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Extreme high temperatures are associated with increased incidences of rail buckles. Climate change is predicted to alter the temperature profile in the United Kingdom with extreme high temperatures becoming an increasingly frequent occurrence. The result is that the number of buckles, and therefore delays, expected peryear will increase if the track is maintained to the current standard. This paper uses a combination of analogue techniques and a weather generator to quantify the increase in the number of buckles and rail related delays in the southeast of the United Kingdom. The paper concludes by assigning a cost to the resultant rise in delays and damage before making recommendations on how these effects can be mitigated. Copyright © 2008 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

This paper describes a new seamless blended multi‐model ensemble configuration of an existing probabilistic medium‐ to extended‐range weather pattern forecasting tool (called Decider) run operationally at the Met Office. In its initial configuration, the tool calculated and presented probabilistic weather pattern forecast information for five individual ensemble forecasting systems, which varied in terms of their number of ensemble members, horizontal resolution, update frequencies and forecast lead time. This resulted in multiple forecasts for the same validity time which varied in terms of forecast skill depending on the lead time in question. This presented challenges for end‐users (e.g., operational meteorologists) in terms of knowing which forecast output is best to use and at which lead time, as well as knowing what to do in situations where forecasts varied between ensembles. To get around these challenges, a new seamless blended multi‐model ensemble configuration has been implemented operationally, comprising of output from five separate ensembles, and provides a single best forecast from day one out to day 45. Objective verification for a set of eight weather pattern groups covering forecasts initialized over a 6‐year period (2017–2022) shows that the seamless blended multi‐model ensemble forecasts are at least as good as, if not better than the best performing individual model. [ABSTRACT FROM AUTHOR]

Reserve power systems are widely used to provide power to critical infrastructure systems in the event of power outages. The reserve power system may be subject to regulation, typically focussing on a strict operational time commitment, but the energy involved in supplying reserve power may be highly variable. For example, if heating or cooling is involved, energy consumption may be strongly influenced by prevailing weather conditions and seasonality. Replacing legacy assets (often diesel generators) with modern technologies could offer potential benefits and services back to the wider electricity system when not in use, therefore supporting a transition to low‐carbon energy networks. Drawing on the Great Britain telecommunications systems as an example, this paper demonstrates that meteorological reanalyses can be used to evaluate capacity requirements to maintain the regulated target of 5‐days operational reserve. Across three case‐study regions with diverse weather sensitivities, infrastructure with cooling‐driven electricity demand is shown to increase energy consumption during summer, thus determining the overall capacity of the reserve required and the availability of 'surplus' capacity. Lower risk tolerance is shown to lead to a substantial cost increase in terms of capacity required but also enhanced opportunities for surplus capacity. The use of meteorological forecast information is shown to facilitate increased surplus capacity. Availability of surplus capacity is compared to a measure of supply–stress (demand‐net‐wind) on the wider energy network. For infrastructure with cooling‐driven demand (typical of most UK telecommunication assets), it is shown that surplus availability peaks during periods of supply–stress, offering the greatest potential benefit to the national electricity grid. [ABSTRACT FROM AUTHOR]

Extreme weather events can cause significant damage to power distribution network infrastructure, often resulting in power outages. Distribution Network Operators (DNOs) are faced with the challenging task of responding to these outages in real time while maintaining a resilient grid. Our paper presents an innovative approach to alert operators about the potential risk associated with upcoming extreme weather through a normalized fragility curve. The uniqueness of the curve is the ability to capture regional differences across a DNO's territory while presenting operators with a means of setting unified risk thresholds. This can support a proactive response and allow the staging of necessary resources to minimize the threat posed by such events. Our approach captures the changes in failure probability associated with differing wind regimes and demonstrates the benefit of sub‐regional meteorological information. The proposed approach is demonstrated for wind events using 20 years of historical fault records from a DNO in the United Kingdom (UK). While its efficacy is demonstrated for windstorms in the UK, the approach could be applied globally to develop normalized fragility curves for other types of seasonal extreme weather events such as snowstorms, hurricanes, or linked hazards such as wildfires. The approach can also facilitate an understanding of how infrastructure may operate under future climate conditions, supporting proactive adaptation. [ABSTRACT FROM AUTHOR]

