Significant warming took place last week across the eastern equatorial Pacific Ocean. The Nino34 SSTA region warmed 0.5C to -0.7C which is just-below the La Nina threshold. The Nino3 and Nino12 regions warmed to neutral phase.

The cold season started with a warm November followed by a December which was also warm coming-in near the 10-year normal. Mid-winter was very warm, almost as warm as November regarding the HDD departure. February is the only cold month of the season while March is projected warmer than normal. The tendency for extremes dominated as observed with a very warm November and January and a frigid February.

La Nina’s SSTA observations in the Nino regions near and east of the Dateline are fluctuating each week as La Nina classification is “unsteady”. The upper ocean heat in February indicates warming took place implying the subsurface cool waters to sustain La Nina is diminishing.

We’ve watched the GFS project arctic air for the extended-range for about one week generally indicating high intensity but mostly confined to the Central U.S. Last night the GFS indicated the arctic air may stretch into the East with intensity but most models continued to doubt that scenario. This afternoon the ECMWF forecast projects super cold arctic air into the central U.S. next weekend shifting east and southeast with authority for early next week.