampling interval represents an unbiased assessment of wind conditions. 



97. The annual average wind speed is in excess of 5 m/sec, with a strong 

 western tendency (see Table 5). The highest speed (not gusts) was 20.6 m/sec 

 from the northeast recorded late on 2 March as the result of a very intense 

 low-pressure system (shown in Figure 9) off the Virginia-Carolina coast on the 

 morning of 3 March. 



98. The annual wind rose for 1980 (Figure 10) indicates the winds blew 

 onshore from the north side of the FRF pier (i.e., from north-northeast, north- 

 east, and east-northeast directions) in excess of 26 percent of the time and 

 from the south side 15 percent of the time. The strongest winds occurred dur- 

 ing the cold months (Figure 11) and blew out of the north-northeast. Winds 

 blowing from the north through east-northeast directions produce onshore mov- 

 ing waves and southerly moving surface currents, while winds from the east 

 through south directions generally produce onshore waves and northerly moving 

 surface currents. Over 51 percent of the time in 1980, the winds were off- 

 shore not producing onshore waves. 



99. Wind roses (see Figure 12) for the spring and summer seasons April- 

 September show the strong influence of the tropical maritime air mass which 

 produces winds that blow from the southwesterly direction. A more northerly 

 tendency for the winds during January through March is the result of the 

 dominance of the arctic and polar continental air mass. The high speeds and 

 frequent north-northeasterly directions observed for winds during the winter 

 result from the continental high-pressure systems as well as extratropical and 

 tropical cyclones (low-pressure systems;). Extratropical winds originating as 

 arctic and polar "Canadian high" air masses with clockwise circulations move 

 east across the United States producing initially eastern and finally northern 

 or northeasterly winds along this coast; extratropical "northeaster" storms 

 associated with low-pressure (counterclockwise circulation) systems tend to 

 move north along the Atlantic coast producing strong northeasterly winds 

 followed by winds from north and northwest. October through December is a 

 transition time when both the tropical and arctic air masses cause a great 

 variety in the wind conditions. 



41 



