There are a few things in a pilot’s life that affects him as much as the METAR. The METAR can ground you or tell you that you’re legal to try an approach. It’s one of those few things which follows you on every flight. Since a pilot spends a fair amount of time reading these things, occasionally something odd pops up. And then it nags at you. An example of that is the METAR descriptor GR. Why does GR mean hail? Wouldn’t you think they’d choose HL? Perhaps that’s too close to HELL. And that might confuse pilots who frequently see SS (Sandstorms) DS (Dust Storms) and VA (Volcanic Ash) which I think of as forms of weather hell.
So I decided to look at the whole list of METAR descriptors. Here they are: