NWS active weather alerts monitor

What it does

Reads active alerts from the U.S. National Weather Service. Filters by area, zone, event, severity, and urgency. Alert text passes through unchanged.

Why

Use scheduled runs to collect active alerts and track which alert IDs your monitor has already emitted.

Input

Field	Default	Meaning
areas	[]	Two-letter state or marine codes. Editor prefill is ["TX"]. Empty selects all US areas.
zones	[]	NWS zone IDs such as TXZ183. Zones override areas with a warning.
events	[]	Event names such as Tornado Warning. Empty selects all.
severities	[]	Extreme, Severe, Moderate, Minor, Unknown. Empty selects all.
urgencies	[]	Immediate, Expected, Future, Past, Unknown. Empty selects all.
onlyNew	false	Skip alert IDs previously emitted to the state store.
maxItems	100	Integer from 1 to 10000. Maximum source alerts examined before duplicate and onlyNew filtering.
stateStoreName	nws-weather-alerts-monitor-state	Named store for cross-run history.

Requests always use status=actual. The endpoint returns all active matching alerts in one response. The Actor sends no limit or paging parameters and truncates locally. A run can emit fewer than maxItems after duplicate and onlyNew filtering.

Output

Each record includes alert text, timing, codes, references, and attribution. Missing scalar fields are null. Missing lists are empty. Geometry is represented by hasGeometry, without coordinates. Both web and sourceUrl use the alert's properties["@id"] URL.

Example record from the supplied fixture follows.

{
  "alertId": "urn:oid:2.49.0.1.840.0.b79c043702c63b741ebd1959280202b549a6bd15.001.1",
  "event": "Flash Flood Warning",
  "headline": "Flash Flood Warning issued October 30 at 3:16AM CDT until October 30 at 7:15AM CDT by NWS Midland/Odessa TX",
  "severity": "Severe",
  "urgency": "Immediate",
  "certainty": "Likely",
  "status": "Actual",
  "messageType": "Alert",
  "category": "Met",
  "areaDesc": "Ector, TX; Midland, TX",
  "sameCodes": [
    "048135",
    "048329"
  ],
  "ugcCodes": [
    "TXC135",
    "TXC329"
  ],
  "affectedZones": [
    "https://api.weather.gov/zones/county/TXC135",
    "https://api.weather.gov/zones/county/TXC329"
  ],
  "sent": "2026-10-30T03:16:00-05:00",
  "effective": "2026-10-30T03:16:00-05:00",
  "onset": "2026-10-30T03:16:00-05:00",
  "expires": "2026-10-30T07:15:00-05:00",
  "ends": "2026-10-30T07:15:00-05:00",
  "senderName": "NWS Midland/Odessa TX",
  "description": "FFWMAF\n\nThe National Weather Service in Midland/Odessa has issued a\n\n* Flash Flood Warning for...\nEast Central Ector County in western Texas...\nNorthwestern Midland County in western Texas...\n\n* Until 715 AM CDT.\n\n* At 316 AM CDT, Doppler radar indicated thunderstorms producing\nheavy rain across the warned area. Between 0.5 and 1 inch of rain\nhas fallen. Additional rainfall amounts up to 1 inch are possible\nin the warned area. Flash flooding is ongoing or expected to begin\nshortly. Use caution driving this morning, especially in roads\nprone to poor drainage flooding.\n\nHAZARD...Flash flooding caused by thunderstorms.\n\nSOURCE...Radar indicated.\n\nIMPACT...Flash flooding of small creeks and streams, urban areas,\nhighways, streets and underpasses as well as other poor\ndrainage and low-lying areas.\n\n* Some locations that will experience flash flooding include...\nMidland, Odessa, Midland International Air and Space Port, West\nOdessa, Warfield, Odessa Schlemeyer Field, Midland Airpark and\nCotton Flat.",
  "instruction": "Turn around, don't drown when encountering flooded roads. Most flood\ndeaths occur in vehicles.\n\nBe especially cautious at night when it is harder to recognize the\ndangers of flooding.\n\nBe aware of your surroundings and do not drive on flooded roads.",
  "response": "Avoid",
  "references": [],
  "web": "https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.b79c043702c63b741ebd1959280202b549a6bd15.001.1",
  "hasGeometry": true,
  "source": "U.S. National Weather Service (api.weather.gov)",
  "sourceUrl": "https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.b79c043702c63b741ebd1959280202b549a6bd15.001.1",
  "licence": "U.S. Government public domain (https://www.weather.gov/disclaimer)",
  "disclaimer": "Information from the U.S. National Weather Service, not subject to copyright protection (17 U.S.C. 403). Alert text is passed on unmodified. Not endorsed by NOAA/NWS. Not an official warning channel; check weather.gov for current alerts.",
  "generatedId": "NWS:urn:oid:2.49.0.1.840.0.b79c043702c63b741ebd1959280202b549a6bd15.001.1",
  "changeType": "new",
  "scrapedAt": "2026-10-30T09:30:00.000Z"
}

The dataset includes a table view. RUN_SUMMARY in the default key-value store contains timestamps, fetched, eligible, and pushed counts, charge-limit status, and any error.

State and pricing

The named state store holds alert IDs under SEEN_ALERT_IDS. Only successful pushes enter the set. Existing IDs receive changeType "seen". New IDs receive "new". With onlyNew enabled, seen IDs are skipped. Changes to text under an existing ID do not count as new. Separate monitors can use separate store names. A permission error opening the named store causes a warning and fallback to the default store with onlyNew disabled.

Pricing is $0.001 per result, no start fee. Each emitted record uses the result billing event. The Actor stops at the available charge limit. Skipped records incur no result charge. Platform compute and storage charges may apply separately.

Source, licence, and disclaimer

Source endpoint: https://api.weather.gov/alerts/active

U.S. Government public domain (https://www.weather.gov/disclaimer)

Information from the U.S. National Weather Service, not subject to copyright protection (17 U.S.C. 403). Alert text is passed on unmodified. Not endorsed by NOAA/NWS. Not an official warning channel; check weather.gov for current alerts.

Requests send Accept: application/geo+json and User-Agent: keepable_injera-apify-monitor (cheechiawbot@mail.grokbot.com). No API keys or proxies are used.

Limits

This is a snapshot of active alerts, not an archive or an official warning channel. Check weather.gov for current alerts. Source availability and active alert counts vary. Text is passed through without edits. The Actor waits at least one second between request starts per host and retries HTTP 429 and 5xx responses up to three times. Network errors stop the run and appear in RUN_SUMMARY.

Local verification

Run npm test for offline tests. Use a fresh storage directory for the fixture-backed local run.

CRAWLEE_STORAGE_DIR=/tmp/nws-check APIFY_LOCAL_STORAGE_DIR=/tmp/nws-check NODE_OPTIONS="--import ./scripts/offline-fixture.js" npm start
node scripts/verify-output.js /tmp/nws-check

The preload disables network requests and serves the supplied fixture. It does not simulate source filtering. Live source access was not used for verification.