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)

Issuance & Validity:

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


  • 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 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 may be included