StormScope

Real-time US weather data for AI assistants via MCP. Uses the NWS API, NOAA Storm Prediction Center data, NOAA Weather Prediction Center surface analysis, Iowa Environmental Mesonet radar, and Open-Meteo pressure-level model data. Optionally uses data from your Tempest personal weather station.

US locations only. Covers all 50 states, DC, and US territories (Puerto Rico, Guam, USVI, American Samoa). Requests for non-US locations return a clear error. The SPC national outlook covers the contiguous US only.

What it does

Most tools support a detail parameter: standard gives a clean summary, full adds the technical depth (METAR, VTEC codes, polygon geometry, probabilistic outlooks).

• Current conditions: temperature, wind, humidity, sky, pressure
• Forecast in daily narrative periods, hourly, or raw gridpoint time-value series
• Active weather alerts with severity filtering
• SPC severe weather outlook, both categorical risk and probabilistic tornado/wind/hail
• National severe outlook with human-readable region descriptions
• NEXRAD radar station metadata and imagery URLs
• 500mb upper-air analysis: geopotential heights, temperature, wind, and derived vorticity (synoptic-scale resolution from a 5-point finite-difference grid — useful for identifying troughs, ridges, and jet stream patterns, but not mesoscale features)
• Surface analysis: fronts, pressure centers (highs/lows), and warm/cold sector detection relative to the nearest cold front
• Combined briefing that pulls everything together and adapts to the situation

Installation

Requires Python 3.11+ and uv.

claude mcp add --scope user stormscope -- uvx --from git+https://github.com/thornjad/stormscope stormscope

Or add to your Claude Code MCP config:

{
  "mcpServers": {
    "stormscope": {
      "command": "uvx",
      "args": ["--from", "git+https://github.com/thornjad/stormscope", "stormscope"],
      "env": {
        "PRIMARY_LATITUDE": "YOUR_LATITUDE",
        "PRIMARY_LONGITUDE": "YOUR_LONGITUDE"
      }
    }
  }
}

Configuration

Variable	Default	Description
PRIMARY_LATITUDE	none	Default latitude when coordinates aren't passed explicitly
PRIMARY_LONGITUDE	none	Default longitude when coordinates aren't passed explicitly
UNITS	us	Unit system (us or si)
ENABLE_CORELOCATION	false	Set to true to enable macOS CoreLocation (requires Xcode Command Line Tools)
DISABLE_AUTO_GEOLOCATION	false	Set to true to disable CoreLocation and IP geolocation
TEMPEST_TOKEN	none	Tempest Personal Access Token — enables Tempest station integration
TEMPEST_STATION_ID	none	Explicit station ID to use (optional, see Tempest station)
TEMPEST_STATION_NAME	none	Station name to match instead of ID (optional)
USE_TEMPEST_STATION_GEOLOCATION	false	Use Tempest station coordinates as the primary location

Location detection

All location-aware tools accept optional latitude and longitude parameters. When omitted, the server resolves location through a fallback chain:

1. Explicit latitude/longitude params — the AI can pass coordinates for any location
2. Tempest station location (opt-in) — set USE_TEMPEST_STATION_GEOLOCATION=true with a configured station to use its coordinates
3. PRIMARY_LATITUDE/PRIMARY_LONGITUDE env vars — precise, recommended for your home location
4. macOS CoreLocation (opt-in) — set ENABLE_CORELOCATION=true, requires Xcode Command Line Tools, ~100m WiFi-based accuracy, prompts for location permission on first use. Compiles a small Swift helper into ~/Library/Application Support/stormscope/
5. IP geolocation via ipinfo.io — automatic, city-level accuracy, one request per session

Setting DISABLE_AUTO_GEOLOCATION=true disables both CoreLocation and IP geolocation (tiers 4 and 5). With auto-geolocation disabled and no env vars or explicit params, tools return an error.

Tempest personal weather station

If you have a Tempest personal weather station, StormScope can enrich NWS data with hyper-local sensor readings that NWS cannot provide: solar radiation, UV index, lightning strike counts, air density, and wet bulb temperature. Tempest also supplies sunrise/sunset times in its forecast, which are added to get_forecast output.

Tempest data supplements NWS, it doesn't replace it. NWS provides authoritative alert text, detailed narrative forecasts, and broad coverage. Tempest provides hyper-local precision at your exact station location. When a Tempest station is within range, StormScope uses Tempest values for temperature, feels-like, humidity, wind, and pressure, and sets data_source: "tempest" in the response.

If the Tempest API is unavailable, all tools fall back to NWS data without error.

Setup

1. Get a Personal Access Token from the Tempest developer portal.
2. Find your station ID from the Tempest app or API (Settings → Stations, or from the URL at tempestwx.com/station/<id>).
3. Add to your MCP environment:

{
  "TEMPEST_TOKEN": "your-token-here",
  "TEMPEST_STATION_ID": "your-station-id"
}

Station resolution

When TEMPEST_STATION_ID is not set, StormScope auto-discovers the nearest station associated with your token. If the nearest station is more than 5 miles from the request coordinates, it is not used (to avoid attaching irrelevant data to a distant location). You can also identify a station by name with TEMPEST_STATION_NAME (matched case-insensitively against the station's name and public_name fields).