Against an academic and policy backdrop of interest in (and concerns about) the issue, this paper draws on a range of academic writing in various disciplines to explore visual strategies of climate change communication. The geographic scope of the investigation is the United Kingdom, with particular attention to recognizable icons of climate change in UK media and the images used in political campaigns. The paper is in two parts. The first part concentrates on various efforts to put a 'face' on the climate change issue, while part two suggests that weather and renewable energy are the dominant alternative motifs. The paper draws a basic distinction between fear-laden representations of climate change and a variety of visual efforts to use so-called inspirational imagery. All of the images reviewed suggest an affirmative answer to the question in the title, there are multiple efforts underway to move beyond polar bears and represent climate change in more creative and meaningful ways. The bigger question addressed is one raised already by photographers as well as academics, i.e. whether documentary photography (rather than particular types of images) is the more fundamental issue. The answer in the paper is that photographs are no different from other visual images in their capacity to draw attention to messages. The challenge is to use visuals creatively, in ways that prompt positive engagement with climate change without enhancing public disengagement and fatalism. Copyright © 2010 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

This paper discusses developments in the last five to six years in the provision of operational flood forecasting in England, Wales, and Scotland. Before the formation of the Environment Agency EA in England and Wales and the Scottish Environment Protection Agency SEPA, flood forecasting capabilities were fragmented. Just over a decade ago both organisations received governmental mandates for the provision of flood forecasting and warning nationally, and have as a result in recent years established systems providing national coverage: the National Flood Forecasting System, and Flood Early Warning System FEWS Scotland. These have facilitated a rapid expansion of catchments for which forecasts are provided, and the common framework used has enabled a more rapid introduction of scientific advances in forecasting techniques. This paper gives an overview of some of these recent developments, as well as providing an outlook to further developments to be undertaken in the near future. Copyright © 2009 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Radar has been applied to the study of insect migration for almost 40 years, but most entomological radars operate at Xband 9.4 GHz, 3.2 cm wavelength and can only detect individuals of relatively large species, such as migratory grasshoppers and noctuid moths, over all of their flight altitudes. Many insects including economically important species are much smaller than this, but development of the requisite higher power andor higher frequency radar systems to detect these species is often prohibitively expensive. In this paper, attention is focused upon the uses of some recentlydeployed meteorological sensing devices to investigate insect migratory flight behaviour, and especially its interactions with boundary layer processes. Records were examined from the verticallypointing 35 GHz ‘Copernicus’ and 94 GHz ‘Galileo’ cloud radars at Chilbolton Hampshire, England for 12 cloudless and convective occasions in summer 2003, and one of these occasions 13 July is presented in detail. Insects were frequently found at heights above aerosol particles, which represent passive tracers, indicating active insect movement. It was found that insect flight above the convective boundary layer occurs most often during the morning. The maximum radar reflectivity an indicator of aerial insect biomass was found to be positively correlated with maximum screen temperature. Copyright © 2009 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Drawing on evidence from the United Kingdom and elsewhere in Europe, this paper explores how people have responded to flood warning information and how these responses impact upon the effectiveness of a flood warning through saving lives and injuries, and reducing economic damages. Methods of flood warning that the public rely upon are discussed alongside empirical evidence of how flood victims prepare for, and respond to, flood warnings in rapid to mediumonset floods. The paper investigates why some members of the public fail to act appropriately, or most effectively, to flood warning information, touching on ideas of a lack of understanding, mistrust in authority and a lack of ownership of flood reducing actions. The paper examines the styles of public learning about flood warning response which might be most appropriate and effective, and how recent positive steps to increase the publics understanding of effective response might be further enhanced in the United Kingdom. Copyright © 2009 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

ABSTRACT A huge change has occurred in the way people obtain weather information in the last few years and a large percentage of the population now get weather forecasts on their mobile phones. There is currently a wide range of smartphone weather apps available: in 2014, iTunes App Store alone offered 5043 active applications in the weather category. The rapid penetration of new broadcasting technologies strongly affects the way weather forecasts are communicated to, and used by, people. Portability, permanent connectivity and geolocalization allow location-specific and time-sensitive weather forecasts to be provided. This paper explores the main features emerging in the 39 most popular weather apps in the United States, United Kingdom and Italy, and focuses on the implications in the communication of uncertainty. The results show that even if the advances in mobile communication technologies could, in principle, improve the effectiveness of weather communication enormously, the expectations created around weather forecasts appear to be inconsistent with current forecasting capabilities, particularly with their inherent uncertainties in space and time, as well as in the nature of the predicted weather events. [ABSTRACT FROM AUTHOR]

