BOULOGNE-BILLANCOURT (92) 29.09.2012

The title dates this Boulogne-Billancourt (92) case to 29 September 2012, but the French narrative gives 29 September 2009. At 15:00, a witness looking through a window saw a small flashing white luminous shape high in the sky. After 1 minute it stopped, then resumed its path without flashing. In a telephone follow-up, the witness said he was looking south and the object moved east; see the map. Ground weather records showed a northwesterly wind at 14:00 and northerly wind at 15:00, inconsistent with a low-altitude windborne object. Météo-France launches sounding balloons daily from Trappes around 12:00 UT, or 14:00 local time, 1 hour before this sighting. The record shows a weak northwesterly ground wind of 5 knots at 14:00, changing to a stronger westerly wind of 25 knots above 2, 800 m, then northwest again higher up. Easterly travel under the upper winds would fit a balloon around 1 hour after release. GEIPAN attributes the flashing to rotation of the balloon or reflectors. The case is classified as A: observation of a Météo-France sounding balloon launched from Trappes at 14:00.