National Weather Service United States Department of Commerce

Heavy Rainfall Along the Eastern Seaboard; Dangerous Heat Wave Shifting East Next Week

Showers and thunderstorms may produce heavy to excessive rainfall along the east coast today. The associated rainfall will likely create localized areas of flash and urban flooding. An extremely dangerous heat wave will shift into portions of the central and eastern U.S. late this weekend, lasting through the next work week. Widespread daily record high temperatures are expected. Read More >


NWS Communications
Header Policy Document

Including the
Full AWIPS Product Identification Structure

This is the overall communications header structure developed for the NWS in the modernization of field offices. The communications header will permit exchange of the National and International received products and NWS field products freely without loss of a higher descriptive syntax for defining data content and will provide for handling by computer systems to manage the storing of information. The following AWIPS product identification structure is intended to meet the requirements for

  1. using a valid WMO abbreviated heading (SRSI Appendix M) that conforms with international practices;
  2. that provides an AWIPS Identifier (SRSI paragraph 11.2.2) that is unique and provides a mapping between the AI and the WMO abbreviated heading;
  3. that accommodates the AFOS message structures (SRSI paragraph 3.6); and
  4. that meets the requirements for Originating Station and AWIPS Identifier in message creation (SRSI paragraph 11.2, parameters a. and c. only).

The NWSTG will perform all data format and protocol conversions necessary for the two-way flow of data between the AWIPS Network Control Facility (NCF) interface and the Gateway for AFOS SMCC (SRSI paragraph 3.6). For products originating from AFOS, the NWSTG will combine the WMO abbreviated heading and the AFOS PIL to make a two line product identifier called ;The AWIPS Product Identifier as shown here:

T1 T2 A1 A2 ii   CCCC   YYGGgg [ BBB ] (cr)(cr)(lf)
NNNxxx (cr)(cr)(lf)

The second line is the AWIPS Identifier (AI) Line. The AI is very similar to the old AFOS product identifier (CCCNNNxxx). It is composed of 5-6 characters in the following format:

NNNxxx - the portion of the old AFOS PIL without the CCC

The three letter CCC part of the old AFOS PIL is dropped and the four letter CCCC is used instead which is located in the first line of the AWIPS Product Identifier, therefore; the 4-letter CCCC (originating office) is identical to the CCCC part of the WMO abbreviated heading, shown here:

T1T2 A1 A2 ii   CCCC   YYGGgg [ BBB ] (cr)(cr)(lf)

The CCCC shall be a valid International Civil Aviation Organization (ICAO)-approved identifier of the office originating the product (refer to ICAO Doc 7910, Location Indicators). The first character shall be K for the CONUS offices followed by the 3-letter FAA identifier. For offices outside the CONUS, the first two characters shall be PA for Alaska, PH for Hawaii, and TJ for Puerto Rico followed by an additional two characters. The national centers use a national practice form of the K(CCC) for CCC.

The 3-character NNN (product category) further defines the content of the message (bulletin) defined by the AWIPS first produict identifier line. The AWIPS software shall be flexible to allow future expansion in the number of characters in the product category.

The xxx
The 1-3 character xxx (product designator) field is a geographical designator in the AWIPS product identifier second line. If the xxx is less than 3 characters, the character(s) shall be left justified and filled with blanks to complete the 3-character field. The AWIPS software shall be flexible to allow future expansion in the number of characters in the product designator.

Using the two line AWIPS Product Identifier heading

Products originating from AWIPS shall be transmitted with the AWIPS Product Identifier.

Products not originated by the NWS that pass through the NWSTG for distribution to AWIPS, as well as collectives of reports in ASCII text format that are formulated by the NWSTG, will not necessarily contain the NNNxxx as the first line of text immediately below the WMO abbreviated heading. Therefore, they would not contain the complete AWIPS Product Identifier as defined above. For these products the text message begins immediately below the WMO abbreviated heading. Within the text itself of such products there is other information that is useful in fully identifying the product for data basing. In the case of report collectives, each individual report will begin with the location identifier; and for certain product types, the WMO code standards require the text message to begin with a specified MiMiMjMj group, e.g., T1 T 2 A1 A2 to indicate Part A of an upper air report for the block/station number indicated in the report. For these text products received without the NNNxxx information, the AWIPS software will need to use the WMO abbreviated heading and the code of the text to uniquely identify the product.

Realignment of AWIPS Product Identifier

The NWS' Telecommunications Operations Center, which manages the NWSTG, assigns and maintains the WMO abbreviated headings for NWS products as part of the configuration management process. The WMO abbreviated headings in the NWSTG switching directory require routine maintenance to reflect changes in products or location identifiers, or to conform to changes in the WMO standards.

The NWSTG, in addition to writing additional software to accommodate the combination of the WMO abbreviated heading and the AWIPS Identifier as described earlier in section III, plans to reassign WMO abbreviated headings for AWIPS so that the ii group of the T1 T2 A1 A2 ii is assigned logically. The iis will range from 40 to 89 according to the following logic, that is based geographically upon the current FA structure.

ii = 40, 50, ... 80  Issued from U.S. Pacific WFO
     41, 51, ... 81  Issued from Northeast U.S. WFO or RFC
     42, 52, ... 82  Issued from southeast U.S. WFO or RFC        
                     (Includes San Juan, PR)
     43, 53, ... 83  Issued from North Central U.S. WFO or RFC
     44, 54, ... 84  Issued from South Central U.S. WFO or RFC
     45, 55, ... 85  Issued from U.S. Rocky Mountains WFO or RFC
     46, 56, ... 86  Issued from West Coast WFO or RFC
     47, 57, ... 87  Issued from SE Alaska WFO (Juneau, AK)
     48, 58, ... 88  Issued from Central Alaska WFO or RFC
                     (Anchorage, AK)
     49, 59, ... 89  Issued from NE Alaska WFO (Fairbanks, AK)