Climate change impact assessments require detailed information regarding the impact of weather in the current climate. This study focuses on the road network, using UK Highways Agency Traffic Information System data and NIMROD precipitation radar data to determine the impact of precipitation on traffic speeds along the M1 and M6 corridors for use in future impact assessments. The results show that whilst precipitation does impact on traffic speeds, there is no universal significant single factor relationship between the two variables and only a small amount of variance in traffic speeds can be explained by the intensity of precipitation. However, a threshold appears to exist simply at 0 mm h−1 (i.e. precipitation/no precipitation). The significance of this threshold is tested in this paper, but it appears clear that a universal relationship between precipitation intensity and vehicle speeds is unlikely to exist and local conditions such as capacity and drainage are equally as important to take into account. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

ABSTRACT Atmospheric observations from aircraft have played an important role in meteorological research for many years; this paper presents an overview of meteorological research done with research aircraft in the United Kingdom. Key developments from throughout the history of meteorological research flying in the United Kingdom are presented, along with highlights of UK atmospheric research flying done in the last decade using the Facility for Airborne Atmospheric Measurements ( FAAM) BAe-146 aircraft. The work presented includes research into thermodynamics, cloud processes, atmospheric aerosol, radiative transfer and atmospheric chemistry. Research aircraft provide a unique platform for the observation of atmospheric processes, allowing targeted measurement of specific parameters at a range of altitudes throughout the atmosphere. These measurements have improved greatly the understanding of the Earth's atmosphere, and the impact of these measurements has been seen through improvements in the representation of physical processes within numerical weather prediction ( NWP) and climate models. Research aircraft have also been used extensively for the calibration and validation of remote sensing measurements, providing a unique test-bed for satellite observations. This research has led to improved use of satellite observations that have enhanced greatly how the atmosphere is viewed. Many developments in atmospheric research would not have been possible without the use of aircraft measurements, and these measurements will continue to play a key role in future developments of meteorological observation and prediction, as the complexity and resolution of weather and climate models increases. [ABSTRACT FROM AUTHOR]

ABSTRACT The two World Area Forecast Centres (WAFC) are responsible for providing aviation hazard forecasts above 800 hPa (6000 ft) including clear air turbulence (CAT) to aviation customers around the world. A new automated gridded forecast for CAT is now being produced by the two WAFCs along with the traditional forecaster-produced Significant Weather (SIGWX) charts. Until now little objective verification has been available for the WAFC products. However, the increasing availability of high-resolution in situ aircraft observations now makes routine objective verification a possibility. The Global Aircraft Data Set (GADS) formed from the fleet of British Airways Boeing 747-400 aircraft is a particularly useful resource. This paper proposes an objective verification scheme using Relative Operating Characteristic analysis to investigate the skill in both the operational SIGWX and new gridded CAT forecasts from both WAFC London and WAFC Washington. Global verification results using GADS data are presented for 4 months during winter November 2008 to February 2009. [ABSTRACT FROM AUTHOR]

Five years of UK Met Office global model analyses from 1 January 2004 to 31 December 2008 have been used to generate a global hail climatology at 1° latitude by 1° longitude resolution. Hail has been diagnosed from model vertical profiles of temperature and humidity using a simple algorithm based on a paper by Fawbush and Miller (). Results have been compared with published observational climatologies on both a global and regional basis. The model diagnoses compare favourably with the observed data with both orographic and seasonal signals. However, there are differences, and possible reasons for these are discussed. These include limitations of the simple algorithm, the difficulty of observing hail in sparsely populated areas and the problem of population growth influencing the number of hail reports. Copyright © 2011 Royal Meteorological Society and Crown Copyright [ABSTRACT FROM AUTHOR]

Weather forecasts on BBC radio and television are recognized as the bench mark by which all other weather broadcasts in the United Kingdom are judged. Having spent many years at the BBC Weather Centre, as forecaster and senior meteorologist, the author reflects on the development of television weather forecasts on the national, licence fee funded, broadcaster in the United Kingdom. The period referred to in the paper saw technology evolve rapidly with television weather graphics at the forefront of the technological revolution. Changes in the recruitment and training of forecasters over time are discussed, giving an insight into the behind the scenes evolution of the workings of television and radio weather broadcasts. Copyright © 2010 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

An important aspect of flood risk management is the issuing of timely flood alerts. The spatial, as well as temporal, scale of these warnings is important. In many situations efficient risk management may be aided by the provision of local flood predictions at a high spatial resolution. Examples of such situations include issuing warnings for small groups of outlying houses or key infrastructure locations such as power substations. In this paper a methodology for providing automated, detailed and location specific warnings which are computed ‘onsite’ is presented. Copyright © 2009 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

