Weather API · ZASNet Weather Service

Overview

A familiar alerts interface

The API is a read-only view of currently active, non-practice ZASNet products. Responses use GeoJSON and include CAP-style status, urgency, severity, certainty, event text, geocodes, timing, instructions, and geometry.

Important

This is an unofficial ZASNet service. For life-safety decisions, follow official warnings and local emergency instructions.

Base URL
Authentication: None
Response format: GeoJSON / JSON
CORS: Allowed from all origins
Cache lifetime: 15 seconds
Maximum page size: 500 alerts

Reference

Endpoints

GET/api/public/alerts/active

List active alerts. Apply query parameters to filter the collection.

GET/api/public/alerts/active/area/{state}

Active alerts for a two-letter state or territory code.

GET/api/public/alerts/active/zone/{zone}

Active alerts for a UGC county or forecast-zone identifier.

GET/api/public/alerts/active/count

Small JSON summary grouped by event name.

GET/api/public/alerts/{id}

Retrieve one active alert by its internal ID or product ID.

GET/api/public/alerts/{id}.txt

Retrieve the complete plain-text warning bulletin.

Query parameters

Filter active alerts

Parameter	Value	Description
`area`	`TN`	Two-letter state or territory. Comma-separated values are accepted.
`zone`	`TN006`	UGC county or forecast-zone identifier.
`point`	`36.16,-86.78`	Latitude and longitude. Returns alerts whose geometry contains the point.
`event`	`Tornado Warning`	Exact event name, case-insensitive.
`code`	`TOR`	ZASNet/AWIPS product code.
`severity`	`Severe`	Extreme, Severe, Moderate, Minor, or Unknown.
`urgency`	`Immediate`	Immediate, Expected, Future, Past, or Unknown.
`certainty`	`Observed`	Observed, Likely, Possible, Unlikely, or Unknown.
`limit`	`100`	Results per page, from 1 through 500.
`cursor`	`100`	Result offset supplied by `pagination.next`.

Repeat a parameter or use comma-separated values to request multiple matches. Different filters are combined with AND.

Recipes

Example requests

curl "/api/public/alerts/active?event=Tornado%20Warning&area=TN"

const url = new URL("/api/public/alerts/active");
url.searchParams.set("point", "36.16,-86.78");

const response = await fetch(url);
if (!response.ok) throw new Error(`API ${response.status}`);
const alerts = await response.json();
console.log(alerts.features);

import requests

response = requests.get(
    "/api/public/alerts/active",
    params={"area": "TN", "severity": "Severe"},
    timeout=20,
)
response.raise_for_status()
alerts = response.json()["features"]

Data model

Alert feature

Every collection member is a GeoJSON Feature. Polygon or MultiPolygon geometry describes the alert area; geometry may be null when no usable area is available.

id

Canonical URL for this alert.

geometry

GeoJSON Polygon or MultiPolygon.

properties.id

Stable ZASNet alert identifier.

properties.event

Human-readable hazard name.

properties.areaDesc

Plain-language affected area.

properties.geocode

SAME/FIPS and UGC identifiers.

properties.sent / effective / onset / expires / ends

ISO 8601 lifecycle times.

properties.status

CAP status; public products are Actual.

properties.severity / urgency / certainty

CAP-style hazard classification.

properties.headline / description / instruction

Human-readable alert content.

properties.sender / senderName

Issuing office identity.

properties.parameters

Product code, product ID, and state metadata.

For exact types and enumerations, use the OpenAPI 3.1 document.

Collections

Pagination

Set limit to control page size. When more results exist, the response contains a complete URL in pagination.next. Follow that URL as provided. A null value means the final page has been reached.

{
  "pagination": {
    "next": "/api/public/alerts/active?limit=100&cursor=100"
  }
}

Operations

Errors, caching, and use

200 — request succeeded, including an empty collection.
404 — an individual alert does not exist or is no longer active.
5xx — service-side failure; retry with exponential backoff.

Collection responses advertise Cache-Control: public, max-age=15. Clients should honor that cache window and avoid aggressive polling. Cross-origin GET, HEAD, and OPTIONS requests are supported without credentials.

Compatibility

Existing response formats

Clients built for the original ZASNet API can continue using these routes:

/api/public/alerts — compact ZASNet JSON
/api/public/alerts?format=geojson — map-oriented GeoJSON
/api/public/alerts?format=catalog — lightweight product catalog
/api/public/summary — active product summary