permits plotting of the wind vectors directly from Field Artillery or Air
Weather Service upper air wind data. The plotting scale is constructed of
clear plastic and consists of two main parts.
The Fallout Prediction
Plotting Scale, ML-556/UM, is requisitioned through supply channels using
a. An azimuth dial with an inner scale in degrees and an outer scale in
hundreds of mils.
b. A series of 11 slots representing various wind layers (altitude
zones) with wind speeds graduated in knots along each slot for use with
three different map scales signified by three colors: green, red, and black.
The weight factors have been used to convert wind speeds from knots
(nautical miles per hour) to vector lengths in kilometers.
Prepare a Wind
Most NBC Centers within the U.S. Army will have access to Field Artillery
meteorological upper air wind data on a regular basis. The plotting scale
usually is available for preparation of wind vector plots. Because of the
speed and accuracy of preparing a wind vector plot using the plotting scale,
this is normally the preferred method.
Plotting Air Weather Service (AWS) Upper Air Wind Data.
Plotting AWS upper air wind data with the plotting scale is accomplished in
much the same manner as for Field Artillery upper air wind data, except that
different slots are used for the wind layers; for heights above 45,000 feet,
the vector is drawn to a point on the slot scale equal to one half of the
reported wind speed.
Table 2-5 provides weighting factors and plotting
scale data to be used with AWS wind data.
plot, using the plotting scale and U.S. Army Field Artillery upper air wind
Assume that the field artillery upper air wind data, Table 2-1 on
page 2-4, have been received by the NBCC.
plotting scale, prepare the fallout wind vector plot.
To convert mils to degrees, divide mils by 17.8.