Precipitation 



19. Precipitation is generally well distributed throughout the year. 

 Precipitation from midlatitude cyclones (northeasters) predominates in the 

 winter, while local convection (thunderstorms) accounts for most of the summer 

 rainfall. 



Measurement instruments 



20. Electronic rain gage. A Belfort Instrument Company (Baltimore, MD) 

 30-cm weighing rain gage, located near the instrument shelter 47 m behind the 

 dune, measured daily precipitation. According to the manufacturer, the instru- 

 ment's accuracy was 0.5 percent for precipitation amounts less than 15 cm and 

 1.0 percent for amounts greater than 15 cm. 



21. The rain gage was inspected daily, and the analog chart recorder 

 was maintained by procedures similar to those for the microbarograph. 



22. Plastic rain gage. An Edwards Manufacturing Company (Alberta Lea, 

 MN) True Check 15-cm-capacity clear plastic rain gage with a 0.025-cm resolu- 

 tion was used to monitor the performance of the weighing rain gage. This 

 gage, located near the weighing gage, was compared daily; and very few dis- 

 crepancies were identified during the year. 



Results 



23. Daily precipitation values are shown in Figure 7. Total precipita- 

 tion for each month during this year and average totals for all years combined 

 are shown in Figure 8, while similar statistics are presented in Table 2. 



Wind Speed and Direction 



24. Winds at the FRF are dominated by tropical maritime air masses 

 which create low to moderate, warm southern breezes; artic and polar air 

 masses which produce cold winds from northerly directions; and smaller scale 

 cyclonic, low pressure systems, which originate either in the tropics (and 

 move north along the coast) or on land (and move eastward offshore) . The dom- 

 inant wind direction changes with season, being generally from northern direc- 

 tions in the fall and winter and from southern directions in the spring and 

 summer. It is common for fall and winter storms (northeasters) to produce 

 winds with average speeds in excess of 15 m/sec. 



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