Aerial reconnaissance
Prior to shuttle launches or landings, pilots fly aircraft that provide cloud, wind, turbulence, visibility, and precipitation information. Aircraft are flown along the future flight path of the shuttle and observations are noted. This complements radar and satellite data and only provides information that is useful for short-term (up to four hours before launch or landing) but not long-term forecasting. Aerial reconnaissance often provides a more accurate assessment of weather conditions than radar or satellite imagery.