National Weather Service United States Department of Commerce

High Flood Risk For Saturated Tennessee Valley and South; Near-Blizzard Conditions Possible for the Plains and Upper Midwest This Weekend

A high risk for flash flooding near a stalled front will continue across the saturated Tennessee Valley and South today. Meanwhile, a storm system producing heavy mountain and rare low elevation snows will shift from the Southwest across the Plains this weekend, with near blizzard conditions. To the south, an outbreak of severe thunderstorms is expected for the Mississippi Valley on Saturday. Read More >

Overview

The National Weather Service (NWS) API allows developers access to critrical forecasts, alerts, and observations, along with other weather data. The API was designed with a cache-friendly approach that expires content based upon the information life cycle. The API is based upon of JSON-LD to prommote machine data discovery.

Content Negotiation

The API uses the request headers to modify the response returned. See the FAQ tab for more information. Example of parameters include:

  • Request new features
  • Format the response

Authentication

A User Agent is required to identify your application. This string can be anything, and the more unique to your application the less likely it will be affected by a security event. If you include contact information (website or email), we can contact you if your string is associated to a security event. This will be replaced with an API key in the future.

Endpoints

The API is located at: https://api.weather.gov

Formats

Endpoints typically have a GeoJSON default format, given the inclusion of geometry data. Additional formats may be requested using the request header. See the Specification tab for details on each endpoint. Below are common formats available by the API.

  • GeoJSON: application/geo+json
  • JSON-LD: application/ld+json
  • DWML: application/vnd.noaa.dwml+xml
  • OXML: application/vnd.noaa.obs+xml
  • CAP: application/cap+xml
  • ATOM: application/atom+xml

How do I discover weather data using the API?

The API uses linked data to allow applications to discover content. Similar to a web site that provides HTML links to help users navigate to each page; linked data helps applications navigate to each endpoint. The /points/location endpoint is the most common endpoint to discover additional API content given the popularity of weather data based upon a location (latitude and longitude). For example, to discover the endpoint of the raw forecast, the application would first request:

https://api.weather.gov/points/39.7456,-97.0892

This response tells the application where to find relative information–including office, zone and forecast data–for a given point. The application can then use the linked data in the previous response to locate the raw forecast:

https://api.weather.gov/gridpoints/TOP/31,80

General Questions

What is an Accept header?

The new API will use headers to modify the version and format of the response. Every request, either by browser or application, sends header information every time you visit any website. For example, a commonly used header called "UserAgent" tells a website what type of device you are using so it can tailor the best experience for you. No private information is shared in a header, and this is a standard practice for all government and private sites. Developers can override these headers for specific purposes (see the "API Specifications" tab for more information). You can get full details by visiting the header field definitions page at the World Wide Web Consortium site.

Known Issues

Before contacting us, please review the following list of issues that have been identified for a future update.

  1. Delayed observations

    An infrastructure issue is causing delayed processing of observation station data. Observations may be intermittently delayed or not available. This is being worked, and will likely take several weeks to resolve.

    Updated 09/05/2018


Upstream Issues

  1. HCE does not provide Alaska Region marine products

    HazCollect Extended (HCE) creates the CAP products that are provided by the API /alerts endpoints. Alaska Region does not issue alerts in a manner that is processed by HCE, therefore the marine products are not returned on the API. The National Weather Service is investigating a resolution.

    Updated 06/08/2018

 

The following issues have been recently resolved.

  • There are no recently resolved issues to report

Specification

Important! Only the following endpoints are considered operational. Changes to operational endpoints are subject to PNS and SCN notices. All other endpoints are subject to change without notice.

  • /alerts/*