Abstract The economic value of the European Centre for Medium‐Range Weather Forecasts (ECMWF) operational ensemble prediction system (EPS) is assessed relative to a perfect deterministic forecast. EPS has substantial throughout medium range. Probability forecasts derived from are greater benefit than forecast produced by same model. Indeed, many users, probability have more shorter‐range Based on measures used here, additional information in (reflecting uncertainty initial conditions)...

Effective disaster risk management relies on science-based solutions to close the gap between prevention and preparedness measures. The consultation United Nations post-2015 framework for reduction highlights need cross-border early warning systems strengthen phases of management, in order save lives property reduce overall impact severe events. Continental global scale flood forecasting provide vital information national international civil protection authorities, who can use this make...

This text provides a forum for leading specialists in trade and international economics to explore whether changes the world economy have increased usefulness of accounts drawn up on basis ownership rather than geography. The papers this volume suggest that ownership-based national are helpful understanding financial transactions among globalized enterprises. Individual chapters emphasize perspective through accounting exercises, studies individual countries, foreign direct investment its...

The potential economic benefit associated with the use of an ensemble forecasts versus equivalent or higher-resolution control forecast is discussed. Neither systems are postprocessed, except a simple calibration that applied to make them reliable. A decision-making model used where all users weather characterized by ratio between cost their action prevent weather-related damages, and loss they incur in case do not protect operations. It shown system can be much wider range users....

In operational hydrological forecasting systems, improvements are directly related to the continuous monitoring of forecast performance. An efficient evaluation framework must be able spot issues and limitations provide feedback system developers. regional expertise analysts on duty is a major component daily evaluation. On other hand, large scale systems need complemented with semi-automated tools evaluate quality forecasts equitably in every part their domain. This article presents current...

Abstract Four recent papers have investigated the effects of ensemble size on Brier score (BS) and discrete ranked probability (RPS) attained by ensemble‐based probabilistic forecasts. The connections between these are described their results generalized. In particular, expressions, explanations estimators for expected effect RPS continuous (CRPS) obtained. Copyright © 2008 Royal Meteorological Society

Although over a hundred thermal indices can be used for assessing health hazards, many ignore the human heat budget, physiology and clothing. The Universal Thermal Climate Index (UTCI) addresses these shortcomings by using an advanced thermo-physiological model. This paper assesses potential of UTCI forecasting hazards. Traditionally, such hazard has had two further limitations: it been narrowly focused on particular region or nation relied use single 'deterministic' forecasts. Here, is...

The potential of early warning for severe cold conditions is explored using the Subseasonal to Seasonal (S2S) Prediction research project data archive. We explore use a two‐dimensional phase space based on leading empirical orthogonal functions (EOFs) mid‐tropospheric flow computed over Euro‐Atlantic region in order study time evolution patterns associated with high‐impact temperature anomalies. find that an effective tool monitoring predictions regime transitions at medium and extended...

Abstract A probabilistic analysis is made of seasonal ensemble integrations from the PROVOST project (PRediction Of climate Variations On Seasonal to interannual Time‐scales), with emphasis on Brier score and related Murphy decomposition, relative operating characteristic. To illustrate significance these results potential users, characteristic are input a simple decision model. The decision‐model used define user‐specific objective measure economic value forecasts. for two meteorological...

Abstract Ensemble forecasts provide probabilistic predictions for the future state of atmosphere. Usually probability a given event E is determined from fraction ensemble members which predict event. Hence there degree sampling error inherent in predictions. In this paper theoretical study made effect size on forecast performance as measured by reliability diagram and Brier (skill) score, users using simple cost‐loss decision model. The relationship between skill value, generalized dependent...

Abstract Tropical cyclones are some of the most devastating natural hazards and “three beasts”—Harvey, Irma, Maria—during Atlantic hurricane season 2017 recent examples. The European Centre for Medium-Range Weather Forecasts (ECMWF) is working on fulfilling its 2016–25 strategy in which early warnings extreme events will be made possible by a high-resolution Earth system ensemble forecasting system. Several verification reports acknowledge deterministic probabilistic tropical cyclone tracks...

Abstract In winter, heavy precipitation and floods along the west coasts of midlatitude continents are largely caused by intense water vapor transport (integrated (IVT)) within atmospheric river extratropical cyclones. This study builds on previous findings that showed forecasts IVT have higher predictability than precipitation, applying evaluating European Centre for Medium‐Range Weather Forecasts Extreme Forecast Index (EFI) in ensemble during three winters across Europe. We show EFI is...

