Day 17 of the Perdigao IOP. The weather was only a bit cooler, with more cumulus development than in recent days. A cold front passed in the late afternoon, increasing wind gusts and cooling things off.
Four sondes launched at 00 UTC, 06 UTC, 12 UTC & 18 UTC. The 12 and 18 UTC sondes had weak signals above 300 hPa and lost signal completely above ~250 hPa.