Major Influence: Current Moderate, Basin-Wide El Nino Episode
If the current El Nino episode unfolds as the numerical models forecast, the eastern portion of the warm water field in the Pacific Basin will cool while the western and central sectors remain relatively above normal. Madden-Julian Oscillation impulses or percolations should mostly fall in Phases 6, 7, 8, and 1, which could have the effect of setting up a West (Modoki) or Central El Nino. Basin wide or East-based positive ENSO events almost always lead to bearish/mild/snowless DJFM periods in the populated lower 48 states east of the Continental Divide. West-oriented warmings often help to amplify ridges in western North America, which can produce the coldest winters.
Most parameters suggest a cold West vs. warm East alignment. But the vigorous southern branch storm track may alter that picture if it comes in through Baja California and emerges over the open Gulf of Mexico. Note that precipitation potential which suggests Gulf Coaster > Nor’easter tracks, which would bring cP air masses southward in concert with Alaska ridging.
There is actually good agreement between the analogs and the ECMWF model results for January. A strong -NAO ridge signal, somewhat like 2010, may condense and suppress the jet streams. A cAk vortex in British Columbia and an mAk gyre over the Flemish Cap are possible core features. This is a recipe for alternating strong Arctic intrusions and lower-latitude ice and snow events. In theory, when the two vortices separate enough, ridging in the middle of the continent might bring about a January Thaw in the third week of 2024.
Rather than a genuine split flow, common to El Nino events, this February may be a special case where a unified Arctic/polar/subtropical jet stream is forced far below a -EPO/+PNA/-AO/-NAO ridge complex. A mild Canada vs. cold USA configuration with the potential for ice and snow (depending on actual air mass alignment) might visit northern Mexico, Texas and the Deep South. This pattern may replicate in northern Eurasia. Of all the months in the coming winter, the best chance for a high-impact frozen precipitation event looks to be the second month of 2024. Ridging may suppress chances for snow in the Great Lakes and the Northeast.
The impression I get from the forecast depiction is of a “last hurrah” winter storm in early March that moves out of the Southwest through Dixie, then into the open Atlantic Ocean. All guidance reverts the temperature field to much warmer air from the Great Plains to the East Coast. Late season cold and snow would cover the West and possibly West Texas/Oklahoma Panhandle. The “fill the space” ridge signal reminds me strongly of 1973, where the spring along the Eastern Seaboard quickly turned warm and stayed that way through the following summer. There may also be a vertically stacked storm involving the High Plains and Rocky Mountains.