Hi folks, I wrote a long article this morning but for some reason the Examiner zapped it and it disappeared, and I didn’t save the text, so I just thought I would start over and focus on this storm. I have attached the 6 day forecast I made this morning so if you are interested in that feel free to look at it.
The 12z solutions are certainly interesting. What is going to happen synoptically is a system in the Pacific Ocean is going to rotate into southern California Wednesday evening and then take a southerly route across the southern US thanks to a big 500mb low near Newfoundland (Newfoundland Low/50/50 low). As this system moves across the southern US, we are going to see energy in the northern branch of the jet stream try to drop into the system as it moves into the southeast US and help to expand the precipitation on the northern and western side of the storm, deepen the storm quickly, and also pull it north. Exactly where and when this happen is the key to who gets snow and who doesn’t.
The most impressive of today’s models is the 12z ECMWF. This run of the model shows phasing occurring just in time to bring an gigantic snowstorm to much of the southeast into the northeast US. We would see a storm bombing out Christmas night as it moves across northern Florida and then off the southeast coast. This solution literally spits out probably 10-20 inches of snow across most of NC, the western half of NC, and Virginia, not to mention further north from Christmas afternoon through Monday morning. Across eastern TN and north Georgia it would be more of a 3-6 or 4-8 inch type snowfall with less amounts over N Al and N MS. This occurs because the ECMWF model phases the two streams at the perfect time. This is just like the Jan 2000 storm, except the precip is a bit more expansive on the western side of the storm. It will be interesting to see the 12z ECMWF ensembles later this afternoon.
The 12z GFS however is much different. It keeps the two streams more separate and we do not see any phasing until it is too late. This would result in a widespread light snow event on Christmas Day across much of the southeast, TN Valley, and eastern US, but more on the 1-3 or 2-4 inch side of things. Keep in mind however that the GFS was showing a further north solution until the 12z run shifted south so it still may be playing catch up. Many of the GFS Ensemble members are wetter but only 2 want to give areas from the Triangle west 0.5 inches or more.
The 12z GGEM is closer to the GFS than the ECMWF as it shows widespread 0.25 to 0.5 inches of liquid QPF across NC, SC, and parts of TN/GA. This would equate to a 2-4 or 3-5 inch snow event for many. The streams do phase but too late for a very heavy snow in the southeast, it does hit parts of the NE pretty good. The 12z GGEM Ensembles will be out later this afternoon.
The 12z UKMET is rather far south at hour 120 with a 1004mb low just south of the Big Bend, but by hour 144 it is a 967 monster a few hundred miles east of Hatteras. It is unclear as to how much moisture would be spun back west on the UKMET, but it could be a big storm for coastal sections and eastern parts of the southeast.
So where are we at this afternoon? The 12z ECMWF is an extreme solution with a historic snowstorm for many. The model has been consistent in showing a bigger event than the other models for several runs now and the model has made it’s name on being more accurate earlier than the other models for big storms. If there is one trend it is that no model guidance I have seen is showing an Ohio Valley track but all have shifted south and now just differ on how much interaction the two streams have and how strong the system gets. More than like the 12z ECMWF is overdone, but there is also a good chance that the GFS is too weak. It is too early to throw out any predictions but I still think much of the southeast is in line for snow on Christmas Day and perhaps the following day with potential for a biggie.