Fig. 1: ECM ENS temperature anomaly forecast for Europe/Western Russia for 8-14-days from now.
Discussion: An evolving longwave upper trough extending from Western Russia to Southwest Europe causes deepening and expansion of Western Eurasia snow cover and steady intensification of an attendant winter chill. Supported by strong negative phase of both the arctic oscillation and North Atlantic oscillation this feature locks-in for the last third of December into early January. Arctic air in Western Russia is drawn into Europe by days 11-15. Sudden stratospheric warming is indicated across Eurasia in the 11-15-day period and a likely catalyst to the intensity of the arctic air in Western Russia heading toward Eastern Europe in the 11-15-day period. Coldest daytime temperatures in the 15-day forecast include around zero in Moscow Dec. 23-24, in the 20’s in Warsaw beginning Dec. 23 (through the end of the month), near 32 for the rest of the month beginning Dec. 23 in Berlin and mostly in the 30’s beginning Dec. 24 in Paris. The zero line (at night) reaches all of Western Russia and just east of the Baltic Nations Dec. 23. Moscow should dip to -10F. The model used is the ECM ENS. Meanwhile temperatures of 30F to 40F below normal are amassing in West/Southwest Canada during this time. The U.S. stays warm but deep arctic air is not far away.