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.

NOAA/CPC issues another heavy snow risk alert for the East U.S. valid February 19-21. Additionally, state rankings for January 2025 were released by NOAA. The month was 33rd coldest on record in the 1895-2025 climatology. The month was very dry ranking 6th driest all-time!

The U.S. gas population weight HDD forecast is becoming impressively cold for next week and late February with a significant colder revision since yesterday. Medium-range forecasts shift the cold across the high population of the East U.S. to increase national heating demand into late meteorological winter.