Originally Posted by
43Inches
TTF was a METAR with trend forecast attached allowing its use for planning up to 3 hours from observation. A METAR is simply what in most cases the automated sensor saw exactly up above it, meaning its significance in isolation means nothing for what will happen in the next 30 minutes let alone 2 hours. All you use a METAR for is to confirm that the TAF is running true, or not.
Outside the aviation bubble that is Australia, METARs are often appended with a trend, valid for two hours after the observation. They're still labeled 'METAR', but they're a trend forecast.