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WinstonSalemArlington

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Posts posted by WinstonSalemArlington

    Mid to long range discussion- 2025

    in Southeastern States

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    Larry Cosgrove: “

    With many model forecasts and human projections of a major warm-up across the lower 48 states for the holiday period, those like me who want a big cold wave or heavy snow and ice event have to wait out at least 6 days of some cases of record warmth before an Arctic intrusion returns to the lower 48 states. The question is, could the warmth last further? If you based odds on the model guidance alone, the odds on a cAk placement below the Canadian border are about 3 in 7. The American and European series are closest to the analog support, but the GEFS and ECMWF versions have members that show a return to a broad +PNA/-AO/-NAO signature that would return the eastern half of the continent to an extremely cold scenario with chances for snow in the Great Lakes and the Eastern Seaboard.
     
    Cautions I apply to the forecast: do NOT make assumptions based on the Madden-Julian Oscillation predictions (see what I mean about all of that "Phase 8" nonsense that was the talk of the internet?). Remind yourself that for an MJO cold influence in North America, the lead impulse should be between Phases 6 and 1, be very strong, and have at least some connection to the polar westerlies. The numerical model Wheeler diagrams are not useful in this regard. Also, for a Sudden Stratospheric Warming alteration in sensible weather, consider that the 10MB warm anomaly should be on the American side of the North Pole, should foreshadow a high-latitude blocking signature and will occur 2 to 4 weeks following the SSW. You would want to see either some splitting or persistent positioning of the warming pool. Using previous stratospheric warming projections, I suspect that the lower 48 states are going to feel another cold wave in the Christmas/New Year hammock week, and maybe 5 to 7 days beyond. On the idea that we see a climatologically-favored "January Thaw, the middle of next month could be as warm as what we are looking at by this weekend. But I concur with the analog set that the latter third of the first month of the new year will turn quite cold, perhaps lasting through February with better potential for ice, snow further south and east than before.
     
    Clues to look at: the expanded snow and ice cover, similarities to 2007 and 2024-25. Around Christmas or shortly thereafter, winter should fight its way back into the U.S.”
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