This paper reviews recent advances in weather forecasting capability in the United Kingdom and their implications for increasing the lead time with which flood warnings can be issued. The events of summer 2007 have highlighted the vulnerability of parts of the United Kingdom to flooding and the need for long lead time flood warnings to enable the protection of people and critical infrastructure. Historically, computer weather forecasting models have been unable to forecast at the scales of importance for flood warning, and so the warning processes have been forced to rely on measurements on the ground. Examples are presented to demonstrate that new forecasting technologies, currently being implemented, enable warnings to be produced much earlier, provided they are couched in probabilistic terms and interpreted appropriately. Crown Copyright © 2009. Reproduced with the permission of the Controller of HMSO. Published by John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Global warming is projected to have major implications on global health. It is however not yet clear how this will translate to impacts on the healthcare system. By linking changes in temperature with changes in required bed days at a hospital level, through the use of a simple bed model, we quantify the projected impacts UK hospitals will need to adapt to. We show that there is already a local peak of bed days required in the main summer months due to hot temperatures. The results further show that there will be a significant increase during the main summer in both the mean and maximum number of beds needed, but a non‐significant decrease during the peak winter months. These changes lead to a more constant need of care of the year and shift the seasonal cycle of lowest hospital needs. [ABSTRACT FROM AUTHOR]

Adapting to climate change in the water sector requires abandoning two crucial assumptions. First, that the climate represented in the instrumental record is representative of the future. Instead, future water resource planning cannot be based on old measurements (or sequences derived from attaching change factors to instrumental data) and it should be recognized that stationarity is no longer viable, and, second, that climate modelling can be expected to give precise and certain predictions of the future. Instead, probabilistic projections of the future that take into account the full range of uncertainty should form the basis of robust climate change adaptation plans. As a response to the first assumption, it is suggested that stochastic weather generators represent a particularly useful approach to understanding the impacts of future climate change on water resources at a catchment scale, particularly given the recent release of 'science-hidden' tools such as the UKCP09 weather generator. With regards to the second assumption, it is suggested that modelling activity should identify the range of plausible futures to develop probabilities of risk, using those robust decision-making techniques which can gauge the performance of potential adaptation strategies. The best practice for delivering a replicable and practical hydroclimatological impact assessment for UK water resources at a catchment scale is identified, and an hypothetical example is outlined. It is suggested that although augmenting the resilience of water resources to climate change on a catchment scale is dependent on using the correct modelling tools, the robustness of the method with which that information is used to make adaptation decisions is equally as important. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

In 2005 the Royal Meteorological Society commissioned a study to examine current issues regarding the quality fitness for purpose of commercial weather forecasts in the United Kingdom. UK commercial weather forecast providers and users were consulted by means of online questionnaires, interviews, visits and an open workshop discussion. Results from this consultation uncovered significant deficiencies in the methodologies and in the communication of forecast quality assessments, a lack of open dialogue and transparency in the industry, and that some users may be indifferent to forecast quality. Descriptive or worded forecasts cannot be assessed objectively. However, suitable quality assessment methods are available for nearly all types of quantitative forecasts identified in the consultation. The crucial importance of choosing proper quality assessment metrics, the impact of their statistical properties on results and the need to estimate the statistical significance of quality assessment results were exemplified by means of four case studies, one of which is presented in this paper. The findings from this study have led to a set of practical recommendations aiming to establish the discipline and rigour that are necessary for achieving best practice in the quality assessment of weather forecasts. Specific recommendations were also made to the Royal Meteorological Society to set up a special commission that would promote a sense of community within the industry, and to run an accreditation scheme that would encourage best practice on a voluntary basis. Copyright © 2008 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

A new approach to improve the ocean surface boundary condition used in regional numerical weather prediction is proposed. Typically, regional atmosphere forecast systems assume a fixed sea surface temperature during a simulation. The study assesses the use of ocean temperature from an operational regional ocean model as an evolving lower boundary in a kilometrescale regional atmosphere configuration centred on the UK. Simulations of a winter and two five day duration summer case studies associated with anomalously warm temperatures are considered. The largest impact is found in summer, when a growing cold bias in mean temperature over land compared with observations is apparent when using a fixed global-scale analysis lower boundary condition. The mean error is improved by 0.1 K when using a fixed temperature boundary condition from a kilometre-scale regional ocean model initial condition. When using hourly surface temperature data from the same regional ocean model, the error is improved by 0.5 K for this case. Prediction of daytime maximum air temperature is also improved during the summer heat wave cases. A winter case study shows marginal improvement over the ocean and negligible changes over land. These results are confirmed in longer duration experiments using an hourly cycling regional forecast system with data assimilation for summer and winter periods. A systematic and statistically significant improvement of near-surface temperature verification relative to the observations over land is demonstrated for both summer and winter using the new approach. This study supports future operational implementation of a time-varying lower boundary for regional numerical weather prediction. [ABSTRACT FROM AUTHOR]

