2 Surface Wind Analyses 



A series of surface wind analyses were prepared by the staff of the Hurri- 

 cane Research Division, Atlantic Oceanographic and Meteorological Labora- 

 tory, National Oceanic and Atmospheric Administration. The analyses are 

 based upon wind data acquired from a variety of sources including reconnais- 

 sance aircraft, moored buoys, coastal meteorological stations, and ship reports. 

 A description of the analysis techniques used may be found in Powell, Dodge, 

 and Black (1991) and Powell, Houston, and Reinhold (in preparation). 



Three analyses were selected for inclusion in this report; 1400 hr Coordi- 

 nated Universal Time (UTQ 31 August, 2200 hr UTC 31 August, and 0200 hr 

 UTC 1 September, 1993 (Figures 4, 5, and 6, respectively). These analyses 

 were selected as depicting Emily's surface wind fields shortly before the point 

 of closest approach to land (PCA), at the time of PCA, and just subsequent to 

 PCA. The solid lines in these figures are streamlines indicating the wind 

 direction. The dashed line are isotachs, i.e., contours of constant windspeed. 



At 1400 hr UTC on 31 August (Figure 4), the eye of Emily was approxi- 

 mately 130 miles from Cape Hatteras, with the dominant motion toward the 

 north-northwest. Maximum surface winds were approximately 86 knots 

 (Burpee et al. 1994). At the time, the dominant wind direction over Pamlico 

 Sound was from the east-northeast at approximately 40 knots. 



During the next 8 hr, Emily took a slightly more northerly course and 

 moved to within about 15 miles of Cape Hatteras (Figure 5). The maximum 

 winds at this time were slightly greater than 100 knots and the winds over 

 Pamlico Sound had increased to between 70 and 90 knots. The wind direc- 

 tions over the Sound varied from north-northeast to south-southeast, depending 

 upon location. It is apparent from the streamline depiction at this time that 

 high surge levels would be expected to occur on the Pamlico Sound side of the 

 Outer Banks south of Cape Hatteras. 



By 0200 hr UTC 1 September 1993, the center of Emily had moved to 

 about 100 km northeast of Cape Hatteras (Figure 6) on a track that was contin- 

 uing to turn more toward the east Although the maximum sustained wind 

 speed in Emily was still slightly in excess of 100 knots, the storm's movement 

 away from Cape Hatteras had reduced the wind speeds over Pamlico Sound to 

 between 30 and 70 knots with the direction predominantly from the northwest. 



Chapter 2 Surface Wind Analyses 



