POISSY (78) 07.09.2013

On Saturday 7 September 2013, between 13:10 and 13:40, a motorist traveling northeast toward Poissy (78) saw a long white cylinder at 15° elevation. It moved away in a straight line and disappeared toward Poissy. No other account was collected. Météociel recorded a southwest wind at Toussus-le-Noble, described in the source as southeast of Poissy, and a west wind at Pontoise, suggesting southwest-to-west winds at Poissy. A cylindrical windborne balloon fits the observation. Its shape suggests a thermal or solar balloon released from Orgeval, Feucherolles or farther away, since these balloons can fly for hours. Association fairs were held in both towns that day. Such balloons are often dark gray or transparent, and white could result from sunlight reflecting off them, with the Sun described as nearly overhead. GEIPAN classifies this low-strangeness sighting B: probable balloon. It did not consider a field investigation justified, as locating such a source in an urban area would be too uncertain.