Medium- to long-range precipitation forecasts are a crucial component in mitigating the impacts of fluvial flood events. Although precipitation is difficult to predict at these lead times, the forecast skill of atmospheric circulation tends to be greater. The study explores using weather patterns (WPs) as a preliminary step in producing forecasts of upper-tail precipitation threshold exceedance probabilities for the UK. The WPs are predefined, discrete states representing daily mean sea-level pressure (MSLP) over a European--North Atlantic domain. The WPs most likely to be associated with flooding are highlighted by calculating upper-tail exceedance probabilities derived from the conditional distributions of regional precipitation given each WP. WPs associated with higher probabilities of extreme precipitation are shown to have occurred during two well-known flood events: the 2014 Somerset Levels floods in southwest England; and Storm Desmond over the northern UK in December 2015. To illustrate the potential of this WP-based prediction framework, a forecast guidance tool called Fluvial Decider is introduced. It is intended for use by hydro-meteorologists in the England and Wales Flood Forecasting Centre (FFC). Forecasts of the MSLP from ensemble prediction systems (EPSs) are assigned to the closest-matching WP, providing daily probabilistic forecasts of WPs out to the chosen lead time. Combining these probabilities with observed precipitation threshold exceedance probabilities provides a parsimonious tool for highlighting potential periods with increased risk of flooding. Model forecasts using the European Centre forMedium-range Weather Forecasts (ECMWF) EPS highlighted both flood events as being at a higher than average risk of heavy extreme precipitation at lead times of over five days. [ABSTRACT FROM AUTHOR]

Despite increasing use of impact‐based weather warnings, the social impacts of extreme weather events lie beyond the reach of conventional meteorological observations and remain difficult to quantify. This presents a challenge for validation of warnings and weather impact models. This study considers the application of social sensing, the systematic analysis of unsolicited social media data to observe real‐world events, to determine the impacts of named storms in the United Kingdom and Ireland during the winter storm season 2017–2018. User posts on Twitter are analysed to show that social sensing can robustly detect and locate storm events. Comprehensive filtering of tweets containing weather keywords reveals that ~3% of tweets are relevant to severe weather events and, for those, locations could be derived for about 75%. Impacts of storms on Twitter users are explored using the text content of storm‐related tweets to assess changes in sentiment and topics of discussion over the period before, during and after each storm event. Sentiment shows a consistent response to storms, with an increase in expressed negative emotion. Topics of discussion move from warnings as the storm approaches, to local observations and reportage during the storm, to accounts of damage/disruption and sharing of news reports following the event. There is a high level of humour expressed throughout. This study demonstrates a novel methodology for identifying tweets which can be used to assess the impacts of storms and other extreme weather events. Further development could lead to improved understanding of social impacts of storms and impact model validation. [ABSTRACT FROM AUTHOR]

Forecasts of high‐impact weather systems require sufficiently high resolution of state‐of‐the‐art numerical models in order to resolve the small‐scale features. At the National Centre for Medium Range Weather Forecasting (NCMRWF) in India, a global ensemble prediction system (EPS—called the NEPS) has been implemented operationally at 12 km horizontal grid size. The NEPS configuration is based on the UK Met Office Global and Regional Ensemble Prediction System (MOGREPS). Initial condition perturbations are generated by the ensemble transform Kalman filter (ETKF) method. Model uncertainties are taken care of by stochastic kinetic energy backscatter (SKEB) and random parameters (RP) schemes. Forecast perturbations obtained from 6 hr short forecasts of 22 ensemble members are updated by the ETKF four times a day (0000, 0600, 1200 and 1800 UTC). Perturbations of surface parameters such as sea‐surface temperature, soil moisture content and soil temperature are also included in the new NEPS. The NEPS aims to provide 10 day probabilistic long forecasts using 23 ensemble members (22 perturbed plus one control). The long forecast provided at 0000 UTC is the combination of 11 members from the 0000 UTC cycle and lagged 11 members from the 1200 UTC cycle. The new NEPS shows improvements in terms of forecast agreement among the members in comparison with the previously operational NEPS that was running at 33 km horizontal grid size with 44 perturbed members. The ratio between the root mean square error of the ensemble mean and ensemble spread as a function of lead time has improved in both the Northern and Southern Hemispheres in the new NEPS. [ABSTRACT FROM AUTHOR]

