Southwest has installed water-vapor sensors on 87 of its 737s, and is sharing the data with the National Weather Service. “We have seen improvements in the capabilities for forecasting severe thunderstorms, and also the forecast of whether the storm is going to produce rain, snow, freezing rain, or sleet,” said Carl Weiss, an aviation meteorologist with the National Oceanic and Atmospheric Administration, the parent agency for NWS. The aircraft collect data continuously at every altitude, from the surface to the flight levels, at locations around the country. “Now we don’t have to wait for the 12-hour updates [for data collected from weather balloons], we get data almost real-time,” said Rick Curtis, of Southwest.
“Water vapor is the most rapid-changing and under-sampled element in the atmosphere,” said Weiss.”WVSS-II [Water Vapor Sensing Systems] data upon takeoffs and landings allow forecasters to monitor and stay on top of how moisture is changing in the atmosphere, specifically in severe weather situations when preparedness is especially important.” The system was designed and installed by Aeronautical Radio Incorporated and SpectraSensors. It has the potential to “revolutionize weather forecasting — especially when predicting thunderstorms,” according to Jeannine Hendricks, ARINC’s manager for the program. A small scoop attached to the outside of the fuselage funnels air to a shoebox-size sensor inside the aircraft.
