3. TAF Editor

The TAF editor is a text editor with all the standard capabilities such as cut, copy, paste, find and replace, auto backup. Forecast specific functionality involves syntax checking, climate and current weather consistency, and if configured, airport impact checks. It can also be invoked as a forecast viewer, where inconsistencies between forecast and the recent observations are highlighted.

3.1. Starting the TAF Editor

The editor is invoked from the TAF Monitoring GUI. There are two ways to do it.

  • Pressing the TAF Editor button starts the editor without loading any forecasts. Normally, one would use this method when preparing the routinely-issued TAFs.

  • Use one of the Editor Shortcuts for the selected TAF on the right-hand site of the AvnWatch GUI window. This will display the editor in the edit mode, with the most recent, valid TAF loaded for you.

The upper portion of the TAF Editor can be used to either view, "read-only", or edit the TAFs. Two "recipe tabs" near the top of the editor allow you to choose between these two modes.

3.2. Using the TAF Viewer

TAF Editor - Viewer Mode

TAF Editor - Viewer Mode

The TAF Viewer Window shows one or more TAF products issued for a site. If the lower portion of the TAF Editor is set to show METARs, and the TAF disagrees with observations for that site, then portions of the TAF and the observation are highlighted to show the discreptancy. The Text Editor button will change the window to the TAF Editor Window and load the most recent TAF into a new tab. The Show Headers toggle will add/remove header information from the TAF products currently in the viewer. The menu labeled Num TAFs allows you to choose the number of TAF product versions that will appear in the viewer. The Site ID pull-down just below the viewer allows you to choose which TAFs, will appear in the viewer.

3.3. Using the TAF Editor

TAF Editor - Edit Mode

TAF Editor - Edit Mode

When the Editor recipe tab near the top of the TAF Editor is selected, the upper portion of GUI becomes a specialized TAF editor. Near the top of the Editor Window is a row of command buttons that perform several functions that can aid TAF preparation. Below the command buttons is a row of recipe tabs that allow you to edit a number of TAFs simultaneously. The text-editing window occupies roughly the upper half of the the GUI. Below the text window are options for running TAF Tools. TAF Tools are user defined functions that manipulate forecasts loaded in the TAF Editor.

To edit the text of a TAF that is loaded in the TAF Editor Window, click within the window. An insert cursor will appear at the point where you click. Edit text as you would with any application. Copy/paste functions are available from the Edit menu and from a right-click menu within the window. Search/replace functions are available from the Edit menu. Header information can be changed by using the menu items above the editing window. The current recipe tab can be cleared by selecting the Clear button.

Information on using the Command Buttons and TAF Tools can be found in the following sections.

3.3.1. Command Buttons


Invokes the forecast selection dialogue.

Forecast Selection Dialog

Forecast Selection Dialog

To load TAFs in an TAF Editor window:
  1. Select one or more products from the Products menu.
  2. Select one or more sites from the Site menu.
  3. Select an option from the Initialize From menu.
  4. Select a Forecast Type.

If you want to select more than one item from the product or Sites list, either press and drag the mouse (this works for consecutive items), or click at the items while pressing the Ctrl key.

Options for initializing a TAF include the following:
latestUse the most recent TAF otherwise use the template. Most useful for amended and corrected forecasts.
templateUse the template. Most useful for preparing routine forecasts.
mergeMerges the latest TAF (earlier portions of the forecast) and the template (end of the forecast). Most useful for sites with scheduled part time observations.

If a forecast is waiting for transmission in /awips/adapt/avnfps/OB9/xmit/pending directory, it will be loaded into editor, regardless of the 'Initialize From' menu choice and then deleted from the pending queue.


Syntax stands for syntax quality control. When you press this button, the editor will attempt to decode all forecasts and reassemble them, assuring proper indentation and maximum line length. Any errors/warnings will be highlighted in the displayed bulletin. There are 3 levels of errors:

  • Red - if the decoder cannot determine the meaning of particular word. This is a fatal error, the rest of the forecast (for a given site) is not decoded.

  • Orange - this indicates an error as specified by NWSI 10-813 (shall not ...).

  • Green - this indicates a warning as specified by NWSI 10-813 (should not ...).

Positioning the mouse pointer over the highlighted text will cause an explanatory message to appear.

Syntax QC

Syntax QC


The QC combines several checks. Currently implemented are: Current Weather Check, Climate Quality Control and Impact Check. When clicking on the QC button using the left-mouse click, the QC settings for that particular TAF Section 4.2, “Editing TAF Site Information” will be performed.

The QC check is optional. Any highlighted text resulting from this action does not necessarily indicate that the TAF(s) is incorrect. Results from these checks merely require an evaluation “Are you sure?” before dissemination.

To override the default settings for the TAFs shown in the editor text window, right clicking on the QC button will bring up the following dialog.

QC Selection Dialog

QC Selection Dialog

By selecting or deselecting the options provided, and then pressing the Apply button, this will temporarily override the default QC checks performed for each TAF.

