aviation-weather-mcp-server

Previous value: -"Machine-readable failure mode. Declared by this tool: `station_not_found`: None of the requested IDs match any known station. `missing_search_criteria`: None of station_ids, bbox, or state was provided. `conflicting_location`: More than one of station_ids, bbox, or state was provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `invalid_state`: The state code is not one of the 50 US states or DC. `conflicting_limit`: limit was provided together with station_ids, where the caller has already named the set. `upstream_rejected`: The AWC station registry rejected the request as malformed rather than answering it. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `station_not_found`: None of the requested IDs match any known station, or the bbox or state search found none. `missing_search_criteria`: None of station_ids, bbox, or state was provided. `conflicting_location`: More than one of station_ids, bbox, or state was provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `invalid_state`: The state code is not one of the 50 US states or DC. `conflicting_limit`: limit was provided together with station_ids, where the caller has already named the set. `upstream_rejected`: The AWC station registry rejected the request as malformed rather than answering it. Other values are possible when a failure originates below the handler."

Previous value: -"Guidance for whichever disclosures fired: the lever that narrows a truncated draw, what a requested limit withheld, or the cause and fix for identifiers that resolved to nothing. The cap and the limit can both fire on one result, and the text keeps them apart; the reconciliation cannot join them, since only bbox and state reach the row cap or accept a limit, and only station_ids reconciles a request."New value: +"Guidance for whichever disclosures fired: the lever that narrows a truncated draw, what a requested limit withheld, that limit bounds the response without changing the area searched (on a bbox or state result of more than 130 stations from a call that set no limit), or the cause and fix for identifiers that resolved to nothing. The cap and either limit statement can fire on one result, and the text keeps them apart; the reconciliation cannot join them, since only bbox and state reach the row cap or take a limit, and only station_ids reconciles a request."

Added value: +{
+  "description": "Return only the stations whose flight category is one of these (e.g., [\"IFR\", \"LIFR\"] to find where conditions are poor). Applied in the tool after the draw is reduced to the latest observation per station and before limit, so it changes which stations come back, not what AWC draws or the upstream row cap. A station AWC could not rate (flight_category \"unknown\") never matches. Belongs to the bbox mode; supplying it alongside station_ids is rejected, since each named station already reports its own category. Optional.",
+  "items": {
+    "description": "A flight category: VFR, MVFR, IFR, or LIFR.",
+    "enum": [
+      "VFR",
+      "MVFR",
+      "IFR",
+      "LIFR"
+    ],
+    "type": "string"
+  },
+  "minItems": 1,
+  "type": "array"
+}

Previous value: -"Maximum stations to return, applied after the draw is reduced to the latest observation per station and ordered by station ID ascending — so the same query with the same limit returns the same stations. It bounds the response without changing the area searched, which a smaller bbox would. Distinct from the 400-row upstream cap: a limited result examined every station it counted and withheld some, while a capped one never drew the rest. Belongs to the bbox mode; supplying it alongside station_ids is rejected, since that mode already names the set. Omit to return every station in the box. Optional."New value: +"Maximum stations to return, applied after the draw is reduced to the latest observation per station, after any flight_category filter, and ordered by station ID ascending — so the same query with the same limit returns the same stations. It bounds the response without changing the area searched, which a smaller bbox would, and it keeps an alphabetical slice rather than a region or a condition. Distinct from the 400-row upstream cap: a limited result examined every station it counted and withheld some, while a capped one never drew the rest. Belongs to the bbox mode; supplying it alongside station_ids is rejected, since that mode already names the set. Omit to return every station in the box. Optional."

Previous value: -"Machine-readable failure mode. Declared by this tool: `no_stations_found`: No station returned METAR data — none of the requested IDs, or no station inside the bounding box. `missing_location`: Neither station_ids nor bbox was provided. `conflicting_location`: Both station_ids and bbox were provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `conflicting_limit`: limit was provided together with station_ids, where the caller has already named the set. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `no_stations_found`: No station returned METAR data — none of the requested IDs, or no station inside the bounding box. `missing_location`: Neither station_ids nor bbox was provided. `conflicting_location`: Both station_ids and bbox were provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `conflicting_limit`: limit was provided together with station_ids, where the caller has already named the set. `conflicting_flight_category`: flight_category was provided together with station_ids, where the caller has already named the set. Other values are possible when a failure originates below the handler."

Previous value: -[
-  "no_stations_found",
-  "missing_location",
-  "conflicting_location",
-  "invalid_bbox",
-  "conflicting_limit"
-]New value: +[
+  "no_stations_found",
+  "missing_location",
+  "conflicting_location",
+  "invalid_bbox",
+  "conflicting_limit",
+  "conflicting_flight_category"
+]

Previous value: -"Stations the draw held before the limit selected from them. Present only on a limited result. Where the result is also truncated this counts the capped draw and not the box — the observations the cap dropped were never examined, so no count can include them."New value: +"Stations the draw held before the limit selected from them — after the flight_category filter, where one was supplied. Present only on a limited result. Where the result is also truncated this counts the capped draw and not the box — the observations the cap dropped were never examined, so no count can include them."

Previous value: -"Guidance for whichever disclosures fired: the levers that narrow a truncated draw, what a requested limit withheld, or the station IDs that returned nothing. The cap and the limit can both fire on one result, and the text keeps them apart; the reconciliation cannot join them, since only bbox reaches the row cap or accepts a limit, and only station_ids reconciles a request."New value: +"Guidance for whichever disclosures fired, in this order: the levers that narrow a truncated draw; what the flight_category filter kept of the stations surveyed, or that it emptied the result; what a requested limit withheld; and — on a survey of more than 40 stations from a call that set no limit — that limit bounds the response but keeps an alphabetical slice, not a region. Or, on a station_ids lookup, the station IDs that returned nothing. The survey statements share one notice and the text keeps them apart; the reconciliation cannot join them, since only bbox reaches the row cap or takes a filter or a limit, and only station_ids reconciles a request."

Previous value: -"Stations in this result, counted after the reduction to one observation per station and after any limit. Present only on a bbox survey."New value: +"Stations in this result, counted after the reduction to one observation per station, after any flight_category filter, and after any limit. Present only on a bbox survey."

Added value: +{
+  "description": "Stations the survey reached — one per station, the latest observation of each — before the flight_category filter selected from them. Present only when a bbox survey supplied flight_category; the count after the filter is shown, or matched where a limit then withheld stations. Where the result is also truncated this counts the capped draw and not the box.",
+  "type": "number"
+}

Previous value: -"Guidance for whichever disclosures fired: the levers that narrow the query before the cap applies, and what a requested limit withheld. Both can fire on one result, and the text keeps them apart."New value: +"Guidance for whichever disclosures fired: the levers that narrow the query before the cap applies, what a requested limit withheld, and — on a result of more than 50 reports from a call that set no limit — that limit bounds the response without changing what is searched, keeping the most recent. The cap and either limit statement can fire on one result, and the text keeps them apart."

