Carvers Gap

Agree. As noted by a poster in another forum(maybe ENSO on the main page), this is a pattern which is often hard to break down, i.e. cold over the Hudson Bay, a small ridge over the Southwest, and kind of a flat, stable trough in the East. That Alaska feed into the SE is a classic old-school pattern. I know we've talked about it before. It seems like modeling has shown this in the past only for it not to verify. This time it is in place. That is a cold, cold feed at times.

I kind of see this more as a system where NE TN folks(SW VA) see the snow hang on just a hair longer w/ NW flow to follow. It isn't a big NW flow event, but it is present on all short range models, especially for the Plateau.

This is probably a more favorable trend for our folks in North Carolina, but you can see the various iterations of precip backing.

I really thought there would be zero support for the 18z GFS solution w/ ensemble members, but there are a decent number which have similarity. There were almost none of those at 12z.

The 18z ICON hints at it w/ a second wave of precip. I would be really surprised to see it deepen this close to the event, but the dynamics are there. Just a timing thing I guess. All I can see as a difference is a weak area of lp forming along the coast. I am not sure if a lee side forms or an inverted trough forms. I am terrible at seeing inverted troughs.

The 18z GFS apparently popped a weak coastal and backed the flow. Definitely want to look at ensemble members regarding that. For a progressive model to form a weak coastal....that might be something to watch. It would normally be the first OTS.

You know, the 12z AIFS had a similar solution to the 18z GFS. I just didn't look that closely. It just wasn't as much snow, but still 1-3" of it.

They added 09-10 today.

Best I can tell is that we caught the same jet streak from the 12z run, but it backed flow just a bit. That is an extreme outlier, but interesting. Doubt it will be there in the future, but something to keep an eye on w/ low expectations.

Might have been a hiccup, but the 18z GFS lollipopped NE TN and SW VA for Sunday into Monday....as in half of a foot.

Someone remind me…the SOI tanking means a potential bigger winter storm, right? Strong amplification incoming and stormy.

I mentioned 95-96 yesterday. Interestingly, the d8-14 analogs have that analog(I didn't see it until today FTR). I am glad not to see 83-84 in that mix! Dec 2012 is double weighted as well. 19951129 20161209 20121128 20221129 19961223 20101212 19951204 20211222 20121203 20081231

Just looking at northern hemispheres modeling, the coldest air on the planet will likely be over the Yukon d8-15 roughly. The mechanism to deliver that into the Upper South is present in the forum of a flat western ridge. The colder of the air (for now) will slide across the upper MidWest and into the NE. HOWEVER, any kind of cutter or storm which gains latitude could send all of that into the Tenn Valley region. Both the 6z GFS and 12z Euro have minor slp events which do it. I cannot imagine what a big storm would wrap in. A portion of the TPV is basically parked over the Hudson Bay, and just pinwheels cold air southward. In other words, we have a trough modeled. The source region for that trough is very cold air. Remember these winters where NA was void of BN air...not this year!

The 12z GEFS has temps twenty-five degrees below normal in WI at 195 w/ all of that headed SE. During that same hour, our forum area has departures of fifteen degrees BN. That is frigid for an ensemble at this range. The 12z GEPS is even colder over our forum area w/ temps 20 degrees BN over much of the area. The GEPS brings another cold shot around the 21st. The 12z EPS is rolling. It has the same cold shot, and is a bit "warmer." It is only 10-15 degrees BN. That is cold for a model w/ a bit of a warm bias in d10-15. Short story, even at this range, there is a growing likelihood of very cold air making it to our latitude by mid-month. Both the GEPS and AIFS ensemble(to some extent), show the second cold shot around the 20th. With so much snowpack immediately to our north, these cold air masses are on greased skids.

The 12z Euro is frigid w/ a couple of days of real feels that have below zero readings. Both the 12z GEFS and GEPS ensembles show cold temps some time between Dec 14-17th. I suspect we see an anafront(a constant them of mine I know) at some point in that time frame. I think we could see 1-2 very cold air masses push through the area mid-month. And honestly, all of us would probably appreciate some moderation if those come to pass.