National Weather Service United States Department of Commerce

Record High Temperatures Likely Across the Mid-Atlantic; Severe Weather in the Upper Midwest and Southwest

An intense heat wave will peak across the Mid-Atlantic and I-95 Urban Corridor this weekend. Record high temperatures are likely with widespread heat indices exceeding 100 degrees. In the Midwest, severe storms capable of producing strong winds, hail, a few tornadoes and heavy rain will be possible Saturday. Additionally, strong storms will also be possible Saturday in the Four Corners region. Read More >


FTP Input Service
Guidance Documentation

This capability requires prior establishment of an account.
You may email a request for an account to RTH Washington.

NOTICE:  This is an automatic file transfer process and every submission will be disseminated world-wide as determined by the routing established for the WMO abbreviated heading you use in the bulletin contained in the file. The provider is responsible for the content.


File Handling Process:  This portal can receive observational and forecast product WMO bulletins as contents of a file. The files are uploaded to the RTH using standard FTP. After the initial account implementation is programmed and established, file transfers can begin. All files will be automatically processed by the RTH upon receipt. As the files contain bulletins for delivery on the GTS, there is no additional metadata files required. The WMO bulletins are removed from the files and immediately switched by the RTH. The received files will be erased from the receiving file server sub directory. The standard WMO bulletins will be handled just like they were received from any GTS circuit. The file names can only be duplicated monthly. If the Internet is used as the path for delivery, the RTH may not always be reachable.

FTP Input Service Rules and Definitions:

  • File Structure
    1. The file must contain WMO bulletins as defined in WMO Manual 386 Part II, not WMO messages [see note 1]
    2. The file submitted must contain at least one WMO bulletin
    3. The contents of the file is automatically parsed
    4. The received file is not retained in the RTH
    5. The CCCC used in the file name is the identifier of the sender
    6. The contents of the file is constructed with two components
           1. A flag field separating bulletins
           2. A WMO bulletin starting with the abbreviated heading
  • Content Structure
    1. The format of the Abbreviated Heading Line is: T1T2A1A2ii   CCCC   YYGGgg   (BBB)
    2. The four fields of the heading shall meet WMO message standard rules in construction
    3. The WMO abbreviated heading is constructed in capital letters
    4. The data time field must meet WMO standards
    5. The Pxx form of the BBB optional group is not allowed
    6. The abbreviated heading must be previously defined by the receiving RTH
    7. The bulletin must follow all standard construction rules such as line length
    8. The first line following the heading must be the SECTION 0 of the code form (MiMiMjMj code) as defined in WMO manual 306, if required
    9. All ASCII alphabet 5 bulletin control notations must be included, such as the report separator [ = ] signal, when required
    10. The "WMO end-of-message" field is not part of the WMO bulletin

Note 1 : The "WMO message" envelopes the "WMO bulletin"
with a beginning sequence called a:

Starting line: [ SOH ] [ cr ] [cr ] [ lf ] nnn

and has an end sequence called a:

Ending line: [ cr ] [ cr ] [ lf ] [ETX]

These two lines are not allowed in this process.

Structure of the File

File Name format to be used:
  The format of the file name is a combination of WMO Recommendation 2, FTP procedures [1,025K PDF] (described in CBS XII, Geneva, 29 November - 8 December 2000) and the U.S. Telecommunication Gateway TOC Directory and File Name Standard. The WMO has developed a NEW FILENAME FORMAT as a recommended practice for file delivery (FTP PUSH) over the GTS. This new recommendation will become published as part of WMO Manual 386 on 3 November 2003. The Gateway will begin using this new recommendation.

File Name Practice Currently Used
(see the new filename guidance for future use)

Old Format



_si. & _dt. are keys (do not change) see the TOC Directory and File Name Standard
cccc = Four letter ID of transmitting NMC or center; documented in WMO Manual 9, or Nationally defined

[si.aaaaaaaaaa] is an optional group to allow additional file name definition for multiple data processes within a providing data supplier ( Length of definition aaaaaaaaaa is a variable field up to 10 characters as needed. )

dt.hhnnss = hour-minute-second the file was generated for transfer (file names can not be duplicated within a day). The {SI|si}.(aa)aaa and {DT|dt}.hhmmss fields are taken from the Gateway TOC Directory and File Name Standard

Example filename
Using assumed account established with RTH Melbourne (AMMC)
File Content Structure

The files sent may contain one or more bulletins. Each bulletin in the file (including the first one) must be prefixed with a flag field to separate bulletins. The bulletin size should meet the WMO standard to achieve switching of the bulletins onto the MTN of the GTS.

The receiving center will define which "flag field separator" the data providers will use. This flag field is written in International Alphabet No. 5 and is always required in the contents of the file, even for a one bulletin product.

An example Bulletin Flag Field Separator format


#### = 4 pound signs
lll = length of prefix
bbbbbb = length of bulletin
"0A" = ASCII line feed

Example Content
SIAU40 AMMC 261500 RRA
AAXX 26154
94129 35/// /1305 10281 30066 40089 57008=
94289 35/// /1213 10286 30086 40095 57009=
94307 35/// /1503 10254 30111 40151 52004=
94371 35/// /1115 10279 30108 40114 57010=
94379 35/// /0000 10281 30108 40117 57013=
SIIN23 DEMS 261500 RRA
AAXX 26154
43063 32996 02706 10280 20134 39456 40067 333 59001=
Note: For potentially large bulletins, such as large GRIB or BUFR model derived products it was necessary to develop a new OPTION 2 to allow large capacity FLAG FIELD (option 2) form to be used.

Portal Service Establishment

The file transfer requires that an account be established with the U.S. Telecommunication Gateway (RTH Washington). The RTH will provide the computer location for FTP "send" transfers and will provide the requesting provider with the following information:

  1. The server URL address
  2. A unique portal ID & password for the file transmission.

Establishing this account requires an initial exchange of information between the sending center and the RTH. Contact RTH Washington by email to request an account.