Previous value: -[
-  {
-    "items": {
-      "additionalProperties": false,
-      "description": "A cloud layer, whose base and top are each present only if reported.",
-      "properties": {
-        "base_ft": {
-          "description": "Cloud base altitude in feet MSL, or null if the pilot reported no base.",
-          "type": [
-            "number",
-            "null"
-          ]
-        },
-        "cover": {
-          "description": "Cloud cover code: FEW, SCT, BKN, OVC, SKC, or CLR. The field also carries the flight-condition markers VMC and IMC, which describe the flight environment rather than a cloud layer and arrive with no base or top.",
-          "type": "string"
-        },
-        "top_ft": {
-          "description": "Cloud top altitude in feet MSL, or null if the pilot reported no top.",
-          "type": [
-            "number",
-            "null"
-          ]
-        }
-      },
-      "required": [
-        "cover",
-        "base_ft",
-        "top_ft"
-      ],
-      "type": "object"
-    },
-    "type": "array"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "items": {
+      "additionalProperties": false,
+      "description": "A cloud layer, whose base and top are each present only if reported.",
+      "properties": {
+        "base_ft": {
+          "description": "Cloud base altitude in feet MSL, or null if the pilot reported no base.",
+          "type": [
+            "number",
+            "null"
+          ]
+        },
+        "cover": {
+          "description": "Cloud cover code: FEW, SCT, BKN, OVC, SKC, or CLR. SKC and CLR state a clear sky and never carry a base or top. The field also carries the flight-condition markers VMC and IMC, which describe the flight environment rather than a cloud layer and arrive with no base or top.",
+          "type": "string"
+        },
+        "top_ft": {
+          "description": "Cloud top altitude in feet MSL, or null if the pilot reported no top.",
+          "type": [
+            "number",
+            "null"
+          ]
+        }
+      },
+      "required": [
+        "cover",
+        "base_ft",
+        "top_ft"
+      ],
+      "type": "object"
+    },
+    "type": "array"
+  },
+  {
+    "type": "null"
+  }
+]

Removed value: -{
-  "description": "Weather remarks or additional conditions, or null if none.",
-  "type": [
-    "string",
-    "null"
-  ]
-}

Added value: +{
+  "description": "Outside air temperature in degrees Celsius at the report altitude, as AWC decoded it — the /TA group on a PIREP, the MS or PS temperature group on an AIREP. 0 is a real reading; null means the report carried none or gave it as unknown (/TA UNKN).",
+  "type": [
+    "number",
+    "null"
+  ]
+}

Added value: +{
+  "anyOf": [
+    {
+      "additionalProperties": false,
+      "properties": {
+        "decoded": {
+          "description": "Plain-English reading of each group, joined with \"; \" (e.g., \"heavy rain\", \"fog; light rain\"). A group the decoder does not recognize is carried through as its own raw token, so compare against raw when a reading still looks coded.",
+          "type": "string"
+        },
+        "raw": {
+          "description": "Weather groups exactly as encoded, space-delimited (e.g., \"+RA\", \"FG -RA\").",
+          "type": "string"
+        }
+      },
+      "required": [
+        "raw",
+        "decoded"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "Flight weather AWC decoded from the /WX group, or null when it decoded no weather phenomena from it. A flight visibility AWC can read (FV07SM, 10SM) lands in visibility_sm instead. /WX text AWC cannot decode is dropped or trimmed — CEILING 017 returns null and RA FL300 AOB returns RA alone — so raw_pirep is the only source for it. This is not the /RM remarks text, which AWC does not decode either — raw_pirep carries it."
+}

Added value: +{
+  "anyOf": [
+    {
+      "additionalProperties": false,
+      "properties": {
+        "direction_deg": {
+          "description": "Wind direction aloft in degrees, as reported and not converted. A PIREP /WV group is referenced to magnetic north (AIM TBL 7-1-18), unlike the true-north METAR and TAF winds, so apply the local magnetic variation before combining a PIREP's direction with a true track; an AIREP's reference is not stated here.",
+          "type": "number"
+        },
+        "speed_kt": {
+          "description": "Wind speed aloft in knots. 0 is a reported calm.",
+          "type": "number"
+        }
+      },
+      "required": [
+        "direction_deg",
+        "speed_kt"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "Wind aloft at the report altitude, as AWC decoded it — the /WV group on a PIREP, the direction/speed group (e.g., 291/035KT) on an AIREP. Null unless AWC decoded both direction and speed. AWC leaves some forms undecoded — a gust suffix (/WV 03020G30), a single-digit AIREP speed (252/9 KT), a variation (/WV +/- 5KT) — and those return null here, with raw_pirep as the only source."
+}

Previous value: -[
-  "observed_at",
-  "lat",
-  "lon",
-  "altitude_ft",
-  "aircraft_type",
-  "pirep_type",
-  "turbulence",
-  "icing",
-  "clouds",
-  "visibility_sm",
-  "remarks",
-  "raw_pirep"
-]New value: +[
+  "observed_at",
+  "lat",
+  "lon",
+  "altitude_ft",
+  "aircraft_type",
+  "pirep_type",
+  "turbulence",
+  "icing",
+  "clouds",
+  "visibility_sm",
+  "temp_c",
+  "wind",
+  "weather",
+  "raw_pirep"
+]

Previous value: -"One or more station identifiers (e.g., KSEA, KJFK). A lookup matches the registry's own identifier: a 4-letter ICAO ID for an airport, and other shapes for the buoys and mesonet sites the registry also carries, which resolve by those. A 3-letter IATA code (e.g., SEA) never resolves, even for a station whose entry carries one. Whitespace around an entry is trimmed, so a padded identifier resolves the same as the bare one; an empty or whitespace-only entry is rejected. Use bbox or state to discover identifiers by location."New value: +"One or more station identifiers (e.g., KSEA, KJFK). A lookup matches the registry's own identifier: a 4-character ICAO ID for an airport (e.g., KSEA, K0S9), and other shapes for the buoys and mesonet sites the registry also carries, which resolve by those. A 3-letter IATA code (e.g., SEA) never resolves, even for a station whose entry carries one. Whitespace around an entry is trimmed, so a padded identifier resolves the same as the bare one; an empty or whitespace-only entry is rejected. Use bbox or state to discover identifiers by location."

Previous value: -"ICAO 4-letter station ID, or null if not assigned."New value: +"ICAO station ID, 4 uppercase letters or digits (e.g., KSEA, K0S9), or null if not assigned."

Added value: +{
+  "description": "Geographic bounding box for an area observation survey.",
+  "properties": {
+    "maxLat": {
+      "description": "Northern boundary latitude in decimal degrees.",
+      "maximum": 90,
+      "minimum": -90,
+      "type": "number"
+    },
+    "maxLon": {
+      "description": "Eastern boundary longitude in decimal degrees.",
+      "maximum": 180,
+      "minimum": -180,
+      "type": "number"
+    },
+    "minLat": {
+      "description": "Southern boundary latitude in decimal degrees.",
+      "maximum": 90,
+      "minimum": -90,
+      "type": "number"
+    },
+    "minLon": {
+      "description": "Western boundary longitude in decimal degrees.",
+      "maximum": 180,
+      "minimum": -180,
+      "type": "number"
+    }
+  },
+  "required": [
+    "minLat",
+    "minLon",
+    "maxLat",
+    "maxLon"
+  ],
+  "type": "object"
+}

Previous value: -"Lookback window in hours (1–12), not a row limit: every observation inside the window is returned, so a station reporting more often than hourly yields more than one row per hour. At the default of 1, half-hourly stations return two observations and SPECI-issuing stations can return more. Budget rows by the station reporting interval, never one per station."New value: +"Lookback window in hours (1–12), not a row limit. With station_ids every observation inside the window is returned, so a station reporting more often than hourly yields more than one row per hour: at the default of 1, half-hourly stations return two observations and SPECI-issuing stations can return more, so budget rows by the station reporting interval, never one per station. With bbox the result is reduced to the latest observation per station, but the window still shapes the draw the upstream row cap applies to — a wide window spends that cap on repeat readings from busy stations instead of on more stations, so lower it before narrowing the box."

Added value: +{
+  "description": "Maximum stations to return, applied after the draw is reduced to the latest observation per station and ordered by station ID ascending — so the same query with the same limit returns the same stations. It bounds the response without changing the area searched, which a smaller bbox would. Distinct from the 400-row upstream cap: a limited result examined every station it counted and withheld some, while a capped one never drew the rest. Belongs to the bbox mode; supplying it alongside station_ids is rejected, since that mode already names the set. Omit to return every station in the box. Optional.",
+  "maximum": 400,
+  "minimum": 1,
+  "type": "integer"
+}

Previous value: -"ICAO station IDs to query. 1–10 stations per call."New value: +"ICAO station IDs to query. 1–10 stations per call, and every observation inside the hours window is returned for each. Supplying it alongside bbox is rejected — use bbox to ask about an area rather than a named set."

Previous value: -"4-letter ICAO station ID (e.g., KSEA, KJFK)."New value: +"ICAO station ID: 4 uppercase letters or digits (e.g., KSEA, KJFK, K0S9)."

