960626: METAR/TAF Implementation-NOUS (fwd)

828 
NOUS41 KWBC 262031
PNSNMC
 
NATIONAL TECHNICAL INFORMATION MESSAGE 96-17
NATIONAL WEATHER SERVICE HEADQUARTERS
430 PM EDT WED JUN 26 1996
 
TO:         NWS OFFICES WITH CURRENT TAF RESPONSIBILITY AND 
            NWS AVIATION TERMINAL FORECAST CUSTOMERS
 
FROM:       THERESE Z. PIERCE
            CHIEF - INTEGRATED HYDROMETEOROLOGICAL SERVICES CORE
 
SUBJECT:    METAR/TAF IMPLEMENTATION:  CLARIFICATION REGARDING
            REISSUANCE OF 101 INTERNATIONAL TERMINAL FORECASTS
            (TAFS) ON JULY 1 1996 BETWEEN 0700 AND 0800 UTC
 
REFERENCE:  NATIONAL TECHNICAL INFORMATION MESSAGE (NTIM) 96-16 
            (CORRECTION #2) DATED 6/25/96
 
THIS IS ADDITIONAL GUIDANCE FOR NWS OFFICES CURRENTLY PREPARING
TAFS.  OFFICES ISSUING TAFS FOR THE FIRST TIME FOR A PARTICULAR
AIRPORT ON JULY 1 1996 SHOULD REFER TO NTIM 96-16 FOR
INSTRUCTIONS ON ISSUING THE FIRST TAFS AT 0800 UTC ON JULY 1
1996.
 
CURRENTLY THERE ARE A TOTAL OF 101 TERMINAL FORECASTS IN THE
INTERNATIONAL FORMAT (TAFS) PREPARED BY NWS OFFICES.  NWS OFFICES
WHO CURRENTLY PREPARE ONE OR MORE OF THESE 101 TAFS SHALL FOLLOW
THE INSTRUCTIONS BELOW FOR ISSUING TAFS ON JULY 1 1996:
 
ON JULY 1 1996...THE 101 NWS-PREPARED TAFS VALID FOR 24 HOURS
BEGINNING AT 0000 UTC AND 0600 UTC SHALL BE ISSUED AS FOLLOWS:
 
     ISSUANCE TIME (UTC)           VALID TIME (UTC)
          2230 UTC                      0000 UTC
          0430 UTC                      0600 UTC
 
THEN A TAF VALID AT A SPECIAL VALID TIME (0800 UTC) WILL BE
ISSUED TO COINCIDE WITH THE 0800 UTC IMPLEMENTATION OF METAR AND
TAF.  THE SPECIAL TAF VALID AT 0800 UTC SHALL BE ISSUED BETWEEN
0720 AND 0740 UTC FOR THE 101 EXISTING TAF LOCATIONS AS WELL AS
THE 431 SITES THAT WILL HAVE A TAF FOR THE FIRST TIME (REPLACING
AND MAKING THE DOMESTIC TERMINAL FORECAST...FT...OBSOLETE
EFFECTIVE 0800 UTC ON JULY 1 1996).  A TOTAL OF 532 NWS-PREPARED
TAFS SHALL BE PREPARED FOR THE SPECIAL....ONE-TIME ONLY...
0800 UTC VALID TIME.
 
THE 101 CURRENTLY AVAILABLE TAFS SHALL BE REISSUED BETWEEN 0720
AND 0740 UTC (VALID AT 0800 UTC) IN ORDER TO DELIVER THEM TO THE
DOMESTIC AIRLINE CUSTOMERS FOR THE FIRST TIME.  THE MAJORITY OF
THE DOMESTIC AIRLINES ARE NOT CURRENTLY RECEIVING ANY OF THE 101
TAFS...BUT THEY WILL BEGIN RECEIVING THEM BETWEEN 0720 AND 0740
UTC ON JULY 1 1996.
 
OFFICES PREPARING THE 101 EXISTING TAFS SHALL ISSUE THE SPECIAL
TAFS...VALID FOR 22 HOURS FROM 0800 UTC JULY 1 1996 UNTIL 
0600 UTC JULY 2 1996...AS FOLLOWS: 
 
     ISSUANCE WINDOW (UTC)         VALID TIME (UTC)
        0720 - 0740 UTC                 0800 UTC
 
IF NO AMENDMENT OR CORRECTION IS NEEDED BASED ON THE TAF VALID AT
0600 UTC ON JULY 1...THE 0600 UTC TAF CAN BE SLIGHTLY REVISED
AS SHOWN BELOW TO BECOME THE SPECIAL TAF VALID AT 0800 UTC.  THE
SLIGHT REVISIONS REQUIRED ARE (ALSO REFER TO THE EXAMPLE BELOW):
 
  1) CHANGE THE DATE/TIME GROUP IN THE ABBREVIATED WMO HEADING;
  2) CHANGE THE DATE/TIME OF FORECAST ORIGIN (YYGGGGZ) IN THE
     FORECAST TEXT OF THE BODY OF THE TAF; AND
  3) CHANGE THE VALID PERIOD (Y1Y1G1G1G2G2) IN THE FORECAST TEXT
     OF THE BODY OF THE TAF
 
EXAMPLE 0600 UTC TAF:
 
     LAXTAFLAX
     TTAA00 KLAX 010432
     TAF
     KLAX 010435Z 010606 VRB05KT P6SM OVC020 BECMG 1718 25012KT
           SCT025 BKN100
 
EXAMPLE SPECIAL TAF VALID AT 0800 UTC (IF FORECAST HASN'T
CHANGED):
 
     LAXTAFLAX
     TTAA00 KLAX 010728
     TAF
     KLAX 010725Z 010806 VRB05KT P6SM OVC020 BECMG 1718 25012KT
           SCT025 BKN100
 
IF THE FORECAST NEEDS TO BE ADJUSTED IN THE SPECIAL TAF VALID AT
0800 UTC...AN AMENDED TAF SHALL BE ISSUED RATHER THAN REISSUING
THE TAF VALID AT 0600 UTC AS SHOWN IN THE EXAMPLE ABOVE.
 
BEGINNING ON JULY 1 1996 AT 0800 UTC...THE ISSUANCE WINDOW FOR
TAFS WILL CHANGE TO 20-40 MINUTES BEFORE THE BEGINNING OF THE
VALID TIME AS FOLLOWS:
 
     TAF ISSUANCE TIME (UTC)          TAF VALID TIME (UTC)
           2320-2340                       0000
           0520-0540                       0600
           1120-1140                       1200
           1720-1740                       1800
 
FOR MORE DETAILS ON TAFS...REFER TO WEATHER SERVICE OPERATIONS
MANUAL D-31...AVIATION TERMINAL FORECASTS (DRAFT DATED 6/20/96). 
THAT DOCUMENT IS AVAILABLE ON THE NWS' METAR/TAF HOME PAGE AT THE
FOLLOWING ADDRESS ON THE WORLD WIDE WEB:
 
           HTTP://WWW.NWS.NOAA.GOV/OSO/OSO1/OSO12/METAR.HTM
 
IF YOU HAVE QUESTIONS ABOUT NWS-PREPARED TAFS...PLEASE CONTACT
CHRIS ALEX AT (301)-713-1726 X 142 OR BY E-MAIL AT THE FOLLOWING
ADDRESS:   CALEX@xxxxxxxxxxxxxxxxxxxxxx
 
END