Winter Storm #2 - January 22-23

Good morning again! 
The winter storm that's about to form will have serious implications for many millions of people, from Georgia all the way to the New England states. There are currently 74 million people under a blizzard watch. Many people will be hammered by feet of snow and others will hear the sound of trees crashing to the ground from heavy icing. This will be a major winter storm if there ever was one, and major storms can sometimes have major consequences and unexpected twist and turns

By now you have hopefully read Step 1, the latest Area Forecast Discussion from the NWS. If not click here to read it.

It appears they are being conservative for now, and rightfully so. I never try to second guess the NWS, they are the experts, they make the forecast, and they are the final answer. But in some cases, I will give you my thoughts and how they differ from theirs. Right or wrong. :-)
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First, freezing rain probability maps. The one on the left is for 0.01" and the right is 0.10". I think they are way underdone and believe they will be changed, and I'll show you why I think that in a minute. I expect ice to be a very serious concern for many people, as far south as the metro area

Both major models converged on a solution last night and this morning. First, here's a look at our current surface map and where our future storm is this morning. The red circle is the low pressure at the moment, and the read dotted line is the expected path. Notice how the low will come north toward GA and then rapidly move east. That is a Miller B type storm. The energy transfers from GA to the coast rapidly as it approaches the mountains. It the sotm continued tracking on a southerly course and then made a turn near the coast of FL/GA, that would be a Miller A type of storm. Right now, that is what next Tuesday/Wednesday looks like, and those are our most favorable type of storms.

As you can see, precip is already breaking to the north and east of the developing low, and that rain will be on the increase today.  These maps show the expected rainfall through 1 PM today. The HRRR simulated radar image is for 11 AM today.

As the day goes on, a wedge or CAD (cold air damming) begins to build southwest our of the Carolina's. The air there this morning is very cold, and as the high pressure to our north slides east, the clockwise flow will push cold air southwest down the side of the mountains. As the low pressure approaches, the gradient from the low to the south and the high to the north strengthens the CAD. 
Here's a look at the 06Z GFS. It shows the low pressure moving toward north Georgia, then making the transfer to the coast.  I talked with by friend Robert @ Wxsouth.com this morning to see if his thoughts had changed since yesterday, and this is what he had to say about the deformation band:
"The GFS latest run and the ECMWF both have that strong wrap around deformation banding swirling snow through NC, eastern TN, eastern KY, and all of Virginia for quite a long time for a storm system... again, I think the models are doing that because the storm tends to go east slowly, rather than rocket up the East Coast as a traditional nor'easter would do. A foot or more of snow now covers more of central and western NC and more of western SC, northeast GA...  with still not enough shown in my opinion in Alabama and Georgia with the deformation band later on. We'll see though."

Robert also had this to say...

"I am thinking the 5h, 7h and 850 lows will come right over Birmingham to Atlanta or just right north of there tomorrow night and then roll east, not northeast. That will initially allow a backside deformation band. Now I know there's a tight play from downslope in that flow for Atlanta,  but still a few hours of moderate snow is doable, and especially east off the northeast side of the chain,  going into Upstate SC to western NC, where I think for a few hours, the flow will really hit them, and maybe have some thundersnow. I'm not sold, but its slightly possible. This 850 low is really going to wind up nicely and the mountains will force it to the southeast of the chain. I think all models are still too light on the deformation band immediately behind it, but then again, the mountains play funny tricks all the time.  If this were March, I'd definitely honk Thunder-snow.  I see the new Hi Res NAM just went south and due east... the folks in NYC are in  a panic I bet.  I think todays 12z may drop a fraction more, won't surprise me.

Robert made a post yesterday, and he has graciously allowed me to share some pieces from it. Here you'll get a inside look at what Robert is thinking about when, where, and how much.  So here are Robert's bulleted points from yesterday. 

