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WMO 1996 PARAPHRASED VERSION
GUIDELINES on the USE of the INDICATOR BBB

with GENERAL EXAMPLES
(only alphabet 5 (ASCII) and binary are shown in bulletin examples)

The format of the

WMO Abbreviated Heading Line

T1T2A1A2ii   CCCC   YYGGgg   (BBB)

This line, which is preceeded by "format effectors" [ cr ] [ cr ] [ lf ], constitutes the complete WMO abbreviated heading line, which can contain the optional BBB group, indicated by the open and closed parenthesis ( ).

General Instructions

  1. The WMO abbreviated heading line, including each unique YYGGgg (date time group), shall be used only once a month, due to the day of the month being part of the heading. The indicator BBB shall only be added when a WMO abbreviated heading has already been used for transmission of an initial bulletin. It indicates that the contents to be a delayed, corrected or amended bulletin. The indicator BBB can also be used for segmentation as described below in paragraph 5.
  2. The indicator BBB shall only be included in the WMO abbreviated headings of delayed (retard), corrected, or amended bulletins by those centres which are responsible for preparing, or compiling the bulletins concerned, or for communication transmission reasons by any system as a segment sequence indicator when bulletins are segmented to control bulletin size.
  3. Once the initial bulletin has been transmitted, the centre responsible for preparing or compiling the original bulletin uses the indicator BBB to transmit delayed or corrected reports or to amend information for the same abbreviated heading containing the same YYGGgg.
  4. A centre shall not construct an abbreviated heading with the indicator BBB for delayed, corrected, amended, bulletins having a size larger than the limit defined in TABLE A as it would cause a communications system to segment it before transmission.
  5. The Bulletin Segment Heading is a special form of the WMO abbreviated heading where the indicator BBB takes the form of Pxx. The bulletin segment heading replaces the normal WMO abbreviated heading when bulletins are larger than size limit defined in WMO Table A. The bulletin segment heading shall take the place of the WMO abbreviated heading for electronic transmission purposes. The bulletin segment heading is a repeating heading, with a unique Pxx group for each segment. The original WMO bulletin shall be re-constructed from these segments before use.
  6. The bulletin segment heading cannot be used in place of a standard WMO abbreviated heading of a bulletin if any of the other indicator BBB options are present. This normally will not be a problem as a delayed, corrected, or amended bulletin with the indicator BBB should be smaller then the initial message. However, the U.S. has established a National practice to support the transmission of plain text bulletins containing an abbreviated heading with a BBB group which are too large for transmission.

BBB Forms

The four forms of the BBB indicator group are:
  • RRx - Delayed (Retard)
  • CCx - Correction
  • AAx - Amendment
  • Pxx - Segment number
Each form precludes the use of the others in the same bulletin. The RRx, CCx, and AAx forms are attributes of the content of the bulletin, and the Pxx is an attribute of the segment number not the content. Each form is described separately below.

  1. RRx Indicator Group - Delayed Routine Meteorological Reports [retard]

    This indicator group has the form RRx; where: x = A through X. It is used to transmit a collection of one or more weather reports which are normally contained in the initial bulletin but which were received after the initial bulletin has been transmitted. The value of x = A is for the first bulletin containing additional reports; a value of x = B for a second bulletin containing additional reports, if necessary, and, so on up to and including x = X. For x = Y it represents a loss of the record of the sequence by the issuing center. For x = Z it represents the compiled bulletin is over 24 hours after the time of observation.

    EXAMPLE

    INITIAL BULLETIN

         345
         SMIN04 DEMS 171200
         AAXX 17124
         42634 NIL=
         42647 NIL=     
         42737 NIL=
         42840 NIL=
         42909 NIL=
         43003 31569 53204 10326 20243 40086 70411 82830 333 10351 59001
              82620 83360=
         43013 NIL=
         43063 32597 60903 10300 20157 39479 40088 83801 333 10315 58020
             81828 83630 85070=
         43110 32598 33204 10295 20245 40093 81502 333 10328 48001 81620=
         43117 32697 51404 10306 20161 40086 83431 333 10328 58015=
         43192 31569 42905 10296 20241 40085 70511 82402 33 10324 58001=
            

    SECOND TRANSMISSION (AFTER INITIAL)
         377
         SMIN04 DEMS 171200 RRA
         AAXX 17124
         42634 32997 00206 10324 20067 40113 333 10347 58010=
         42647 32997 10000 10328 20118 81300 333 10351 58010 81360=
         42737 32597 10508 10344 20114 40101 81100 333 10358 58012 81825=
         42840 32996 10000 10320 20192 40098 81030 333 10338 58012 81360=
         42909 32597 31612 10302 20263 40096 82230 222// 20000 333 10359 58000
             82820=
            
    Note: The second transmission only contains reports not sent previously.


