NOUS41 KWBC 011600



Service Change Notice 17-98

National Weather Service Headquarters Washington DC

1200 PM EDT Fri Sep 1 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:  Termination of Common Alerting Protocol

          Version 1.1 CAP (v1.1) to be No Sooner than

          November 1, 2017


NWS will terminate CAP v1.1 no sooner than November 1, 2017. 

NWS also reminds users of the dissemination channels and

documentation for Common Alerting Protocol version 1.2 

(CAP v1.2).


SCN 17-35, referenced below, announced the operational NWS

implementation of Watches/Warnings/Advisories (WWA) in CAP v1.2

format effective on April 30, 2017. The notice identified a

planned termination of CAP v1.1 no sooner than September 

1, 2017.


NWS will continue providing CAP v1.1 until at least November 1, 2017 at


On or after November 1, 2017, 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

this service termination. Note that 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 move 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.


Since the release of SCN 17-35, NWS CAP v1.2 has been enhanced

with the addition of CAP parameters for some convective warnings

as noted in item 5 of the April 4 Change Log entry.  These

include hail size, wind gust potential, tornado potential, and

tornado damage potential as well as storm motion, location, and



For operational issues including CAP access and connectivity,

please contact:


Senior Duty Meteorologist

National Centers for Environmental Prediction (NCEP) Central



For other non-operational technical questions, please 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: