Dec 6-8 storm discussion thread

[Cheeznado]

Thought I would kick off a more specific thread for the upcoming system. Looks like broken record IMBY, heavier amounts in far western/northwestern GA, model consensus here is .5 to a max of 1" of rain.

[calculus1]

Here's an 850 shot from the 12Z GFS. I notice there's a high pressure that has developed into New England. Would that have the possibility of edging any cold air down the eastern side of the Apps underneath the warmer air aloft? There looks to be potential snow for eastern TN and the mountains of NC, but I'm not sure if those 850s are going to be chasing the moisture.

[Cheeznado]

Both the NAM and GFS suggest there will be at least a threat of accumulating snow in the NC and maybe TN mountains:

[MotoWeatherman]

Hmm....

[Lee]

The GFS actually shows more projected depth @ hour 66 than what either of the maps you all posted, of which would be a significant snowfall for parts of the area.

[Cheeznado]

12Z Euro is very gung ho for the mountains- at least several inches even in the southern sections....

[burgertime]

Here is the 12z Euro snow map from Wunderground...

[Jon]

The GFS actually shows more projected depth @ hour 66 than what either of the maps you all posted, of which would be a significant snowfall for parts of the area.

You can only estimate so much on low res models...but you're right, it does appear more depth at 66 than 84.

Herei s the 120hr total snowfall from 12z GFS...note this is not 10:1 snowfall ratio, it would actually be a lot higher which would probably be closer to the op GFS on allan's site. With much of the dark green being in the 6"+

[1234snow]

_{This is going to be a quick snow on the northwest side, probably a 6 hour or less event. But the timing looks good as the wave rolls thru Wednesday Night into early Thursday.}

[appstate00]

Overdone?

[ajaronw10]

If that AccuWeather map would just move east about another 50 miles I'd be happy!.. And maybe south just 25 miles

[pcbjr]

DT's 1st call:

http://1664596.sites.myregisteredsite.com/meteorology/1stguess.jpg

[BIG FROSTY]

DT's 1st call:

http://1664596.sites...gy/1stguess.jpg

I'll take my trace and hope for next storm to produce wintry weather...

[calculus1]

If that AccuWeather map would just move east about another 50 miles I'd be happy!.. And maybe south just 25 miles

I'm sure Henry could do that, but the problem would be that it's still gonna be wrong. To be fair, Henry paints in quite wide brush strokes, but his knowledge of geography in the southern Apps is quite lacking. His region of snow extends too far east into the piedmont of NC and then ends exactly on the southern border of NC (as if the Apps stop right there!).

DT's map shows a much better geographical knowledge as he has his one inch line passing thru central Caldwell/Burke counties southward. That's just about spot on where the Blue Ridge comes to an end. He does have a token flake or two expanding east into the Lenoir/Hickory/Morganton area, but I'm afraid that's about the extent of what we can hope for in those locales. I'm not even really banking on that happening. The latest 18Z run of the GFS seems to be a little warmer on the east side of the Apps. I want snow just as much as anyone, but I think this system is for the mountains and our friends on the west side of the Apps.

[strongwxnc]

HAZARDOUS WEATHER OUTLOOK

NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC

403 PM EST MON DEC 5 2011

NCZ033-048>053-058-059-062>065-062115-

AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-

NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-

403 PM EST MON DEC 5 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA.

.DAY ONE...TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

RAIN SHOWERS WILL MIX WITH AND CHANGE OVER TO SNOW SHOWERS ACROSS

THE WESTERN NORTH CAROLINA MOUNTAINS WEDNESDAY NIGHT. SNOWFALL

ACCUMULATIONS OF 1 TO 2 INCHES WILL BE POSSIBLE BY DAYBREAK

THURSDAY...MAINLY OVER HIGHER RIDGES AND PEAKS OF THE SMOKIES...

BALSAMS AND NORTHERN MOUNTAINS NEAR THE TENNESSEE BORDER.

