The polar vortex event for the week of February 16-22, 2025, is preliminarily projected to generate 270 HDD for the U.S. which is comparable to the arctic outbreak and Winter Storm “Enzo” during January 19-25, 2025, and the arctic outbreak and Winter Storm “Uri” during February 14-20, 2021.

Late winter chill has emerged across Western Russia, Ukraine, and most of the Black Sea region as the middle third of February arrives. The chilly weather has extended west to France, Germany, and parts of U.K. The colder weather is enhanced by generation of snow cover, previously unavailable, across Eastern Europe to Southwest Russia. Western Europe remains snow-free. The latest 7-day temperature forecast utilizing ECM indicates widening and strengthening cold surrounding the Black Sea region with additional snowfall included.

High impact weather affects most of the U.S. this week due to a February “polar vortex” episode. Currently, Extreme Cold Warnings are in effect for the North-central U.S. as temperatures have plummeted well below zero. A veil of fresh snow ahead of the arctic air across the central Great Plains where Winter Storm Warnings are issued will allow the southward flowing arctic air to maintain intensity.

The 2024-25 ENSO regime has featured evolution of La Nina although occasional surprises remain consistent with the latest the sharp warming of the Nino12 SSTA region off the northwest coast of South America. The daily Nino12 SSTA is +0.88C which is an El Nino-like observation. The Nino12 SSTA warming will affect the South America rainfall pattern through the next several weeks.