The Global Precipitation Measurement mission's Core Observatory flew over Hurricane Arthur five times between July 1 and July 6, 2014. Arthur is the first tropical cyclone of the 2014 Atlantic Hurricane season. It formed as a tropical storm on Tuesday, July 1 and reached maximum intensity as a Category 2 hurricane on July 4, disrupting some coastal U.S. Independence Day celebrations. This visualization is taken from the flyover on July 3, 2014 with Hurricane Arthur just off the South Carolina coast. GPM data showed that the hurricane was asymmetrical, with spiral arms, called rain bands, on the eastern side of the storm but not on the western side.

The GPM Core Observatory carries two instruments that show the location and intensity of the rain, which defines a crucial part of the storm structure – and how it will behave. The GPM Microwave Imager sees through the tops of clouds to observe how much and where precipitation occurs, and the Dual-frequency Precipitation Radar observes precise details of precipitation in 3-dimensions.

For forecasters, GPM's microwave and radar data are part of the toolbox of satellite data, including other low Earth orbit and geostationary satellites, that they use to monitor tropical cyclones and hurricanes. 

The addition of GPM data to the current suite of satellite data is timely. Its predecessor precipitation satellite, the Tropical Rainfall Measuring Mission, is 18 years into what was originally a three-year mission. GPM's new high-resolution microwave imager data and the unique radar data ensure that forecasters and modelers won't have a gap in coverage. GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency. The satellite launched Feb. 27, and after its check-out period began its prime mission on May 29, in time for hurricane season. All GPM data products will be released to the public by September 2, 2104. Current and future data sets are available to registered users from NASA Goddard's Precipitation Processing Center website.