NOUS41 KWBC 191840



Service Change Notice 17-110

National Weather Service Headquarters Washington DC

240 PM EDT Thu Oct 19 2017


TO:       Subscribers:

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS Partners and NWS Employees


FROM:     Ben Kyger

          Director, NCEP Central Operations (NCO)


SUBJECT:  Update on Changes to Access, Planned Termination of

          Common Alerting Protocol version 1.1, and Operational

          Implementation of Common Alerting Protocol Version 1.2

          Effective on or after March 1, 2018


Reference: NWS Service Change Notice (SCN) 17-35


SCN 17-35 announced the operational NWS implementation of

Watches/ Warnings/ Advisories (WWA) in Common Alerting Protocol

(CAP) version 1.2 (v1.2) format effective on April 30, 2017. The

notice identified a planned termination of CAP version 1.1

(v1.1) no sooner than September 1, 2017. Today's notice updates

users that NWS termination of CAP v1.1 will be no sooner than

March 1, 2018, and reminds users of the dissemination channels

and detailed documentation for CAP v1.2.


NWS will continue providing CAP v1.1 until at least March 1,

2018 at


On or after March 1, 2018, NWS will permanently cease production

of CAP v1.1 in any form or on any NWS dissemination channel. A

future SCN will specify the exact effective date of these

service terminations. On the effective date, the documentation

for accessing CAP v1.2 and the 7 day archive of NWS CAP v1.2

messages currently located at


will be moved to


CAP v1.2 messages are provided through multiple dissemination

channels, including the NWS Application Programming Interface

(API), http and ftp file listings, and NOAAPORT satellite

broadcast as summarized in sections 1-3 below. More details are

provided on the above web page.


1) The NWS API endpoint at


provides access to CAP v1.2 messages, a digest of active CAP

v1.2 messages in Atomic Syndication Format (ATOM), and CAP

content in JavaScript Object Notation (JSON) format. Users of

the API have reported issues with the availability, timeliness,

and time stamps in the ATOM and JSON formatted outputs via the

API. These issues are being addressed and further updates to

these issues will be provided on the Change Log tab at


2) CAP v1.2 messages are available via http and ftp file

listings at


These file listings provide a traditional directory listing of

all CAP alerts issued for the past 7 days as well as directory

lists (ls-l and ls-lt) for CAP consumers wishing to frequently

check for any new CAP messages in the directory.


3) CAP v1.2 messages are available via NOAAPORT satellite

broadcast under the WMO Heading XOaa5i KWBC, where aa

corresponds to US, AK, CA, GM, HW, or ZS, and i is equal to 0

(zero) to 9.


As a reflection of continued improvements to NWS service

delivery, NWS CAP v1.2 messages may periodically undergo minor

changes or updates to the CAP elements or parameters. Since CAP

is eXtensible Markup Language (XML)-based, these minor changes

or updates should not impact the ability of NWS partners and

users to properly parse the CAP messages; however, partners and

users are encouraged to monitor the continuously updated Change

Log tab reference above for all changes or updates to the CAP

v1.2 elements and parameters that might impact use of NWS CAP or

provide additional value.


For any operational issues, including CAP access and

connectivity, contact:


Senior Duty Meteorologist

National Centers for Environmental Prediction (NCEP) Central



For other non-operational technical questions, contact:


Software Development Branch  

NCEP Central Operations


For questions or suggestions about meteorological or hydrologic

content within CAP messages and CAP documentation, contact:


Mike Gerber

Office of Dissemination


National Service Change Notices are online at: