Many of these terms are used interchangeable and are grouped together. At times this is okay and at other times it is incorrect. This essay aims at defining each of these terms and informing on which ones are synonyms and which ones are not.

A chart is a generic term to describe the graphical or numerical labeling of meteorological data. The following are called charts: DIFAX displays, thermodynamic indice displays and many other displays of meteorological variables (surface chart, any upper level chart, dewpoint chart, temperature chart, etc.). The term chart should NOT be used when referring to output from a forecast model (unless it is via DIFAX).

The term panel can be used when referring to model progs. Panels are often in reference to 4-panels or any time several "windows" of model output are next to each other, such as a time sequence of model output.

The word prog is a short version of the word prognostication. ALL model images that show a future state of the atmosphere are termed progs.

An analysis is the most recent current conditions of the atmosphere. Analysis is combined with the word chart (analysis chart) to show a current display of meteorological variables. Analysis is combined with the word prog (analysis prog) to show the zero hour display of model data. The term initialization is BETTER to use than the term "analysis prog" (oxymoron) because analysis means "current" and prog means "future state".

The term image is used in reference to the graphical display of model data or graphical displays from satellite and radar data. Any computer-generated graphic can be called an image.

The term model should only be used in reference to model output.

A diagnostic analysis is the current state of some meteorological parameter. These words are close synonyms: panel, prog, model. These words/terms are close synonyms: chart, diagnostic, analysis chart, diagnostic analysis, diagnostic analysis chart (although too redundant).

Try to avoid:
(1) calling model output (especially colored graphics) a chart (call it a prog)
(2) referring to zero hour model output as a prog or analysis prog (it is an initialization or sometimes referenced as just plain analysis)
(3) calling an analysis chart an initialization (initialization is only for zero-hour model data).