The Jan 9-11 Storm

[chapelhillwx]

Looking at the GFS, I'm reminded of Dec 2002. 2" snow plus 0.5" ice. Synoptically different of course.

[FoothillsNC]

By the way, I know there's been mention of the High placement. There's a 1025mb high over eastern Ky/Srn ohio area Sunday and that pressure field is what feeds the low level cold into the Tenn Valley and southeast, and the low so far south in combo with the ridged high in southern Canada is all thats needed for the low level cold to remain entrenched. We haven't seen it in a while really not many times in most poster's short life on here (did numerous in the similarly displaced pattern of 1960--and to some degree the Dec 2005 icestorm).

[georgiawx11]

Ok, I just want to straighten something out. When people say N GA does that include all of the Atlanta metro area ? Or does it include areas mainly from Rome to Gainesville and northward ?

[ams30721us]

As a pro forecaster I'm sure your having a memory that can go back almost three weeks is a very valuable asset.

Hahaha not always! lol but I try!

[audioguy3107]

GGEM looks absolutely spectacular for northern GA.....one thing I'm excited about is that the timing of this thing seems to be working in our favor......a start time evening and overnight on Sunday is much better than the last three events that started around 12 to 1 PM. We seemed to waste a lot of our QPF on late afternoon melting. Hope this works out better on the timing.

[Cold Rain]

All one has to do is look at the 850mb maps over the past 4 runs to see the GFS is still struggling on strength and placement of the low. At-least the Euro has been consistent in this area, and I expect the GFS to trend in that direction within the 72hr window. An 850 track through E TN or W NC is not conducive for all SN in central and eastern NC, any way you slice it. From my understanding, and those in the know correct me if I am wrong, the 850 should track just to the SW of the H5 vort, and that would yield a track from LA to the OBX, or just south of there based on the GFS's H5 depiction. The Euro is a safer bet currently, with a weak 850 taking a more plausible track given it's UL setup.

Yeah, that makes more sense. Thanks for the explanation. The 850 line didn't seem to line up with the placement of the storm.

[EmersonGA]

Ok, I just want to straighten something out. When people say N GA does that include all of the Atlanta metro area ? Or does it include areas mainly from Rome to Gainesville and northward ?

Most people would consider I-20 north as North Georgia. That is the usually dividing line in storms it seems.

[georgiawx11]

Most people would consider I-20 north as North Georgia. That is the usually dividing line in storms it seems.

Ok, so that would mean the Atlanta airport is in Central Georgia, correct ? I ask because the local tv met's always refer to areas as far south as Griffin and LaGrange as North GA.

[RevDodd]

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

The 12Z Canadian pasted areas south and east of a line from Charlotte to RDU with some unpleasant ice. At least the last 6-8 hours it shows, with more on the way across South Carolina with the low sitting right off Beaufort, SC.

[BIG FROSTY]

I know I shouldn't be concerned , But I am. It seems that most of the 12z runs is keeping it futher south of N.NC ? Enough with that, I would like to see a little northward trend, !

[Lookout]

overall, I'm amazed at the agreement. ECMWF, GGEM, NAM GFS all very similar now with the track and setup. The GGEM is almost a carbon copy of the GFS, and another big hit for the same areas. Lets hope the ECMWF is the same.

I am too, in fact they have been in decent agreement fir a while and all the talk of a north/warmer trend aloft was premature last night imo. Thus run and the gfs is colder here than prior runs.

[EmersonGA]

Ok, so that would mean the Atlanta airport is in Central Georgia, correct ? I ask because the local tv met's always refer to areas as far south as Griffin and LaGrange as North GA.

Sometimes it seems like the airport is in central Georgia based on its temperature and snowfall compared to those just north but I wouldn't say it's in central Georgia.

Maybe it would be better to say 20 miles on either side of I-20.

[Itunis]

Ok, so that would mean the Atlanta airport is in Central Georgia, correct ? I ask because the local tv met's always refer to areas as far south as Griffin and LaGrange as North GA.

I think for the sake of convenience the ATL metro area is considered to be in N GA by most, even places a bit south of 20. On this forum, I'd say north of 20 is N GA, the mountains (north of Rome-Lake Lanier-Hartwell) are far N GA.

[Lookout]

GGEM looks absolutely spectacular for northern GA.....one thing I'm excited about is that the timing of this thing seems to be working in our favor......a start time evening and overnight on Sunday is much better than the last three events that started around 12 to 1 PM. We seemed to waste a lot of our QPF on late afternoon melting. Hope this works out better on the timing.

Great point. And again combine that with cold ground temps, we really are fortunate this time around..assuming the timing remains the same.

