A Difficult Pattern Ahead...Could A Christmas Day Snowstorm Be At Hand?

Hello this is Student Meteorologist Kyle Elliott...and though there has been rumors of big storms running around the past week or so, I chose not to post as I honestly did not see potential for anything big along the eastern seaboard. Many factors that need to be in place were not, and I was not going to be so foolish as to post hype about a storm that indeed is not going to materialize tonight into tomorrow. Granted, folks from the Cape into Maine will get there snowstorm...but other than that, everybody else is going to get missed wide right. Anyhow, enough being said about that, there is much more to look forward to in the next week leading up to Christmas, and I will indeed post about these two snowfall potentials as I see them as much more valid threats than the fantasy storm of this weekend. First, folks from the Midwest to the Mid-Atlantic will have to keep their eye on a clipper coming along in the late Monday-Wednesday timeframe. Snow should break out in the Dakotas and Minnesota on Monday and spread eastward through the Ohio Valley on Monday night and Tuesday. That much is pretty set in stone right now as a general 2-4, 3-6 inch band will be common through those areas. The question then becomes, does the clipper make it over the mountains or get squashed before doing so? The answer to that question lies in what happens with the storm developing far off the Mid-Atlantic coast tonight. If that storm remains weak and doesn't deepen and establish itself as a block across Atlantic Canada, then the clipper should have free reign to cruise over the mountains give places from Washington, DC, to Harrisburg, PA, a general 1-3 inch band of snowfall. If the storm does deepen like the latest 18z NAM shows, though, then nobody east of the mountains sees more than a coating of snow as the moisture will be blocked south and thinned out moving into an unfavorably dry and windy environment. It's that simple as far as the clipper is concerned: either the major cities from D.C. to Baltimore to Philly see 1-3" of snow and the storm off the coast remains weak...or the cities see nothing as the storm off the coast deepens and blocks the clipper out. Honestly, I'm not sure what to say about it all right now...I feel as though waiting till tomorrow evening to see what this storm offshore does is the better thing to do right now. I will say this, though: I wouldn't get my hopes up as the 2nd solution of nothing in the major cities seems to be more probable at this point.

Now, as far as the Christmas Day storm threat is concerned, that is a different story in my opinion. Once again, we have to wait and see just how strong the block over the Gulf of Maine/Atlantic Canada gets over the next few days and how fast it moves away. The 18z DGEX had it remain strong for an incredible long time and squashed the Christmas storm south too, as a result. I'm not buying that solution, though, as I think the Christmas storm will not go as far south of the DGEX is portraying. A hybrid solution of the 12 and 18z GFS model runs is what I am leaning toward right now...a moderate 4-8" snowstorm from central Virginia to about as far north as the Pennsylvania Turnpike. I don't think that the 18z GFS is right in keeping the snowstorm confined to areas south of the Mason/Dixon line with all snow as far south as northern North Carolina. On the same token, I don't believe the 12z GFS is right in bombing the storm out to cause a virtual blizzard from D.C. to Philly on Christmas Day. There is potential this thing could bomb out as it is meeting up with an arctic airmass and, if the block weakens, little resistance from charging up the coast and exploding into a major snowstorm. What I don't think will happen is that this storm will skirt across the south and miss the entire Mid-Atlantic States as there is nothing to cause it to do so. The cold airmass coming in behind the clipper on Tuesday/Wednesday is not that strong, and I believe the DGEX is making an error in pushing this storm as far south as it did on 18z. The one factor that is lacking, though, is an arctic 1025 millibar high sitting north of New York State...a classic factor involved in nearly every great Mid-Atlantic snowstorm. The one thing we do have going for us, though, is that the Greenland block which has been causing storms to go out to sea is going to practically weaken and vanish in the next couple of days...so that should help the storm's cause. Without the high to the north in southeastern Canada, though, I cannot at this time get excited for more than a minor to moderate snowfall in the Mid-Atlantic States on Christmas Eve and Christmas Day. I will issue a snowfall map either later tonight or tomorrow on where I think the best chance of accumulating snow will be around the Christmas Day time frame. For now, that's all I have...so hope ya'll have a great evening and I'll post the snow map later! This is Student Meteorologist Kyle Elliott reporting for the AKStormtracker Forecasting Center.