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FM 34-81: Weather Support for Army Operations

CHAPTER 5

WEATHER SUPPORT COMMUNICATIONS

The ability to provide accurate weather support depends directly on a specialized and highly responsive communications system. The responsiveness of support to the Army is directly related to the quality of communications support provided. The vital link between weather support and communications is shown in the following examples:

  • The extreme perishability of weather data requires responsive communications, especially during periods of approaching weather disturbances.
  • Round-the-clock weather observations and forecasting requirements continue regardless of the nature of tactical operations or force configurations.
  • Numerous elements and activities at various echelons require specialized weather forecasts, summaries, and climatological reports.

For support, WETM's rely on--

  • Centralized weather forecasts and products.
  • Other WETMs.
  • ARTYMET section observations.
  • FALOP observations.
  • Indigenous weather data.

Because of this requirement for substantial communications support, they must have the availability of communication circuits to receive all necessary information to provide necessary weather products and services. WETMs also--

  • Intercept military and World Meteorological Organization (WMO) weather broadcasts and meteorological satellite imagery.
  • Communicate with other weather units within the theater of operations.

COMMUNICATIONS FACTORS

The following factors must be considered when planning or providing communications support for tactical weather elements:

  • Rapid transmission of a high volume of data.
  • Interfacing between the Army and other service communication circuits and ADP systems.
  • Compatibility with supported unit's communication equipment.
  • Signal security (SIGSEC).
  • Redundant communications to reduce impact of radio electronic combat (REC) operations.
  • Automatic exchange of data base information between critical elements such as the AFGWC, FUs, and TFUs.

COMMUNICATIONS RESPONSIBILITIES

Communications for weather support is a joint Army and Air Force responsibility requiring continuous cooperation to ensure compatibility of communications systems. The Air Force Communication Command (AFCC) provides long-line communications facilities for inter-theater exchange of weather data. In addition, AFCC installs, operates, and maintains complete communication systems down to the designated DCS interface point.

The interface between DCS and Army tactical systems is designated by the commander of the unified or specified command or JTF for oversea operations. The Army is responsible for communications below this interface point.

AIR FORCE COMMUNICATIONS

The capability of AWS to provide effective support to tactical Army commands depends on a specialized, complex, and responsive communications system. Normally, AWS uses automated communication displays and machine processing systems to collect, assemble, analyze, display, and disseminate weather information to commanders and their supporting staffs. Because of the amount of data processed, automated systems are required for accurate forecasts, timely observations, and climatic studies.

AFGWC is the focal point for worldwide weather analysis and forecasting. AFGWC prepares global and regional weather analyses and forecasts continuously. In addition, AFGWC forms contingency response teams to provide tailored products for individual theaters. USAFETAC provides climatological data and studies. Products produced are transmitted by the Air Force to the designated DCS interface point.

Normally, the tactical Air Force headquarters and the highest Army echelon will be designated the AFFOR and ARFOR headquarters, respectively. The ARFOR headquarters also is known as the EAC. For large-scale and theaterwide conflicts, the communications structure within the theater down to the TACC and the highest ARFOR headquarters will be tailored to meet requirements.

The TACC normally is collocated with the AFFOR headquarters. When combined commands are created, the standard JTF organization may not apply and additional LOC are required. Because requirements will differ with the type and scope of each operation, and the forces involved, weather communications for all operations are not addressed in this manual. WETMs will be located and tailored to support the command structure regardless of the theater or operation. The command structure and WETM requirements will drive communication requirements.

Disruption of communications during combat operations must be considered and plans formulated to provide mission-essential products. When the FU or TFU cannot perform its mission, the next lower AFFOR WETM will produce weather data for lower echelons and ensure products are relayed, as necessary, to the ARFOR headquarters WETM (EAC WETM).

The regional broadcast system (RBS) is a series of HF broadcast stations presently being developed by AFCC to provide limited support for AWS weather data requirements. These HF transmission sites will broadcast AFGWC-generated products and data continuously. For many world contingency areas, this broadcast initially will be the only source of AFGWC information to the deployed WETMs. When the theater communications system is established, the RBS becomes a critical backup source of weather information in the event that communication links cannot be maintained with higher echelon weather units.

ARMY COMMUNICATIONS

The SWOs at corps and EACs must specify weather communication requirements in an appropriate annex of the supported Army plan. This is to ensure adequate communications are provided to all tactical WETMs. SWOs at all subordinate units also must ensure communication requirements are in their supported unit's plan The Army's communications responsibilities start at the DCS theater communications interface point.

The Army --

  • Provides installation, operation, and maintenance of Army standard communications systems required by Air Force weather units below the DCS interface point.
  • Is responsible for tactical or transportable interface equipment that can meet the DCS circuit factors and interface point criteria.

