Hello,
I am having trouble understanding the definition of TAF3. If you can please explain in more detail the TAF3 and if it relates directly to the TAF or METAR.
Thank you.
Reference page: 185 Q.21
Essentially, a TAF3 is the same as a TAF but is issued every 3 hours, therefore making it more reliable for aerodrome forecasts due to it updating frequently.
A METAR is a report issued every half hour or hourly, 24 hours a day.
The METAR is included in the TAF as a report from the aerodrome reference report, whereas a TAF is the overall forecast.
Going through BOM's resource which explains the forecasts and reports will help you have an overall understanding on these:
http://www.bom.gov.au/aviation/data/education/taf.pdf
http://www.bom.gov.au/aviation/data/education/metar-speci.pdf