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Experimental XML/CAP 1.1 Feeds and Web Displays of Watches,
Warnings, and Advisories
NOAA's National Weather Service offers several XML services
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This page provides access to NWS watches, warnings, advisories, and other similar products several different formats. Select a state or product name to view a list of active alerts in your web browser. These files are updated about every two minutes.
This version makes use of the XML based ATOM format (The Atom
Syndication Format is an XML language used for web feeds) to provide
a state based index for active messges in ATOM and CAP formats.
The CAP 1.1 messages feature more detailed pre-parsing of NWS text
messages than has been offered previously. In addition, these feeds make use of the Extensible Stylesheet Language (XSL) to describe how files encoded in the XML standard are to be formatted or transformed for display by your web browser. Be sure to view source if you want to see the actual XML/CAP data of the alert.
We welcome your comments on these alerts. You can also view the Service Description Document.
Feeds based on state and NWS forecast zones are provided to aid
the automated dissemination of this information. More information
on ATOM and CAP/XML formats/feeds. This is an experimental
product of the National Weather Service. Comments and feedback
are welcome.
About
Select
any state to see a list of alerts for that state. Select from the "By County/Zone" column to
select from a list of NWS forecast zones. In many locations, these zones roughly follow
county lines.
The display
of the active state watches/warnings/advisories is controlled by
the XSL
stylesheet posted at http://www.weather.gov/wwarss-tst/capatomproduct.xsl
About ATOM
ATOM is an XML based document format for syndicating news and other
timely news-like information. It provides headlines, URLs to the
source document and brief description information in an easy to understand
and use format. ATOM based News Readers and News
Aggregators allow the display of ATOM headlines on workstation
desktops. Software libraries exist to read the ATOM format and present
ATOM headlines on webpages and other online applications.
Subscribe to one of the ATOM feeds by selecting the 2nd column by clicking on the
ATOM  logo.
For comsumers of these feeds as indexes to the CAP messages, the ATOM feeds contain
several CAP data fields to assist in the tracking of available CAP messages with the goal
of reducing the need to query the complete CAP message at every refresh.
About CAP 1.1/XML
Common Alertings Protocol (CAP) is an non-proprietary standard data
format for the interchange of hazard warning and reports. More information
on CAP can be found at the CAP information:
The
CAP: What, Why and How
Technical information about CAP is available from this non-US
Government maintained website: CAP Cookbook.
Technical Notes about the CAP 1.1 Messages
- Unlike the NWS CAP 1.0 feeds, in this version is there is a single alert per CAP message.
This more closely brings the feeds in line with the original intend of CAP;
- It is assumed consumers of the CAP 1.1 feeds will use the ATOM index files to track
active alerts in near real time and pulling the complete CAP messages as needed;
- The ATOM indexes contain a number of CAP 1.1 fields as an extension to the ATOM fields
(thus the switch from RSS to ATOM in this version). These fields are included to provide
additional information to the consumer with the intent of reducing the need to pull the
entire CAP message every time;
- An XML style sheet is used to display the CAP message in a human readable format in
modern web browsers. Not all CAP fields are displayed in the human view. Be sure to
view the message source to see all available fields;
- NWS based UGC and VTEC codes have been
parsed out to provide cross reference to these code systems.
- SAME codes are provided when available
(not all NWS products are issued with a SAME code);
- NWS Storm Based Warning lat/lon pairs are
made available when provided. Not all NWS products are issued with this information;
- County FIPS codes are provided
for all CAP 1.1 messages;
- NWS provides
shapefiles of NWS forecast zones that are provided in the UGC system and also parsed
into fields in the CAP 1.1 messages. These are provided for all CAP 1.1 messages;
- A list of possible data that is populated in the <event> field
is available.
Known issues and bugs (updated 9/10/09);
- Need to send a valid XML response if the Alert has expired;
- Various valid issues with the ATOM feeds, including white spaces and line feeds;
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