[en] This report describes the Weather Service Nuclear Support Office (WSNSO) analyses of the radiological and meteorological data collected for the NANCY nuclear test of Operation UPSHOT-KNOTHOLE. Inconsistencies in the radiological data and their resolution are discussed. The methods of normalizing the radiological data to a standard time, of converting aerial radiological data to equivalent ground-level values, and of estimating fallout arrival times are presented. The meteorological situation on the event day and a few days following is described. A comparison of the WSNSO fallout analysis with an analysis performed during the 1950's is presented. The radiological data used to derive the WSNSO fallout pattern are tabulated in an appendix