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Comparative quality analysis of ensemble radar precipitation nowcasting based on the test results for the warm (May–September 2020) and cold (November 2021–March 2022) seasons is presented. The composite precipitation intensity fields obtained from radar observations serve as control data for verification. In both periods, a slight but systematic advantage of the forecasts from the mean ensemble field is revealed, which indicates the expediency of using even small-volume ensembles. For all the skill scores used (except for the frequency bias), forecasts in the cold season turn out to be better than forecasts in the warm one, however, the sample sizes for verification in the cold season may be significantly lower than the corresponding sample sizes in the warm one. The problems of comparative quality analysis that are caused, in particular, by the loss of spatial connectivity of the composite field during the cold season are discussed. [ABSTRACT FROM AUTHOR]

The Extreme Forecast Index (EFI) calculations are performed using the ECMWF 2-m air temperature forecasts produced in the framework of the Subseasonal to Seasonal (S2S) Prediction Project. Four computation schemes are implemented using empirical and theoretical distributions of heat wave characteristics as well as the one-dimensional test statistics of histograms and linear interpolation formulas. Case studies (for different initial dates and regions) characterized by the significant air temperature anomalies in Northern Eurasia are performed using traditional forecast skill scores and the spatial verification methods to evaluate the efficiency of the proposed schemes for different threshold values of EFI. It is shown that the forecast quality can be considered satisfactory in most cases. The dependence of forecast skill on the intensity, spatial scales, and duration of temperature anomalies is revealed. Further studies should be carried out using larger samples based on several hydrodynamic models and the multimodel approach. [ABSTRACT FROM AUTHOR]

The monthly and seasonal anomalies of temperature and precipitation over the Arctic are considered depending on the global and regional patterns of atmospheric circulation. Climate indices are used to identify patterns. The composite analysis allowed identifying the geographic regions where the influence of atmospheric circulation modes on temperature and precipitation is statistically significant. The contingency of atmospheric circulation patterns in the Northern Hemisphere was statistically estimated. Special attention is paid to the case studies where the extreme episodes of circulation indices are associated with the significant anomalies of air temperature and precipitation. The potential is demonstrated of the numerical simulation of extreme episodes on monthly and seasonal timescales with the global semi-Lagrangian model SL-AV developed in the Institute of Numerical Mathematics jointly with the Hydrometcenter of Russia. [ABSTRACT FROM AUTHOR]

In February–March 2014 the Winter Olympic Games will be held in Sochi. Sharp weather contrasts and high spatiotemporal variability are typical of the region of the Sochi-2014 Games. The complex mountain terrain and the intricate mixture of marine subtropical and Alpine conditions make the weather forecasting in this region extremely challenging. Although all lead times of the forecast are important for the Games, primary needs for these sport events are associated with the nowcasting and the short-range weather forecasting. The complexity of the Sochi region stimulates the development of high-resolution mesoscale modeling as a backbone of the Olympic meteorological services. Presented are the main branches of the current research in this area carried out in Roshydromet. [ABSTRACT FROM AUTHOR]

The COSMO-Ru1Mp prototype of the numerical weather prediction system for the Moscow region with a grid spacing of 1 km and with the included and adapted TERRA_URB parameterization module for the urban areas is implemented. The module is provided with necessary information on the urban development and on the sources of anthropogenic heat based on the adaptation of open data. The module is interfaced with the COSMO-Ru operational system for the regional numerical weather prediction developed in the Hydrometcenter of Russia. The primary testing of the COSMO-Ru1Mp is performed, including daily forecasts based on operational data. The advantage of this forecast system and the prospects of its further development are revealed. [ABSTRACT FROM AUTHOR]

The study presents the new system for operational short-range numerical weather prediction with the grid spacing of 1 km for the Moscow region that considers the features of urbanized surface and is based on the COSMO-Ru1M model configuration. This system is implemented in the Hydrometcenter of Russia. The results of the trial testing of the optimum model configuration for the Moscow region using observations from the dense network of weather stations and MTP-5 temperature profilers are presented. High prediction capabilities of the new forecasting system are demonstrated. The approaches to the minimization of the time of calculations for the technology chain implemented at the Roshydromet supercomputer are described. A case study of modeling with the grid spacing of 500 m versus 1000 m for summer convective weather events in the Moscow region has been analyzed. [ABSTRACT FROM AUTHOR]

Development of the multiscale version of the global atmosphere model SL-AV required many improvements in the dynamical core, replacement or refinement of parameterization algorithms and complex tuning of the model. These modifications were initially tested with the experiments on modern climate simulation and then incorporated into the model configuration for medium-range numerical weather prediction. The impact of these model improvements on forecast quality is studied in this paper. The increase in accuracy of model climate characteristics has led to the reduction of forecast errors. The comparison of quality for numerical forecasts starting from the initial data of Hydrometcenter of Russia and ECMWF is carried out. The effect of replacing the initial data turned out to be comparable to the effect of multi-year works on model development. This shows the importance and necessity of development and improvement of the Hydrometcenter of Russia data assimilation system. [ABSTRACT FROM AUTHOR]