-“ne order of twelve to eighteen hours fo> significant wz tO occur. The variation in tine arises froz consideraof Wind shear, with more diffuse and less sigzificast ine :68 at agiven time associated with large anguler asd _, bear. For this reason, it was required thst actuel wisd .--ratd ons and forecasts imnsdiately before shot tine aad wzout shot day be continuously considered in their reletioan “zg forecast conditions for the first twenty-foar hours -3e shot e - PRE-SHOT BRIEFINGS: -e-shot command briefings: The following were presented et - a. - Weather Weather conditions during the five days prior to ' adicated a favorable trend for BRAVO day witheasterly - elow 15,000 feet and winds of a southerly ca=zponeat .. The situation presented at E-6 hours for the sudsequest + period (18 hours after shot time) was satisfactory. The be RadSafe (1) Resultant wind diagrams including latest . ~~“ winds and forecast winds for H Hour and the 72 hour . | cajectories, which gave a fellout pattern in a narrow "* the east northeast and a wids (140°) sector to the “ch very slow resultant winds. (See Figure 1). es ve GE + - > period to begin 18 hours after shot time was predicted ~ an unfavorable trend as northwest winds were forecast # 10,000 to 20,000 foot levels. .. (2) Surface radex, EH to H plus 6 hours. (See dn cee “ibe (S$) Outlooks for: (a) Bikini: Unfavorable; Eniwetok: Favorable; favorable, end the native populated atolls in soutbeast from ground zero favorable, since resultant winds in “tion of these arees were considered too slow to sove at fallout to the atolls involved. (b) Task Force fleet: Favoradle, provided ‘34 out at least 50 ciles. i on or 2ee ih ay wee ne. Fee EEEr coGinnchaircovahigde2scalyAOMEIIUD. 20%, e. Acritical problem fa predicting fall-out ise a forecasting the stability or lack of stability of tbe -* vattern after snot time. Since radioactive particle tree ~~ | determined vrinarily by the winds et each level, it is * wd that winds must be from favorable directions o> vasye* (shin the outer limits on fevorable directions during the * sf fallout. The criticel fallout period was cossidered to