If communications at the DCS interface point become inoperable, the next lower Air Force echelon (or Army echelon if necessary) will become the new DCS interface point.

The ARFOR headquarters WETM located at the EAC, or possibly at the corps (in a small contingency), receives information from the TFU or JTF TFU and refines it to meet the tactical needs of the subordinate commands. The information (as received from the TFU and refined by the EAC WETM) is transmitted to all corps, divisions, separate brigades, aviation brigades, ACRs, and SOF WETMs for their use in supporting tactical operations.

Within each supported Army command, weather information products are disseminated to Army users through a number of Army communication channels. The primary means of dissemination is through common users' communication nets.

Army ATC requires real-time weather information from the WETM. The ATC operates a network of flight operations centers (FOCs) to control aircraft operating within the corps airspace and to provide weather information to Army, aircrews on request. FOC communications with the WETM are installed by aviation units and coordinated with the SWO. A flight coordination center (FCC) extends the communications capability of each FOC. This serves as the link between the SWO, the FOC, and the terminal traffic control facilities at tactical airfields.

While weather data is being processed and disseminated down the tactical chain, new data is being collected, processed, and disseminated up the communication chain to higher elements for inclusion in analysis and forecast preparation. Weather products prepared by the TFU and at lower WETMs depend on a reliable and steady upward and downward exchange of weather data from both Air Force and Army tactical units.

The essential element for tactical weather support is a high speed, timely communications system. The system must--

  • Be reliable, secure, and easy to maintain.
  • Support highly mobile operations.
  • Interface with the AFCC, Joint Communications Service Element (JCSE), and the Army Tactical Command and Control Systems (ATCCS).

Currently, two systems provide this capability: HF RATT and the Army tactical area communications system (ATACS) network.

HF RATT

The HF RATT--

  • Establishes initial communications and is the primary means of communication in a fluid tactical situation.
  • Provides initial communications between the main CP and the jump or tactical CP.
  • Is used for initial communications between the corps and the division until multichannel ATACS links can be established.
  • Can be used to receive meteorological data from the RBS.

Figure 5-1 shows WETM communication requirements.

ATACS (Multichannel)

Once operational, ATACS (or multichannel) becomes the primary means for exchanging weather information and for interfacing with the AFCC weather communications system. The ATACS carries alphanumerical products (teletype), graphic products (facsimile), and voice.

For division operations HF radio, very high frequency (VHF) and FM radio, and HF RATT maintain continuity of operations during CP moves. Additionally, FM radio provides service to airborne forward air controllers. FM radio is the primary communications link between the division CP WETM and their subordinate WETMs, and serves as the pilot to the forecaster communications link.

The critical echelon for Army weather communications is the echelon where the DCS interfaces with Army tactical communications. At this level, intra-Army ATACS communications must interface with AFCC weather communications systems from the FU and JTF TFU. The ARFOR headquarter (EAC) WETM uses HF RATT and facsimile to interface with the FU and TFU, AFFOR headquarters WETM, and supporting WETMs with subordinate Army commands. The ATACS teletype must be multipointed to permit adequate, rapid transmission of environmental information to and from the tactical AO.

Environmental messages are transmitted on a recurring basis or upon request. These messages are composed of raw data, analyzed data, forecasts, and special products. Because most environmental messages are perishable, rapid transmission is essential. During periods of unstable weather conditions, the normal data load can be expected to increase tremendously. Rapid receipt of weather data is most critical during these periods. Army communications circuits must be capable of handling the data load and should provide backup circuits in case of loss of primary circuits.

On a rapidly changing battlefield with multiple jumps of the TOC, communications provided for WETM support must be operative as soon as the TOC relocates to receive the large volume of data required to make reliable forecasts, and to update the battle staff.

Should contact be lost with the EAC WETM or it is destroyed, the next lower Air Force echelon will be required to interface with the FU or JTF TFU and Air Force communications circuits. Figure 5-2 shows weather support communications.

US Message Text Format

The messages identified below are considered viable instruments for transmitting data using JCS Publication 25 (formerly JINTACCS) and Army Command and Control System (ACCS) formats. Further description of these messages may be obtained from the tactical IEW Character-Oriented Message Catalog (which can be found in the G2 or S2 office) or JCS Publication 25.

The message format contains two messages that are designed to facilitate passing weather information in a tactical environment. The first message is for severe weather warnings (SVWXWARNs). This message is used to warn commanders of severe weather that could affect an AO. It is transmitted as required until the normal weather conditions prevail. The second message is for a weather forecast (WXFCST). This message provides the commander with a WXFCST for a point or area. Forecasts are updated at least every 6 hours.

There is a free text format which can be used for any bulletins (such as a corps SWO bulletin or a group of observations) that do not fit the two standard weather formats.

A FALOP weather observation message format is in Appendix A. This FALOP message is in the USMTF format as a voice message template.



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