Previous value: -"^[A-Z]{4}$"New value: +"^[A-Z0-9]{4}$"

Removed value: -[
-  "station_ids"
-]

Previous value: -[
-  {
-    "not": {
-      "required": [
-        "error"
-      ]
-    },
-    "required": [
-      "observations",
-      "requested",
-      "returned",
-      "partial"
-    ]
-  },
-  {
-    "required": [
-      "error"
-    ]
-  }
-]New value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "observations"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "description": "The upstream row maximum that was applied to the draw. Present only on a truncated result.",
+  "type": "number"
+}

Previous value: -"Machine-readable failure mode. Declared by this tool: `no_stations_found`: None of the requested station IDs returned METAR data. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `no_stations_found`: No station returned METAR data — none of the requested IDs, or no station inside the bounding box. `missing_location`: Neither station_ids nor bbox was provided. `conflicting_location`: Both station_ids and bbox were provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `conflicting_limit`: limit was provided together with station_ids, where the caller has already named the set. Other values are possible when a failure originates below the handler."

Previous value: -[
-  "no_stations_found"
-]New value: +[
+  "no_stations_found",
+  "missing_location",
+  "conflicting_location",
+  "invalid_bbox",
+  "conflicting_limit"
+]

Added value: +{
+  "description": "True when the requested limit withheld stations that matched — the caller asked to see fewer of them. False affirms the limit did not bite, so every station drawn is here. Present only when a bbox survey supplied a limit. It never states anything about the upstream cap: a limited result examined every station it counted, while a truncated one never drew the rest.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Stations the draw held before the limit selected from them. Present only on a limited result. Where the result is also truncated this counts the capped draw and not the box — the observations the cap dropped were never examined, so no count can include them.",
+  "type": "number"
+}

Previous value: -"Recovery guidance naming the missing station IDs. Present only on a partial result. It lists the candidate causes without asserting one — upstream omits the row either way."New value: +"Guidance for whichever disclosures fired: the levers that narrow a truncated draw, what a requested limit withheld, or the station IDs that returned nothing. The cap and the limit can both fire on one result, and the text keeps them apart; the reconciliation cannot join them, since only bbox reaches the row cap or accepts a limit, and only station_ids reconciles a request."

Previous value: -"Weather observations, one per station/time pair. Multiple entries per station when hours > 1."New value: +"Weather observations. With station_ids, one per station/time pair — multiple entries per station when the hours window holds more than one observation. With bbox, one per station: the latest observation inside that window."

Previous value: -"All reported cloud layers from lowest to highest. Empty whenever the observation published no layer heights, which covers a clear sky, an obscuration with no determinable height, and an observation that reported no sky condition at all; sky_condition distinguishes them. An empty array is not a clear sky on its own."New value: +"Cloud layers from lowest to highest, as AWC decoded them — at most four, so a fifth or higher reported layer is left out with no marker and raw_metar is the complete source. Empty whenever the observation published no layer heights, which covers a clear sky, an obscuration with no determinable height, and an observation that reported no sky condition at all; sky_condition distinguishes them. An empty array is not a clear sky on its own."

Previous value: -"ICAO 4-letter station identifier (e.g., KSEA)."New value: +"ICAO station identifier, 4 uppercase letters or digits (e.g., KSEA, K0S9)."

Previous value: -"Wind direction in degrees true. Null when variable."New value: +"Wind direction in degrees true. Null when the observation reported a variable wind (VRB), and also when it carried no wind group at all — speed_kt is a number in the first case and null in the second."

Previous value: -"True when a requested station produced no observation. False affirms the result covers every requested station, so full coverage is distinguishable from a short batch rather than being inferred from the count."New value: +"True when a requested station produced no observation. False affirms the result covers every requested station, so full coverage is distinguishable from a short batch rather than being inferred from the count. Present only on a station_ids lookup."

Previous value: -"Station IDs this call asked for, in the order given."New value: +"Station IDs this call asked for, in the order given. Present only on a station_ids lookup — a bbox survey asks for an area, not a list."

Previous value: -"Distinct station IDs that produced at least one observation. Counted per station, not per row — with hours > 1 a station reporting six times still appears once."New value: +"Distinct station IDs that produced at least one observation. Counted per station, not per row — with hours > 1 a station reporting six times still appears once. Present only on a station_ids lookup."

Added value: +{
+  "description": "Stations in this result, counted after the reduction to one observation per station and after any limit. Present only on a bbox survey.",
+  "type": "number"
+}

Added value: +{
+  "description": "True when the upstream draw hit the AWC row cap, so stations inside the box are missing from this result. False says the draw did not reach that cap, which a count alone cannot establish — the draw is reduced to one row per station, so the returned count sits far below the cap either way. It is not a completeness claim: AWC also thins a dense box by station priority, independently of the cap and with nothing in the response to mark it, so re-run over smaller quadrants and union the results when the box must be complete. Present only on a bbox survey.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Observations AWC returned before the reduction to one row per station. Present only on a truncated draw the reduction then narrowed, where the station count sits below the cap and so cannot reveal the truncation on its own.",
+  "type": "number"
+}

Previous value: -"Filter by maximum altitude in feet MSL (e.g., 35000 for FL350). Reports with an unknown altitude (altitude_ft null) cannot be shown to satisfy a bound and are dropped whenever either bound is set. Optional."New value: +"Filter by maximum altitude in feet MSL (e.g., 35000 for FL350), from 0 to 60000 ft — AWC searches no band below sea level, and none centred above FL600, which is already above the altitude any pilot report carries. Reports with an unknown altitude (altitude_ft null) cannot be shown to satisfy a bound and are dropped whenever either bound is set. Optional."

Previous value: -9007199254740991New value: +60000

Previous value: --9007199254740991New value: +0

Previous value: -"Filter by minimum altitude in feet MSL (e.g., 18000 for FL180). Reports with an unknown altitude (altitude_ft null) cannot be shown to satisfy a bound and are dropped whenever either bound is set. Optional."New value: +"Filter by minimum altitude in feet MSL (e.g., 18000 for FL180), from 0 to 60000 ft — AWC searches no band below sea level, and none centred above FL600, which is already above the altitude any pilot report carries. Reports with an unknown altitude (altitude_ft null) cannot be shown to satisfy a bound and are dropped whenever either bound is set. Optional."

Previous value: -9007199254740991New value: +60000

Previous value: --9007199254740991New value: +0

Previous value: -"ICAO station ID as center point for radial search (e.g., KSEA). Use with distance_nm."New value: +"ICAO station ID as center point for radial search — 4 uppercase letters or digits (e.g., KSEA, K0S9). Use with distance_nm."

Previous value: -"^[A-Z]{4}$"New value: +"^[A-Z0-9]{4}$"

Previous value: -"Machine-readable failure mode. Declared by this tool: `no_pireps_found`: No pilot reports found in the search area and time window. `missing_location`: Neither station_id nor bbox was provided. `conflicting_location`: Both station_id and bbox were provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `conflicting_distance`: distance_nm was provided together with bbox, where a search radius has no meaning. `invalid_altitude_range`: altitude_min_ft is greater than altitude_max_ft, so no report can match both bounds. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `no_pireps_found`: No pilot reports found in the search area and time window. `station_not_recognized`: AWC does not recognize station_id as a PIREP search center — a closed or retired airport, for example — and rejects the request. `missing_location`: Neither station_id nor bbox was provided. `conflicting_location`: Both station_id and bbox were provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `conflicting_distance`: distance_nm was provided together with bbox, where a search radius has no meaning. `invalid_altitude_range`: altitude_min_ft is greater than altitude_max_ft, so no report can match both bounds. Other values are possible when a failure originates below the handler."

Previous value: -[
-  "no_pireps_found",
-  "missing_location",
-  "conflicting_location",
-  "invalid_bbox",
-  "conflicting_distance",
-  "invalid_altitude_range"
-]New value: +[
+  "no_pireps_found",
+  "station_not_recognized",
+  "missing_location",
+  "conflicting_location",
+  "invalid_bbox",
+  "conflicting_distance",
+  "invalid_altitude_range"
+]

Previous value: -"4-letter ICAO station ID (e.g., KSEA, KJFK)."New value: +"ICAO station ID: 4 uppercase letters or digits (e.g., KSEA, KJFK, K36U)."

