ИСТИНА

The detailed investigation of the conditions of the durational stabilization of the subtropical anticyclone in the unusual region of the temperate zone was done and the reasons of the anticyclone repeated regeneration were found out. Five periods of the subtropical anticyclone regeneration were defined, which were associated with the entering in its circulation of the active and relatively cold anticyclones of the temperate and high latitudes, developing at the back of the cyclonic series. Herewith, all invasions were divided in three types depending on the trajectories of the active anticyclones shift: the polar entering from the north and northwest; the ultra polar entering from the east or northeast; and the entering from the west (Atlantic Ocean and Baltic Sea). For the quantitative assessment of the existence period of the blocking process the instability index, introduced by V.P. Dymnikov, was used. It was shown, that this index is informative enough and could be used for the lifetime forecast of the specific quasi-stationary atmospheric circulation regimes.