SHEBA ship was on the west side of a large high pressure system in the Beaufort Sea. Winds were southerly. Radar, lidar and satellite data all show no clouds above a dense boundary layer fog. The ship reported 0.5 mile visibility at 00 UT in the fog. The sounding humidity profile shows a very rapid drying at 0.5 km above the saturated surface layer.
The trajectories to SHEBA ship show air at all levels coming from the south. The surface to 1.0 km air originated along Alaska's northern coast flowing west before curving north to the ship. From 1.5 to 9.0 km, all trajectories show the air came from along Alaska's southeastern coast on the Pacific Ocean.