  2. CCx Indicator Group -Corrections to Previously Transmitted Reports

    This indicator group has the form: CCx; where x = A through X. It is used to transmit a bulletin containing corrections to reports that have already been included in a bulletin previously transmitted. The value of x = A is for the first bulletin containing corrected reports; a value of x = B for a second bulletin containing additional corrected reports, if necessary, and, so on up to and including x = X. For x = Y it represents a loss of the record of the sequence by the issuing center. For x = Z it represents the compiled bulletin is over 24 hours after the time of observation.

    EXAMPLE

    INITIAL BULLETIN


         
         321
         SMIE01 EIDB 171200
         AAXX 17124
         03953 11470 81317 10144 20102 40187 57008 69901 70562 886//
         333 85716 87635 92447 90710 91135=
         03955 11357 81316 10111 20091 40213 56008 60031 74065 887//
         333 86706 88708=
         03957 32570 71313 10117 20076 40246 57008 875//
         333 85624 87640 92448=
         03962 11464 81114 10130 20105 40212 57006 69901 71062 886//
         333 83713 87716=
         03969 ..... .....  and so on ..... .....
            

    SECOND TRANSMISSION (AFTER INITIAL)
         392
         SMIN04 DEMS 171200 CCA
         AAXX 17124
         03955 11357 81316 10111 20101 40213 56008 60031 75065 887//
         333 86706 88708=
            
    Note: The second transmission only contains a report which corrects a previously sent report. It can contain more than one corrected report.


  3. AAx Indicator Group - Amendments to Processed Information

    This indicator group has the form AAx; where x = A through X. It is used to transmit a bulletin containing amendments to processed information in a bulletin which has previously been sent. The value of x = A is for the first bulletin containing information amending the basic (initial) bulletin; a value of x = B for a second bulletin containing information amending the basic (initial) bulletin, if necessary, and so on up to and including x = X. For x = Y it represents a loss of the record of the sequence by the issuing center. For x = Z it represents the compiled bulletin is over 24 hours after the time of observation.

    EXAMPLE

    INITIAL BULLETIN


         345
         FPJM20 MKJP 171200
         PUBLIC FORECAST FOR JAMACIA AND SURROUNDING AREAS OCTOBER 12.
         THE AREA NORTH WILL HAVE WARM TEMPERATURES NEAR 80 WITH SKY 
         CLEAR.  THE SOUTH WILL SEE HIGH SCATTERED CLOUDS AND A LIGHT ON 
         SHORE WIND WITH TEMPERATURES IN AROUND 75.  THERE WILL BE LATE 
         AFTERNOON THUNDERSTORMS MOVING IN FROM THE SOUTH.  SEAS WILL    
         BE LIGHT..... .....  and so on ..... .....
            

    SECOND TRANSMISSION (AFTER INITIAL)


         392
         FPJM20 MKJP 171200 AAA
         PUBLIC FORECAST FOR JAMACIA AND SURROUNDING AREAS OCTOBER 12.
         THE AREA NORTH WILL HAVE WARM TEMPERATURES NEAR 80 WITH SKY 
         CLEAR.  THE SOUTH WILL SEE HIGH SCATTERED CLOUDS AND A LIGHT ON 
         SHORE WIND WITH TEMPERATURES IN AROUND 75.  THERE WILL BE LATE 
         AFTERNOON THUNDERSTORMS MOVING IN FROM THE SOUTH.  SEAS WILL    
         BE LIGHT TO THE NORTH AND MODERATE TO THE SOUTH AFTER 4 WITH      
         THE SOUTH HAVING SEAS MODERATE TO STRONG DURING                          
         THUNDERSTORMS..... .....
         and so on ..... .....
            

    Note: The second transmission contains previously sent text of a WMO message in the first transmission with amendments. If the amendment is to a product which is data field constructed, such as GRID bulletins, the amendment bulletin should only address the corrected field or small group of fields sufficient enough for clearly explaining the change, or the amended bulletin may exceed the size limit specified in WMO TABLE A. The content of the original bulletin was correct at time of transmission, however, conditions have changed such that "ammending" the bulletin is necessary.



  4. Pxx Indicator Group - Segmentation of a Large Bulletin

    When a bulletin exceeds the length limit defined in Table A, it shall be segmented for communications purposes using a bulletin segment heading line utilizing the Pxx Indicator Group. There are two different structures possible for segments.

    1. Segmented alphanumeric products have a supplementary identification line which repeats information in addition to the bulletin segment heading line in each segment.
    2. Segmented binary products do not repeat the supplemrntary identification line information in a second line for each subsequent segment. Only the bulletin segment heading line is repeated.

