Statistical analysis of extreme drought and wet events in Russia has been carried out using the SPI index calculated over 500 stations, using records of monthly precipitations from 1966 to 2010. Different statistical parameters were calculated to characterize the spatiotemporal variability of drought and wet events. The calculations show a trend toward an increase in the intensity of drought and wetness extremes in Russia during the past 20 years, with a prevalence of wet events over drought ones. The drought propagation decreases for the European territory of Russia in June and August and increases in July. A trend for the wetness is opposite. For the Asian territory of Russia, drought significantly increases in July along with a decrease in wetness.

The issues related to the intraseasonal variability and predictability of regional scale atmospheric processes in the Northern Hemisphere are considered. To identify the latter, circulation indices characterizing large-scale modes of atmospheric variability are used. An assessment is made of the regional intraseasonal variability of the atmospheric processes in the summer and winter seasons of 1991–2020. A study of practical predictability of regional atmospheric processes is carried out using the global semi-Lagrangian model developed at the Institute of Numerical Mathematics, Russian Academy of Sciences, jointly with the Hydrometeorological Center of Russia, as well as reanalyses of the European Center for Medium-Range Weather Forecasts on weekly and monthly time scales. It is concluded that, beyond the first prognostic week, the quality of deterministic (ensemble average) forecasts drops sharply. In winter, the Pacific–North American Oscillation region is an exception, where a signal is traced not only over the first, but also over the second forecast week. The application of probabilistic forecasts makes it possible to increase the time interval of predictability compared to the deterministic approach from one week to a month. The largest errors are revealed in the forecasts of circulation regimes in the Northwest Atlantic and in the North Pacific, in the regions of the most significant intraseasonal variability. The results are planned to be used in the operational practice of intraseasonal forecasting of the North Eurasian Climate Center (NEACC).

Moored near-bottom current velocity and water temperature measurements were performed during a period of 194 days (from October 2022 through April 2023) with a 15-min sampling rate at two locations on the shelf of the Kazakhstan sector of the Caspian Sea in its Middle Caspian basin. The area has not been covered by in situ measurements over several decades. The two stations were separated by a distance of 22 km along the coast. The velocity and temperature data collected at 14 m depth were analyzed together with the wind data from the local meteorological station, NCEP/NCAR reanalysis of wind curl data over the Caspian Sea, as well as multi-mission satellite imagery. The analysis revealed that the currents were predominantly along-shore and highly variable in direction, with nearly zero average over the observation period. The along-shore and cross-shore components of velocity exhibited rather high correlation with the along-shore wind stress with the maximum (r = 0.68 and r = 0.53, respectively) at a time lag of about 9.5 h. The velocity series were not significantly correlated with the wind curl averaged over the entire Caspian Sea at any temporal lag, while there were weak but significant correlations between the along-shore current velocity and the curl of the wind fields over the Middle Caspian and Northern Caspian basins with time lags from one to nine days. The along-shore current velocities at the two stations were highly correlated (r = 0.78) with each other at no temporal lag. The temperature at both stations demonstrated nearly identical seasonal march, but a higher frequency variability superimposed on the latter was also evident with amplitudes as high as 2.79 °C. Somewhat surprisingly, the series of these anomalies at the two stations were not correlated either with each other or with surface wind forcing. However, there is evidence pointing to their connection with the cross-shore component of near bottom velocity, i.e., the cross-shore, up or down the bottom slope excursions of water from deeper or shallower depths, retaining a different temperature. During intense winter cooling of the surface layer, this effect is manifested as «warm upwelling» creating strong positive temperature anomalies or the opposite «cold downwelling» and negative anomalies.

The main features of the temperature regime and atmospheric circulation in the Northern Hemisphere in the summer of 2021 are considered based on the ERA5 reanalysis (ECMWF) of surface air temperature and 500 hPa geopotential height with a daily resolution. Using the operational version of the SL-AV semi-Lagrangian atmosphere model for long-term forecasting, the potential of forecasting heat and cold waves, as well as the Extreme Forecast Index (EFI) against a background of quasi-stable circulation modes of the blocking type are determined. The dependence of the forecast skill on the phase of development of the blocking anticyclone (initiation, mature phase, dissipation) is shown. The results can be used to make forecasts of extreme weather events on intraseasonal timescales. Keywords: extreme weather events, heat and cold waves, blocking anticyclones, long-term weather forecasts