Weather Radar Coverage Improvement ActThis bill requires the National Oceanic and Atmospheric Administration to develop a plan to replace the Next Generation Weather Radar (NEXRAD) system of the National Weather Service by September 30, 2040. (The NEXRAD system is a network of weather radars used to detect precipitation and wind.)Under the bill, the plan must incorporate certain elements, including estimates of improvements to coverage and accuracy made possible by replacement of the system and an evaluation of the potential use of commercial radars to replace or supplement the system. The bill also authorizes the National Weather Service to contract with third parties to fill gaps in radar coverage so as to better detect significant weather events over a larger area.