nws-weather-mcp-server

v0.10.0 pre-1.0

Get US weather forecasts, active alerts, and current observations via the National Weather Service API. STDIO or Streamable HTTP.

nws.caseyjhand.com/mcp
claude mcp add --transport http nws-weather-mcp-server https://nws.caseyjhand.com/mcp
codex mcp add nws-weather-mcp-server --url https://nws.caseyjhand.com/mcp
{
  "mcpServers": {
    "nws-weather-mcp-server": {
      "url": "https://nws.caseyjhand.com/mcp"
    }
  }
}
gemini mcp add --transport http nws-weather-mcp-server https://nws.caseyjhand.com/mcp
{
  "mcpServers": {
    "nws-weather-mcp-server": {
      "command": "bunx",
      "args": [
        "mcp-remote",
        "https://nws.caseyjhand.com/mcp"
      ]
    }
  }
}
{
  "mcpServers": {
    "nws-weather-mcp-server": {
      "type": "http",
      "url": "https://nws.caseyjhand.com/mcp"
    }
  }
}
curl -X POST https://nws.caseyjhand.com/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"curl","version":"1.0.0"}}}'

Tools

9

nws_get_forecast

Get the weather forecast for a US location. Returns either named 12-hour periods (default) or hourly breakdowns.

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_get_forecast",
    "arguments": {
      "latitude": "<latitude>",
      "longitude": "<longitude>"
    }
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "latitude": {
      "type": "number",
      "minimum": -90,
      "maximum": 90,
      "description": "Latitude in decimal degrees (e.g., 47.6062)."
    },
    "longitude": {
      "type": "number",
      "minimum": -180,
      "maximum": 180,
      "description": "Longitude in decimal degrees (e.g., -122.3321)."
    },
    "hourly": {
      "default": false,
      "description": "If true, returns hourly forecast (48 one-hour periods per page, ~156 available) instead of 12-hour named periods (14 periods). Hourly includes dewpoint and relative humidity.",
      "type": "boolean"
    },
    "cursor": {
      "description": "Opaque continuation token from a previous response's nextCursor, to retrieve the next 48 periods. Omit for the first page. Every call re-fetches the forecast, so consecutive periods are contiguous within one response; NWS reissues forecasts through the day, so a later call can window a regenerated period array.",
      "type": "string"
    }
  },
  "required": [
    "latitude",
    "longitude",
    "hourly"
  ],
  "additionalProperties": false
}
view source ↗

nws_search_alerts

Search active weather alerts (watches, warnings, advisories) across the US. Filter by state, coordinates, zone, land/marine region, event type, severity, urgency, or certainty. area, point, zone, region_type, and region are mutually exclusive — provide at most one. Omit all filters for a national search.

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_search_alerts",
    "arguments": {}
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "area": {
      "description": "US state/territory code (e.g., \"WA\", \"OK\", \"PR\") or marine area code (e.g., \"GM\"). Mutually exclusive with point and zone.",
      "type": "string"
    },
    "point": {
      "description": "Coordinates as \"lat,lon\" (e.g., \"47.6,-122.3\"). Returns alerts whose geometry contains this point. Mutually exclusive with area and zone.",
      "type": "string"
    },
    "zone": {
      "description": "NWS forecast zone (e.g., \"WAZ558\") or county zone (e.g., \"WAC033\"). Mutually exclusive with area and point.",
      "type": "string"
    },
    "region_type": {
      "description": "Restrict to land-based or marine alerts. Mutually exclusive with area, point, zone, and region.",
      "type": "string",
      "enum": [
        "Land",
        "Marine"
      ]
    },
    "region": {
      "description": "Restrict to NWS marine region groups: \"AL\" (Alaska waters), \"AT\" (Atlantic Ocean), \"GL\" (Great Lakes), \"GM\" (Gulf of Mexico), \"PA\" (Eastern Pacific and US West Coast), \"PI\" (Central and Western Pacific). Marine alerts only — a land alert never matches. Mutually exclusive with area, point, zone, and region_type.",
      "type": "array",
      "items": {
        "type": "string",
        "enum": [
          "AL",
          "AT",
          "GL",
          "GM",
          "PA",
          "PI"
        ]
      }
    },
    "event": {
      "description": "Filter to specific event types (e.g., [\"Tornado Warning\"]). Matches are case-insensitive and partial, so \"tornado\" matches both \"Tornado Warning\" and \"Tornado Watch\". Use nws_list_alert_types to discover valid names.",
      "type": "array",
      "items": {
        "type": "string"
      }
    },
    "severity": {
      "description": "Filter by severity level.",
      "type": "array",
      "items": {
        "type": "string",
        "enum": [
          "Extreme",
          "Severe",
          "Moderate",
          "Minor",
          "Unknown"
        ]
      }
    },
    "urgency": {
      "description": "Filter by urgency level.",
      "type": "array",
      "items": {
        "type": "string",
        "enum": [
          "Immediate",
          "Expected",
          "Future",
          "Past"
        ]
      }
    },
    "certainty": {
      "description": "Filter by certainty level.",
      "type": "array",
      "items": {
        "type": "string",
        "enum": [
          "Observed",
          "Likely",
          "Possible",
          "Unlikely",
          "Unknown"
        ]
      }
    },
    "status": {
      "description": "Alert status filter. Default \"Actual\". Use a different value only when you specifically need non-live alerts.",
      "default": "Actual",
      "type": "string",
      "enum": [
        "Actual",
        "Exercise",
        "System",
        "Test",
        "Draft"
      ]
    },
    "limit": {
      "default": 25,
      "description": "Maximum number of alerts to include in this page (1-25, default 25). totalCount still reports the full number of distinct matches, so a small limit returns a digest of broad or national searches without dropping the total; pass the returned nextCursor as cursor to reach the rest.",
      "type": "integer",
      "minimum": 1,
      "maximum": 25
    },
    "cursor": {
      "description": "Opaque continuation token from a previous response's nextCursor. Omit for the first page. The token carries its own page size, so limit applies to the first page only. Every call re-fetches the active-alert feed, so alerts are contiguous within one response but not across calls — the active set changes continuously as alerts are issued and expire, so a continued page covers the collection as it stands at that moment.",
      "type": "string"
    }
  },
  "required": [
    "status",
    "limit"
  ],
  "additionalProperties": false
}
view source ↗

