During December, La Nina onset emerged as both the surface and subsurface equatorial East Pacific shifted very cool. However, since that time, a transient Madden Julian oscillation (MJO) weakened the upwelling trade winds across the eastern equatorial Pacific and surface waters have warmed to borderline La Nina conditions in the Nino34 SSTA zone.

As the weekend begins, a plethora of weather watch, warnings, and advisories are issued with many more ahead into early next week. Currently, an Extreme Cold Warning is issued for the northern Great Plains. In the warning area, temperatures routinely collapse to -20F (or colder) with wind chills of -40F (or colder) by Monday morning. A Cold Weather Advisory is issued into the central Great Plains, certain to expand southward later today.

West of Chile a new and potent marine heatwave (MHW) has formed. The northeastern South Pacific MHW is intensifying rapidly. A long-standing MHW in the Caribbean Sea remains impressive. Aloft, each MHW has an influence on the upper air pattern. The new MHW off the Chilean Coast is well-correlated to an amplified high-pressure area forecast by AIFS through the next 15 days. High pressure also rests over the warm Caribbean Sea.

The Australia outlook for FEB/MAR/APR 2025 indicates unusually hot and dry climate across northern continent, persistent rains on the East Coast, and marginally hot and dry across Southwest Australia. Drought concern is across the northern and east-central continent plus the interior southeastern region. A fine line exists between wet and dry soil regions away from the coast in the East. The forecast is propelled by ongoing weak La Nina and the marine heat waves on either side of the continent.

The waves of cold air into the U.S. during January 2025 has caused the projected U.S. population weight HDD to 1060 for the mid-winter month which eclipses the previous high of 1045 in 2014 (Table 1). The cold spikes are vividly indicated in important energy sectors such as PJM-East, PJM-West, and ERCOT.