Much to my surprise (as I had not see it do that before), it flared twice. At about 17:54:11 UTC (25 Jan) the first brief but bright flare, to mag. -1 occurred. Unfortunately, I was re-aiming the camera at that moment. The satellite flared again however, to mag. +0.5, at 17:54:37.0 UTC, and this time the camera was photographing. Below is the resulting image, and the brightness curve derived from it. It are actually two flares, as a slightly fainter flare at 17:54:35.7 preceeds the main flare.
Later that evening, during a second brief period of clear sky, I imaged Mentor 2 (98-029A) in Orion.
I also observed on the 20th (The FIA Radar 1 again, and Milstar 5r (02 001B)) and the 22nd (USA 200, 08-010A), during short clear spells.