The states comprising these 10 geographic areas are as follows:

     0  HI  (Pacific) 
     1  NH, RI, CT, NJ, MD, DC, DE, VA, NY, MA, VT, OH, PA, ME,   
        WV (North East U.S.)
     2  SC, GA, NC, FL, PR   (South East U.S. & Puerto Rico)    
     3  SD, MI, WI, ND, KS, MN, IA, MO, NE, IL, IN, KY   
        (North Central U.S.)
     4  TX, AL, MS, LA, AR, TN, OK   (South Central U.S.)
     5  NM, MT, ID, CO, WY, AZ, NV, UT   (Rocky Mountains)
     6  CA, OR, WA  , West Coast U.S.)
     7  AK  (South East Alaskan Area - Juneau)
     8  AK  (Central Pacific Area - Anchorage)
     9  AK  (Northern Alaskan Area - Fairbanks)

Note: Products issued under the CCCC of KWBC for the Washington RTH or NCEP (center CCCCs) will not be required to adhere to the ii convention for WFO and RFC issuances.

The National Centers may choose to apply the ii logical assignment for their product issuances as appropriate.

The 50s series and on up will be assigned only if there is a need to differentiate among significantly different types of products assigned the same T1 T2 A1 A2 , e.g., TAFs both assigned FTUS. The NWS will provide substantial advance written notification to other agencies and external users prior to the implementation of the reassignment of WMO abbreviated headings for existing products.

The following examples are provided to illustrate the AWIPS product identification as specified in this section.

          ABUS41 KLWX 272200 
          State Weather Summary for the District of Columbia      
          issued by WFO Sterling, VA, AWIPS Identifier =          

          FEUS45 KPSR 181642 AAA
          Local Forecast for Phoenix issued by WFO Phoenix, AZ
          (Amendment number 1), AWIPS Identifier = KPSRLFPPHX
          FTUS45 KPSR 220000
          International Terminal Forecast for Phoenix Airport
          issued by WFO Phoenix, AZ, -- note: WMO & ICAO standard 
          second line -- no AWIPS Identifier = KPSRTAFPHX

          FTUS55 KPSR 111500 
          Terminal Forecast for Phoenix Airport issued by 
          WFO Phoenix, AZ, AWIPS Identifier = KPSRFTAPHX

          USUS10 KWBC 021200
          TTAA 52121 72562 ... [remainder of the report]
          Upper Air Report - Part A compiled by KWBC (the
          Washington WMO Regional Telecommunication Hub)

AWIPS Message Composition and Product Identification

The AWIPS operator shall not be required to know the WMO abbreviated heading to compose a message for transmission. One option for identifying a product in composition is for the operator to specify the AI along with the other relevant product information listed in SRSI paragraph 11.2. (No assumptions are made here concerning how this information is entered. The entry of this information can be accomplished through completion of a header block preformat, menu selections, combinations thereof, or other options designed in the graphical user interface.) The AWIPS system shall use the specified CCCC (the local office shall be the default) as the CCCC portion of the WMO abbreviated heading. The WMO abreviated heading shall be created from a look-up table that maps the specified NNN portion of the AI to the T1 T2 A1 A2ii .

AWIPS Product Retrieval and Display

The AWIPS software shall provide the capability of ASCII text product retrieval by entering of the AI (CCCCNNNxxx) at the AWIPS workstation. The entry of the CCCC portion of the AI for retrieval purposes shall be optional where the NNNxxx (4-6 characters) is unique. The capability of retrieval of text products by entry of the AI shall be in addition to the capability of retrieval of the product by clicking on the product retrieval menus and submenus.

For ASCII text products received without the NNNxxx portion of the AI as the first line of text, the AWIPS software shall assign an appropriate NNNxxx based upon the WMO abbreviated heading and the decoding of the text.

The display of text products on the AWIPS workstations shall provide the WMO abbreviated heading as the first line, with the NNNxxx appearing on the line immediately below. These two lines of information provide all the elements of the AI (CCCCNNNxxx) and provide the unique identification of each ASCII text product on AWIPS. Multiple versions of the same product are differentiated by the date/time group and/or the BBB portion of the WMO abbreviated heading.

AWIPS Forecast Office Areas of Responsibilities

The forecast offices within the United States operate on specific geographical forecast areas and/or zones of responsibilities. For a better understand of what and where they are you should review the mapping for these areas.


The NWS data stream provided to the Network Control Facility (NCF) of the AWIPS system through the NWSTG interface will use the World Meteorological Organization, (WMO) abbreviated heading for product identification. This product identification structure is described in the WMO Manual on the Global Telecommunication System (GTS), WMO Publication No. 386, under

The WMO abbreviated heading will precede the data but follow the NWSTG Communications Control Block (CCB) for graphics products, grid products, point data, and free text products to be provided through the NWSTG interface to the NCF. The WMO abbreviated heading will be contained in a 21-character WMO header block (or 25 characters if a BBB indicator is included). This block structure is defined in OFCM FCM-3.

The NWS CCCC Defintions

Products originated at the NWS National Centers across the country pass through the NWSTG and use their site (center) specific originators. The NWSTG designator KWBC for the CCCC portion of the heading indicating that the products were compiled at the Washington RTH. The definitions of the sites for both Forecast Office field locations and National Center locations are contained in these two documents:
(1) the NCEP Centers unique 4-letter identifier and
(2) the NWS Forecast Offices national practice version of the K-CCC(x) across the United States.