Variable	Purpose
TEMPEST_TOKEN	Required. Enables all Tempest functionality.
TEMPEST_STATION_ID	Use a specific station by numeric ID.
TEMPEST_STATION_NAME	Use a specific station by name.
USE_TEMPEST_STATION_GEOLOCATION	Set to true to use the station's GPS coordinates as the primary location. Requires TEMPEST_STATION_ID or TEMPEST_STATION_NAME.

Tools

Tool	Description	Key params
get_conditions	Current conditions at a station	detail: standard or full
get_forecast	Forecast in multiple formats	mode: daily, hourly, or raw; days (1-7, default 7); hours (1-48, default 24)
get_alerts	Active weather alerts	severity_filter: Extreme, Severe, Moderate, or Minor; detail: standard or full
get_spc_outlook	SPC outlook for a point	outlook_type: categorical, tornado, wind, or hail; day: 1-3
get_national_outlook	CONUS-wide risk areas (no lat/lon)	day: 1-3
get_radar	NEXRAD radar with textual summary and clickable links
get_upper_air	500mb heights, temperature, wind, derived vorticity (Open-Meteo)
get_surface_analysis	Fronts, pressure centers, warm/cold sector detection (WPC)	day: 1-3; detail: standard or full
get_briefing	Combined briefing, the default for general weather questions	detail: standard or full

All location-aware tools accept optional latitude/longitude, falling back to the configured location (see Location detection).

Upper-air data provided by Open-Meteo under CC-BY 4.0. Vorticity is derived from model wind fields at ~110km grid spacing — this captures synoptic-scale features (shortwave troughs, jet maxima) but not mesoscale detail.

Example conversation

These examples show how an AI assistant might present StormScope data. The tools return structured JSON, and the assistant formats it for the user.

"What's the weather?" (uses get_briefing):

Currently 72F and Mostly Sunny in Minneapolis, MN.
Feels like 72F. Wind SW 8 mph. Humidity 45%.
Today: High 78F, increasing clouds, chance of PM thunderstorms.
Tonight: Low 58F, scattered thunderstorms likely.
Severe Weather: Marginal Risk (MRGL) - isolated severe storms possible.
Alerts: None active.

"What's the severe weather outlook?" (uses get_briefing detail=full):

...plus dewpoint 50F, cloud layers FEW at 3000m, METAR: KMSP 041200Z...
Probabilistic: 5% tornado (significant), 15% wind, 15% hail
National: SLGT risk in central Oklahoma, MRGL in northern Texas
Radar: KMPX, latest scan 12:00Z, N0B/N0S available
Day 2: TSTM, Day 3: NONE

Skill suggestions

Create .claude/skills/ skills for common patterns:

• Morning briefing: get_briefing detail=full for a full picture to start the day
• Quick check: get_conditions for just current conditions
• Evening review: get_forecast mode=daily days=2 for tonight and tomorrow
• Chase prep: get_spc_outlook outlook_type=tornado + get_surface_analysis + get_upper_air + get_radar + get_alerts detail=full

Data sources

StormScope aggregates data from several upstream services. None of these services require authentication or API keys.

National Weather Service (NWS) — api.weather.gov (terms) Conditions, forecasts, alerts, and gridpoint data. NWS data is produced by the US federal government and is in the public domain under 17 U.S.C. § 105. Use of NWS data does not imply NOAA or NWS endorsement of this project.

NOAA Storm Prediction Center (SPC) — spc.noaa.gov (terms) Categorical and probabilistic severe weather outlooks (days 1-3). SPC data is US government public domain under the same statute as NWS.

NOAA Weather Prediction Center (WPC) — mapservices.weather.noaa.gov Surface analysis charts with fronts and pressure centers (days 1-3). WPC data is US government public domain under the same statute as NWS. Analysis charts are updated approximately 4 times per day. No pressure values are provided for H/L centers.

Iowa Environmental Mesonet (IEM) — mesonet.agron.iastate.edu (disclaimer) NEXRAD radar station metadata and imagery. IEM data is in the public domain and may be used freely by anyone for any lawful purpose. Data provided by the Iowa Environmental Mesonet of Iowa State University.

Open-Meteo — open-meteo.com (terms) 500mb upper-air pressure-level data (geopotential heights, temperature, wind). Provided under CC-BY 4.0. StormScope uses the free non-commercial tier and does not support paid Open-Meteo subscriptions.

ipinfo.io — ipinfo.io (terms) IP-based geolocation, used only as a last-resort fallback when no coordinates are configured and CoreLocation is unavailable. One request per server session. StormScope uses the free tier of this service and does not resell or redistribute the geolocation data. Set DISABLE_AUTO_GEOLOCATION=true to prevent this request entirely.

All upstream services provide data without warranty of accuracy or availability. StormScope caches responses to reduce request volume but cannot guarantee data freshness. Users of StormScope are responsible for complying with each service's terms of use. The authors of StormScope are not liable for how others use this software or the upstream APIs it connects to.

Disclaimer

This application is for informational and educational purposes only. It is not intended for use in life-threatening weather conditions or emergency situations, and should not be relied on as a sole source of weather information. Do not rely on this application for critical weather decisions. Always consult official weather services and emergency broadcasts during severe weather. This application may not provide real-time or accurate weather information. The authors shall not be held liable in the event of injury, death, or property damage resulting from reliance on this software. See the included license for specific language limiting liability.

Development

git clone https://github.com/thornjad/stormscope.git
cd stormscope
uv sync --group dev
uv run python -m pytest

License

ISC

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