SEA 



SCIENCE 



says Pietrafesa. "This contributed to the Wright 

 Brothers' robust and effective wind field." 



EXTRATROPICAL FORMATIONS 



Another reason for the high winds is that 

 extratropical cyclones or midlateral storms are 

 further intensified and can form off the North 

 Carolina coast, particularly Cape Hatteras. 

 Pietrefesa and Raman have conducted studies on 

 the storm formation processes. 



When the cold air comes down from 

 Canada, it cannot move west because of the 

 mountains. You also often get warm moist air 

 from the Gulf Stream. 



If the conditions are rigfit, gravity pulls 

 cold, heavier air under warmer, lighter air, 

 according to USA Today's The Weather Book. 



"Contrasts between warm and cold air 

 have potential energy. When something happens 

 to start warm and cold air masses moving over 

 and under each other, their potential energy 

 becomes a storm's kinetic energy," the book 

 explains. 



"Storms can form in 15 to 30 hours off the 

 Outer Banks," says Pietrafesa. "These storms 

 can create a strong wind field." 



While global winds determine the weather 

 over a large area, smaller winds can create other 

 weather changes. 



One of the most common local winds is a 

 sea breeze along the ocean. 



"During the summer, sea breezes blow 

 from the south to north at an average of 5 to 10 

 knots," says Pietrafesa. "Winter sea breezes 

 typically blow from north to south from 10 to 20 

 knots." 



WIND AND RECREATION 



Along the Outer Banks, recreational 

 activities are often defined by wind. 



"The best surfing waves are sculpted by a 

 northeast blow that shifts cleanly to the west," 

 according to Jan DeBlieu's Wind. 



"But if the west wind blows too long, the 

 breakers are knocked flat. Surfers disappear, 

 replaced by commercial fishermen, who row 

 dories just offshore to set their nets for bluefish 

 and trout." 



Locals have their favorite winds, according 

 to DeBlieu: 



Outer Banks surf casters like a land breeze, 

 because as they say, 



Wind from the east, fish bite the least. 



Wind from the west, fish bite the best. 



"A westerly breeze draws trout, mullet and 

 other species to the calm waters in the lee of the 

 shore. During duck hunting season it also pushes 

 waterfowl from the middle of the Pamlico Sound 

 toward the islands, putting them in easy range of 

 hunting blinds." 



During the summer, light easterly winds 

 slow along the barrier islands, says DeBlieu. 



"West winds muddy the ocean waters, but 

 east winds clear them" she wrote. "West winds 

 bring biting flies to the beach, but east winds 

 banish them to the north. The most pleasant 

 summer days are those with an ocean breeze 

 strong enough to set up a little surf, but not so 

 strong as to make swimming dangerous." 



FORECASTING WIND 



Over the years, wind technology has 

 become more advanced. Meteorologists now use 

 a wind sensor to measure speed and direction. 

 During rainy weather, they use doppler radar to 

 measure the winds off the ground. 



"Doppler radar is the most important 

 development in weather technology," says 

 Raman. "It can even spot a small tornado. It can 

 detect winds up to several kilometers." 



To improve local weather information and 

 forecasts in North Carolina and create a database 

 for future research, the State Climate Office, in 

 cooperation with federal and state agencies, has 

 initiated the development of the North Carolina 

 Environment and Climate Observing Network 

 (NC ECONet). 



When completed, the network will have at 

 least one automated weather station in each North 

 Carolina county. 



Data from these stations will be provided to 

 government agencies to improve emergency 

 management, weather forecasts, energy planning 

 and natural resource management. Data also will 

 be made available in "realtime" to the general 

 public. 



"We are using it to get the average wind 

 speed," says Raman. "When the whole system is 

 up, it will provide information to predict droughts 

 and improved planning for tourists who want 

 weather information from beaches to mountains. 

 With improved forecasts, it can save the state 

 $91 million." □ 



To find about more about ECONet, visit 

 the Web: www.nc-climate.ncsu.edu. 



For more information about the First 

 Flight Centennial Celebration at the Outer 

 Banks — which culminates with a celebration 

 Dec. 13-17— go online to: www.outerbanks.org. 



Flying Fundamentals 



WANT TO KNOW ABOUT THE BASICS OF FLYING? 



As the curved wings of airplanes go through the air, the wind goes above and below it, 

 according to David G. Haase, director of North Carolina State University's Science House. 



"The air below it hits the wing and gets pushed downward," says Haase. "By the law of 

 action and reaction, the wind forced downward pushes back upward on the wing." 



Also, the air underneath the wing goes a shorter distance than the air that goes over the 

 curved wing. To keep up with the total airflow, the air on top of the wing must move faster. 



According to the Bernoulli principle, when the air is slow, it creates higher pressure. 

 When the air moves faster, the pressure becomes lower. 



"High pressure on the bottom and low pressure on the top forces the wing upward," 

 says Haase. "You need a steady wind for flying, and it helps to fly into the wind — not with the 

 wind. You have to have wind over the wing." 



For more information about the principles of flight, go online to: 

 www. aero. hq. nasa.gov/edu/ 



COASTWATCH 25 