The Current Wx check is intended for rapidly changing conditions during forecast preparation, or when a routinely issued forecast is prepared well in advance of the transmission window. If current observation and the the first line of the forecast do not pass all of the monitoring checks, the first line of the TAF will be highlighted.

The Climate Quality Control check assesses the climatological frequency of the weather element combinations found in the TAF. It scans the climatological dataset of hourly and special observations, comparing combinations found in the TAF with observations available for that station. If a combination in the TAF has a low climatological frequency, an alert is displayed on the screen, alerting the forecaster to a climatologically rare event.

See Appendix C, Climate Quality Control for detailed description of the algorithm.

The Impact Check examines each line of a TAF against airport specific conditions, such as low ceilings and visibility or significant crosswinds as these may affect aircraft arrival and departure rates. The impact rules can (and should) be customized for each airport.

See the section called “Impact QC Definition File” for detailed description of the configuration file and how to customize it for each airport.

QC Example

Current Wx and Climate Output


Stores current TAF bulletin into a temporary file tmp/CCCWRKTAF.type, where CCC is your node id and type is the forecast type.


Restores bulletin previously stored in a temporary file tmp/CCCWRKTAF.type. type must match the type selected in the editor.


Puts forecast in the transmission queue. In order to succeed, the forecast must successfully pass the Syntax check. In your resource file, there is an item *disalowSend, by default set to error. This means you can't inadverently send a forecast which does not follow the directive. If you have an error flagged, but are certain that the forecast is correct and either the software or directive is wrong, use Clear Errors before pressing Send. A confirmation dialog will be shown, where you will have to choose your name from the list. The corresponding forecaster ID number will be logged for forecast verification purposes.

Send Dialog

Send Dialog

You can manually set the transmission time of the product. This feature is provided to allow for sending routine forecasts closer or at the end of transmission window in case of rapidly changing weather conditions.


The transmit flag in the etc/forecasters file controls whether this button appears or not in the TAF editor. This feature is useful if users wish to use AvnFPS without the risk of inadvertant transmission of a TAF.

3.3.2. TAF Tools

TAF Tools are user-defined functions that manipulate forecasts loaded in the TAF Editor. Additional TAF Tools can be developed and implemented by programmers at your WFO, much like the locally-developed Smart Tools that can edit grids in the Graphical Forecast Editor. TAF Tools are written in Python, just like Smart Tools. TAF Tools can access just about any data source that appears in AvnFPS. This includes the TAF in the TAF Editor, other TAFs, METARs, and various forms of guidance.

A small set of TAF Tools are delivered with AvnFPS. These tools were developed for their instructional value as well as their utility. They are described below:

TAF Tools

TAF Tools

Adjust Times

Modifies TAF by removing past periods, adjusts issue and valid times. If you use this tool before running syntax quality control, you can avoid error messages about invalid forecast periods.

Copy Forecasts

Allows for interactive copy of forecasts in a collective. The idea is that you prepare forecast for one site, and want to replicate weather conditions for some other TAF sites nearby. This tool can be an alternative for copy-and-paste.

Use METAR For Prevailing

Updates forecasts with the current observations. Also incorporates functionality of the Adjust Times tool.

West Flow

An example of a more sophisticated tool; it addresses a situation that commonly occurs in West Virginia. The tool creates forecasts for a number of other sites based on forecasts for KPKB and KHTS. The tool advects clouds and weather, adjusting cloud heights for elevation. Since the tool specifically access the WV TAF sites by name, it cannot be used “as is” by other WFOs.

3.4. Using the Guidance Viewer

The Guidance Viewer Window allows you to view various forms of guidance as you compose TAFs. Currently, AvnFPS can be configured to display up to eight data sources. These are Metars, GFS-MOS, NAM-MOS, NGM-MOS, LAMP, TAF/LAMP, NAM DMO (Direct Model Output), NDFD Grids, . Each source has a dedicated display window which you select by clicking its tab.

All viewers have toggle All, if set, will display data for all sites associated with the currently monitored product. The toggle Flight categories will highlight periods according to the observed (METARs) and forecasted weather. Most of the guidance available in the TAF Editor can displayed in one of the 3 formats, depending on the toggle Format:

table The display is similar to that of MOS text messages, with added optional display of probabilities for VIS and CIG categories (the MOS text bulletins contain only the best category).
long The data is formatted as a TAF. There is one line per each forecast period (1 or 3 hours).
short The data is formatted as a TAF. Forecast periods with similar weather are combined.

The toggling Flight Categories button will higlight each forecast period/line depending on the flight category.

The algorithm to combine periods with similar weather is based on COMET training module. Major rules applied are:

  • Flight category: time periods are not combined in one TAF line unless it is configured by the users to merge by using grp_taf.cfg.

  • Weather and wind condition changes: when there is a change (starting or ending) in weather conditions and wind changes, new line of TAF is always formed.

  • Combining rules: Rules used to pack TAFs into more concise form. These rules are site configurable and are stored in grp_taf.cfg.


Displays METARs for a selected site. You can select the site from the Site ID list. The items on the list are set to the currently monitored product(s).

