Meteorological Impact Statements

Meteorological Impact Statements provide strategic weather guidance that helps pilots anticipate large-scale operational challenges. Understanding meteorological impact statements helps pilots see how significant weather systems may affect traffic flow, routing, and airspace usage across wide regions.

Meteorological Impact Statements

Introduction to Meteorological Impact Statements

  • The Meteorological Impact Statements (MIS) is a nontechnical plain language product intended primarily for FAA traffic managers and those involved in planning aircraft routing. MISs are issued by NWS Center Weather Service Units (CWSU)
Meteorological Impact Statements

Meteorological Impact Statements Key Highlights

  • Meteorological Impact Statements (MIS) provide aviation weather forecasters and air traffic managers with strategic weather impact information affecting air traffic operations.
  • MIS products summarize expected weather hazards such as thunderstorms, turbulence, icing, low ceilings, reduced visibility, and convective activity.
  • Air Route Traffic Control Centers and aviation weather units use MIS information to support traffic flow management and operational planning.
  • Meteorological Impact Statements help identify weather conditions likely to affect routing, delays, airport capacity, and airspace utilization.
  • MIS products are generally focused on large-scale operational impacts rather than tactical pilot weather decision-making.
  • Forecasters develop MIS guidance using weather models, radar imagery, satellite data, pilot reports, and forecast products.
  • Convective weather, winter storms, volcanic ash, and widespread IFR conditions commonly generate significant MIS operational concerns.
  • Pilots may encounter MIS-related weather impacts through reroutes, delays, ground stops, or airspace flow restrictions.
  • Weather conditions described in MIS products can evolve rapidly and should be monitored with current aviation weather information.
  • Understanding Meteorological Impact Statements improves weather awareness, operational planning knowledge, and overall aviation safety.
Meteorological Impact Statements

Issuance & Validity

  • The MIS valid times are determined according to local policy
  • The MIS is limited to not exceed a 48-hour valid period
Meteorological Impact Statements

Information

  • The MIS is a brief nontechnical discussion of meteorological events causing or expecting to cause the disruption of the safe flow of air traffic. This is followed by specifics such as what is causing the disruption, area, altitudes, and movement. The MIS may refer to an online graphic, especially for complex situations, using a specific Web address and provide a brief description of the weather that is included in the text MIS. MIS products are numbered sequentially beginning at midnight local time each day. The MIS is disseminated and stored as a "replaceable product." If the expiration time of the MIS is after the closing time of the CWSU, then a "No updates available after ddhhmmZ" message should be included at the end of the MIS text, where dd = date, hh = hour, mm = minutes.
Meteorological Impact Statements

Meteorological Impact Statement Formatting

  • The MIS format consists of a communication header line, the words "FOR ATC PLANNING PURPOSES ONLY," and the text

  • MIR Header:

    • zzz MIS ii Valid ddtttt-ddtttt
    • Zzz is the ARTCC identification (i.e. ZJX), MIS is the product type, ii is the 2-digit sequential issuance number, and ddtttt is the valid beginning and ending date/time UTC

  • MIR Disclaimer:

    • The line immediately below the header line reads "FOR ATC PLANNING PURPOSES ONLY"

  • MIR Content:

    • The maximum length of the MIS is four lines. The MIS is nontechnical in nature to convey expected weather and impacts in the clearest and simplest manner possible to the user. References to a graphical product on the local CWSU website or https://www.aviationweather.gov may be included
Meteorological Impact Statements

Meteorological Impact Statements Conclusion

Meteorological Impact Statements

Meteorological Impact Statements References