The effects of observation errors on rank histograms and reliability diagrams are investigated using a perfect model approach. three-variable Lorenz-63 was used to simulate an idealized ensemble prediction system (EPS) with 50 perturbed members one control forecast. Observation at verification time were introduced by adding normally distributed noise the true state time. Besides these simulations, theoretical analysis also performed. One major findings that very sensitive presence errors,...

Abstract A new equitable score is developed for monitoring precipitation forecasts and guiding forecast system development. To accommodate the difficult distribution of precipitation, measures error in ‘probability space’ through use climatological cumulative function. For sufficiently skilful forecasting systems, less sensitive to sampling uncertainty than other established scores. It therefore called here ‘Stable Equitable Error Probability Space’ (SEEPS). Weather partitioned into three...

Abstract Precipitation forecasts from five global numerical weather prediction (NWP) models are verified against rain gauge observations using the new stable equitable error in probability space (SEEPS) score. It is based on a 3 × contingency table and measures ability of forecast to discriminate between “dry,” “light precipitation,” “heavy precipitation.” In SEEPS, threshold defining boundary light heavy categories varies systematically with precipitation climate. Results obtained for SEEPS...

A key attribute of a probabilistic forecast system is its reliability: the degree to which probabilities agree with outcome frequencies. Here, we focus on short‐lead‐time (12 h) reliability in nonlinear background forecasts Ensemble Data Assimilations (EDA) from European Centre for Medium‐Range Weather Forecasts (ECMWF). ‘reliability budget’, derived consistency arguments, used separate mean‐squared departures ensemble mean (relative observations) into bias, variance and observation‐error...

IMproving PRedictions and management of hydrological EXtremes (IMPREX) was a European Union Horizon 2020 project that ran from September 2015 to 2019. IMPREX aimed improve society’s ability anticipate respond future extreme events in Europe across variety uses the water-related sectors (flood forecasting, drought risk assessment, agriculture, navigation, hydropower water supply utilities). Through engagement with stakeholders continuous feedback between model outputs applications, progress...

Abstract In November 2000 the resolution of forecast model in operational European Centre for Medium‐Range Weather Forecasts Ensemble Prediction System was increased from a 120 km truncation scale (EPS) to an 80 (High‐resolution EPS or HEPS). The HEPS performance is compared with that and different flavours poor‐man's ensembles. Average results based on Brier skill scores potential economic value probabilistic predictions 57 winter 30 summer cases indicate new system about 12 hours more...

Abstract There are numerous occasions on which operational forecasts from different meteorological centres diverge in the medium range. These differing evolutions may be due to analyses used by or a result of models produce forecasts; combination both factors involved. Ensemble routine production at European Centre for Medium‐Range Weather Forecasts (ECMWF) designed address problem impact small analysis differences forecast evolution. initial perturbations, generated using singular‐vector...

Abstract While chaos ensures that probabilistic weather forecasts cannot always be “sharp,” it is important for users and developers they are reliable. For example, should not overconfident or underconfident. The “spread–error” relationship often used as a first-order assessment of the reliability ensemble forecasts. This states standard deviation (a measure forecast uncertainty) match root-mean-square error on mean (when averaged over sufficient number start dates). It shown here this now...

Abstract We evaluate the skill and jumpiness of ECMWF medium-range ensemble (ENS) in predicting tropical cyclone genesis Atlantic basin. Focusing on probabilistic performance ENS, we assess how far advance ENS can predict genesis, quantify consistency (jumpiness) from run to investigate what factors influence consistency. find that first indications are picked up at least 7 days ahead 50% observed cases, although strong signals often only appear less than 3 before genesis. There significant...

Abstract The two latest changes introduced during 1998 into the Ensemble Prediction System (EPS) operational at European Centre for Medium‐Range Weather Forecasts (ECMWF) are described. first change, inclusion of instabilities growing data assimilation period in generation EPS initial perturbations, increased probability that analysis lies inside ensemble forecast range. second introduction a simulation random model errors due to parametrized physical processes, improved particular...

Abstract Global hydrological forecasts are now produced operationally on a daily basis. However, the lack of global river discharge observations precludes routine flood forecast evaluation, an essential step in providing more skilful and reliable forecasts. A vision is expounded for greater timely exchange observations, which would result improved awareness socioeconomic benefits some World’s most vulnerable countries.