METAR Viewer

METAR Viewer

The number of displayed reports is controlled by the Num Hours menu. If there is a discrepancy between the TAF and the most recent METAR, the offending weather element will be highlighted. There are two display modes: text and decoded. In the text mode you may switch the display of WMO headers. In decoded mode there is an option to highlight reports according to the flight category. The toggle Headers is to display WMO headers. The toggle All, if set, will display all METARs for the selected product(s). It replaces All METARs found in the previous releases of AvnFPS.

GFS MOS Viewer

Displays GFS MOS guidance for a selected site. You can select the site from the Site ID list.

GFS MOS Viewer

GFS MOS Viewer

The toggle Routine button switches TAF valid period between amending the current TAF and the next cardial issue -- easier to see, rather than explain. The Probabilities button displays the probability of the categorical elements in the product. These probabilistic data are not available in the MOS text products, but rather are disseminated in the BUFR bulletins.

NAM MOS Viewer

Displays NAM MOS guidance for a selected site. The display format and control options are the same as for GFS MOS.

NGM MOS Viewer

Displays NGM MOS guidance for a selected site. The display format and control options are the same as for GFS MOS.

LAMP Viewer

Displays LAMP guidance for the selected site. LAMP is based on GFS MOS and provides updates every hour using surface observations, satellite and lightning data. [LAMP]


Displays the official TAF updated with LAMP guidance. Since this is a synthesis of LAMP guidance and the Official TAF, it's not meaningful to have a 'table' format, just 'short' and 'long' TAF formats are available. [Oberfield, et. al.]

NAM DMO (Direct Model Output) Viewer

Displays minimally processed output from the NAM model for a selected site.

NAM DMO Viewer

NAM DMO Viewer

The display is similar as for GFS MOS guidance. There is no Probabilities button as this is data taken directly from a single deterministic run of the NAM. Visibility and cloud ceilings are not state variables in the model but are derived according to algorithms described here. [Smirnova, et. al.]

NDFD Grids Viewer

Displays data taken from NDFD grids for the gridpoint closest to the selected site. The display format and control options are similar to those for the GFS MOS Viewer, with the exception of Probabilities button.

3.5. TAF Editor Menu Bar

The Menu Bar allows you to access controls for many features of the TAF Editor. Entries in parentheses indicate keyboard shortcuts that will access that menu item.

File Menu

File Menu

Print (Alt-f-p)

Launches the print dialogue. The dialogue displays the default print command: lpr and print on the default printer for your workstation. If you want to use a different printer, enter appropriate options (for example: lpr -Plp2).


You can use this dialogue to add content of the text window to fxatext database: enter textdb -w CCCNNNXXX with the appropriate AFOS PIL.

Clear Errors (Alt-f-c)

Clears error tags set by quality check actions. It can also be used to force transmission of forecasts that did not pass QC.

Update Times (Alt-f-u)

Updates issue and valid times in all forecasts loaded in the TAF Editor.

Save As (Alt-f-s)

Allows users to save edited forecast to a file. Invokes the file selection dialogue.

Restore From (Alt-f-r)

Allows users to restore forecast from a timed-backup file. Invokes the file selection dialogue.

Store in DB (Alt-f-t)

Stores current TAF bulletin to fxatext database, under the AFOS PIL CCCWRKTAF, where CCC is your node id.

Options Menu

Options Menu

Auto Save (Alt-o-a)

When selected, the content of the window is saved every 60 seconds to a backup file. If needed, the file can be restored by using the Files->Restore From (Alt-f-r) The directory where the backup file is stored is /awips/adapt/avnfps/3.1/tmp. The file is named taf.host.kind, where kind is either taf or twb (for example taf.lx3). When a bulletin is reloaded, the file is renamed to taf.host.kind.prev.

Auto Print (Alt-o-u)

When selected, the forecast will be printed on the default printer when the Send button is pressed.

Update Times on Format (Alt-o-p)

When selected, issue and valid times in all forecasts will be updated (with values depending on the forecast type) when the SynQC button is pressed.

Send in Collective (Alt-o-s)

Normally, the bulletin is split before transmission, so that each TAF is sent separately. When this option is selected, the whole bulletin is transmitted as one file. This option is required at some OCONUS sites.

Edit Menu

Edit Menu

Cut (Alt-e-c) , Copy (Alt-e-o) , Paste (Alt-e-p) , Undo (Alt-e-u) , Redo (Alt-e-r) ,

These options provide standard editing capabilities. Undo and Redo options have very large histories.

Find (Alt-e-f)
Find and Replace Dialog

Find and Replace Dialog

This option invokes find and replace dialog with undo capability.


By pressing the right mouse button in the text area, you will get a popup menu, which also provides editing capabilities.

Editor Popup Menu

Editor Popup Menu

Key Bindings (Alt-h-k)

Displays key bindings valid in the text editor window. These are standard bindings as implemented in Tk. For complete list, see Appendix 1.

Usage (Alt-h-u)

Displays on-line help.