GaWx

12Z GFS: very close in this area on Jan 10th: near freezing at sfc 1PM with cold NNE sfc winds, 850 temp near 0C, and radar showing sleet/mix falling then @Awesomesauce81might be interested

Stronger sfc high to the north on 12Z GFS. I’d like to see that continue to trend back stronger.

6Z GEFS mean not good at all for 1/10-1 (can kicking):

Compared to both the 0Z GEFS (quoted above) and the 12Z EPS, the 0Z EPS has a good bit less snow in most areas: Night night!

Indeed, I was just getting ready to post the 0Z GEFS snow, which I’d say has improved even more than marginally vs 18Z from Charlotte/Greensboro to N GA (~1” higher) and is also higher than 12Z/close to 6Z there: **Edit: However, this would still be can-kicking on the 0Z GEFS because the increases are for after 1/10-1. Next up: Euro ensemble. Then lights out! @SnowDawgto check what I added in an edit about the 0Z GEFS can kicking 1/10-1.

If the 1/10-1 Miller A were to not return, I’d consider it a classic case of can kicking unlike 1/6. I don’t like the trends at all but it’s still early enough for the trend to reverse and 1/10-1 to return as it has been only 12 hours on the GFS among others and that’s still 8 days away.

0Z Euro: not good for SE snow lovers as 2nd shortwave is so weak that there’s no surface low.

It would be nice if there could be a decent amount of cold surface high pressure maintaining itself to the north in the OH Valley but on the 0Z GFS it instead collapses rapidly when turning that way vs the respectable high that is retained there on the 12z (GFS run with big snowstorm): 12Z GFS: 1029 mb high 0Z GFS: only ~1022 mb high

You can see it visually in the HDD image below. Look how much less cold 1/10-12 have gotten since the 6Z GEFS run. For example, the 18Z run is a whopping nearly 5 HDD warmer on 1/11 vs the 6Z! Regardless, it is still quite cold and it can easily reverse back to how cold it was. With the combo of indices we have, I feel confident that the intensity and duration of the cold will maintain being impressive.

18Z GEFS snowfall: less vs recent runs for most and the run overall was significantly warmer

The 12Z Euro AI has qpf of 0.8-0.9” during 1/10-11 for much of N GA, NW 1/2 of SC, and much of NC. 850s never get above 0C meaning all snow (a whopping ~8-9”) at Rome, Gainesville, GSP, Charlotte, and RDU along with places in between, which would easily be the most widespread big SE snowstorm in many years. In ATL, AHN, AUG, and CAE, 850s do get just above 0C during a part of this implying sleet likely during part of it.

Per the avg of the last 12 runs of the 4 member CFS ens, part of the E US is forecasted to be near 10 F BN for the two week period Jan 8-21 and is forecasted to be the coldest area anomalywise on the entire globe through that period! These runs suggest these areas of the E US will be ~7 BN for Jan as a whole.

Per the avg of the last 12 runs of the 4 member CFS ens, much of the SE is forecasted to be near 10 F BN for the two week period Jan 8-21! The SE is forecasted to be the coldest area anomalywise on the entire globe through that period!

12Z Euro ensemble mean snow: pretty similar to GEFS Here was 12Z GEFS:

This is kind of an odd setup and would actually be an extremely close call on/near the coast on the 12Z Euro if it were to somehow play out closely to this: 850 mb temps several degrees <0C during start of precip and even the coast never gets close to the 0C line: 1000-500 mb thicknesses at start of precip well below the common 546 dm needed to support snow in SE as these are in the mid to high 530s and they actually drop from this point: Surface dewpoints well below 32 just in advance: But surface flow is then a warm SW flow that warms low levels up rapidly just in time: Clipper surface low coming down allows SW flow ahead of it on backside of Arctic high moving offshore, a pretty unusual setup with a low also in the Gulf: The qpf ends up too light (<0.15”) to allow the easily cold enough levels between 850 and 500 to have sunk enough to counteract the warming surface SW flow:

6Z GEFS mean:

0Z Euro ens mean: most areas have more than on 12Z with largest increase C GA/SC to 1.1-1.5” range with all of that falling starting 8 days from now; that’s a lot of snow showing up that far out for that area: @jburns@buckeyefan1please pin this thread

It looks like Dec NAO will probably come in moderately positive in the table…..~+0.6 to +0.8. Then we’ll have the very strong first half of Jan -NAO. It may be as low as -2 tabular equivalent. But then it should rise quite a bit per model consensus. However, Jan as a whole should still come out decently negative, possibly sub -1. If it were to end up lower than -1.11, it would be the lowest since the mid 80s! If so, Dec-Jan would average a weak -NAO with only Feb left. So, there’d then be a shot at a sub -0.25 NAO near a solar max though I wouldn’t bet on it as of yet.

18Z Euro ens mean:

Based on thicknesses (546 is usually snow line in SE), 850 mb temp anoms, and qpf (2m are too warm), that’s actually likely a major (3-7”) snowstorm on the 12Z Euro AI with the NW extent of the 3” Columbus to Macon to Augusta to Fayetteville to Greenville, NC, with ~5-7” from NC coast down to ~Charleston.

As I expected, today’s Euro weekly for 1/6-12 isn’t quite as cold as the last two runs although it’s still very cold: The subsequent week (1/13-19) is about as cold as yesterday’s (solid cold but not as cold as 1/6-12).

I saw only one Euro ens member out of 50 (2%) (#44) holding a surface low back for 72 hours in the W Gulf like the op. and only a couple of others remotely resembling that scenario. So, the 12Z Euro op was clearly a major outlier and will likely change a lot in some way at 0Z.

12Z Euro mean snow: not as much as recent runs for most areas but still enough to end ATL 0.5”+ snow drought of prior 6 winters:

12Z Euro: The 2nd storm, while the upper level energy is held back and there’s a surface low well down in the W Gulf, gives ZR (as much as ~1” far S LA) 1/10-11 to part of the Gulf coast:

12Z GEFS has less for most areas vs recent runs though still notable amounts N GA and much of Carolinas: