Python Powered SCDwriter 3.1.1 User Documentation Python Powered

Hi! Introduction

SCDwriter, version 3.1.1, is a Python/Tk (Pmw) program designed to simplify the creation and dissemination (via AWIPS) of the 6-hourly, midnight, and "sunshine" SCDs. This documentation is provided as a basic guide for using the SCDwriter program. In order to keep this document as painless as possible, I'm assuming that you know the principles of SCDs and how to use a typical graphical user interface.

Cracked egg Background Information

This documentation is for SCDwriter 3.1.1, as implemented at WFO Norman OK. This version was completed February 17, 2004. See New Features, below, for a description of changes from previous versions.

SCD icon Running the Program

On any Linux PC, click the AWIPS icon, select "Local Apps," and click the SCDwriter 3.1 entry (it'll run 3.1.1), or click the SCD icon (similar to the one above and left) on the Linux task bar, if it's available. A window should pop up with a progress bar (jerky progress advance is normal), then the program itself will appear with an entry window for the next scheduled SCD. If it's not the one you want, click "Controls" and select the correct SCD time.

Pencil and pad Entering the Data

6-hourly Tab

The only non-intuitive items here should be "Type" and a few "Clouds" items. There is also a new button for remotely-observed snowfall and snow depth (new with version 3.1). See the highlighted screen shot below:

6-hourly tab


Select the weather types in SCD order. As you do, the 2-letter abbreviation will appear in the text bar to the right. If you make an incorrect selection, select "(Clear Entries)" to start over.

Present weather example


You can shorten your task by picking certain items before others. Examples:

Most or all of the remaining items will be automatically selected to match.

Remote Snow Measurements

Enter the data supplied by the observer(s) as in the example below. You can leave the fields blank for zero amounts.

Remote snow measurement entries

0800Z and 1755Z Tabs

These items should be self-explanatory.

Midnight Tab

The temperatures you enter here will be converted to °C and displayed on the "Controls " page.

Controls Tab

Text Box

In version 3.1+, the scrollable multi-line text box replaces the single-line entry box from previous versions of the program. Its use should be intuitive, except that long lines that scroll onto the next line down are still considered to be part of the first line, as far as the arrow keys are concerned. The SCD will also be transmitted as such (the text box is 69 characters wide, unless you resize the box). See Bugs, below, for more information.


The "Make SCD" button formats the SCD according to the data entered in the other tabs, for the time shown in the "SCD time (UTC)" drop-down box on this tab.

The "Queue/Send/Cancel" button toggles according to the "Send SCD now" checkbox, and becomes "Cancel" when an SCD is queued. "Send" immediately begins the transmit-to-AWIPS process. "Queue" will begin this process at the time shown in the SCD itself (not the "SCD time (UTC)" entry).

Finished Controls Tab
Example of completed multi-line SCD, after clicking "Queue" button

Check Transmission

If you wish to verify that the SCD was correctly transmitted, wait a few minutes (usually about 5 to 10), then check SRH's archive for the latest SCD.

Menu Bar

Most items in the menu bar should be self-explanatory. You can activate "tooltips" by selecting Help->Tooltips. This provides an explanation of most buttons, entry boxes, etc. when you point to them. Options->Test mode allows you to play with the program without worrying about transmitting anything. Note that both of these are toggles.

File->Decode edited SCD lets you alter the SCD on the Controls tab, then set the appropriate entry widgets accordingly. It may also be used with File->Get AWIPS SCD to set widgets to the values equivalent to the latest SCD stored in AWIPS.

File->Reset to defaults returns all widgets to their initial values.

A bug Bugs


If you find a bug that isn't described below, please contact the maintenance programmer (see For Further Information, below). If practical, please provide a complete description of the error, the action that caused the error, and, if a program crash was involved, a complete copy of the stack trace (usually called a "Traceback"). Errors in this documentation should be addressed to the person who maintains it (again, see For Further Information).


Importing multi-line SCDs from AWIPS, particularly those whose main line is broken into two text lines, is not tested, and may not work properly. Since this is a rare situation and unlikely to be used, it will not be fixed except by special request.

Omission of high cloud type with lower overcast layer is not flagged as an error. This should be fixed in later versions.

Exclamation point New Features

Question markFor Further Information

See the Hydrometeorological Duties binder, Appendix A, for more information on the SCD.

See or e-mail me ( for more information on SCDwriter. At this time, I am entirely responsible for SCDwriter and its documentation.

Program maintenance documentation is contained within the program.

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Begun September 7, 2003. Latest update: October 21, 2004

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