The big story of the day with regards to the upcoming weather system is that the ECMWF has maintained its extreme solution with just incredible amounts of snow for the Carolinas, Georgia, Virginia and further north. Taken literally we would see widespread amounts of 1-2 feet from central Georgia north with perhaps, as far as the southeast is concerned, the eastern piedmont and coastal plains of NC and Virginia being the big winters. This would include Raleigh and Richmond among other areas.
The model wants to phase 3 different shortwaves into a rapidly deepening storm off the southeast coast. The storm takes a track similar to the one I outlined in the previous discussion across northern Florida to off the Ga coast where it is around 1002mb as of 7am Sunday. It then bombs to 969mb by 7am Monday just of the Tidewater of Virginia. This track and the evolution of the storm would place central Georgia into the eastern halves of SC and NC and eastern Virginia under the comma head of a rapidly strengthening storm system. In this “comma head” very heavy snow will fall and with the storm moving so slowly it will fall for a long period of time with significant accumulations. That is according to the ECMWF model. The 12z UKMET has output only every 24 hours from 72 to 144 hours, so it is difficult to say for sure what happens with it but it takes a 1007mb low from central Florida north to a 971mb low east of the Virginia Tidewater region. It looks to take a slightly further east track than the 12z ECMWF model but is further west than the 00z run and very similar to the ECMWF in terms of the general ideas.
I have just seen the 12z ECMWF Ensembles and they are supportive of the operational ECMWF. The operational version remains a bit of an intense and west outlier but there a good number of members with similar depictions and the total ensemble mean QPF increased and shifted west from the 00z run. It is not as much as the operational ECMWF, but it is not expected to be since it is average of many (51) members.
The 12z GFS and GGEM models were much less intense and showed flatter solutions where the storm tried to turn up the coast but ultimately the turn and the intensification came too late. The GFS does bring decent QPF to central and southern Georgia and the eastern 1/3’s of the Carolinas with 0.5 to 1 inches there, but further inland it is a light event. The GFS would bring a decent snow to the NC and SC coastal plain but it would likely be rain in Georgia. The 12z GGEM keeps most of the significant precipitation off shore but did trend a little west in the southeast but further east in the northeast. Overall these models trended more towards the ECMWF solution, but there is still some significant differences that result in wildly different sensible weather outcomes. Two of the 12z GFS Ensemble members showed the big dog scenario, with 3 showing a more moderate event, and 6 showing an event similar to the operational GFS. I have not yet seen the GGEM ensemble and am watching the ECMWF ensemble come in as we speak.
In general, the extreme solution is still on the table. This is the third run in a row of the operational ECMWF showing a mega snowstorm for parts of the southeast and the eastern US. The models are now all showing a rather similar synoptic scenario unfolding but differ in the timing and exact nature of the phasing of the two streams. It could be that the ECMWF’s superior resolution is helping it resolve this better. Only time will tell.
I still think the operational ECMWF solution is a bit too extreme, but it is scarily consistent the last few runs. My hunch is that the ECMWF will trend a little east while the GFS and GGEM trend west and they meet towards the middle perhaps shaded more towards the ECMWF solution and close to the ECMWF Ensemble solution. If this is right a significant snowstorm is on tap late Christmas Day through the 26thor 27thfrom Georgia to Virginia if not further north. The only bummer for Triangle residents is that the timing continues to slow down a bit and we may now only see a little snow on Christmas Day during the evening.
Stay tuned I will update as needed.