So last week I cut a video and talked about this pattern and how for the most part December was projected to be and will be a mild month. I also mentioned how I did have this in my winter forecast. However, we still need to see a pattern evolution towards our winter pattern. What I mean by that is we need to start seeing signs that this pattern could flip by late December. If we do not then I will start to get concerned.
The main factor I am looking at right now is a very strong polar vortex (polar vortex is way up in the atmosphere).
Looking above you can see a nice wound up tight vortex at the pole. That is not good for colder weather as it supports a positive phase of the Arctic Oscillation (lower pressures near pole). What we need to start seeing is this vortex come under stress. When the happens, pieces of it can break off or it becomes stretched out enough that it can have a drastic effect in the lower latitudes. A main factor that causes this is heating in the stratosphere.
As we get to longer in the period you can see models are starting to show this vortex being a little knocked off its center..
Looking below you can see how based on the gfs model, it becomes off center and elongated. The problem is we do not know if this will verify. The models sometimes have a very hard time with accuracy regarding the conditions that high up in the atmosphere.
So we will keep an eye on this. If we get some heating in the strasophere and the vortex does in fact start to come under stress, I will feel very good about the prospects of a pattern change. In the meantime the same pattern will be on repeat. Looking below we can see our big trough out west and ridge on the east..
This is a pattern that in the next 10 days will support storms to effect the western and central part of the country possibly with snow. We could get lucky and northern New England can see snow as well but thats not a high probability until we get past December 15th.
Right now those areas and in particular the Midwest need to watch for a developing storm system for early next week. This could be a snowstorm if the factors align properly.
So we sit here and continue to wait as this boring pattern continues. Although we see some weak signals that the pattern can flip I have nothing at this time to take a hard stance. I can only rely on the evolution I expected in my winter forecast which should eventually start to show itself in the coming weeks. If it does not, then I will be the first to admit. Let's not jump the gun yet however ;-).