[FoothillsNC]

I'm not sure I buy the sudden weakening shown by GFS and NAM later Wednesday evening, but I didn't stray much from it. A pretty tight and stout system that swings neutral tilt in a good spot for eastern Tennessee and southeast Kentucky, and eventually the mountains of NC, including Asheville. The 850 temps steadily fall in tandem with the approaching 5H strong system, but the system is warming as it crosses the Apps. Overall I'd expect a blossoming of RH right ahead of the system as it crosses northern Alabama and central Tenn late Wednesday when snow or rain snow mix will occur, giving way to snow a couple hours around Huntsville to Nashville. Meanwhile the system develops a surface low over western SC which should develop a decent comma head over eastern Tenn and extreme eastern Ky up into western Va and much of West Virginia where quickly rain will change to snow, from west to east. Heavy rain will be falling in the foothills and piedmont of NC and Upstate SC into central VA during the night as the surface low and cold air aloft comes across, and a period of thunderstorms possible in central NC eventually eastern NC, possibly in Upstate SC as well. The best timing for accumulating snow is in eastern Tennessee just west of the Apps, then into the Apps overnight and in West Virginia...and then into the mountains of NC as a few hours of moderate or even heavy snow before the moisture pulls out. Several inches possible in the mountains and even in the Bristol Johnson City region of Tennessee. Moving east of the mountains in Virginia the low level cold will have a hard time making it across, unlike areas west of the Apps, but the dynamics might be enough in central Va to switch over to brief period of snow right up to DC where this region is on the line of rain/snow. If the dynamics are strong enough or its a little colder than I think, this region will turn to moderate snow but if not, then it could remain mostly rain in the city, but with a brief changeover. For most of NC outside the mountains, very little chance of snow except in possible far northern piedmont very briefly. There's a large bubble of warm air shown in Upstate SC and GA as the 5H system comes across, which shows up a lot in situations like this, so I don't see much snow in the ne GA mountains and virtually zero chance in Upstate SC and piedmont of NC.

For the way this is setting up, it appears the duration, the coldest temps , the orientation of the trough and location relative to maximum lift and dynamics would favor eastern Tn, and especially ne TN and into southern West Virginia as a good spot for the longest period of moderate snow. Then wraparound snow kicks in as well, including NC mountains. Northern VA around DC and into Maryland is another potential bust, with mostly of the precip as snow instead of rain, depends on track and temp profile which can't be nailed down just yet. Systems have been loaded with moisture and this one looks very healthy as it approaches the southern Apps, and I'm not sure why models want to weaken it so quickly east of the mountains, but regardless, north and west of the track is the place to be for a period of snow. If it were slower, it would be a very good snow producer but models are pretty quick with it. Still has some potential esp in the Tenn Valley side and in northern VA as well as most of the southern Apps. Some areas in the mountains of West VA , western VA or ne TN/NC might get 6" quick inches overnight Wednesday night into Thursday.

[MADDOGG]

well atleast we can expect rain.. not the best but it will do just fine

i see the NWS bumped us up to 39 thrusday night, they had us @ 34.. If i had a inch of snow for everytime the NWS was wrong id never see the light of day!

[Local Yokel Wx]

I'm not sure I buy the sudden weakening shown by GFS and NAM later Wednesday evening, but I didn't stray much from it. A pretty tight and stout system that swings neutral tilt in a good spot for eastern Tennessee and southeast Kentucky, and eventually the mountains of NC, including Asheville. The 850 temps steadily fall in tandem with the approaching 5H strong system, but the system is warming as it crosses the Apps. Overall I'd expect a blossoming of RH right ahead of the system as it crosses northern Alabama and central Tenn late Wednesday when snow or rain snow mix will occur, giving way to snow a couple hours around Huntsville to Nashville. Meanwhile the system develops a surface low over western SC which should develop a decent comma head over eastern Tenn and extreme eastern Ky up into western Va and much of West Virginia where quickly rain will change to snow, from west to east. Heavy rain will be falling in the foothills and piedmont of NC and Upstate SC into central VA during the night as the surface low and cold air aloft comes across, and a period of thunderstorms possible in central NC eventually eastern NC, possibly in Upstate SC as well. The best timing for accumulating snow is in eastern Tennessee just west of the Apps, then into the Apps overnight and in West Virginia...and then into the mountains of NC as a few hours of moderate or even heavy snow before the moisture pulls out. Several inches possible in the mountains and even in the Bristol Johnson City region of Tennessee. Moving east of the mountains in Virginia the low level cold will have a hard time making it across, unlike areas west of the Apps, but the dynamics might be enough in central Va to switch over to brief period of snow right up to DC where this region is on the line of rain/snow. If the dynamics are strong enough or its a little colder than I think, this region will turn to moderate snow but if not, then it could remain mostly rain in the city, but with a brief changeover. For most of NC outside the mountains, very little chance of snow except in possible far northern piedmont very briefly. There's a large bubble of warm air shown in Upstate SC and GA as the 5H system comes across, which shows up a lot in situations like this, so I don't see much snow in the ne GA mountains and virtually zero chance in Upstate SC and piedmont of NC.

