NWS Severe Weather Alert Tracker – Weather Warning API

A National Weather Service alerts API wrapper and severe-weather feed that pulls active NWS warnings, watches and advisories and normalizes each into a clean record: event type, severity, urgency, certainty, affected area, effective/expiry timing and protective instructions. Use it to build a severe-weather alerting system for logistics, insurance, agriculture and utilities, or a location-based warning feed.

Who uses it

Logistics and fleet operations, property/casualty insurers, agriculture and energy/utility operations, event and construction managers, and safety/alerting products.

Why this is worth charging for

Active weather warnings drive routing, claims-readiness and safety decisions in real time. The NWS API returns GeoJSON features with alert data nested under properties and requires a descriptive User-Agent. This actor flattens features, filters by area/severity/event, and delivers a deduplicated active-alert feed ready to poll on a tight schedule.

Output

Each dataset item is one normalized record:

{
  "id": "urn:oid:2.49.0.1.840.0.abc",
  "event": "Tornado Warning",
  "severity": "Extreme",
  "urgency": "Immediate",
  "certainty": "Observed",
  "headline": "Tornado Warning issued for...",
  "areaDesc": "Dallas, TX",
  "senderName": "NWS Fort Worth TX",
  "effective": "2024-05-01T20:00:00-05:00",
  "expires": "2024-05-01T20:45:00-05:00",
  "status": "Actual",
  "instruction": "TAKE COVER NOW!",
  "source": "NWS"
}

Input

Field	Description
area	2-letter state or marine area code, e.g. TX. Leave blank for nationwide.
severity	Filter by alert severity.
urgency	Filter by urgency.
event	Filter by event, e.g. 'Tornado Warning', 'Flood Watch'.
status	Alert status (default actual).
onlyNewSinceLastRun	Recommended for schedules — skips records already returned by a previous run using persisted state, so you're only charged for genuinely new items.
maxItems	Stop after this many normalized records.

Pricing (Pay-Per-Event)

• query — $0.01, charged once per run for the API query/poll.
• alert-record — $0.005 per normalized record pushed. This is the primary event.
• apify-actor-start (Apify-managed) — covers baseline compute per run.

Active alerts for a state are usually a handful of records per poll, costing pennies. A tight schedule with onlyNewSinceLastRun bills only newly-issued alerts.

Source & reliability

Data comes from the official api.weather.gov/alerts/active service. A descriptive User-Agent is sent as NWS requires. No key or proxies required. Run npm test for the offline self-test covering the normalizer, including edge cases and missing-field handling.

FAQ

Do I need an API key?

No — the NWS API is open. A descriptive User-Agent is required and is sent automatically.

Can I alert for one state?

Yes. Set area to the state code (and optionally severity/event) and schedule with onlyNewSinceLastRun for near-real-time alerts.

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