Previous value: -"^[A-Z]{4}$"New value: +"^[A-Z0-9]{4}$"

Previous value: -"Forecast cloud layers for this period. Empty whenever the period published no layer heights, which covers a forecast clear sky and a period carrying no cloud element at all; sky_condition distinguishes them. An empty array is not a forecast of a clear sky on its own."New value: +"Forecast cloud layers for this period, as AWC decoded them — at most three, so a further layer is left out of this array and its text surfaces in not_decoded, with raw_taf the complete source. Empty whenever the period published no layer heights, which covers a forecast clear sky and a period carrying no cloud element at all; sky_condition distinguishes them. An empty array is not a forecast of a clear sky on its own."

Added value: +{
+  "description": "Text AWC attached to this period without decoding it, trimmed — usually a cloud layer past the three-layer decode limit, sometimes another group such as VV///. Null when nothing was left undecoded. Non-null marks a partial decode. Upstream can attach the leftover of one group, such as a TEMPO, to the period after it, so the text is published on the period it arrived on and never reassigned or parsed into clouds; raw_taf is the complete forecast.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -[
-  "from",
-  "to",
-  "change_type",
-  "probability",
-  "wind",
-  "wind_shear",
-  "visibility_sm",
-  "vertical_visibility_ft",
-  "weather",
-  "clouds",
-  "sky_condition"
-]New value: +[
+  "from",
+  "to",
+  "change_type",
+  "probability",
+  "wind",
+  "wind_shear",
+  "visibility_sm",
+  "vertical_visibility_ft",
+  "weather",
+  "clouds",
+  "sky_condition",
+  "not_decoded"
+]

Previous value: -"ICAO 4-letter station identifier (e.g., KSEA)."New value: +"ICAO station identifier, 4 uppercase letters or digits (e.g., KSEA, K36U)."

Added value: +{
+  "description": "Maximum stations to return, applied after ordering by ICAO identifier ascending with identifier-less stations last — so the same query with the same limit returns the same stations, and airports rather than unidentified sites lead the first page. It bounds the response without changing the area searched, which a smaller bbox or a different state would. Distinct from the 400-row upstream cap: a limited result examined every station it counted and withheld some, while a capped one never drew the rest. Belongs to the bbox and state modes; supplying it alongside station_ids is rejected, since that mode already names the set. Omit to return every match. Optional.",
+  "maximum": 400,
+  "minimum": 1,
+  "type": "integer"
+}

Previous value: -"One or more 4-letter ICAO station IDs (e.g., KSEA, KJFK). The upstream API only accepts ICAO format — 3-letter IATA codes (e.g., SEA) will return no results. Use bbox or state to discover ICAO IDs by location."New value: +"One or more station identifiers (e.g., KSEA, KJFK). A lookup matches the registry's own identifier: a 4-letter ICAO ID for an airport, and other shapes for the buoys and mesonet sites the registry also carries, which resolve by those. A 3-letter IATA code (e.g., SEA) never resolves, even for a station whose entry carries one. Whitespace around an entry is trimmed, so a padded identifier resolves the same as the bare one; an empty or whitespace-only entry is rejected. Use bbox or state to discover identifiers by location."

Previous value: -"A 4-letter ICAO station identifier (e.g., KSEA)."New value: +"One station identifier (e.g., KSEA)."

Added value: +"\\S"

Previous value: -"Machine-readable failure mode. Declared by this tool: `station_not_found`: None of the requested IDs match any known station. `missing_search_criteria`: None of station_ids, bbox, or state was provided. `conflicting_location`: More than one of station_ids, bbox, or state was provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `invalid_state`: The state code is not one of the 50 US states or DC. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `station_not_found`: None of the requested IDs match any known station. `missing_search_criteria`: None of station_ids, bbox, or state was provided. `conflicting_location`: More than one of station_ids, bbox, or state was provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `invalid_state`: The state code is not one of the 50 US states or DC. `conflicting_limit`: limit was provided together with station_ids, where the caller has already named the set. `upstream_rejected`: The AWC station registry rejected the request as malformed rather than answering it. Other values are possible when a failure originates below the handler."

Previous value: -[
-  "station_not_found",
-  "missing_search_criteria",
-  "conflicting_location",
-  "invalid_bbox",
-  "invalid_state"
-]New value: +[
+  "station_not_found",
+  "missing_search_criteria",
+  "conflicting_location",
+  "invalid_bbox",
+  "invalid_state",
+  "conflicting_limit",
+  "upstream_rejected"
+]

Added value: +{
+  "description": "True when the requested limit withheld stations that matched — the caller asked to see fewer of them. False affirms the limit did not bite, so every matching station is here. Present only when the call supplied a limit. It never states anything about the upstream cap: a limited result examined every station it counted, while a truncated one never drew the rest.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Stations that matched this query before the limit selected from them. Present only on a limited result. Where the result is also truncated this counts the capped draw and not the search area — the stations the cap dropped were never examined, so no count can include them.",
+  "type": "number"
+}

Previous value: -"Guidance for whichever disclosure fired: the lever that narrows a truncated draw, or the cause and fix for identifiers that resolved to nothing. The two cannot co-occur — only bbox and state can reach the row cap, and only station_ids reconciles a request."New value: +"Guidance for whichever disclosures fired: the lever that narrows a truncated draw, what a requested limit withheld, or the cause and fix for identifiers that resolved to nothing. The cap and the limit can both fire on one result, and the text keeps them apart; the reconciliation cannot join them, since only bbox and state reach the row cap or accept a limit, and only station_ids reconciles a request."

Previous value: -"Stations in this result, counted after any client-side state filter."New value: +"Stations in this result, counted after any client-side state filter and after any limit."

Added value: +{
+  "description": "Maximum reports to return, applied last — after every filter and after ordering by observation time descending, so a limited result is the most recent reports rather than an arbitrary slice. It bounds the response without changing what is searched, which every other parameter does. Distinct from the 400-row upstream cap: a limited result examined every report it counted and withheld some, while a capped one never drew the rest. Selection is by recency alone, so pair it with min_intensity to bound a result by severity. Omit to return every match. Optional.",
+  "maximum": 400,
+  "minimum": 1,
+  "type": "integer"
+}

Added value: +{
+  "description": "True when the requested limit withheld reports that matched — the caller asked to see fewer of them. False affirms the limit did not bite, so every matching report is here. Present only when the call supplied a limit. It never states anything about the upstream cap: a limited result examined every report it counted, while a truncated one never drew the rest.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Reports that matched this query before the limit selected from them. Present only on a limited result. Where the result is also truncated this counts the capped page and not the search area — the reports the cap dropped were never examined, so no count can include them.",
+  "type": "number"
+}

Previous value: -"Guidance naming the levers that narrow the query before the cap applies. Present only on a truncated result."New value: +"Guidance for whichever disclosures fired: the levers that narrow the query before the cap applies, and what a requested limit withheld. Both can fire on one result, and the text keeps them apart."

Previous value: -"Reports in this result, counted after any altitude filter."New value: +"Reports in this result, counted after any altitude filter and after any limit."

Previous value: -"Optional hazard filter. CONVECTIVE, TURBULENCE, ICING, and IFR match the four hazard classes the domestic SIGMET feed carries. MTN OBSCN, SURFACE WIND, and LLWS are AIRMET-family phenomena with no upstream counterpart here and are rejected rather than returning an empty result."New value: +"Optional hazard filter, applied upstream by AWC. CONVECTIVE, TURBULENCE, ICING, and IFR are the four hazard classes the domestic SIGMET feed carries, and an empty result under one of them means no advisory of that class is active — it says nothing about the others. MTN OBSCN, SURFACE WIND, and LLWS are AIRMET-family phenomena with no upstream counterpart here and are rejected rather than returning an empty result."