Reliable and affordable telecommunications are an integral part of service‐based economies, but the nature of the associated physical infrastructure leads to considerable exposure to weather. With unique access to observational records of the UK fixed‐line telecommunications infrastructure, an end‐to‐end demonstration of how extended range forecasts can be used to improve the management of weather risk is presented, assessing forecast value on both short‐term "operational" (weeks) and long‐term "planning" timeframes (months/years). A robust long‐term weather‐related fault‐rate climatology is first constructed at weekly resolution, based on the ERA‐Interim reanalysis. A clear dependence of winter fault rates on large‐scale atmospheric circulation indices is demonstrated. The European Centre for Medium‐Range Weather Forecasts (ECMWF) sub‐seasonal forecast system is subsequently shown to produce skilful forecast of winter weekly fault rates at lead times of three to four weeks ahead (i.e. days 14–20 and 21–28). Forecast skill at a given lead time is, however, a necessary rather than a sufficient condition for improved risk management. It is shown that practical decision‐making leads to dependencies across multiple forecasts times that cannot be modelled using traditional "cost‐loss matrix" methods as errors in previous forecasts influence the value of subsequent forecasts. A parsimonious model representing operational decision‐making for fault repair scheduling is therefore constructed to show that fault‐rate forecast skill does improve both short‐ and long‐term management outcomes (in this case meeting performance targets more often in the short term, or reducing the resources required to achieve these targets in the long term). Consequently, it is argued that new methods are needed for forecast skill assessment in complex decision environments. [ABSTRACT FROM AUTHOR]

ABSTRACT In recent years (2013-2016), extreme weather events have caused substantial disruption to Great Britain's ( GB's) railway infrastructure. In the coming decades this vulnerability is unlikely to subside as the effects of climate change become more intense. Railway stakeholders in GB are strongly engaged with understanding climate change impacts on the railway system and how the industry could adapt to these impacts. Since 2010, Network Rail and RSSB have supported research into these topics under the Tomorrow's Railway and Climate Change Adaptation programme. Under this programme, an analogue study was performed to determine whether lessons could be learned from other countries' weather management. Two types of analogue were used to identify suitable locations. First, climate data from 20 models of the Coupled Model Intercomparison Project phase 5 ( CMIP5) were used to identify regions with similar present-day climate to that projected for GB in the future. The analogue locations were found to be largely insensitive to the climate indicators and the methods used to compare climate at different locations. Next, railway networks in many countries were studied to find those with similar physical and operational characteristics to the GB network. The regions with both climate and railway analogues are France, the Netherlands, Belgium, Germany and Denmark. As part of a wider aim to support the GB railway network's weather resilience and climate change adaptation ( WR/ CCA) activities, focused stakeholder engagement has been undertaken with representatives of most of these countries' railways. This targeted approach is complementary to a broader collation of existing WR/ CCA measures used globally. [ABSTRACT FROM AUTHOR]

ABSTRACT A lee wave forecast system has been run operationally at the UK Met Office since 2006. The forecasts are produced by a numerical model for flow over complex terrain (3DVOM) which is run for five separate hilly regions across the UK. These regions cover Dartmoor (southwest England), Snowdonia (north Wales), Cumbria and the Pennines (northern England), the Grampians (Scotland) and the Mourne and Sperrin mountains (Northern Ireland). Examples of verification of the model forecasts against aircraft and satellite observations are presented. Three years of forecast data for these regions have been used to generate a lee wave climatology for the UK. The model predicts large geographical differences, with lee waves occurring least frequently over Dartmoor and most frequently over Snowdonia and the Grampians. Large amplitude waves, with peak vertical velocities exceeding 3 m s−1 at 700 hPa or above, are more common in forecasts for the Grampian region than others. Lee waves occur more frequently in forecasts during winter months than in summer. The most favourable conditions are those in which there is little turning of the lower tropospheric winds and analysis suggests that the waves are typically trapped in the lower troposphere. The influence of the lee waves on the near-surface flow has also been investigated. Large accelerations and flow deflections can occur beneath the waves. It is suggested that the latter correspond to turbulent lee wave rotors. Preferred locations for this behaviour have been identified in the model forecasts for the Grampians and Pennines. [ABSTRACT FROM AUTHOR]