RIDDLE ME A RIDGE....
I've finally seen some consistency in the evolving pattern the next 7 days. Yea, there are still some significant issues to resolve but at least the major models have all trended in a similar direction...it's been a long time since that's happened. (Hopefully it continues with Christmas week looming on the horizon).
Going forward what everything is going to be based on is a ridge that is forecast to build over the southeast U.S. The strength and position of that ridge will determine the storm track and how far cold air can penetrate into the country. Below you can see the GFS, EURO, and CANADIAN 500mb forecasts December 24th.
The southeast ridge is strengthening in all three models but each has a slightly different depiction of what the central U.S. trough looks like. The Canadian is the coldest solution but in all of these scenarios low level cold air will be pushing hard and oozing like syrup towards the east and south. However, there will be a point where the ridge fights back and that is where the storm track will be established post Christmas.
So the riddle of the ridge needs to be solved to for two reasons. One to determine how cold it gets around Christmas (I am confident it will be cold and well below normal, just how cold). The GFS has this for highs Christmas Day.
And two, to determine where it snows.
As of Thursday all 3 models showed a decent Midwest snow system in the period December 21-23rd. All have different tracks which is to be expected at this early point. What's most important is the consistent signal for a snow producing system. Confidence is growing that some part of the central or upper Midwest could see a healthy snow a just before Christmas. Odds are with cold air lacking before the disturbance most of the heavier snow will be north of my local area. Here's some of the early snowfall projections. Don't get caught up in the amounts, they will change and move around in coming runs. Right now the trend is all were interested in. Having said that Wisconsin in particular looks to be setting in a very snowy spot.
The bottom line in the Christmas week weather pattern is simply this, solve the riddle of the ridge and the weather picture is going to show itself. Roll weather...TS