Aviation Weather Services  Chapter 13  Introduction  In aviation, weather service is a combined effort of the  National Weather Service (NWS), Federal Aviation  Administration (FAA), Department of Defense (DOD), other  aviation groups, and individuals. Because of the increasing  need for worldwide weather services, foreign weather  organizations also provide vital input.  While weather forecasts are not 100 percent accurate,  meteorologists, through careful scientific study and computer  modeling, have the ability to predict weather patterns, trends,  and characteristics with increasing accuracy. Through a  complex system of weather services, government agencies,  and independent weather observers, pilots and other aviation  professionals receive the benefit of this vast knowledge base  in the form of up-to-date weather reports and forecasts.  These reports and forecasts enable pilots to make informed  decisions regarding weather and flight safety before and  during a flight. 