An anonymous reader quotes a report from Ars Technica: A U.S. Navy memo warns that 5G mobile networks are likely to interfere with weather satellites, and senators are urging the Federal Communications Commission to avoid issuing new spectrum licenses to wireless carriers until changes are made to prevent harms to weather forecasting. The FCC has already begun an auction of 24GHz spectrum that would be used in 5G networks. But Sens. Ron Wyden (D-Ore.) and Maria Cantwell (D-Wash.) today wrote a letter to FCC Chairman Ajit Pai, asking him to avoid issuing licenses to winning bidders "until the FCC approves the passive band protection limits that the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) determine are necessary to protect critical satellite-based measurements of atmospheric water vapor needed to forecast the weather." The internal Navy memo on the topic, written on March 27 by U.S. Naval Observatory Superintendent Marc Eckardt, was made public by Wyden and Cantwell today. The Navy memo cited NOAA and NASA studies on interference from 24GHz spectrum, which is intended for mobile use and is adjacent to spectrum used for weather operations. "[A]s such, it is expected that interference will result in a partial-to-complete loss of remotely sensed water-vapor measurements," the Navy memo said. "It is also expected that impacts will be concentrated in urban areas of the United States first." The problem could affect Navy and Marine Corps forecasts of tropical cyclones as well as rain, ice, and snow, the memo said. The Navy memo recommends asking the FCC to "tighten out-of-band interference by reducing bleed-over limits to -57dB." The memo also says the Navy should "work with NOAA and NASA to continually assess and quantify actual impacts" and develop mitigations including "limited use of other channels, substitution of lesser-fidelity parameters, and the development of new techniques and algorithms through new research and development."Read more of this story at Slashdot. Click here to read full news..