Added value: +{
+  "description": "Present only when the result is empty, naming the stage that emptied it: no domestic SIGMETs are active at all, none carry the requested hazard, or none intersect the requested bbox — and which filter to broaden. A hazard-scoped empty draw states only that no advisory carries that hazard; AWC applies the hazard filter, so the response cannot say whether other classes are active.",
+  "type": "string"
+}

Added value: +{
+  "description": "Requested identifiers absent from the result. Deduplicated the way returned is: a repeated or differently-cased identifier appears once, under its first spelling. Absent when none are missing.",
+  "items": {
+    "description": "A requested identifier that resolved to no station.",
+    "type": "string"
+  },
+  "type": "array"
+}

Previous value: -"Guidance naming the lever that narrows the draw. Present only on a truncated result."New value: +"Guidance for whichever disclosure fired: the lever that narrows a truncated draw, or the cause and fix for identifiers that resolved to nothing. The two cannot co-occur — only bbox and state can reach the row cap, and only station_ids reconciles a request."

Added value: +{
+  "description": "True when a requested identifier resolved to nothing. False affirms every requested identifier resolved, which a count cannot establish — upstream case-folds and deduplicates, so a shorter list is not itself a gap. Present only on a station_ids lookup.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Station identifiers this call asked for, spelled as the caller wrote them and in the order given. Present only on a station_ids lookup — the bbox and state modes ask for an area, not a list.",
+  "items": {
+    "description": "A station identifier as requested.",
+    "type": "string"
+  },
+  "type": "array"
+}

Added value: +{
+  "description": "Requested identifiers that resolved, spelled as the caller wrote them rather than as upstream returned them. Deduplicated the way upstream deduplicates: a repeated or differently-cased identifier appears once, under its first spelling. Present only on a station_ids lookup.",
+  "items": {
+    "description": "A requested identifier that resolved to a station.",
+    "type": "string"
+  },
+  "type": "array"
+}

Previous value: -"Hours of observation history to return (1–12). Default 1 returns only the most recent observation per station."New value: +"Lookback window in hours (1–12), not a row limit: every observation inside the window is returned, so a station reporting more often than hourly yields more than one row per hour. At the default of 1, half-hourly stations return two observations and SPECI-issuing stations can return more. Budget rows by the station reporting interval, never one per station."

Previous value: -"Ceiling in feet AGL — the lowest broken, overcast, or obscuration layer. Per FAA AIM 7-1-29 the ceiling is the lowest broken or overcast layer, or the vertical visibility into an obscuration; few and scattered layers are never ceilings. Null when the observation reported no such layer."New value: +"Ceiling in feet AGL — the lowest broken, overcast, or obscuration layer. Per FAA AIM 7-1-29 the ceiling is the lowest broken or overcast layer, or the vertical visibility into an obscuration; few and scattered layers are never ceilings. Null in two cases that are not the same: the observation reported no such layer, or it reported an obscuration whose vertical visibility the station could not determine (a VV/// group), where the ceiling exists and only its height is missing. A sky_condition of OVX marks the second."

Previous value: -"All reported cloud layers from lowest to highest."New value: +"All reported cloud layers from lowest to highest. Empty whenever the observation published no layer heights, which covers a clear sky, an obscuration with no determinable height, and an observation that reported no sky condition at all; sky_condition distinguishes them. An empty array is not a clear sky on its own."

Added value: +{
+  "description": "The sky condition the observation stated when it published no layer heights: CLR, SKC, or CAVOK for a clear or insignificant-cloud report, OVX for an obscuration whose layer carried no height (a VV/// group, and the opposite of clear). Null when clouds carries layers — those are the statement — and also when the observation carried no sky-condition group at all. An empty clouds array beside a null here is an unreported sky, never a clear one.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -"Prevailing visibility in statute miles (e.g., \"10+\", \"3\", \"1/2\")."New value: +"Prevailing visibility in statute miles (e.g., \"10+\", \"3\", \"1/2\"), or the string \"unknown\" when the observation carried no visibility group. \"unknown\" is not a measurement and carries no unit."

Previous value: -[
-  "station_id",
-  "name",
-  "lat",
-  "lon",
-  "elevation_ft",
-  "flight_category",
-  "metar_type",
-  "observed_at",
-  "wind",
-  "visibility_sm",
-  "ceiling_ft",
-  "ceiling_type",
-  "clouds",
-  "present_weather",
-  "temp_c",
-  "dewpoint_c",
-  "altimeter_inhg",
-  "raw_metar"
-]New value: +[
+  "station_id",
+  "name",
+  "lat",
+  "lon",
+  "elevation_ft",
+  "flight_category",
+  "metar_type",
+  "observed_at",
+  "wind",
+  "visibility_sm",
+  "ceiling_ft",
+  "ceiling_type",
+  "clouds",
+  "sky_condition",
+  "present_weather",
+  "temp_c",
+  "dewpoint_c",
+  "altimeter_inhg",
+  "raw_metar"
+]

Previous value: -"Change indicator: FM (from), TEMPO (temporary), BECMG (becoming), or null for the base period."New value: +"Change indicator: FM (from), TEMPO (temporary), BECMG (becoming), PROB (a standalone probability group), or null for the base period. A PROB30 or PROB40 qualifying a temporary group arrives as TEMPO; standing alone, with no temporary group after it, it arrives as PROB. Either way the percentage is in probability."

Previous value: -"Forecast cloud layers for this period."New value: +"Forecast cloud layers for this period. Empty whenever the period published no layer heights, which covers a forecast clear sky and a period carrying no cloud element at all; sky_condition distinguishes them. An empty array is not a forecast of a clear sky on its own."

Added value: +{
+  "description": "The sky condition this period forecast when it published no layer heights: SKC or NSC for a clear or insignificant-cloud forecast (a CAVOK group arrives as NSC), OVX for a forecast obscuration carrying no vertical visibility. Null when clouds carries layers — those are the statement — and also when the period carried no cloud element at all. An empty clouds array beside a null here forecasts nothing about cloud; on a TEMPO, PROB, or BECMG group that means the prevailing forecast stands unchanged, never that the sky will be clear.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -[
-  "from",
-  "to",
-  "change_type",
-  "probability",
-  "wind",
-  "wind_shear",
-  "visibility_sm",
-  "vertical_visibility_ft",
-  "weather",
-  "clouds"
-]New value: +[
+  "from",
+  "to",
+  "change_type",
+  "probability",
+  "wind",
+  "wind_shear",
+  "visibility_sm",
+  "vertical_visibility_ft",
+  "weather",
+  "clouds",
+  "sky_condition"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "direction_deg": {
-        "anyOf": [
-          {
-            "type": "number"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "description": "Movement direction in degrees true, or null if stationary."
-      },
-      "speed_kt": {
-        "anyOf": [
-          {
-            "type": "number"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "description": "Movement speed in knots, or null if stationary."
-      }
-    },
-    "required": [
-      "direction_deg",
-      "speed_kt"
-    ],
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "direction_deg": {
+        "description": "Movement direction in degrees true, or null if stationary.",
+        "type": [
+          "number",
+          "null"
+        ]
+      },
+      "speed_kt": {
+        "description": "Movement speed in knots, or null if stationary.",
+        "type": [
+          "number",
+          "null"
+        ]
+      }
+    },
+    "required": [
+      "direction_deg",
+      "speed_kt"
+    ],
+    "type": "object"
+  },
+  {
+    "type": "null"
+  }
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Added value: +{
+  "description": "Return only reports carrying at least one turbulence or icing layer at this intensity or above. The filter selects reports, not layers — a matching report still carries its lighter layers, so a result may include NEG, TRC, or LGT entries alongside the layer that matched. Optional.",
+  "enum": [
+    "lgt",
+    "mod",
+    "sev"
+  ],
+  "type": "string"
+}

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Previous value: -"Reported altitude in feet MSL, or null when the pilot gave no flight level (raw /FLUNKN/, /FLDURC/, or /FLDURD/). A raw /FL000/ is a reported flight level of zero and returns 0."New value: +"Reported altitude in feet MSL, or null when the raw flight-level group carries no usable altitude. That covers /FLUNKN/ and the during-climb and during-descent markers, and equally any other group AWC could not read — including one made only of digits, such as /FL2130/. A raw /FL000/ is a reported flight level of zero and returns 0."

