{
  "$schema": "https://json-structure.org/meta/core/v0/#",
  "$id": "https://raw.githubusercontent.com/api-evangelist/aviationweather/refs/heads/main/json-structure/aviationweather-airsigmet-structure.json",
  "name": "AviationWeather Domestic SIGMET",
  "description": "Decoded domestic SIGMET as returned by GET /api/data/airsigmet?format=json.",
  "type": "object",
  "properties": {
    "airSigmetId": {
      "type": "int32",
      "description": "Internal AWC identifier."
    },
    "icaoId": {
      "type": "string",
      "description": "Issuing center ICAO (typically KKCI for AWC)."
    },
    "receiptTime": {
      "type": "string"
    },
    "validTimeFrom": {
      "type": "int32",
      "description": "UNIX epoch start."
    },
    "validTimeTo": {
      "type": "int32",
      "description": "UNIX epoch end."
    },
    "alphaChar": {
      "type": [
        "string",
        "null"
      ],
      "description": "Alpha designator (A-Z) for the SIGMET series."
    },
    "hazard": {
      "type": "string",
      "enum": [
        "CONV",
        "TURB",
        "ICE",
        "IFR",
        "MTN_OBSC",
        "ASH",
        "TC",
        "DS",
        "SS"
      ],
      "description": "Hazard type."
    },
    "severity": {
      "type": [
        "string",
        "null"
      ],
      "description": "Severity (e.g. MOD, SEV)."
    },
    "rawAirSigmet": {
      "type": "string",
      "description": "Raw SIGMET text."
    },
    "altitudeHi1": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Top altitude (feet)."
    },
    "altitudeLow1": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Base altitude (feet)."
    },
    "movementDir": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Movement direction (degrees true)."
    },
    "movementSpd": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Movement speed (knots)."
    },
    "geometry": {
      "type": [
        "string",
        "null"
      ],
      "description": "Geometry as WKT polygon."
    }
  }
}