Significant Weather Information (SIGMET)
The Hong Kong Observatory's Airport Meteorological Office is responsible for issuing SIGMET on hazardous weather and phenomena in the atmosphere that may affect the safety of aircraft operations within a designated airspace over the northern part of the South China Sea (see map below).
Hazardous weather and phenomena in the atmosphere include:
- thunderstorms
- tropical cyclones
- turbulence
- icing
- mountain wave
- duststorm
- sandstorm
- volcanic ash
- radioactive cloud
Some abbreviations used in SIGMET:
| Abbreviations | Meaning |
|---|---|
| TS | thunderstorm |
| TC | tropical cyclone |
| VA | volcanic ash |
| TURB | turbulence |
| ICE | icing |
| MTW | mountain wave |
| GR | hail |
| DS | duststorm |
| SS | sandstorm |
| CB | cumulonimbus |
| OBSC | obscured |
| EMBD | embedded |
| FRQ | frequent |
| SQL | squally |
| HVY | heavy |
| SEV | severe |
| INTSF | intensify |
| NC | no change |
| WKN | weaken |
| MOV | move |
| RDOACT CLD | radioactive cloud |