Test allows users to try out the mobile apps without the necessity of experiencing any significant weather. Test submissions will be visible on thePING viewer if they are selected for display.
None may seem like Test, but these two are intended for different purposes. Test is exactly that: simply to try out the mobile app and make sure that you can send data. None is intended for use when weather is either imminent or has been occurring and precipitation stops. If precipitation has actually ended, additional None reports do no harm, but once it has been over for a while, there is no need to send any more. The idea is to use None reports to help us determine when precipitation is not reaching the ground, even though radar shows a weak echo over your location.
The "Mixed" categories are usually transitional precipitation types. While they don't usually last for very long, occasionally an entire storm is made up of mixed precipitation types. Mixed rain and snow usually occurs as rain is changing to snow or vice versa. Mixed rain and ice pellets occurs as rain changes to ice pellets or ice pellets change to rain, and Mixed ice pellets and snow occurs as ice pellets are changing to snow and, on occasion, the other way around. When you note these conditions, now you have a way to report them!
Rain differs from drizzle only in the size of the droplets. If you can see individual drops falling (or hear them at night), it's rain. If it's very fine and the individual droplets can't be seen easily (or heard at night) it's drizzle.
Freezing precipitation (freezing rain and freezing drizzle) may not always be easy to detect. Obviously, the air temperature must be below freezing for freezing precipitation and that's almost always sufficient. To be sure, look for ice forming on shrubs or tree limbs. Looking for ice on the ground isn't a good strategy, because the ground is almost always warmer than the air and is one of the last places to accumulate ice.
Snow is, well, snow. That's an easy one. You can read more about identifying the different types of snowflakes in the Snowflake Identification Manual.
Wet snow is a category that has no official definition, but here we mean snow that tends to be heavy when it's shoveled and that can be easily packed into solid, firm snowballs -- this stuff is perfect for building snow men, for a snowball fight or for building snow forts. We do not mean to limit this only to the usually brief episodes of rain mixed with snow. If the snow is light and fluffy, it isn't what we mean by "wet snow."
Hail comes exclusively from thunderstorms. Hail in winter is rare, but especially in winter when thunderstorms occur, it's always a possibility. In winter, the temperature within the thunderstorm is cooler overall, allowing hail to be formed at lower altitudes. Because the temperature below the thunderstorm is also cooler than in spring or summer, even small hail is likely to survive to reach the ground.
Ice pellets/sleet looks like little ice BBs. A few are nearly perfect spheres, but most are hemispheres. They have the clear/translucent character of ice.
Graupel/snow grains are like bits of frost you might scrape off of a freezer or, alternatively, tiny bits of Styrofoam. They are white and sometimes shaped like tiny Apollo capsules. Graupel particles tend to be very light, fall more slowly than ice pellets, and can be easily crushed under finger pressure. They're literally grains of snow. We don't see graupel/snow grains here often so if you do see it, you're getting a real treat.