Added value: +[
+  "number",
+  "null"
+]

Previous value: -[
-  {
-    "items": {
-      "additionalProperties": false,
-      "description": "A cloud layer, whose base and top are each present only if reported.",
-      "properties": {
-        "base_ft": {
-          "anyOf": [
-            {
-              "type": "number"
-            },
-            {
-              "type": "null"
-            }
-          ],
-          "description": "Cloud base altitude in feet MSL, or null if the pilot reported no base."
-        },
-        "cover": {
-          "description": "Cloud cover code: FEW, SCT, BKN, OVC, SKC, or CLR. The field also carries the flight-condition markers VMC and IMC, which describe the flight environment rather than a cloud layer and arrive with no base or top.",
-          "type": "string"
-        },
-        "top_ft": {
-          "anyOf": [
-            {
-              "type": "number"
-            },
-            {
-              "type": "null"
-            }
-          ],
-          "description": "Cloud top altitude in feet MSL, or null if the pilot reported no top."
-        }
-      },
-      "required": [
-        "cover",
-        "base_ft",
-        "top_ft"
-      ],
-      "type": "object"
-    },
-    "type": "array"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "items": {
+      "additionalProperties": false,
+      "description": "A cloud layer, whose base and top are each present only if reported.",
+      "properties": {
+        "base_ft": {
+          "description": "Cloud base altitude in feet MSL, or null if the pilot reported no base.",
+          "type": [
+            "number",
+            "null"
+          ]
+        },
+        "cover": {
+          "description": "Cloud cover code: FEW, SCT, BKN, OVC, SKC, or CLR. The field also carries the flight-condition markers VMC and IMC, which describe the flight environment rather than a cloud layer and arrive with no base or top.",
+          "type": "string"
+        },
+        "top_ft": {
+          "description": "Cloud top altitude in feet MSL, or null if the pilot reported no top.",
+          "type": [
+            "number",
+            "null"
+          ]
+        }
+      },
+      "required": [
+        "cover",
+        "base_ft",
+        "top_ft"
+      ],
+      "type": "object"
+    },
+    "type": "array"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Icing layers reported. An explicit negative report is a layer with intensity NEG; an empty array means the PIREP carried no icing group, so the pilot said nothing either way."New value: +"Icing layers the raw report carried. An explicit negative report is a layer with intensity NEG; an empty array means the PIREP carried no icing group, so the pilot said nothing either way. Layers AWC synthesized for a report that never mentioned ice are omitted rather than published."

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "string",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +false

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "stations",
+      "truncated",
+      "shown"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `station_not_found`: None of the requested IDs match any known station. `missing_search_criteria`: None of station_ids, bbox, or state was provided. `conflicting_location`: More than one of station_ids, bbox, or state was provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `invalid_state`: The state code is not one of the 50 US states or DC. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "station_not_found",
+            "missing_search_criteria",
+            "conflicting_location",
+            "invalid_bbox",
+            "invalid_state"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

Removed value: -[
-  "stations",
-  "truncated",
-  "shown"
-]

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +false

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "advisories"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `airmet_not_served`: advisory_type \"airmet\" was requested, or a hazard filter naming an AIRMET-family phenomenon (MTN OBSCN, SURFACE WIND, LLWS) with no counterpart on the SIGMET feed. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "invalid_bbox",
+            "airmet_not_served"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

Removed value: -[
-  "advisories"
-]

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +false

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "observations",
+      "requested",
+      "returned",
+      "partial"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `no_stations_found`: None of the requested station IDs returned METAR data. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "no_stations_found"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

Removed value: -[
-  "observations",
-  "requested",
-  "returned",
-  "partial"
-]

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +false

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "pireps",
+      "truncated",
+      "shown"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `no_pireps_found`: No pilot reports found in the search area and time window. `missing_location`: Neither station_id nor bbox was provided. `conflicting_location`: Both station_id and bbox were provided. `invalid_bbox`: The bounding box is inverted — minLat > maxLat or minLon > maxLon. `conflicting_distance`: distance_nm was provided together with bbox, where a search radius has no meaning. `invalid_altitude_range`: altitude_min_ft is greater than altitude_max_ft, so no report can match both bounds. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "no_pireps_found",
+            "missing_location",
+            "conflicting_location",
+            "invalid_bbox",
+            "conflicting_distance",
+            "invalid_altitude_range"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

Removed value: -[
-  "pireps",
-  "truncated",
-  "shown"
-]

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +false

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "forecasts",
+      "requested",
+      "returned",
+      "partial"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `no_taf_available`: Station does not issue TAFs or no TAF is currently available. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "no_taf_available"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

Removed value: -[
-  "forecasts",
-  "requested",
-  "returned",
-  "partial"
-]

Added value: +{
+  "description": "The upstream row maximum that was applied to the draw. Present only on a truncated result.",
+  "type": "number"
+}

Added value: +{
+  "description": "Guidance naming the lever that narrows the draw. Present only on a truncated result.",
+  "type": "string"
+}

Added value: +{
+  "description": "Stations in this result, counted after any client-side state filter.",
+  "type": "number"
+}

Added value: +{
+  "description": "True when the upstream draw hit the AWC row cap, so stations inside the search area are missing from this result. False affirms the area was drawn in full, which a count alone cannot establish.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Rows AWC returned before the client-side state filter ran. Present only on a truncated state query the filter then narrowed, where the post-filter count sits below the cap and so cannot reveal the truncation on its own.",
+  "type": "number"
+}

Previous value: -[
-  "stations"
-]New value: +[
+  "stations",
+  "truncated",
+  "shown"
+]

Previous value: -"Filter by advisory type. \"sigmet\" includes convective SIGMETs. \"airmet\" includes AIRMET Sierra (IFR/mountain obscuration), Tango (turbulence), and Zulu (icing). \"all\" returns both."New value: +"Filter by advisory type. \"sigmet\" and \"all\" both return the active domestic SIGMET set, which is everything this tool serves. \"airmet\" is rejected with guidance: the upstream feed cannot return an AIRMET, so answering it would mean presenting SIGMETs as AIRMET matches."

Previous value: -"Optional hazard filter. CONVECTIVE = convective SIGMETs; TURBULENCE = AIRMET Tango; ICING = AIRMET Zulu; IFR = AIRMET Sierra (IFR conditions); MTN OBSCN = AIRMET Sierra (mountain obscuration); SURFACE WIND = sustained strong surface winds (typically >30 kt); LLWS = low-level wind shear below 2,000 ft AGL."New value: +"Optional hazard filter. CONVECTIVE, TURBULENCE, ICING, and IFR match the four hazard classes the domestic SIGMET feed carries. MTN OBSCN, SURFACE WIND, and LLWS are AIRMET-family phenomena with no upstream counterpart here and are rejected rather than returning an empty result."

Previous value: -"An active SIGMET or AIRMET advisory."New value: +"An active SIGMET advisory."

Previous value: -"Advisory type: SIGMET or AIRMET."New value: +"Advisory type as issued. The domestic SIGMET feed this tool reads emits SIGMET."

Previous value: -"Hazard type (e.g., CONVECTIVE, TURBULENCE, ICING, IFR, MTN OBSCN)."New value: +"Hazard type — one of CONVECTIVE, TURBULENCE, ICING, or IFR."

Previous value: -"Original encoded SIGMET or AIRMET text as issued by the meteorological watch office."New value: +"Original encoded SIGMET text as issued by the meteorological watch office."

Previous value: -"Severity integer for convective SIGMETs (higher = more intense). Null for AIRMETs."New value: +"Severity integer for convective SIGMETs (higher = more intense). Null when the advisory stated none."

