Under what meteorological conditions is an aerodrome meteorological office required to issue a SPECI (Special Meteorological Report) rather than waiting for the next routine METAR?

1. When weather parameters deteriorate or improve across operational threshold criteria, such as significant wind shifts (>= 30° at >= 10 kt), visibility crossing key minima (800/1500/3000/5000 m), or onset of thunderstorms
2. Whenever the airport barometric pressure changes by exactly 0.1 hPa
3. At exactly 15 minutes past every hour regardless of weather conditions
4. Only when an aircraft declares a formal fuel emergency on frequency