The CTWM is the climate of the UK. As the UK sits beneath the boundary of the Ferrel and polar cells, the presence of the Polar Front Jet Stream and Rossby waves across the northern hemisphere direct the path of high pressure weather systems (anti-cyclones) and low pressure systems (depressions).

Storm events in the UK are attributed to the presence of depressions. Depressions are areas of low pressure and are formed by warm tropical air coming into contact with colder air. As the warm air is of a lower density, it rises due to this collision. Thus, an area of low pressure is created as there is less air at the Earth’s surface. These air masses meet due to the influence of the Polar Front Jet Stream which as it travels in its meandering pattern across the UK (as opposed to being north/south of the UK), the cold air masses north of the PFJS and the warm air masses south meet. As the pressure becomes lower in accordance with more warm air rising, it causes the pressure gradient to steepen, consequently causing the winds to increase in strength and speed (they come from a south-westerly direction due to Coriolis). The rising air cools and eventually condenses, forming clouds which thicken and precipitate. As the depression advances, the cold front will eventually catch up with the warm front and form an occluded front. This is known as the decay of a depression and as the vast majority of the warm air has already been forced upwards, cool air begins to fill in the depression. At this point the weather conditions become more stable as cloud cover decreases, as well as the amount of precipitation and strength/speed of winds. Temperate storms occur when incredibly deep depressions (formed due to extreme amounts of energy creating enormous updrafts and thus a steep pressure gradient). Thus, as the polar air is strikingly cold (these occur in autumn and winter when the polar and artic air masses dominate the UK) they are extremely unstable.

An example of a temperate storm was the Great Storm of 1987. It was formed through a depression developing over the Bay of Biscay (west of France) caused by the collision of warm air from Africa and cold air from the North Atlantic. Despite the depression slowly drifting north towards the British Isles, it was reported that the weather would not reach the UK, consequently rendering the UK unprepared when it did hit. The depression deepened dramatically at 18:00 on October the 15th, creating an exceptionally deep pressure gradient. This was believed to have resulted from the combination of a strong jet stream as well as extreme warming over the Bay of Biscay.

The Great Storm had several impacts. In terms of social impacts, 22 lives were lost as well as schools being closed. 150,000 houses were left without telephone communications and a further 5 million without electricity. These impacts are quite severe considering millions of people were left without power. Thus, it is obvious that the Great Storm of 1987 did damage the infrastructure of the UK .There were also several economic impacts, such as thousands of work employee’s opting to take a few days off as transport links were cancelled. Flights were also cancelled at Heathrow and Gatwick alongside the closing of several, notable ports. It can be deduced from this that the Great Storm did have quite an economic impact on the UK as the closing of airports and ports would’ve consequently delayed the importing/exporting of materials and produce, subsequently damaging the economy. Furthermore, the Great Storm of 1987 was also partly responsible for the biggest London Stock Exchange crash of all time. This was due to many of the City workers being unable to get to work and thus the Stock Exchange was not opened. By Monday night the FTSE 100 index had fallen by nearly 11 per cent and £50 billion was wiped off its value. Shares fell again by a further 12 per cent the next day. This was a dire situation for the British economy to be in. It ruined the trust of the millions of small investors invested in the London Stock Exchange and grossly reduced

confidence in the City. However, the swift recovery of the London Stock Exchange following this incident is testament to the UK's status as a leading MEDC with the capability to recover quickly.

Perhaps the most significant short-term response was the issuing of a severe weather warning from the Met Office to the Ministry of Defence at 0135 UTC on 16th October. This warning entailed the potential need for the civil authorities to ask for military assistance following the storm and its consequences. This was of significance as it allowed adequate time for the civil authorities as well as the military to prepare for the impending storm. A similar warning was also issued to various agencies and emergency services. However, the fact that the warning was not issued on a nationwide scale reduced its effectiveness as it meant that in places in the country, some people were not anticipating the storm at all and were consequently in a very vulnerable position. Thus, if warnings were issued on a scale which would include the vast, vast majority of the population (by perhaps utilising television networks, radio stations and the internet to warn people), impacts such as the loss of life could've been prevented. However, impacts such as the infrastructural damage (such as over 5 million homes being left without electricity) would've been of a similar severity despite extensive warning. Other responses focused on ensuring the country would be better equipped in the future for a similar storm event. For example, in order to prevent an event like Black Monday again (the Monday after the storm) whereby the London Stock Exchange fell by 11%, Offices in London installed a backup generator – in order to ensure that if another blackout occurs, the stock exchange can still be ran. Furthermore, an internal Met Office enquiry scrutinised by two independent assessors acknowledge that improvements were made in increasing observational coverage of the atmosphere over the south and west of the UK in order to predict similar events to the Great Storm of 1987 through increasing the quality and quantity of observations from ships, aircrafts, buoys and satellites. Moreover, airports have now installed sophisticated weather systems which allows for a swift prediction of whether flights will be cancelled, allowing them to inform customers in plenty of time Overall, the responses that focus on ensuring potential for preparation in the wake of another storm event like the one in 1987 are successful. This is because changes and improvements have been made which not only greatly increased the UK's capability to predict severe storm events but also allowing them to respond in a much more swift and efficient manner (advanced airport forecasting to predict cancellations).