15 July 195% MEMOLLNDUM PO? TECOND SUBJECT: Hour: 1. Radsafe Pactors Considered at the Command Briefings Hodographs and issultant wind diagrams; forecast winds for H « a. For each briefing heolographe were constructed for all pertinent cbservoc wincs since the previous briefing im-order to show devel- opment of the wind pattern. in hodograph forn, 2. Forecast winds for H Hour were also prosented Surfece DEX 3 to H plus 6 hours, limited bearings, racial iis- tanees, hot area, coal aree and lung range fall-out plot. a. Using the hodograph for forecast H Hour winds, the surface NeDEX was incicatod by drawing boaring lines from ground sero enclosing all wini vectors from surface to 60,000 foct and all winds betwecn 60,000 amd 90,000 fect. &@ fifteen degree scctor was adied to each limiting bear= ing linc. « representative, or average, redial listence wes incicated for a six-hour period of fall. ~i hot and a cool area wore iniicatac, the hot area boing the sector from surfaco to 60,000 feet; tho cool area being that arca inclosed by bearing lines 60,000 to 90,000 feet. The long-range (2% hour) falleout slot (draw over a chart of native atolls and popula~ tions) was resented in ecnjunetion with the surface radex. 3. Sevonty-twoencur air particle trajectory forecast: a. The air particle trajcctory forecest (constructed by the Weather Contral) was used to approximate sampling arcas, tc evaluaze contaminations cn air routes and to exterxi tho surface UE beyond H plus § hours, be oir DDB: Since the air UDEX <ces act normally affect the snot decision, it was not cirectly used at briefing, unloss requested. iUDEX was plotted and kept displayed in the UDS.FE OFFICE. This 5.° Orklocies: a. SIKIKZ: cast hodograph for the @ outlook for BIKINI was <ctermined from the f.re- wRot atoll. b. ENTVETOK: ‘The outlook for ENTAXETOK was <ctorminel from tho forecast hodograph for the shot atoll. Inclosure 7