text: Denied, Degraded and Disrupted Operations
  overcome initial bore resistance, the projectile begins its forward motion. Table E in the tabular firing tables
  lists the magnitude of change in muzzle velocity resulting from a propellant temperature that is greater or
  less than standard. Appropriate corrections can be extracted from that table. Propellant temperature should
  be determined from ready ammunition on a periodic basis, particularly if there has been a change in the air
  temperature. For more information on accurate weapon and ammunition data see TC 3-09.81.
  ACCURATE METEOROLOGICAL INFORMATION
  C-51. With today's emphasis on FFE and trends toward longer distances, accurate MET corrections for
  artillery fires are crucial. Atmospheric conditions that include wind direction, wind speed, air temperature
  and air density along the trajectory of a projectile or rocket directly affect its accuracy and may cause the
  projectile or rocket to miss the desired point of impact.
  C-52. The Computer Meteorological Data-Profiler (CMD-P) (AN/GMK-2) is a weather measurement system
  developed to provide MET data to support artillery and TA units. CMD-P interfaces with the AFATDS via
  local area network connection and is operated by the AFATDS operator. The BN AFATDS transmits MET
  data to the subordinate FA units. Every effort must be made to obtain the most accurate met corrections
  available. The website that provides the information to the Profiler is:
  * https://www.kc.army.mil/armywx/
  C-53. Meeting the MET requirement in D3SOE conditions can be resolved by a number of techniques if
  CMD-P is unavailable:
  * MET can be received from other units not affected by the D3SOE.
  * MET message via voice.
  * Conduct a registration if conditions are permissive.
  VERIFYING MET MESSAGES
  C-54. When the FDC receives a met message, it should be checked to ensure that it is valid. Any peculiarities
  in the message should be noted. If the timeliness or validity of a met message is doubted, that should be
  questioned and referred to the BN FDC. While most messages are transmitted digitally, verbal transmission
  of met messages may cause copying errors, particularly if the message is copied down on something other
  than the standard (computer) met form. FDC personnel should use the procedures outlined in TC 3-09.81 to
  verify MET messages.
  C-55. Check the computer met message heading as follows:
  * Check message type, octant, and location entries for correctness, ensuring validity for the AO. The
  location of the met message should be the midpoint between the gun and target areas.
  * Check date-time entries to ensure they are current (date-time entries are expressed in Greenwich
  Mean Time).
  * Check for possible line to line errors in the computer met message as follows:
  * Question drastic wind direction changes (1,000 mils or greater) or sudden reverses of wind
  direction from line to line, particularly if wind speeds are more than 10 knots. Direction changes
  greater than 1,000 mils are common when wind speeds are 10 knots or less.
  * Question severe increases or decreases (10 knots or greater) in wind speed from line to line.
  * Temperature accuracy is hard to evaluate because of natural erratic changes. Question a severe
  increase or decrease (over 20°K) in temperature from line to line.
  * Check for increases in pressure. Pressure should decrease smoothly from line to line. Pressure will
  never increase with height.
  C-56. Computer met messages that do not reflect the correct location or current date-time are invalid and do
  not accurately represent the current weather conditions for the AO. Invalid met messages should be brought
  to the attention of the BN FDC for the processing of a new, valid met message.
  C-57. The line-to-line checks reflect basic weather behavior patterns. Regional and topographical
  characteristics can often produce unusual variances in wind direction and speed. The CMD-P numerical
  model does not necessarily produce a 100% accurate forecast, but it does not produce non-physical results.