1. This is an historic event. Each hour that passes, I grow more impressed in many areas, some not where models are impressed
2.  I think the TN Valley, upper Deep South is going to get hit very hard on the wrap around snow , once the ULL and 7H, 850 low rolls east Friday afternoon, night
3.  I lean toward much heavier snow totals throughout TN, southern and central KY and northern half of Mississippi, Alabama and Georgia, especially more than models are showing further south
4.  The snow , ice line in western NC, extreme northern SC is tricky and the temps at 850 may be right , but there's so much massive warm advection I lean toward a lot sleet in southern NC  , northern SC during the Height of the event, with a severe freezing rain (ICE STORM) along 85 from around or just south of Raleigh, Charlotte to Spartanburg to Athens, with Atlanta northeast suburbs a close call on surface temps.  Heavy sleet totals are likely somewhere between the mostly snow and mostly freezing rain zones .
5.  Eastern Virginia will start as snow, and gradually mix in to more sleet (rain coast) and eastern NC coast, but when the storm moves north on Saturday afternoon, all will have back lash, deformation snow
6.  Strong deformation snow behind the slowly moving blizzard just east or near Elizabeth City, will send high winds throughout Virginia, with max winds over 50 MPH in eastern regions, the Delmarva and southern MD, DE.
7.  Deformation wrap around snow is very impressive on the models at 7H and 5H across the Carolinas, northern Georgia, extreme eastern TN and extreme eastern Kentucky  Southwest Virginia early Saturday , and will continue to rotate due south all day, and may reach northern SC, without too much downslope in effect. Heaviest wrap around snow will be in western VA and northern central NC most of Saturday with several more inches on top of what has already fallen, pushing totals over 20" in some areas in central VA and northwest, north central NC possibly.
8.  If the center of the storm is more east, then it may form an "eye".  The warm ocean waters and slow movement, provided by some blocking high will offer this rare chance for a well developed cyclone. The pressure may drop much lower than any models indicate right now, it all depends on where the surface low moves (land or ocean)
9.  Intense snowfall rates associated with the 7h, 850 mid level low that suddenly will develop between Birmingham and Atlanta late Friday will enhance snowfall suddenly in a narrow region of that area, and offer extreme southeast Upslope snowfall back into western SC and western NC for a few hours during the night. The track of that feature will need to be watched, but this is not the same as the main Surface low. Eventually the surface low will pull away from the base of the Southern Apps and reform along coastal SC and then work northeast along the NC coast Saturday afternoon.
10.  Upper lows in the Deep South that round the bend of the Southern Apps can produce thundersnow and thundersleet.  Another area where this may happen is in northern VA to central New Jersey,  due to friction from the warmer water off the Ocean and the colder dense high pressure just inland.  Anywhere is a possibility though, but these two locales have an extra high chance on this phenomenon.

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The unique wind flow directly into the Southern Highlands region of GA, SC, AL, NC will offer up a rare chance for 2" per hour snowfall rates (and thundersnow).  More on the deformation band that I think will bring quite a bit of snowfall to northern MS, northern AL , northern GA. possibly to near BHM and ATL, but especially just north of those locales. Keep your eyes on this def. band Friday night, I think it will mean business for areas that get under and to its west, nw.  Any slight jog south would greatly change a snow forecast from 1 to 3" to 3 to 6" in a hurry, and I strongly suspect that will happen very near these two metros.

As mentioned on the ICE part.. where it's not all snow, and not all sleet, I think northeast GA from Gainesville to Athens , and points northeast are going to experience a severe Ice storm, to the lower and central Upstate to possibly lower NC piedmont but it appears the depth of the cold air may keep it sleet more often in Charlotte metro, but its going to be extremely close. Same for Raleigh and the eastern parts of 95, where the 32 line will hold strong, but working inland every mile toward central NC, the Triad region, more and more sleet then more snow, with time as a change and transition occurs. The rough approximation on transitory types is "near 85" from Atlanta GSP, CLT, RDU, RIC zones, which is typical. The models seem to be growing colder at the surface each run, and I suspect that will continue, thanks to extreme northeast confluence...so the ice may actually get even further south toward the Midlands of SC and the western Sandhills, again close call and worth monitoring.

84 hour totals NAM: Devastating where the solid all ZR is going to occur (actually topped off with snow, but my worst area I think is northeast GA, northwest SC and the periphery region of the piedmont of NC to northern Midlands SC.

Finally, I still think the European has been handling this the best and all models have shifted ever so slightly south, recognizing the strength of the confluence up north, which is classic meteorology in action.  Its one of the reasons I suspected the models would shift a little more south and I hedged toward a colder surface further south in the damming region.
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Still, the ensemble is ever so slightly south again today,  centered just south of the Charlotte region Saturday, as the Miller B nature of this rare event is forced from eastern Alabama due east to the SC coast, then it will begin to crawl north.  That track is also why I suspect the models are TOO LOW in the northern parts of MS, AL and GA on their totals, not recognizing yet the strong banding of a well developed comma head that will likely happen there, including southern TN.

i will have much more to come this afternoon after we get another round of models under our belts.
Get ready, this roller coaster is about to leave the station, it it looks like one heck of a ride. :-)