UAVSonde for NearSys Station, 16 December 2018

The UAVSonde was launched at 13:30 MST today. The visibility is at least 50 miles. A cloud bank or fog is visible to the east.

At SFC,
Temperature: 41.7 deg
Relative Humidity: 60.9%

At FL4,
Temperature: 43.6 deg
Relative Humidity: 42.6%

It's not windy at the surface, but the tilt in the pictures indicates it's windy aloft. That explains the sound of the props I heard on the ground.

East

North

South

West