Project Blue Horizons is a group which is attempting an unmanned Trans-Atlantic balloon flight from the United States to Europe. They are estimating a launch around 0:00-3:00 UTC on the 30th of April and they are supposed to be sending telemetry on 40m. You can follow their updates on twitter.

This will be PBH-10, you can also see the flight of their previous attempt, PBH-9 on this Google Map PBH-9 set a duration record, spending over 49 hours aloft.