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Advertised cold weather pattern should commence around December 6 and work in here well by Dec 7-8. I would like to limit precipitation charts to within 5 days. The exception is NWFS for the Mountains and Plateau, which is more skillful because it does not require an exact storm track. Discussion of favorable pattern (odds) is OK and even encouraged past Day 5, just no charts please. The good news is SER intrusions have departed recent model runs. Oh there is always a trade-off in the South. Northwest flow in the Plains gets as close as the Mississippi Valley at times, which opens the door for mild interludes within the cold pattern. Even with some variability the cold 6-15 day period carries high confidence. I put it near 85% in the 6-10 day; better than 50% in the 11-15 day. Still a slight risk that Day 10 mild interlude is the end, but I think cold reloads for the 11-15 day. Near textbook upper level pattern really lacks surface source region support though. Alaska and most of Canada cold is not strong. Manitoba and Ontario will get cold but it barely gets colder points north. Quebec looks strong but it's not our trajectory. Sustained cross polar flow from Siberia is required for impressive cold this time. A few days would not be enough since temps are AN in Alaska. Northern US snowpack deficit is a gaping hole in the equation for record or even just strong cold. So I think the 6-15 day will be cold enough to put one in the Holiday mood, but not particularly impressive. First front (6-10 day) may under-achieve as usual coming into a warm regime. Second front (11-15 day) should verify so long as it actually gets in here (>50% chance). If the upper level pattern holds through weeks 3-4, we might be able to talk about stronger cold anomalies. Right now looks like some lows in the 20s first half of Dec. If looking for teens or colder, more time in the cold pattern is required. A minority of ensemble members show a decent pattern for winter precipitation in the 11-15 day. Others are cold but dry. A smaller minority is too warm. I am looking for an active southern branch through the Deep South, not NW flow and zero SER attempts.
All the others have their threads, so we're late to the game. Will this be a Nina winter as advertised, and if so, what intensity? If we can achieve weak Nina, it can mean good times ahead for the Valley region. Some of our most epic winters have came during that pattern, including the legendary 1984-85 winter that crushed the entire Mid-South/Tennessee Valley with heavy snows and record shattering cold. As always, many factors go into making a winter though, as we saw in 2011-2012 when the weak Nina mattered not at all and the winter was hardly a winter at all. Looking at some of the analog years, even including the bad winters, almost all areas West of the Apps are below normal in the temps department during weak Nina years. Strong Ninas flip the script however and we are often very warm during intense Nina years. I will take a further look at some of the analogs and at real data across the Valley during these years later on.