Nws Warning Bot

NWS Warning Bot

Polygon-level severe weather monitoring for your actual address.

What This Does

Standard weather alerts are county-level. If you're in a county with 500 square miles, a tornado warning 40 miles north of you triggers the same alert as one approaching your house. This bot changes that.

Core feature: Checks if NWS warning polygons actually contain your coordinates. Only alerts when warnings physically overlap your location—not just your zip code, not just your county—your actual lat/lon.

Quick Start

1. Find Your Coordinates

Options:

• Google Maps: Right-click your house → "What's here?" → copy decimals
• GPS device or phone app
• Address geocoder: curl "https://geocoding.geo.census.gov/geocoder/locations/onelineaddress?address=YOUR%20ADDRESS&format=json"

2. Set Environment Variables

export WARNING_BOT_LAT=YOUR_LAT      # Your latitude
export WARNING_BOT_LON=YOUR_LON      # Your longitude  
export WARNING_BOT_ADDRESS="Your Address, City, State"
export WARNING_BOT_STATE="OH"        # Your state code

3. Run Manual Check

python3 scripts/warning-bot.py

• Exit code 0: No warnings for your address
• Exit code 1: Warning detected, saved to data/alert-pending.txt

4. Automate with Cron

*/5 * * * * /path/to/warning-bot/scripts/warning-bot-cron.sh

Then wire data/alert-pending.txt to your notification system (Telegram, email, etc.)

How It Works

Polygon detection: Uses ray-casting algorithm to test if your lat/lon falls inside NWS GeoJSON warning polygons. Handles both Polygon and MultiPolygon geometries.

Deduplication: SQLite tracks alert IDs for 24h to prevent repeat notifications for the same warning.

Monitoring: By default watches Tornado Warning, Severe Thunderstorm Warning, Tornado Watch, Severe Thunderstorm Watch.

Configuration

Output Files

Testing

Validate your coordinates:

# Test if bot detects warnings for your location
python3 -c "
import os
os.environ['WARNING_BOT_LAT'] = 'YOUR_LAT'
os.environ['WARNING_BOT_LON'] = 'YOUR_LON'
os.environ['WARNING_BOT_ADDRESS'] = 'Test Location'

from scripts.warning_bot import point_in_polygon

# Mock warning polygon (approximate bounding box around test area)
test = [[-83.0, 40.5], [-82.0, 40.5], [-82.0, 41.5], [-83.0, 41.5], [-83.0, 40.5]]
print('Inside:', point_in_polygon(YOUR_LAT, YOUR_LON, test))
"

Requirements

• Python 3.7+
• sqlite3 (stdlib)
• urllib, json, datetime (stdlib)
• No external dependencies

API Notes

Uses api.weather.gov/alerts/active?area={STATE} with:

• 10s timeout
• GeoJSON format
• Standard User-Agent header (update with your email in production)

NWS requires respectful usage. Don't poll more than every 5 minutes. Rate limits are generous but undocumented—be a good citizen.

Integration Examples

Telegram notification:

if [ -f data/alert-pending.txt ]; then
  cat data/alert-pending.txt | telegram-send --stdin
  rm data/alert-pending.txt
fi

Email notification:

if [ -s data/alert-pending.txt ]; then
  mail -s "Severe Weather Alert" user@example.com < data/alert-pending.txt
fi

Limitations

• US only: NWS API covers United States
• Polygon-dependent: If NWS issues a watch without detailed polygons, those are skipped (typically county-level watches lack geometry)
• No forecast: Only monitors active alerts, not future risk
• Point-based: Uses single lat/lon; doesn't account for property size

Safety Notes

This tool augments official sources—doesn't replace them.

• Keep NOAA Weather Radio as backup
• Don't disable county-level alerts entirely
• Test the system before severe weather season
• Monitor NWS directly during active events

Credits

Built on NWS API (api.weather.gov) with GeoJSON polygon data. Ray-casting algorithm standard in computational geometry.