20010702: non-unique WMO headers-ADMIN NOTICE NOUS41 KWBC (fwd)

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: 20010702: non-unique WMO headers-ADMIN NOTICE NOUS41 KWBC (fwd)
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Sun, 1 Jul 2001 20:12:32 -0600 (MDT)

832 
NOUS41 KWBC 292115
PNSWSH

PUBLIC INFO. STATEMENT...TECHNICAL IMPLEMENTATION NOTICE 01-17
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
515 PM EDT FRI JUN 29 2001

TO:       NATIONAL WEATHER SERVICE  /NWS/ EMPLOYEES...FAMILY OF
          SERVICES /FOS/ SUBSCRIBERS...NOAA WEATHER WIRE SERVICE
          /NWWS/ SUBSCRIBERS....EMERGENCY MANAGERS WEATHER
          INFORMATION NETWORK /EMWIN/ SUBSCRIBERS...OTHER NWS
          CUSTOMERS AND PARTNERS

FROM:     ESTHER ATKINS
          CHIEF...INTEGRATED OPERATIONS BRANCH

SUBJECT:  NON-UNIQUE WMO HEADINGS

THE NATIONAL WEATHER SERVICE /NWS/ RECENTLY LEARNED OF A
POTENTIALLY SERIOUS PROBLEM IN WHICH UNIQUE WMO HEADINGS ARE NOT
PROPERLY ASSIGNED TO PRODUCTS IN A LIMITED SET OF CIRCUMSTANCES. 
THIS MESSAGE IS TO ADVISE NWS CUSTOMERS OF THE PROBLEM AND
CORRECTIVE ACTIONS THE NWS IS TAKING.  NWS CUSTOMERS WITH SYSTEMS
THAT AUTOMATICALLY PARSE PRODUCTS ORIGINATING AT NWS FIELD
OFFICES AND CUSTOMERS WHO RECEIVE PRODUCTS FROM THESE SYSTEMS
SHOULD READ THIS MESSAGE.  

DESCRIPTION:  WHEN TWO UNIQUE VERSIONS OF THE SAME PRODUCT TYPE
/E.G. TORNADO WARNING... SEVERE WEATHER STATEMENT... SHORT-TERM
FORECAST/ ARE CREATED BY THE NWS FOR TRANSMISSION DURING THE SAME
MINUTE...TWO MESSAGES WITH IDENTICAL WMO HEADINGS ARE GENERATED. 
THIS IS MOST LIKELY TO OCCUR DURING ADVERSE WEATHER WHEN TWO
MESSAGES /E.G. WARNINGS...STATEMENTS/ OF THE SAME TYPE FOR
DIFFERENT AREAS ARE TRANSMITTED FROM DIFFERENT COMPUTER
WORKSTATIONS IN THE SAME MINUTE.

PROBLEM:  THE SECOND AND SUBSEQUENT VERSIONS OF A PRODUCT TYPE
/E.G. TORNADO WARNING/ TRANSMITTED WITHIN THAT SAME MINUTE DO NOT
HAVE UNIQUE WMO HEADINGS WHICH CAN BE USED BY AN AUTOMATED
DISSEMINATION SYSTEM TO DISTINGUISH ONE MESSAGE FROM THE OTHER. 
BECAUSE IT IS NOT UNIQUELY IDENTIFIED BY WMO HEADING... SOME NWS
AND CUSTOMER DISSEMINATION SYSTEMS DO NOT TRANSMIT THE SECOND AND
SUBSEQUENT MESSAGES BECAUSE THEY ARE FILTERED OUT AS DUPLICATE
MESSAGES WITH IDENTICAL WMO HEADINGS.   THE NWS/S EMERGENCY
MANAGERS WEATHER INFORMATION NETWORK /EMWIN/ SATELLITE BROADCAST
FILTERS OUT DUPLICATE PRODUCTS IN THIS WAY...BUT THE NOAA WEATHER
WIRE SERVICE DOES AN ADDITIONAL BYTE COUNT COMPARISON.

NWS ACTION:  THE NWS HAS STARTED ACTION TO REPAIR THE RESPONSIBLE
SOFTWARE BUT REPAIR MAY NOT BE COMPLETED FOR 6 WEEKS OR MORE.  AS
AN INTERIM ACTION...NWS OPERATIONS STAFF HAVE BEEN ALERTED TO THE
SPECIFIC CIRCUMSTANCES WHICH LEAD TO THIS PROBLEM AND ADVISED OF
A WORKAROUND TO AVOID THE OCCURRENCE OF NON-UNIQUE WMO HEADINGS. 
IF...DESPITE THE BEST STAFF EFFORTS...PRODUCTS WITH NON-UNIQUE
WMO HEADINGS ARE TRANSMITTED...NWS STAFF HAVE BEEN INSTRUCTED TO
TRANSMIT CORRECTED PRODUCTS FOR EACH ORIGINAL PRODUCT TRANSMITTED
WITH NON-UNIQUE WMO HEADINGS.  THE NWS WILL SEND ANOTHER
TECHNICAL IMPLEMENTATION MESSAGE WHEN THE SOFTWARE REPAIR IS
COMPLETED.

WMO HEADING REFERENCES AVAILABLE ON THE INTERNET /USE LOWER CASE
LETTERS/:

     HTTP://WWW.NWS.NOAA.GOV/OSO/HEADEF.HTML

QUESTIONS MAY BE DIRECTED TO ONE OF THE FOLLOWING PEOPLE AT NWS
HEADQUARTERS IN SILVER SPRING MARYLAND:

MR. HERB WHITE                     MR. ASHLEY KELLS
DISSEMINATION SERVICES             INTEGRATED OPERATIONS BRANCH
  PROGRAM MANAGER                  ASHLEY.KELLS@xxxxxxxx
AWARENESS BRANCH                   301-713-0462 EXT. 122
HERBERT.WHITE@xxxxxxxx             
301-713-0090 EXT. 146
  
THIS AND OTHER NWS NOTIFICATIONS ARE AVAILABLE ON THE INTERNET
/USE LOWER CASE/:

     HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM

END