Added value: +{
+  "description": "The upstream row maximum that was applied to the page. Present only on a truncated result.",
+  "type": "number"
+}

Added value: +{
+  "description": "Guidance naming the levers that narrow the query before the cap applies. Present only on a truncated result.",
+  "type": "string"
+}

Added value: +{
+  "description": "Reports in this result, counted after any altitude filter.",
+  "type": "number"
+}

Added value: +{
+  "description": "True when the upstream page hit the AWC row cap, so reports inside the search area and time window are missing from this result. False affirms the whole window was searched, which a count alone cannot establish.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Reports AWC returned before the altitude filter ran. Present only on a truncated result the filter then narrowed, where the remaining count sits below the cap and so cannot reveal the truncation on its own.",
+  "type": "number"
+}

Previous value: -[
-  "pireps"
-]New value: +[
+  "pireps",
+  "truncated",
+  "shown"
+]

Added value: +{
+  "description": "Requested station IDs absent from the result. Absent when none are missing.",
+  "items": {
+    "description": "A requested ICAO station ID that produced no observation.",
+    "type": "string"
+  },
+  "type": "array"
+}

Added value: +{
+  "description": "Recovery guidance naming the missing station IDs. Present only on a partial result. It lists the candidate causes without asserting one — upstream omits the row either way.",
+  "type": "string"
+}

Previous value: -"Ceiling in feet AGL — the lowest broken, overcast, or obscuration layer. Per FAA AIM 7-1-13 the ceiling is the lowest broken or overcast layer, or the vertical visibility into an obscuration; few and scattered layers are never ceilings. Null when the observation reported no such layer."New value: +"Ceiling in feet AGL — the lowest broken, overcast, or obscuration layer. Per FAA AIM 7-1-29 the ceiling is the lowest broken or overcast layer, or the vertical visibility into an obscuration; few and scattered layers are never ceilings. Null when the observation reported no such layer."

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "decoded": {
-        "description": "Plain-English reading of the group (e.g., \"fog\", \"light rain showers\").",
-        "type": "string"
-      },
-      "raw": {
-        "description": "Weather group exactly as encoded (e.g., \"FG\", \"-SHRA\", \"+RA BR\").",
-        "type": "string"
-      }
-    },
-    "required": [
-      "raw",
-      "decoded"
-    ],
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "decoded": {
+        "description": "Plain-English reading of each group, joined with \"; \" (e.g., \"fog\", \"light rain showers; mist\"). A group the decoder does not recognize is carried through as its own raw token rather than half-translated, so compare against raw when a reading still looks coded.",
+        "type": "string"
+      },
+      "raw": {
+        "description": "Weather groups exactly as encoded, space-delimited (e.g., \"FG\", \"-SHRA\", \"VCTS -RA\").",
+        "type": "string"
+      }
+    },
+    "required": [
+      "raw",
+      "decoded"
+    ],
+    "type": "object"
+  },
+  {
+    "type": "null"
+  }
+]

Added value: +{
+  "description": "True when a requested station produced no observation. False affirms the result covers every requested station, so full coverage is distinguishable from a short batch rather than being inferred from the count.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Station IDs this call asked for, in the order given.",
+  "items": {
+    "description": "An ICAO station ID as requested.",
+    "type": "string"
+  },
+  "type": "array"
+}

Added value: +{
+  "description": "Distinct station IDs that produced at least one observation. Counted per station, not per row — with hours > 1 a station reporting six times still appears once.",
+  "items": {
+    "description": "An ICAO station ID present in the result.",
+    "type": "string"
+  },
+  "type": "array"
+}

Previous value: -[
-  "observations"
-]New value: +[
+  "observations",
+  "requested",
+  "returned",
+  "partial"
+]

Previous value: -"Cloud base altitude in feet AGL."New value: +"Cloud base altitude in feet AGL. On an OVX layer this is the vertical visibility into the obscuration rather than a layer bottom, and 0 is a surface-level indefinite ceiling."

Previous value: -"Sky cover code: FEW, SCT, BKN, OVC, SKC, CLR."New value: +"Sky cover code: FEW, SCT, BKN, OVC, SKC, or OVX. OVX is the decoded form of a VVhhh group — the sky is obscured and the base is the vertical visibility into it, not a cloud bottom."

Previous value: -"Cloud type qualifier: CB (cumulonimbus), TCU (towering cumulus), or null."New value: +"Cloud type qualifier: CB (cumulonimbus), TCU (towering cumulus), or null. An obscuration can carry one — a VV008CB group is an OVX layer with type CB."

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "Vertical visibility into a forecast obscuration, in feet AGL — an indefinite ceiling, and the same height as this period OVX cloud layer. 0 is a surface-level indefinite ceiling; null means the period forecasts no obscuration."
+}

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "decoded": {
+        "description": "Plain-English reading of each group, joined with \"; \" (e.g., \"light rain showers; mist\"). A group the decoder does not recognize is carried through as its own raw token rather than half-translated, so compare against raw when a reading still looks coded.",
+        "type": "string"
+      },
+      "raw": {
+        "description": "Weather groups exactly as forecast, space-delimited (e.g., \"-SHRA\", \"-SHRA BR\", \"VCTS -RA\").",
+        "type": "string"
+      }
+    },
+    "required": [
+      "raw",
+      "decoded"
+    ],
+    "type": "object"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Decoded weather condition (e.g., \"light rain showers\", \"thunderstorm with rain\"). Null if none."New value: +"Forecast weather for this period, or null when the period carried no weather group."

Previous value: -"Forecast wind conditions for this period."New value: +"Forecast wind conditions at the surface for this period."

Added value: +{
+  "anyOf": [
+    {
+      "additionalProperties": false,
+      "properties": {
+        "direction_deg": {
+          "description": "Forecast wind direction at the top of the shear layer, in degrees true — not a direction of shear.",
+          "type": "number"
+        },
+        "height_ft": {
+          "description": "Top of the shear layer in feet AGL — not the layer base and not its thickness. A WS020 group is 2000 ft.",
+          "type": "number"
+        },
+        "speed_kt": {
+          "description": "Forecast wind speed at the top of the shear layer, in knots — the wind at that height, not the magnitude of the shear.",
+          "type": "number"
+        }
+      },
+      "required": [
+        "height_ft",
+        "direction_deg",
+        "speed_kt"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "Forecast non-convective low-level wind shear (a WS group), confined to the surface–2,000 ft AGL band. A null means no non-convective LLWS group was issued for this period, rather than no shear expected: the group is excluded from TEMPO and PROB groups, and shear is always assumed present in convective activity."
+}

Previous value: -[
-  "from",
-  "to",
-  "change_type",
-  "probability",
-  "wind",
-  "visibility_sm",
-  "weather",
-  "clouds"
-]New value: +[
+  "from",
+  "to",
+  "change_type",
+  "probability",
+  "wind",
+  "wind_shear",
+  "visibility_sm",
+  "vertical_visibility_ft",
+  "weather",
+  "clouds"
+]

Added value: +{
+  "description": "Requested station IDs absent from the result. Absent when none are missing.",
+  "items": {
+    "description": "A requested ICAO station ID that produced no forecast.",
+    "type": "string"
+  },
+  "type": "array"
+}

Added value: +{
+  "description": "Recovery guidance naming the missing station IDs. Present only on a partial result. It lists the candidate causes without asserting one — upstream omits the row either way.",
+  "type": "string"
+}

Added value: +{
+  "description": "True when a requested station produced no forecast. False affirms the result covers every requested station, so full coverage is distinguishable from a short batch rather than being inferred from the count.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Station IDs this call asked for, in the order given.",
+  "items": {
+    "description": "An ICAO station ID as requested.",
+    "type": "string"
+  },
+  "type": "array"
+}

Added value: +{
+  "description": "Distinct station IDs that produced a forecast.",
+  "items": {
+    "description": "An ICAO station ID present in the result.",
+    "type": "string"
+  },
+  "type": "array"
+}

Previous value: -[
-  "forecasts"
-]New value: +[
+  "forecasts",
+  "requested",
+  "returned",
+  "partial"
+]

Added value: +[
+  {
+    "type": "number"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Station elevation in feet MSL."New value: +"Station elevation in feet MSL. 0 is a sea-level site; null means no elevation is on file upstream, so it is unknown."

