Raleigh Weather Discussion
From a temperature perspective it will feel more like October the next couple of days then December. Temps after a chilly start this morning will soar into the mid 60s and do it once again tomorrow as warm air surges ahead of a strong cold front slated to move through Thursday afternoon and evening.
It looks like this band of rain will likely have some embedded thunderstorms but instability is lacking so as of now I certainly do not expect a widespread severe weather event, but a strong storm or two is possible with a strong wind gust the most likely hazard and most likely south and east of the Triangle where the SPC does have a slightly risk for severe storms.
This front will blast through Thursday night and it will likely be pretty windy Thursday night into Friday and temps will be much colder likely holding in the 40s all day Friday. Winds could gust to 40mph during the day Friday which will make it feel all the more colder. It also looks to be very windy with several inches of snow falling in the NC Mountains Thursday night into Friday.
It looks like we will be in a very unsettled weather pattern beginning Christmas Eve and lasting through much of the week of Christmas. I have seen the 00z Canadian model which shows a snow event for NC Christmas Eve, but so far that is the only piece of model guidance I have seen that shows that and given that traditionally the Canadian is towards the bottom of the model verification stats, for now I throw it out.
The most likely scenario is that we will likely see some showers scoot in Christmas Eve evening and overnight. As of now, Christmas Day looks cold and cloudy with cold air damming likely and rain moving in. Right now I think it will be a cool, damp day in the 40s. The 26th is up in the air but right now it looks very rainy with some potential for some severe storms in the afternoon. However it could still shift to a colder solution ,although as of now wintry precipitation is looking less likely than the past couple of days. I wouldn’t be surprised to see at least a brief period of wintry precipitation in the mountains/foothills sometime between Christmas Eve night and the morning of the 26th but I am not betting on it right now.
It looks like this storm system will wrap up and become a major storm over the Canadian Maritimes and drive more colder air into the area by later Christmas Week.
National Next 10 Days
The Midwest blizzard still looks on track. I don’t have much change from yesterday’s general ideas. I think Chicago sees several inches but the heaviest band will be NW of there across central Iowa into southern Wisconsin and northern Michigan where 8-16 inches will fall. A good area of 6-12 looks likely over the central and northern Appalachians as well with lake effect snow also kicking in.
The big change with the 2nd storm system has been a trend away from the idea of a cut-off system over the Plains. This has shifted the snow threat into the Ohio Valley, Lakes, and interior NE. There could also be severe weather with this system across the Southeast. So this could be a big ticket item from 12/25-12/28 or so.
National Extended Weather Discussion
IT appears that the best cold will continue to be favored over the West and Central US as we head into the 11-15 day period. Although we look to see a west-based –NAO in the ensemble means and an EPO turning more negative, the PNA looks to remain negative which will favor a trough in the interior West and a ridge over the lower Mississippi Valley and Southeast. Cold air will likely cover much of the US, but if the ensembles are right the storm track may be up the Appalachians which will cause warm advection across the southeast ahead of storm systems.
Of course it is possible that the models are not properly accounting for the blocking over NE Canada and we may see a more suppressed storm track. IF that happens then I would look for the cold to cover much of the country. The 00z/06z ensemble guidance has backed off of that idea a bit with again the cold more centered over the central/western US. We will just have to wait and see if we are seeing another false start to any type of cold pattern.
In general, I do think a colder pattern looks more likely than not for the last week of December into early January at least. But as of now it looks to be still be most favored and impactful across the interior West and central US.