nws_get_alert_counts

Count active weather alerts nationwide, per state/territory or marine area, and per marine region, in one small response — the answer to "how many alerts are active, and where" without fetching the alerts themselves. Counts cover every message status, Test and Exercise included, so totalAlerts can run above the totalCount a national nws_search_alerts search reports under its default status of Actual. An alert counts once in each area its zones fall in, so the area counts can sum past totalAlerts; landAlerts plus marineAlerts equals totalAlerts. Takes no filters. For counts per zone or under a filter, call nws_search_alerts with that zone or filter and read its totalCount.

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_get_alert_counts",
    "arguments": {}
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {},
  "additionalProperties": false
}
view source ↗

nws_get_observations

Get current weather observations (actual measured conditions). Accepts coordinates (resolves nearest station automatically) or a station ID directly (e.g., "KSEA").

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_get_observations",
    "arguments": {}
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "latitude": {
      "description": "Latitude for automatic station resolution. Use with longitude. Ignored if station_id is provided.",
      "type": "number",
      "minimum": -90,
      "maximum": 90
    },
    "longitude": {
      "description": "Longitude for automatic station resolution. Use with latitude. Ignored if station_id is provided.",
      "type": "number",
      "minimum": -180,
      "maximum": 180
    },
    "station_id": {
      "description": "Station identifier directly (e.g., \"KSEA\", \"KORD\"). Use nws_find_stations to discover station IDs.",
      "type": "string"
    }
  },
  "additionalProperties": false
}
view source ↗

nws_get_observation_history

Get a station's recent observation history, newest first — the trend behind the single latest reading nws_get_observations returns (is pressure falling, is the wind picking up). NWS keeps about the last 7 days per station, and a busy airport station reports as often as every 5 minutes, so a day can run past 100 observations: narrow with start (inclusive) and end (exclusive), and page back to older observations with nextCursor. Takes a station ID; use nws_find_stations to find one near a coordinate.

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_get_observation_history",
    "arguments": {
      "station_id": "<station_id>"
    }
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "station_id": {
      "type": "string",
      "minLength": 1,
      "description": "Observation station ID (e.g., \"KSEA\"), case-insensitive. Use nws_find_stations to discover station IDs near a coordinate."
    },
    "start": {
      "description": "Earliest observation time to include (inclusive), as an ISO 8601 date-time with seconds and an offset (e.g., \"2026-09-30T00:00:00Z\" or \"2026-09-29T17:00:00-07:00\"). Omit to reach back as far as NWS keeps, about 7 days.",
      "type": "string"
    },
    "end": {
      "description": "Time to stop before (exclusive), in the same format as start. Omit to start from the most recent observation.",
      "type": "string"
    },
    "limit": {
      "default": 24,
      "description": "Observations per page (1-100), newest first. When a page fills the limit, pass its nextCursor back as cursor for older observations.",
      "type": "integer",
      "minimum": 1,
      "maximum": 100
    },
    "cursor": {
      "description": "Opaque continuation token from a previous response's nextCursor. Omit for the first page. It carries that query's start, end, and limit, so those inputs apply to the first page only. Each page continues from just before the oldest observation of the one before it, so pages neither repeat nor skip an observation.",
      "type": "string"
    }
  },
  "required": [
    "station_id",
    "limit"
  ],
  "additionalProperties": false
}
view source ↗

nws_find_stations

Find weather observation stations near a location. Returns stations sorted by proximity with distance and bearing. Use to discover station IDs for nws_get_observations.

