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FM 34-81: Weather Support for Army Operations



The wide dispersion of units on the modern battlefield and the complexity of current and projected weapon systems have increased the requirements for weather information. Weather varies with both time and location--one valley is fogged in while an adjacent one is completely clear; 6 hours later, the situation can be reversed. Weather data must be constantly reappraised and updated to retain its usefulness. The FALOP is designed to obtain timely weather observations from the forward areas of the battlefield.

The FALOP is a G2-directed program under which maneuver brigade and ACR and battalion and squadron S2 personnel collect forward area weather information and transmit this data to the USAF WETM.

The Army uses these observations to support Army weapon systems, NBC planning and operations, terrain analysis, and IPB.

The WETM uses this information in preparing tailored tactical weather support products. Collected data include--

  • Measurements of temperature.
  • Wind direction and speed.
  • Cloud information.
  • Visibility estimate.
  • Type of precipitation and intensity.
  • Road, ground, and water conditions.

A FALOP observation is taken using a belt weather kit. It is then encoded into a 13-digit message. Each digit is represented in the final message by a letter or number representing the observed weather element. The FALOP voice message template is transmitted as a series of numbers and letters to higher echelons. The G2 specifies the frequency that FALOP observations must be taken based on METT-T. Normally, the G2 requires observations three times per day at sunrise, noon, and sunset. Additional observations may be required, based on mission needs or a fast-changing weather situation.

The FALOP voice message template consists of three parts:

  • Universal transverse mercator (UTM) grid location represented by 8 digits, 2 letters, and 6 numbers.
  • A date-time group (DTG) including day of the month and time of observation in Greenwich Mean Time (GMT) (Zulu). This is represented by 6 numbers.
  • An encoded weather observation. This consists of 13 encoded weather elements represented by numbers and letters.

The following tables and figures are used to prepare a FALOP report.

Tables A-1 through A-13 describe the FALOP codes and the 13 weather elements in the report. The encircled code digits correspond to the example in Figure A-1. The free text to support the FALOP report in Figure A-1 would read:

FALOP weather observation at grid location NB131825, taken at time 051200. It is overcast with hills seen through the clouds. The wind is from the southeast at 10 to 19 miles per hour (mph). Visibility is 2 to 4 km. Currently there is a light drizzle. The height of the observation is 500 m. The roads are wet with the ground having pools of water on the surface. Current river level is high, but not overflowing. The temperature is 12 C. No surface pressure was taken. Visibility is lowest in the SW. Higher terrain is obscured. Thunderstorms moving toward NE quadrant.

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