FEB i4 "94 TO 1°22988152 FROM KAMAN SCIENCES CORP 1dsid PAGE . 204/206 7 e. A critical problem in predicting fall-out involves forecasting the stability or lack of stability of the wind pattern after snot time. Since radioactive particle travel is determined primarily by the winds at each level, it is required that winds must be fram favorable directions or vary- ing within the outer limits on Savorable directions during the time of fallout. The criticel fallout period was considered to be on the order of twelve to eighteen hours for significant fallout to occur. The variation in time arises fram considerations of wind shear, with more diffuse and less significant intensities at a given time associated with large angular and speed shear. For this reason, it was required that actual wind observations and forecasts immediately before shot time and throughout shot day be continuously considered in their relation with the forecast conditions for the first twenty-four hours after the shot. §. PRE-SHOT BREEFINGS: the pre-shot command oriefings: a. The following were presented at Weather Weather conditions during the five days prior to BRAVO indicated a favorable trend for SRAVO day with easterly winds below 15,000 feet and winds of a southerly camponant above. The situation vresentsd at H~6 hours for the subsequent 2¢ hour period (18 hours after shot time) was satisfactory. The 24 hour period to begin 18 hours after shot time was predicted to give an unfavorable trend as northwest winds were forecast for the 10,000 to 20,000 foot levels. b. RedSafe (1) Resultant wind diagrams including latest observed winds and forecast winds for H Hour and the 72 hour cloud trajectories, which gave a fallout pattern in a narrow sector to the east northeast and a wide (140°) sector to the south with very slow resultant winds. o~o™. Figura 2). Ujel (See Figure 1). gm - (2) Surface radex, H to H plus 6 houdtws (See (3) Outlooks for: (a) Biking: ; Favorable, Unfavorable; Eniwetok: Favorable; and the native populated atolls in southeast quadrant from ground zero favorable, since resultant winds in the direction of thexe areas were considered too slow to move Significant fallout to the atolls involved. (>) Task Force fleet: Favorable, provided ships moved out at least 50 ciles. = x—>-