[FoothillsNC]

GGEM looks absolutely spectacular for northern GA.....one thing I'm excited about is that the timing of this thing seems to be working in our favor......a start time evening and overnight on Sunday is much better than the last three events that started around 12 to 1 PM. We seemed to waste a lot of our QPF on late afternoon melting. Hope this works out better on the timing.

good point. I'm rooting for the nighttime big rates too, and plan on sleeping in Sunday (if I'm not completely zonked before then). The deformation band looks like its going to lie across the northern 2/3 or both Alabama, Georgia and the western Carolinas early on , overnight and predawn Monday, and beyond that we'll have to wait and see how much lift is generated by the incoming 5h vort and whats lett of the coastal. The rates could be excellent overnight along 85.

I know I shouldn't be concerned , But I am. It seems that most of the 12z runs is keeping it futher south of N.NC ? Enough with that, I would like to see a little northward trend, !

you shouldn't worry about qpf. You'll end with more than here, I'd bet.

[georgiawx11]

I think for the sake of convenience the ATL metro area is considered to be in N GA by most, even places a bit south of 20. On this forum, I'd say north of 20 is N GA, the mountains (north of Rome-Lake Lanier-Hartwell) are far N GA.

To me, I consider North GA areas from Newnan to McDonough and northward.

[EmersonGA]

To me, I consider North GA areas from Newnan to McDonough and northward.

That sounds reasonable. I think the media saying LaGrange is pushing it though.

[FoothillsNC]

I guess i'm on my own with the earlier arrival of precip, but if the Euro doesn't speed up the front edge I guess its time to accept its going to begin overnight here, although I' still bet an unforseen band /axis will branch east quickly, but will be more narrow. The Christmas storm did that, and a lot of storms end up that way. But an overnight start would be good as others have stated for excellent accumulations, but its just plain nice to see fall during the daylight.

[georgiawx11]

That sounds reasonable. I think the media saying LaGrange is pushing it though.

I agree.

[beanskip]

Doesn't everybody?

you shouldn't worry about qpf. You'll end with more than here, I'd bet.

[lilj4425]

We're in storm mode now. Woohoo. I expect the models to start going downhill now.

[dsaur]

Ok, so that would mean the Atlanta airport is in Central Georgia, correct ? I ask because the local tv met's always refer to areas as far south as Griffin and LaGrange as North GA.

I most often get what you and Atl get only more or less of it. Often I get in the sleet zone which is great for me. I think topography plays a role also. Many mets believe Ga. ends with Atl as far as winter weather is concerned, but not the fine mets on this site, as a rule, lol. and Atl mets know better than to draw an arbitrary line along some interstate as it rarely verifys so concisely but they often do for the sake of ease. T

[DLI4SCwx]

I guess i'm on my own with the earlier arrival of precip, but if the Euro doesn't speed up the front edge I guess its time to accept its going to begin overnight here, although I' still bet an unforseen band /axis will branch east quickly, but will be more narrow. The Christmas storm did that, and a lot of storms end up that way. But an overnight start would be good as others have stated for excellent accumulations, but its just plain nice to see fall during the daylight.

Robert, with the dynamics in place and so forth....could you forsee a scenario where the central portions of the Carolinas, get less ice than progged by some of the models? That is a big concern of mine, esp considering the elderly and the less fortunate.

[audioguy3107]

Great point. And again combine that with cold ground temps, we really are fortunate this time around..assuming the timing remains the same.

It's really amazing how I can't seem to remember the last time we've had an overnight into the next day event without wasting a ton of QPF during the peak heating of the day. I swear we probably wasted at least 2 extra inches of snow around here last February......it really didn't start piling up until about 4:30 or so, once the sun started to set. I know timing can change as well as everything else, but this looks to be a really exciting one to follow, especially if we don't have to worry about temps and starting out in the mid to upper 40s.

[Mencken_Fan]

Then everyone is going to get at least 0.10 of freezing rain on top of it. 4 to 6 inches of snow on a frozen ground with temps in the mid to upper 20s and then throw on 0.10 to 0.25 of freezing rain and you are talking about a recipe for The roads to be an absolute nightmare. In fact, travel would be nearly impossible with several inches of snow with ice on top of it. So if this gfs run verified, this is about as high of an impact winter storm as it gets here.

Freezing rain atop 4 to 6 inches of snow, while terribly uncomfortable to walk in (because the broken, jagged ice layer scrapes against your flesh) is not actually a driving nightmare because the ice crumbles under pressure. What is a driving nightmare is to have the ice come first (laying down a solid sheet); then cover it with snow (making it invisible.)

When freezing rain comes first, it bonds to the pavement. Snow atop it makes it invisible...and driving over it is to beg for loss of control. I've seen this happen a few times in Maryland but don't know if that set-up happens in the Deep South.

Whatever the case, I certainly hope you (and the rest here) are spared such an outcome.