    Defining:

    • Pxx = values of xx = AA through YZ and ZA through ZZ

      The following principles shall apply when segmenting alphanumeric bulletins for transmission:

      • The first bulletin segment heading will have sequence indicator xx = AA, the second AB and so on up to the last bulletin segment heading which shall have xx = Zx.

      • The Z is a LAST SEGMENT FLAG and is placed in the first x position of the Pxx group of the last segment of the set of bulletin segments with the second x the sequence letter which would have normally been used if this was not the last segment.

      • This special PZx group is required to inform the receiving center that no more bulletin segments exist for this product.

    • And;
      • Any original code form or product identification indicator shall be included in each bulletin segment heading and is called a supplementary identification line.

      • Except for the last segment, segment lengths shall be as long as possible, within approved bulletin length limits [Table A] and formatting constraints.

      • Segmented bulletin breaks shall immediately follow end-of-report indicator signals ( = signs ) when or where available in close proximity to the size limit. When end-of report indicators can't be used, segmented plain text bulletins will be broken on an end-of-line function or on a space if the end-of-line function can not be found in close proximity to the size limit.

      • All WMO Regional Telecommunication Hubs on the Global Telecommunication System should relay bulletin segments as received on the Main Trunk Network.

      • Upon reciept all plain text bulletin segments the receiving end shall re-built the original bulletin prior to use, as the segmentation procedure is for transmission purposes only.

Alphanumeric Products

  1. The U.S. NWS has additional details on how segmenting is accomplished for alphanumeric products. An example of the segmentation of a decodable alphanumeric WMO bulletin that has been received too large according to Table A for onward transmission without segmentation:

      EXAMPLE

    1. FIRST BULLETIN SEGMENT

           766
           UDAU01 AMMC 181200 PAA
           AMDAR 1812
           LVR AN0086 3514S 14251E 1038 F369 MS557 284/075 TB0 S031
              333 F/// VG000=
           LVR AN0086 3519S 14404E 1045 F369 MS590 281/083 TB0 S031
              333 F/// VG000=
           DES AN0076 2854S 15302E 1032 F335 MS472 253/042 TB0 S031
              333 F/// VG000=
           DES AN0076 2830E 15309E 1035 .....etc... =
            

      [ until last end-of-report indicator prior to 3800 octets have been reached ]

    2. SECOND BULLETIN SEGMENT
           768
           UDAU01 AMMC 181200 PAB
           AMDAR 1812
           LVR QF0010 1910N 08125E 0642 F369 MS491 153/021 TB0 S031
              333 F/// VG006=
           LVR QF0010 1724N 08345E 0704 F369 MS490 086/018 TB0 S031
              333 F/// VG008=
           LVR QF0010 2255N 07308E 0539 F369 MS500 240/051 TB0 S031
              333 F/// VG005=
           LVR AN0046 3554S 14727E 1037 .....etc... =
              

      [ until last end-of-report indicator prior to 3800 octets have been reached ]

    3. THIRD BULLETIN SEGMENT
           770
           UDAU01 AMMC 181200 PAC
           AMDAR 1812
           DES AN0075 3638S 14448E 1056 F235 MS297 284/043 TB3 S031
              333 F239 VG499=
           DES AN0075 3650S 14440E 1059 F182 MS177 273/027 TB0 S031
              333 F185 VG006=
           DES AN0075 3711S 14445E 1104 F096 PS000 281/012 TB3 S031
              333 F098 VG672=
           DES AN0075 3725S 14445E 1109 .....etc... =
              

      [ until last end-of-report indicator prior to 3800 octets have been reached ]

    4. FOURTH and LAST BULLETIN SEGMENT
           772
           UDAU01 AMMC 181200 PZD
           AMDAR 1812
           DES QF0017 1830S 17630E 1134 F183 MS089 256/021 TB0 S031
              333 F/// VG005=
           DES AN0086 3531S 14737E 1105 F297 MS445 265/064 TB0 S031
              333 F302 VG002=
           DES AN0086 3533S 14818E 1110 F182 MS165 265/030 TB0 S031
              333 F140 VG006=
      

      [ last segment is also less than 3800 octets have been reached ]

  2. An example of the segmentation of a non-decodable plain text bulletin that has been received too large according to Table A for onward transmission without segmentatation:

      EXAMPLE

    1. FIRST BULLETIN SEGMENT
           766
           FPUS51 KNYC 181213 PAA
           ZFPCT
           ZONE FORECAST FOR SOUTHERN CONNECTICUT
           NATIONAL WEATHER SERVICE NEW YORK NY 
           etc.............................(end-of line)

      [ last end-of-line prior to 3800 octets have been reached ]

    2. SECOND BULLETIN SEGMENT
           767
           FPUS51 KNYC 181213 PAB
           ZFPCT
           and for the waters off shore the area of thunderstorms will
           will be along a line 30 miles north of cape ...etc..................(end-of-line)

      [ last end-of-line prior to 3800 octets have been reached ]

    3. THIRD and LAST BULLETIN SEGMENT
           768
           FPUS51 KNYC 181213 PZC
           ZFPCT
           The remander of the afternoon and evening will be clear.
           Mountian areas...
           Tuesday afternoon will increase in clouds and frequent showers
           will occur after sunset. Highs in the low 50s with Lows 30 to 35.

