Manop Header with transmit time
Title and Valid Time
IX AdddFFFa BdddFFFa CdddFFFa DdddFFFa
FXEU21 EDZX 110915Z
EFFECTIVE DOWNWIND MESSAGE ZULU 110600Z 11 JAN 1000Z - 1600Z
EdddFFFa FdddFFFa GdddFFFa
Header
V a l i d T i m e
1st area
2nd area
etc.
NL A004 - - - - B133009/ C134014/ D135016/ E136020/ F1530156 C1520206
NM A010010/ B142012/ C145017/ D150020/ E150021/ F160019/ G160022/
Figure 5-1.—Format and example of a typical Effective Downwind Forecast (EDF).
fallout will be carried. After a nuclear device has been
detonated, and the actual weapon yield has been
determined. a nuclear effective downwind message
(EDM) provides specific predicted fallout areas for that
weapon. Both types of products are discussed in the
ATP-45. The following text discusses how to interpret
the various types of nuclear effective downwind
forecast products and the actual NBC 3 NUC reports.
NUCLEAR EFFECTIVE DOWNWIND
FORECAST
Many computerized forecast centers routinely
compose and transmit messages containing forecasts of
effective nuclear fallout wind directions and speeds.
When produced specifically for ground forces, the
messages are entitled Effective Downwind Message. or
Effective Downwind Forecast. When produced
specifically for Naval Forces, the messages are entitled
Naval Effective Downwind Message or Naval Effective
Downwind Forecasts. For simplicity. we will call these
products effective downwind forecasts (EDF). The
primary difference between ground-force messages and
naval messages is that naval messages give locations in
geographical coordinates. distances in nautical miles.
and wind speed in knots, while the messages for ground
forces have locations in UTM coordinates, distances in
meters or kilometers, and wind speeds in kilometers per
hour. Figure 5-1 shows the standard EDF message
format, and a typical EDF message.
In the message heading (fig. 5-1), the term ZULU
precedes the date-time of the wind observation on
which the forecast is based. In the format. the IX is the
area indicator used to identify the two-letter UTM
coordinate 100,000 meter-square grid, such as NL or
NM. The letters A through G identify the yield groups.
as shown in table 5-1. For each weapon-yield group. the
ddd is the effective-downwind direction (direction
Table 5-1.—Yield Groups Used in Effective Downwind Forecasts
Y i e l d G R O U P
G = GOLF
D = DELTA
E = ECHO
F = FOXTROT
RANGE
A = ALPHA
2 kilotons (KT) or less
B = BRAVO
more than 2 kilotons (KT) to 5 kilotons (KT)
C = CHARLIE
more than 5 kilotons (KT) to 30 kilotons (KT)
more than 30 kilotons (KT) to 100 kilotons (KT)
more than 100 kilotons (KT) to 300 kilotons (KT)
more than 300 kilotons (KT) to 1 megaton (MT)
more than 1 megaton (MT) to 3 megatons (MT)
5-2
