The talk about a potential major winter storm affecting parts of the Deep South, Appalachia, and the Eastern Seaboard next week will likely be growing. The disturbance will likely be composed of two entities: energy ejecting out of the sub-Aleutian vortex, and an impulse moving along in the subtropical jet stream (tied very much to the Phase 6-7-8 banding of the Madden-Julian Oscillation). With the aforementioned mAk gyre pumping up a steep +PNA/-AO styled ridge complex, the two disturbances will likely meld in the base of a 500MB trough over the Deep South next Tuesday.
It is way too early to speculate about possible snow amounts, but the unity of the numerical models with regard to this feature is pretty amazing. Therefore the most likely outcome will be a Miller "A" Gulf Coaster/Hatteras/Nor'easter event between February 23 and 27. Yes, I insist on a longer time span because the European and American ensemble platforms suggest a closed off, vertically stacked cyclone that progresses slowly from the NC Outer Banks to the MA Islands, then on toward the Bay of Fundy.
Because the disturbance will be flanked both right and left sides by strong ridging, a huge temperature split is bound to arise by next Wednesday and Thursday. I can easily see some warming developing in coastal New England and Mid-Atlantic locations, enough to allow for precipitation to start as rain. in many places along the Interstate 95 corridor. But I suspect that most of this event will be snow, and potentially a lot of it. With a neutral/negative tilt aloft and inverted trough development over the Virginias, this could be a big snow/ice thunderstorm maker above Interstate 64 near and east of Huntington WV on up into the major cities of the Northeast.
In summary, this disturbance could be "special". Knowing the numerical models often lose such immense systems after pointing them out very far in advance (in this case 15 days if the storm verifies), avoid any rash judgments about its potential until we get to the February 19 runs.
More later....and by the way, there is also a decent shot at another big storm in the South and east in the first week of March. I do not think we fully shake off winter until just after St. Patrick's Day in areas from the Mississippi Valley to the East Coast.