For the way this is setting up, it appears the duration, the coldest temps , the orientation of the trough and location relative to maximum lift and dynamics would favor eastern Tn, and especially ne TN and into southern West Virginia as a good spot for the longest period of moderate snow. Then wraparound snow kicks in as well, including NC mountains. Northern VA around DC and into Maryland is another potential bust, with mostly of the precip as snow instead of rain, depends on track and temp profile which can't be nailed down just yet. Systems have been loaded with moisture and this one looks very healthy as it approaches the southern Apps, and I'm not sure why models want to weaken it so quickly east of the mountains, but regardless, north and west of the track is the place to be for a period of snow. If it were slower, it would be a very good snow producer but models are pretty quick with it. Still has some potential esp in the Tenn Valley side and in northern VA as well as most of the southern Apps. Some areas in the mountains of West VA , western VA or ne TN/NC might get 6" quick inches overnight Wednesday night into Thursday.

Great write up. I think the upper elevations will do fine say above 3500 - 4000' (especially the Balsams), while those of us in the valley only see it fall. But hey, im not complaining.

[ajaronw10]

Gotta think as long as we can stay in this pattern of getting a good rain basically every week, eventually we'll hit the cold air right for a little snow! We'll see.. What ya think Robert?

[FoothillsNC]

Gotta think as long as we can stay in this pattern of getting a good rain basically every week, eventually we'll hit the cold air right for a little snow! We'll see.. What ya think Robert?

Probably. All these upper lows lately , and another one producing more snow for Tenn, Ms, Al, Ky, NC and the Apps by Wednesday night. Colder air is available more and more since we're only getting deeper into Winter, by January we'll get hit most likely.

[tnweathernut]

Robert,

Thank you for your time in detailing all these systems. I am skeptical of snow here in Johnson City, our elevation is around 1650 here. It looks to me like areas above 2500 feet will have a much better shot at a couple of quick inches. Who knows though, I guess if it doesn't weaken as much as shown anything is possible.

It is pretty remarkable that with all this no cold and no pattern change talk there is the chance for a second southeast/midsouth snow before December 10th.........

[ajaronw10]

Probably. All these upper lows lately , and another one producing more snow for Tenn, Ms, Al, Ky, NC and the Apps by Wednesday night. Colder air is available more and more since we're only getting deeper into Winter, by January we'll get hit most likely.

I hope so! It'd be nice to get atleast one good snow this year!.. Think we might have a better shot of getting a good snow or an ice storm this year?

[Reb]

My call:

[FoothillsNC]

Robert,

Thank you for your time in detailing all these systems. I am skeptical of snow here in Johnson City, our elevation is around 1650 here. It looks to me like areas above 2500 feet will have a much better shot at a couple of quick inches. Who knows though, I guess if it doesn't weaken as much as shown anything is possible.

It is pretty remarkable that with all this no cold and no pattern change talk there is the chance for a second southeast/midsouth snow before December 10th.........

Still think northeast Tenn is sitting pretty for a quick couple inches on this , and not just in the mtns. The 850 low by 48 hours is in western NC, putting ne TN in a good spot, and you've got the temps. Added lift from upslope and being in the best quadrant for quick lift should drop large fluffy flakes for a good 3 to 4 hours or so.

