OPC>FAQ>Graphical Product Legend>Terminology & Weather Symbols>Radiofacsimile User's Guide

What is UTC, GMT, or Z time?

 

- By international agreement, the local time at the prime meridian or 0 degrees longitude, which passes through Greenwich, England.  Since there are 15 time zones across the world, UTC acts as a reference time for the scientific community. The terms Coordinated Universal Time (UTC), Zulu (Z), and Greenwich Mean Time (GMT) are equivalent. All of the analysis and forecast products are based on this reference time. This longitude is the line that separates the eastern and western hemispheres.

 

On your analysis and forecast charts what do the terms 'FROM' and 'VALID' mean?  

-The term 'FROM' refers to the reference time and date of the model guidance used to create the forecast product. 'VALID' is the time and date of the actual forecast.