le Samary of weather immediately price te B-Day: There had bees cane on the evening siderable etretecumigs and seme shower activity near Bniwetok ns had bees broken pefores. For the ten days the te owerdast: B-Day cirrus conditio Very persistent essterly winds hed pre- vailed during the precedingweels except for a short interval around 21 March. 2e The Weather Forecasts 3/@ cumulus, scattered patches stratocumius, 7/@ cirrus,, scattered showerte i Observed weather: no showers at shot sites 2/8 cumulus, no stratocumilus, 3/6 cirrus, be Commente on weathers Wilson 1 (reconnaissance aircraft nesr shot site) reported 6/6 te 7/@ cirrus from 01591 to 0350M, At 0405" the cir rus decreased to 4/8 and then remained 3/6 or lese coverage witil the device — was detonated. Showers were reported by OCA at LOLGN, 16 niles of Eniwetols and by aircraft 60 miles west of Bikin4 at 1133 and 11CM. 3e The Wind Forecast: OBSERVED HEGHE gmm—itséB ot Oss 5 8-32 as 70M LAY Son ed LM ESE/15-25 50M 40M 35M 30M ) Lav ESE/15-25 ESE/15=25 ESE/15-25 tC‘= ESE/20 Lav TE/15-25 ae ESB/15-25 200/14 ESE/15-25 1860/1, 2/10=20 110/10 ESB/15-25 B88B/15-25 10M BR/15-25 maRsi0-20 LM 2M BME/15-25 ENB/15-25 aM Qt SFC ESE/15-30 ENE/15-25 EME/15-25 ENE/15-25 s. 180/fll ESE/L5-25 ESE/15-25 ESE/15=30 HNE/10-20 =ENB/10=-20 ENE/10-20 ENE/10-20 Ele 100/45 £8 120 Hele 110 (pour) wns As 200/23 200/05 ooo eas Lav eas, tay Lav 080/28 ESE/15-25 230/16 ESE/15-25 200/15 24, 20M 1” He2hy ofA ns 130A5 / 180/18 200/23 19010 leofl2 180/09 U,0/l0 150/10 160/15 0/15 130/25 130/20 110/20 100/25 200/ose 180/12 150/10 200/36 220/08 130/20 100/25 170/08 100/20 «120/l2 150/. 19/1. 180/08 080/15 (C905 080/10 —070/20-——090/20—070/12 (OF/16 60/18 «OGL 070/1L «20/7 110/20 «=«:120/20~Ss«:100/10 o90/lo 080/10 «=—s-s«aucolo0.-s«ccgefoa«s120/10~Ss:170/07 100/10 o@o/oe cac/os 040/05 «070/18 «OBS 070/12 OFDAL2_~—s«0//10 Coumentea on Winds: (1) we Bikini winds were observed by gun laying radar equip- ment sboard the USS CURTISS... This ship was approximately 30 miles south of ground zero. 36% of the forecast wind direction were within 10 degrees of the observed, and 57% were within 20 degrees. With two exceptions, those that deviated more than 20 degrees had speeds of less than 9 knots. Thetwo exceptions were at the 55,000 and 60,000-foot levels immediately telow and above the tropopause. Incl 1 " ,; IelO.ee.