The FAA has posted a Flight Advisory warning of GPS interference testing over large radiuses around Bremerton, Washington from Oct 16 through Nov 18, 2017. See this PDF file for more details.
https://www.faasafety.gov/files/notices/2017/Oct/FFC_17-09_GPS_Flight_Advisory.pdf
https://www.faasafety.gov/files/notices/2017/Oct/FFC_17-09_GPS_Flight_Advisory.pdf