[DaculaWeather]

I most often get what you and Atl get only more or less of it. Often I get in the sleet zone which is great for me. I think topography plays a role also. Many mets believe Ga. ends with Atl as far as winter weather is concerned, but not the fine mets on this site, as a rule, lol. and Atl mets know better than to draw an arbitrary line along some interstate as it rarely verifys so concisely but they often do for the sake of ease. T

Here in NE Gwinnett, I get more of what the upper part of north Georgia gets. And when there's a wedge, we're right in the middle of it.

[georgiawx11]

This is from James Spann out of Birmingham:

Cold, dry air will start moving into Alabama at low levels Saturday afternoon, as north winds pick up. Temperatures by Sunday morning will likely be in the mid to upper 20s in central Alabama. At the same time, an upper-level storm will move out of the SW US into Texas by Sunday morning.

As this upper-level storm approaches the Gulf Coast, a low pressure area will form somewhere in Louisiana or off the Louisiana Coast Sunday, depending on how far south the cold air pushes Saturday night and Sunday morning. This low pressure area will then move along or near the Gulf Coast Sunday night and Monday.

Precipitation is not a question with this system. It will begin to move into west Alabama Sunday, and overspread the state by Sunday night. As a matter of fact, the precipitation may be heavy, with 0.5 to 1 inch of water equivalent falling. The key to what type of precipitation falls will be the thermal profiles in the atmosphere Sunday night and Monday. Generally, the farther south the low tracks, the colder the air is in central Alabama, since we don’t get any southerly flow ahead of it if it stays near or off the coast.

For snow to form aloft, the temperature in the precipitation formation region usually needs to be 23 degrees F or colder, ideally around 14 F. Clouds are made of water droplets even at temperatures in the teens aloft, and most of these don’t start to freeze until they drop to near 20 degrees. However, once a snowflake forms, any cloud water droplets it comes in contact with will freeze onto it, making it bigger. Bottom line…if it is too warm aloft, even if it is a little below freezing, precip can fall to the ground as rain.

The worst case scenario is that southerly flow at mid-levels, or 4,000 to 10,000 feet) brings in enough warm air there to keep temperatures too warm for snow formation. Then, the precipitation would fall mainly as rain. But, if there is enough cold, dry air at the surface such that the cold raindrops evaporating as they fall cool surface temperatures to freezing, causing freezing rain (rain that freezes on contact), we could have some ice accumulation. Right now, this scenario is what is shown by the latest GFS model run.

Another possibility is that there is just enough cold air aloft for the precipitation to fall as snow. This is more likely in north Alabama (HSV), but could occur in BHM too. In this case, 2-3 inches of snow could fall Sunday night.

The third possibility is that the low moves north of the coast, warm air flows in from the Gulf, and we just get a cold rain, with temperatures in the mid to upper 30s. (Even though lows tend to like to stay near fronts and areas of large temperature changes over short distances like the coast, this inland low was shown by last night’s European model, the one that handled the snow on Christmas so well.)

My gut feeling right now (and I’m not Gibbs on NCIS nor Jack Bauer on 24, so I’m not always right) is that snow is likely from Cullman north. In central Alabama, freezing rain and snow, with ice accumulations Sunday afternoon, are possible. I’d give it a 33/33/33 shot (snow/ice/rain). Farther south, there could be a little freezing rain in Montgomery if the cold temperatures push far enough south, but that seems unlikely.

As is usually the case in Alabama, the potential winter storm system coming in on Sunday and Monday is very complicated, and to jump out and make a bold prediction 3 days out would be inappropriate. Also, don’t hang on the subtle changes in every model run, either. The models are solving very complex equations involving many variables, and some flip-flops are going to occur in what they predict. We have to sit back and take all this in and give it our best shot, accentuating the uncertainties in the forecast.

[FoothillsNC]

Doesn't everybody?

Ouch, bringer of truth. One of these storms, one of these years, has to do us right on widespread basis, right? Has there been a storm in Cleveland County that blanketed the whole county basically evenly? We've been through some weird outcomes, and yes this could be yet another...it would sure fit the trend. The pattern has been trying to get back to "normal" though.

Robert, with the dynamics in place and so forth....could you forsee a scenario where the central portions of the Carolinas, get less ice than progged by some of the models? That is a big concern of mine, esp considering the elderly and the less fortunate.

[RevDodd]

Since it's going to be of major concern to the folks down this way, and since I don't want to denigrate into IMBYism...

Are our soundings the best way to predict whether we see icing, rain or snow? Are there other keys in the models I'm not aware of beyond surface and upper air temps?

[audioguy3107]

This is from James Spann out of Birmingham:

It's too bad FFC couldn't get him to help them out in writing their discussions....it would make a far more interesting read.