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.