The difference between showers and rain becomes readily apparent when you take a top-down look at the weather map. Rain is evident in a large organised band of rainfall moving across the region, while isolated showers spout up and disappear here and there.
Listening to the weather forecast or reading the weather maps is a good habit to establish irrespective of the climate. Keep an eye on the weather near you. Forecasts can sometimes be wrong. Are there fast rising clouds? Does the wind change?
Adapting is a lot easier when you know what’s coming.
If conditions are deteriorating, don’t hesitate to set up your shelter,
go for a quick dip to rinse the sweat and dirt from your wet clothes, and then call it a day.
Rain is the precipitation that falls from a weather front, a boundary between two bodies of air that have different properties. Fronts produce most of their rain through mass ascent. Mass ascent is where one body of air is lifted, bodily upwards, by another body of air. The lifted body of air cools and the water vapour it contains condenses to form clouds and then rain.
Frontal clouds may stretch for hundreds of miles, usually consisting of various types of stratus cloud, including stratus, altostratus and nimbostratus. Such rain systems bring precipitation to a large area which makes it hard to avoid because the rain often stretches along the entire length of the front. This can last for a day or so and they are commonly associated with unsettled weather.
When a weather front brings rain, it will usually bring continuously grey skies, with rain falling through a large portion of the day. In these situations, weather forecasters tend to use the terms 'persistent rain' or 'prolonged rainfall'. The key differences relate to the types of cloud that lead to their formation and the resulting difference in the duration and intensities of the downpours.
While showers are technically a type of rain, they usually fall from individual clouds you can see in the sky so the rain will be on and off, with gaps of drier and brighter weather in between. It is quite hit and miss where they occur, and this means that you could get heavy showers on and off through the day, whereas in the next town their weather stays dry all day. Really heavy downpours penetrate even the coated nylon of a rain cape in seconds.
On any day with a shower in the forecast, it is usually best to prepare to get rained on, even if it looks bright outside. On some days there will be frequent showers, on other days you may just catch one brief shower and then it stays dry the rest of the day.
The best way to tell if you will get a shower soon is on the rainfall map. You can see where the showers are, how heavy or frequent they will be, and if they are moving towards you. If you want to know further ahead, the 'next 24 hours' section shows where the showers are forecast to be in future.
The largest cumulus clouds are called cumulonimbus and reach high enough into the atmosphere to contain ice, rather than water droplets. Whilst cumulonimbus clouds are large relative to an observer on the ground, they are not on the same scale as the body of cloud associated with a front.
A mature cumulonimbus cloud can be tens of thousands of feet high and many miles in diameter,
but unlike frontal cloud, they are relatively narrow.
A cumulonimbus cloud will last for tens of minutes to hours,
and so showers tend to be sudden and brief whereas frontal rain can last for days.
Showers are produced by convective clouds known as cumulus. Rain-bearing cumulus clouds are commonly taller than they are wide and have a fluffy, cauliflower-like appearance to their tops.
A cumulus or cumulonimbus cloud will begin life as a 'bubble' of buoyant air that rises upwards in the atmosphere. The bubble of air will cool as it gains height and this will lead to the formation of the cumulus cloud with its distinctive cauliflower-like top. The head of the cloud shows where buoyant air is continuing to ascend into the air of the surrounding atmosphere.
Once the cumulus cloud reaches a certain height or attains a cold enough cloud top temperature, it will produce rain.
Rain often falls in a downdraught within the cumulus cloud and suppresses the updraught that originally formed the cumulus cloud,
which limits the life-span of a cumulus cloud.