How to Scrape NWS Weather Alerts

The National Weather Service publishes detailed hazard messages as GeoJSON, but operations teams usually need a smaller table they can filter, route, and archive. The NWS Weather Alerts Scraper retrieves active alerts by state or territory and preserves the fields needed for both human review and automation.

Query a bounded set of areas

Test both an active-alert case and a quiet-area case before deploying a consumer. Validate that multiline instructions, null geometry, time-zone offsets, and long affected-area names survive export. These common emergency-data edge cases expose brittle downstream assumptions quickly.

{"areaCodes":["TX","LA"],"severities":["Extreme","Severe"],"maxResultsPerArea":100}

Each row includes event, headline, description, instruction, severity, certainty, urgency, status, affected-area text, effective and expiry times, geocodes, geometry, sender, and the official alert URL. Duplicate alert IDs are saved once when the same message crosses area boundaries.

Exact event filters such as Flood Warning or Tornado Watch are useful for specialized workflows. Keep an unfiltered monitoring Task as a control, because event names and the hazards relevant to a business can change. Severity and urgency are separate dimensions: a severe event may not be immediate, while an immediate message deserves fast routing even when its severity label differs.

For recurring ingestion, upsert on alert ID and retain message timestamps. Alerts may be updated, extended, replaced, or cancelled after the first collection. Never convert a missing row into an all-clear without checking run health and source availability. Most importantly, automated alert feeds should support—not replace—official channels and local emergency guidance when people or property are at risk.