NOUS41 KWBC 051555
PNSWSH

SERVICE CHANGE NOTICE 08-15
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
1055 AM EST WED MAR 5 2008

TO:      NATIONAL WEATHER SERVICE /NWS/ OFFICES
         FEDERAL AVIATION ADMINISTRATION /FAA/ USERS
         FAMILY OF SERVICES /FOS/ SUBSCRIBERS
         OTHER USERS OF NWS AVIATION FORECASTS

FROM:    KEVIN L. JOHNSTON
         CHIEF...AVIATION SERVICES BRANCH 
     
SUBJECT: FORMAT CHANGE FOR TERMINAL AERODROME FORECASTS /TAFS/
         FROM 24-HOUR FORMAT TO 30-HOUR FORMAT: 
         EFFECTIVE NOVEMBER 5 2008  

EFFECTIVE NOVEMBER 5 2008 ALL TAFS ISSUED BY NWS WILL CHANGE THE 
DATE AND TIME INDICATOR FORMAT IN THE TAF FROM THE PRESENT 24-HOUR 
FORMAT TO A NEW 30-HOUR FORMAT CONSISTENT WITH INTERNATIONAL CIVIL 
AVIATION ORGANIZATION /ICAO/ RULES. ALL OF THE NEARLY 625 TAFS 
ISSUED BY NWS WILL BE AFFECTED BY THIS CHANGE. A TABLE LISTING ALL 
THE AFFECTED TAFS IS ONLINE AT /USE LOWER CASE LETTERS/:

  HTTP://WWW.WEATHER.GOV/OS/AVIATION/PDFS/30_HR_TAF_TABLES.PDF

FEDERAL AVIATION ADMINISTRATION /FAA/ PERSONNEL AND OTHER EXTERNAL 
USERS RECEIVING NWS TAFS IN THE TAF COLLECTIVES BELOW WILL ALSO 
NEED TO TAKE ACTION TO ENSURE CONTINUED ABILITY TO DECODE TAFS. 

   WMO HEADINGS     AVAILABLE TO THE FOLLOWING CUSTOMERS
   
   FTUS80 KWBC      NON-FAA DOMESTIC AND FAMILY OF SERVICES

   FTUS90 KWBC      FAA WEATHER MESSAGE SWITCHING CENTER 
                    AND FAA FACILITIES

   FTUS52 KWBC      GLOBAL TELECOMMUNICATION SYSTEM CUSTOMERS

A MONTHLY TEST TAF WILL BE PROVIDED FOR USERS TO CHECK AND 
EVALUATE THEIR ABILITY TO DECODE THE NEW DATE AND TIME FORMAT.  
A SEPARATE TECHNICAL INFORMATION NOTICE WILL DETAIL THE TEST 
STRUCTURE AND METHOD. IN ADDITION REMINDERS OF THE TEST TAF WILL 
BE PROVIDED THREE DAYS BEFORE THE SCHEDULED TEST DAY. A TAF 
TESTBED CAN BE FOUND AT /USE LOWER CASE LETTERS/:

  HTTP://WWW.WEATHER.GOV/OS/AVIATION/TAF_TESTBED.SHTML

IN ADDITION TAFS FOR 32 LARGE AIRPORTS WILL BECOME VALID FOR  
30 HOURS. THE SPECIFIC AIRPORTS AND TAFS AFFECTED BY THE EXTENDED 
VALID TIMES WILL BE ANNOUNCED IN SEPARATE NOTICES.   

NATIONAL GUIDELINES REGARDING THE TAF WILL BE INCLUDED IN AN 
APPENDIX AS PART OF A FUTURE UPDATE OF NWS INSTRUCTION /NWSI/  
10-813 TERMINAL AERODROME FORECASTS AT /USE LOWER CASE LETTERS/:

  HTTP://WWW.NWS.NOAA.GOV/DIRECTIVES/SYM/PD01008013CURR.PDF

GUIDANCE TO NWS FORECASTERS FOR EDITING THE NEW TAF FORMAT WILL BE 
PROVIDED AT /USE LOWER CASE LETTERS/:

  HTTP://AVIATIONWEATHER.GOV/NOTICE/TAF30.PHP

THIS SERVICE CHANGE NOTICE WILL BE REPEATED IN JULY AND SEPTEMBER 
2008 TO REMIND USERS THAT TAF FORMATS WILL CHANGE NOVEMBER 5 2008.

REPEATING: THIS CHANGE IS EFFECTIVE NOVEMBER 5 2008...AND WILL 
AFFECT ALL TAFS PRODUCED BY NWS.  

FOR QUESTIONS REGARDING THIS SERVICE CHANGE NOTICE PLEASE CONTACT:

    BETH MCNULTY
    NATIONAL WEATHER SERVICE
    AVIATION SERVICES BRANCH
    1325 EAST WEST HIGHWAY
    SILVER SPRING MD 20910
    PHONE: 301-713-1726 EXT 116
    EMAIL: BETH.MCNULTY@NOAA.GOV

NWS SERVICE CHANGE NOTICES ARE ONLINE AT /USE LOWER CASE LETTERS/:

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

$$
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