Removed value: -"number"

Added value: +[
+  {
+    "type": "number"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Altimeter setting in inches of mercury."New value: +"Altimeter setting in inches of mercury, or null when the observation carried no altimeter group (common at stations reporting sea-level pressure only)."

Removed value: -"number"

Previous value: -"Ceiling in feet MSL — lowest BKN or OVC layer base. Null when sky is clear."New value: +"Ceiling in feet AGL — the lowest broken, overcast, or obscuration layer. Per FAA AIM 7-1-13 the ceiling is the lowest broken or overcast layer, or the vertical visibility into an obscuration; few and scattered layers are never ceilings. Null when the observation reported no such layer."

Added value: +{
+  "anyOf": [
+    {
+      "enum": [
+        "measured",
+        "indefinite"
+      ],
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "How the ceiling height was determined: \"measured\" for a broken or overcast layer base, \"indefinite\" for vertical visibility into an obscuration (an OVX layer). Null exactly when ceiling_ft is null."
+}

Previous value: -"Cloud base altitude in feet MSL."New value: +"Cloud base altitude in feet AGL."

Previous value: -"Sky cover code: FEW, SCT, BKN, OVC, SKC, CLR."New value: +"Sky cover code: FEW, SCT, BKN, OVC, SKC, CLR, CAVOK, or OVX. OVX is the decoded form of a VVhhh group — the sky is obscured and the base is the vertical visibility into it, not a cloud bottom."

Added value: +[
+  {
+    "type": "number"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Dewpoint in degrees Celsius."New value: +"Dewpoint in degrees Celsius. 0 is a real reading; null means the observation carried no dewpoint, so it is unknown."

Removed value: -"number"

Added value: +{
+  "anyOf": [
+    {
+      "additionalProperties": false,
+      "properties": {
+        "decoded": {
+          "description": "Plain-English reading of the group (e.g., \"fog\", \"light rain showers\").",
+          "type": "string"
+        },
+        "raw": {
+          "description": "Weather group exactly as encoded (e.g., \"FG\", \"-SHRA\", \"+RA BR\").",
+          "type": "string"
+        }
+      },
+      "required": [
+        "raw",
+        "decoded"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "Present weather at the station, or null when the observation carried no weather group (a dry, unobscured day)."
+}

Added value: +[
+  {
+    "type": "number"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Temperature in degrees Celsius."New value: +"Temperature in degrees Celsius. 0 is a real reading; null means the observation carried no temperature, so it is unknown."

Removed value: -"number"

Added value: +[
+  {
+    "type": "number"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Wind speed in knots."New value: +"Wind speed in knots. 0 is calm (a reported 00000KT); null means the observation carried no wind group, so the speed is unknown."

Removed value: -"number"

Previous value: -[
-  "station_id",
-  "name",
-  "lat",
-  "lon",
-  "elevation_ft",
-  "flight_category",
-  "metar_type",
-  "observed_at",
-  "wind",
-  "visibility_sm",
-  "ceiling_ft",
-  "clouds",
-  "temp_c",
-  "dewpoint_c",
-  "altimeter_inhg",
-  "raw_metar"
-]New value: +[
+  "station_id",
+  "name",
+  "lat",
+  "lon",
+  "elevation_ft",
+  "flight_category",
+  "metar_type",
+  "observed_at",
+  "wind",
+  "visibility_sm",
+  "ceiling_ft",
+  "ceiling_type",
+  "clouds",
+  "present_weather",
+  "temp_c",
+  "dewpoint_c",
+  "altimeter_inhg",
+  "raw_metar"
+]

Previous value: -"Filter by maximum altitude in feet MSL (e.g., 35000 for FL350). Optional."New value: +"Filter by maximum altitude in feet MSL (e.g., 35000 for FL350). Reports with an unknown altitude (altitude_ft null) cannot be shown to satisfy a bound and are dropped whenever either bound is set. Optional."

Previous value: -"Filter by minimum altitude in feet MSL (e.g., 18000 for FL180). Optional."New value: +"Filter by minimum altitude in feet MSL (e.g., 18000 for FL180). Reports with an unknown altitude (altitude_ft null) cannot be shown to satisfy a bound and are dropped whenever either bound is set. Optional."

Added value: +[
+  {
+    "type": "number"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Reported altitude in feet MSL."New value: +"Reported altitude in feet MSL, or null when the pilot gave no flight level (raw /FLUNKN/, /FLDURC/, or /FLDURD/). A raw /FL000/ is a reported flight level of zero and returns 0."

Removed value: -"number"

Previous value: -[
-  {
-    "items": {
-      "additionalProperties": false,
-      "description": "A cloud layer with base and top altitudes.",
-      "properties": {
-        "base_ft": {
-          "description": "Cloud base altitude in feet MSL.",
-          "type": "number"
-        },
-        "cover": {
-          "description": "Cloud cover code (e.g., FEW, SCT, BKN, OVC).",
-          "type": "string"
-        },
-        "top_ft": {
-          "description": "Cloud top altitude in feet MSL.",
-          "type": "number"
-        }
-      },
-      "required": [
-        "cover",
-        "base_ft",
-        "top_ft"
-      ],
-      "type": "object"
-    },
-    "type": "array"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "items": {
+      "additionalProperties": false,
+      "description": "A cloud layer, whose base and top are each present only if reported.",
+      "properties": {
+        "base_ft": {
+          "anyOf": [
+            {
+              "type": "number"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "description": "Cloud base altitude in feet MSL, or null if the pilot reported no base."
+        },
+        "cover": {
+          "description": "Cloud cover code: FEW, SCT, BKN, OVC, SKC, or CLR. The field also carries the flight-condition markers VMC and IMC, which describe the flight environment rather than a cloud layer and arrive with no base or top.",
+          "type": "string"
+        },
+        "top_ft": {
+          "anyOf": [
+            {
+              "type": "number"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "description": "Cloud top altitude in feet MSL, or null if the pilot reported no top."
+        }
+      },
+      "required": [
+        "cover",
+        "base_ft",
+        "top_ft"
+      ],
+      "type": "object"
+    },
+    "type": "array"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Cloud layers with base and top altitudes, or null if not reported."New value: +"Cloud layers, or null if the PIREP carried no sky-condition group."

Previous value: -"Icing layers reported. Empty array if no icing encountered (NEG)."New value: +"Icing layers reported. An explicit negative report is a layer with intensity NEG; an empty array means the PIREP carried no icing group, so the pilot said nothing either way."

Previous value: -"Turbulence layers reported. Empty array if no turbulence encountered (NEG)."New value: +"Turbulence layers reported. An explicit negative report is a layer with intensity NEG; an empty array means the PIREP carried no turbulence group, so the pilot said nothing either way."

Previous value: -"Cloud base altitude in feet MSL."New value: +"Cloud base altitude in feet AGL."

Previous value: -"Forecast wind direction in degrees true. Null when variable."New value: +"Forecast wind direction in degrees true. Null when the forecast said VRB (variable), and also when the period carries no wind element at all — speed_kt is null in that second case and a number in the first."

Added value: +[
+  {
+    "type": "number"
+  },
+  {
+    "type": "null"
+  }
+]

Previous value: -"Forecast wind speed in knots."New value: +"Forecast wind speed in knots. 0 is a forecast calm (a 00000KT group); null means the period amends only visibility, weather, or cloud and carries no wind element, so the wind is unknown rather than calm."

Removed value: -"number"

Previous value: -"Two-letter US state abbreviation (e.g., \"WA\") to list all stations in that state."New value: +"Two-letter USPS code for one of the 50 US states or DC (e.g., \"WA\") to list all stations in that jurisdiction. US territories are not supported — use bbox for those."

Removed value: -100

Previous value: -"Search radius in nautical miles around station_id. Only used when station_id is provided. Default 100."New value: +"Search radius in nautical miles around station_id, defaulting to 100 when omitted. Belongs to the station_id search only — supplying it alongside bbox is rejected."