METEOROW
PART FIVE
Yoke D-
1. Introduction
On the days followingX-F@ Day, the weather situationwas characterized by a slow change from tha pNv~U%
southe-terly flow of the
equatorial air in the lower atmospheric layers to a more normal
easterly h
northeasterlyflow. The trade winds blew with moderate
velocities of 15 to 18 knots but the anti-trades above 30,000 feet
occasionallyreached speeds of ~ knots. There was also a high
frequency of occurrence of west-northwestwinds in the anti-trades
at levels between 20,000 d
30,000 feet, a not unusual condition
for this season in the Marshalls. Although the weather conditions
for the days precedi~ Yoke Daywe~
normal ad
typical, the existence
of mat-northwest winds in the mti-trades would cause a possible
hazardous radioactivefall-out if firing were attempted tier these
Prior to Yoke minus th~,
wirricorr,titions.
thre was eleven
impossiblefiring daya because of wind conditions, these being April
19 through 29th. There had to be a definite change in the winds
betoxw the Yoke Day detonation could take place.
2.
Operations
Yoke Day was scheduled for 30 April with H Hour at 0609M. On
the 26th of April, the low, nmdium and high cloudiness increased
rapidly ad frequent moderate showers covered the entire Eniwetok
SECTION XII
44