[Met1985]

I'm not sure I buy the sudden weakening shown by GFS and NAM later Wednesday evening, but I didn't stray much from it. A pretty tight and stout system that swings neutral tilt in a good spot for eastern Tennessee and southeast Kentucky, and eventually the mountains of NC, including Asheville. The 850 temps steadily fall in tandem with the approaching 5H strong system, but the system is warming as it crosses the Apps. Overall I'd expect a blossoming of RH right ahead of the system as it crosses northern Alabama and central Tenn late Wednesday when snow or rain snow mix will occur, giving way to snow a couple hours around Huntsville to Nashville. Meanwhile the system develops a surface low over western SC which should develop a decent comma head over eastern Tenn and extreme eastern Ky up into western Va and much of West Virginia where quickly rain will change to snow, from west to east. Heavy rain will be falling in the foothills and piedmont of NC and Upstate SC into central VA during the night as the surface low and cold air aloft comes across, and a period of thunderstorms possible in central NC eventually eastern NC, possibly in Upstate SC as well. The best timing for accumulating snow is in eastern Tennessee just west of the Apps, then into the Apps overnight and in West Virginia...and then into the mountains of NC as a few hours of moderate or even heavy snow before the moisture pulls out. Several inches possible in the mountains and even in the Bristol Johnson City region of Tennessee. Moving east of the mountains in Virginia the low level cold will have a hard time making it across, unlike areas west of the Apps, but the dynamics might be enough in central Va to switch over to brief period of snow right up to DC where this region is on the line of rain/snow. If the dynamics are strong enough or its a little colder than I think, this region will turn to moderate snow but if not, then it could remain mostly rain in the city, but with a brief changeover. For most of NC outside the mountains, very little chance of snow except in possible far northern piedmont very briefly. There's a large bubble of warm air shown in Upstate SC and GA as the 5H system comes across, which shows up a lot in situations like this, so I don't see much snow in the ne GA mountains and virtually zero chance in Upstate SC and piedmont of NC.

For the way this is setting up, it appears the duration, the coldest temps , the orientation of the trough and location relative to maximum lift and dynamics would favor eastern Tn, and especially ne TN and into southern West Virginia as a good spot for the longest period of moderate snow. Then wraparound snow kicks in as well, including NC mountains. Northern VA around DC and into Maryland is another potential bust, with mostly of the precip as snow instead of rain, depends on track and temp profile which can't be nailed down just yet. Systems have been loaded with moisture and this one looks very healthy as it approaches the southern Apps, and I'm not sure why models want to weaken it so quickly east of the mountains, but regardless, north and west of the track is the place to be for a period of snow. If it were slower, it would be a very good snow producer but models are pretty quick with it. Still has some potential esp in the Tenn Valley side and in northern VA as well as most of the southern Apps. Some areas in the mountains of West VA , western VA or ne TN/NC might get 6" quick inches overnight Wednesday night into Thursday.

Great right up! sounds like i could be in for a good snow! I love these systems! You could get dumped on or just a few snow showers. Living at 3500 feet makes this even better and along the TN/NC boarder hopefully we can get some good NNW flow coming in with on and off snow showers.

[tnweathernut]

My call:

Now THAT is an aggressive snow map! I think it might be a bit too aggressive but i give you an A for it being real pretty. Hope you verify and thanks for your time in putting it together.

[Lee]

Robert,

Thank you for your time in detailing all these systems. I am skeptical of snow here in Johnson City, our elevation is around 1650 here. It looks to me like areas above 2500 feet will have a much better shot at a couple of quick inches. Who knows though, I guess if it doesn't weaken as much as shown anything is possible.

It is pretty remarkable that with all this no cold and no pattern change talk there is the chance for a second southeast/midsouth snow before December 10th.........

Well, if you're buying into most the local Mets forecasts, that's the deal; not much forecasted. I am surprised in light of the 12z runs today, that KMRX still isn't making much of it, even for the higher elevations.? It's as if they are still going with the early morning runs. I'm rather puzzled. I know many of them there and they are very good Mets..There are some newbies of late. Maybe that's the prob..

As far as our other local outlet mets; watched one this evening and they were clearly showing this mornings model run, when they did the Model animation forecast.

[MOD]

My call:

This may be a great first call as the 0Z American models have shifted this ever so slightly towards the coast. GFS model has a slight dusting over extreme northwestern Triad now (haven't look at actual sounding for run). Any more shift in track may allow more of us to at least see the first flakes of the season.

[Reb]

I might need to extend the northern sections of my map a bit east for my final call

[griteater]