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_find_stations",
    "arguments": {
      "latitude": "<latitude>",
      "longitude": "<longitude>"
    }
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "latitude": {
      "type": "number",
      "minimum": -90,
      "maximum": 90,
      "description": "Center latitude for proximity search."
    },
    "longitude": {
      "type": "number",
      "minimum": -180,
      "maximum": 180,
      "description": "Center longitude for proximity search."
    },
    "limit": {
      "default": 10,
      "description": "Max stations per page (1-50). totalCount still reports every station near the point, so pass the returned nextCursor as cursor to reach the rest.",
      "type": "integer",
      "minimum": 1,
      "maximum": 50
    },
    "cursor": {
      "description": "Opaque continuation token from a previous response's nextCursor. Omit for the first page. The token carries its own page size, so limit applies to the first page only. Every call re-fetches the station list, so pages are contiguous within one response; the registry changes rarely, but a later call can window an updated list.",
      "type": "string"
    }
  },
  "required": [
    "latitude",
    "longitude",
    "limit"
  ],
  "additionalProperties": false
}
view source ↗

nws_list_alert_types

List all valid NWS alert event type names. Use to discover valid values for the event filter in nws_search_alerts, or to browse alert categories. No parameters required.

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_list_alert_types",
    "arguments": {}
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {},
  "additionalProperties": false
}
view source ↗

nws_get_office_discussion

Get the latest narrative forecast product from a Weather Forecast Office (WFO). The default product is AFD (Area Forecast Discussion), which explains the meteorological reasoning behind the forecast — synoptic setup, model guidance, and forecaster confidence. Other types: HWO (Hazardous Weather Outlook, 1-7 day severe/flood/winter outlook), ZFP (Zone Forecast Product, zone-by-zone text), SPS (Special Weather Statement, short-fuse advisory). The office code is the 3-letter WFO identifier returned as the "office" field by nws_get_forecast.

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_get_office_discussion",
    "arguments": {
      "office": "<office>"
    }
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "office": {
      "type": "string",
      "minLength": 1,
      "description": "Three-letter Weather Forecast Office (WFO) code (e.g., \"SEW\" for Seattle, \"LOX\" for Los Angeles). Returned as the \"office\" field in nws_get_forecast output."
    },
    "product_type": {
      "description": "Product type code. AFD (Area Forecast Discussion) — meteorological reasoning, model analysis, forecaster confidence. HWO (Hazardous Weather Outlook) — 1-7 day outlook for severe weather, flooding, winter weather. ZFP (Zone Forecast Product) — detailed zone-by-zone text forecast. SPS (Special Weather Statement) — short-fuse advisory for notable non-warning weather.",
      "default": "AFD",
      "type": "string",
      "enum": [
        "AFD",
        "HWO",
        "ZFP",
        "SPS"
      ]
    }
  },
  "required": [
    "office",
    "product_type"
  ],
  "additionalProperties": false
}
view source ↗

nws_get_zone_forecast

Get the text forecast for a public NWS forecast zone. Returns named forecast periods (e.g., "Today", "Tonight", "Monday") with detailed narrative text — the human-readable, zone-level forecast written by local forecasters. Completes the alert-to-forecast chain: nws_search_alerts returns each affected zone in "affectedZones" as a code plus a type, and nws_find_stations returns codes in the "forecastZone" column. Only affectedZones entries with type "forecast" work here; entries typed "county" or "fire" have no text forecast upstream and will not resolve, and neither do marine forecast zones (e.g., "PZZ251", "GMZ056"). Zone codes follow the pattern XXZ### (e.g., "WAZ315" for Western Washington lowlands).

read
invocation
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "nws_get_zone_forecast",
    "arguments": {
      "zone_id": "<zone_id>"
    }
  }
}
schema
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "zone_id": {
      "type": "string",
      "minLength": 1,
      "description": "NWS public forecast zone code (e.g., \"WAZ315\" for the Western Washington lowlands including Seattle). Returned as \"forecastZone\" by nws_get_forecast and nws_find_stations, or as the \"code\" of an \"affectedZones\" entry with type \"forecast\" in nws_search_alerts. Format: two-letter state + \"Z\" + three-digit number."
    }
  },
  "required": [
    "zone_id"
  ],
  "additionalProperties": false
}
view source ↗

Resources

1

Static list of all valid NWS alert event type names. Useful reference when constructing event filters for nws_search_alerts.

uri nws://alert-types mime application/json