In order to achieve effective communication we need to choose our words carefully. Just as every other word used in day to day life, the terminologies used in meteorology are very important.
The challenge, however, is that everybody interprets these words according to their own paradigm. Now the question arises, do we really know what the difference between rain, drizzle and shower is?
According to weather expert James Leham, showers can either be in liquid or solid form and hence, we can have rain showers, snow showers and even hail showers (most commonly known as hail storms). Showers tend to start and end more suddenly and do change in intensity as well.
Precipitation
Precipitation is simply any form of water particles regardless of their state that forms up in the atmosphere and falls to the ground, i.e. liquids or solids (that be snow, hail, sleet or ice).
Rain and drizzle
Rain and drizzle are precipitation in the form of liquid drops. In this case, the size of the drops tells us what they are. Drizzle drops tend to be small, falling much slower than rain. On the other hand, rain drops are bigger and fall slightly faster.
Interesting fact: Believe it or not any drop which has a diameter of 0.5 mm or less, is generally considered to be drizzle while larger than that is considered to be rain. It is true that forecasters do not actually measure the radius of every drop. Rain tends to be associated with fronts and so it usually extends for hundreds to thousands of kilometers, falling at much steadier rates.
Words like 'intermittent', 'continuous' and 'widespread' are often used to describe rain.
Showers
Showers can either be in liquid or solid form and hence, we can have rain showers, snow showers and even hail showers (most commonly known as hail storms). Showers tend to start and end more suddenly and do change in intensity as well.
Showers are also associated with cumulus clouds, which are single clouds that tend to form during hot afternoon hours or in the wake of weather systems. Hence, the sun does shine in between showers.
Words like 'scattered', 'isolated' and 'local' are used to describe showers.
Hopefully by now you will have some appreciation for the different terms used in meteorology and understand what is on the forecaster’s mind while describing the type of precipitation you are likely to get.