Australia’s weather bureau is clearing up confusing terminology in its forecast reporting. When it comes to rain, apparently terms like “scattered”, “isolated” and “patchy” aren’t descriptive enough, and are being replaced with percentage figures.
Weather image via Shutterstock
The ABC reports that the Bureau of Meteorology's change is occurring because the current terminology is too ambiguous, and that terms like scattered, patchy and isolated don't do enough to describe the possibility of rain in any given area.
Those loaded adjectives are being replaced with the cold and distant terms "very high", "high", "medium", and "slight". Those terms, along with the use of no mention of rainfall at all, line up with the chance of rainfall expressed as a percentage of possibility:
- Very high: Over 80 per cent chance of rainfall
- High: 60 to 80 per cent chance of rainfall
- Medium: 40 to 60 per cent chance of rainfall
- Slight: 20 to 40 per cent chance of rainfall
- No mention: 0 to 20 per cent chance of rainfall
It's good to see a little more clarity in the BoM's wording, but it doesn't change the fact that micro- and mesoscale (local) daily weather is, even at its best, unpredictable. (That's an important distinction from weather science more generally, which is concerned with weather on a larger scale and longer timeframe, and has an excellent track record.)
In any case, the extra level of granularity that the five-step system allows means that weather reports will now be slightly more descriptive, even if they are a little drier and less eloquent. The difference between slight and medium might be enough to get you carrying an umbrella, and the difference between high and very high might change your mind about that morning walk to the bus stop or train station in the first place. [ABC]