Let's assume the real raw temp was 80F. The 1-min obs are 5-min means of the raw 1-min averaged temps. So to drop 11F in a minute it would require a delta of 55F change. So in theory 15F of it is on the 95 to 80 side, but you'd have to be losing an ob of +40F on the other end (135F).
Am I missing something here?