Top row: SOHO/MDI images acquired at a): 16:03 UT on 27 Feb.; b): at 01:35 UT on 28 Feb.; c): at 16:03 UT on 28 Feb. The blue and green contours indicate the negative and positive magnetic field at  ± 200 (solid line), 1000 G (dashed line). Bottom row: TRACE 171 Å images acquired at d): 16:03 UT on 27 Feb.; e): 00:07 UT on 28 Feb.; f): 16:03 UT on 28 Feb. The images have a field of view of 192 × 115 Mm². In this and in the following images North is at the top, West is at the right.