At this time of year, we tend to experience howling gales and driving rain, often given obscure names like Storm Gareth which has been wreaking havoc across the UK over the last few days. This is also the third storm to be named this year in the British Isles. But what causes this type of weather system and why is it such a regular occurrence during the long British winters?
Low Pressure Systems
Low pressure systems, known as lows, cold fronts or depressions are the most common weather system in the UK. Lows bring a whole range of weather conditions, including clouds, rain and strong winds. Cold fronts usually form over the North Atlantic and track with the westerly flow. These systems develop as they move and can build to 2000km in diameter, usually lasting 3-10 days, like we have seen with Storm Gareth.
How Do Lows Move?
Cold polar air of low pressure systems typically moves towards the equator. The boundary between a warm and cold front tends to be particularly steep in winter, resulting in the strong winds known as the ‘jet stream’. This jet stream travels from west to east in a wavy pattern, moving mid-latitude weather systems with it. In cases like Storm Gareth, the jet stream passes over the British Isles. This brings with it the clouds, strong winds, rain and changeable weather that constitutes an average British winter.
Predicting & Recognising Low Pressure Systems
One of the most commonly used tools for meteorology is satellite imagery. Whilst it is a great visual aid to show the size and exact movements of a weather system, it does have its limitations. In particular, it can be very difficult to locate the fronts precisely. Instead, forecasters will refer to temperature, dew-point measurements and other meteorological data.
Another strong indicator of weather systems and their developments is cloud formations. Unfortunately, it is not easy to distinguish cloud types via satellite imagery. However, infra-red images can go some way to showing the characteristics of a cloud. By considering the cloud types associated with a low pressure system, it is possible to predict its behaviour. For example, where deep cumulonimbus clouds form, heavy rain will fall. As the cold front passes, it is typical that the temperature will also drop.
Find Out More…
Meteorology is a complex subject with so many layers to pick through. It can be a minefield to understand without expert guidance but is incredibly important if you’re hoping to spend any time on the water. A number of the theory courses available at Ocean Sports Tuition cover the key aspects of weather systems that you will need to know, including:
- RYA Essential Seamanship & Navigation (shorebased or online)
- RYA Day Skipper Theory (shorebased or online)
- RYA Coastal Skipper/Yachtmaster Theory (shorebased or online)
- RYA Intermediate Powerboat
To book your place on one of our RYA theory courses to learn more about weather systems, visit our Course Calendar today.
Ocean Sports Tuition is a specialist training school that provides a complete range of RYA practical and theory courses, as well as boat charter opportunities. Operating from purpose-built facilities in Saxon Wharf Marina, Southampton, we offer courses for those looking to dip their toe in the water to experienced boaters taking their next steps into a career in water sports.
For more information about any of the above services, please contact Andy on 02381 242159 or email firstname.lastname@example.org.