      [ last segment will also be less than 3800 octets ]

Notice: The above two examples (decodable and non-decodable bulletins in segment form) have two lines to remove during re-construction, the segment heading line and the supplementary identification line from segments PAB through PZD or PZC to build the original larger bulletin for use.

Warning !

Bulletin segments must be processed to re-build the original bulletin to obtain a complete plain text product.


U.S. National Practice

If it is necessary to segment a bulletin which exceeds the limits established by WMO and the bulletin already utilizes a bulletin attribute (BBB), the following procedures will be used. A bulletin segmentation heading including the appropriate Pxx indicator group will be used; and the original bulletin attribute (BBB) will be included as a separate line followed immediately by the line function carriage return, carriage return, line feed in the first segment only. (see examples below)

    Example of a corrected text message:

  1. FIRST BULLETIN SEGMENT
         766
         FPUS51 KNYC 181213 PAA
         ZFPCT
         CCx
         ZONE FORECAST FOR SOUTHERN CONNECTICUT
         NATIONAL WEATHER SERVICE NEW YORK NY 
         etc.............................(end-of-line)

    [ until last end-of-line prior to 3800 octets have been reached ]

  2. SECOND BULLETIN SEGMENT
         767
         FPUS51 KNYC 181213 PAB
         ZFPCT
         and for the waters off shore the area of thunderstorms will
         will be along a line 30 miles north of cape ...etc.....(end-of-line)

    [ until last end-of-line prior to 3800 octets have been reached ]

  3. THIRD and LAST BULLETIN SEGMENT
         768
         FPUS51 KNYC 181213 PZC
         ZFPCT
         The remander of the afternoon and evening will be clear.
         Mountian areas...
         Tuesday afternoon will increase in clouds and frequent showers
         will occur after sunset. Highs in the low 50s with Lows 30 to 35.

    [ last segment is also less than 3800 octets ]

    The other bulletin attributes RRx or AAx may also be used as the third line of the first segment.


Binary Bulletins

The following principles shall apply when segmenting binary bulletins (i.e. GRIB, BUFR, and T4 FAX bulletins):
  • Bulletin segment lengths shall be as long as possible, as allowed by approved bulletin length limits (except for the last segment)
  • RTHs should relay bulletin segments as received
  1. An example of the segmentation of a T4 FAX WMO bulletin that has been received too large according to Table A for onward transmission without segmentation:

    Example:

    1. FIRST BULLETIN SEGMENT

           PGEE25 KWBC 181200 PAA
           DFAX 1064  bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbb .....etc...
              

      [ until 15000 octets have been reached ]

    2. SECOND BULLETIN SEGMENT
           PGEE25 KWBC 181200 PAB
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbb .....etc...
                

      [ until 15000 octets have been reached ]

    3. THIRD BULLETIN SEGMENT
           PGEE25 KWBC 181200 PAC
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbb .....etc...
                

      [ until 15000 octets have been reached ]

    4. FOURTH and LAST BULLETIN SEGMENT
           PGEE25 KWBC 181200 PZD
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           bbbbbbbbbbbbbbbbbbbbbbbb .....etc...

      [ until something less than 15000 octets have been reached ]

Warning !

Bulletin segments must be processed to re-build the original bulletin from it's segment parts to be able to obtain the complete binary bulletin prior to further use.

All binary bulletins greater than 15,000 bytes will be segmented unless prior mutual agreement between adjacent centers has established otherwise. The segments will be based upon size only and no consideration will be given to where the break occurs. Bulletin segments will have no additional information added beyond the bulletin segment heading line itself, containing the BBB group of Pxx to accomplish the segmentation process.


Additional comments on the use of the BBB groups.

An RTH on the GTS should ensure the relay of any bulletins received in accordance with its routing directories even if the bulletins are in fact bulletin segment heading lines and have not been received in the correct sequence. All the bulletin segments containing the indicator Pxx shall be relayed to enable the end user to reconstruct and use the original bulletin.

In case of incomplete or incorrect reception, the use of the addressed message for request/reply may be required for recovering incomplete or incorrect bulletin(s). The request for a bulletin segment may be acceptable, or the request for the repeated transmission of the entire set of information (i.e. the whole sequence of bulletin segments) may be necessary, in which case the indicator Pxx would not be used in the request.

 

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     Page last Modified: 4 November, 2013 2:06 PM