FoothillsNC Posted January 23, 2011 Share Posted January 23, 2011 The GFS is very close to NAM through 84 hours, except its a smidge warmer. As with these types of systems, they're probably harder to forecast than any other. If you say "no snow" in a certain spot, then usually the opposite happens, you just can't pinpoint where. But strong dynamics usually do this very thing, play havoc on forecasts. Oddly, this GFS run doesn't get much qpf to Tenn, except the very eastern part. If temps were colder, it would be a heck of a lot easier, but as it is now, you have to be on the northwest part of the upper low at 850 to even have a chance, so atleast we can nail that part down probably. It goes from central Al to roughly south of ATL to near CAE to eastern NC, on most models. Next, the models probably aren't handling dynamic cooling enough yet, but there's hints at it with the pockets of sub zero 850's but overall this is a slightly warmer than normal cutoff low, even for January, which is odd. So, not every place to the northwest of the 850 low is going to get snow, but it will probably come down to 1) elevation and 2) rates. The NAM and GFS have strong UVV crossing in tandem with the cooling 850's across the extreme N. Ga mtns and the western Carolinas, so my area for the greatest chance of snow would still probably in general go from ne Alabama to the mtns of NC, with a safety net from Shreveport to CHA to CLT to RDU line, but once east of the mountains its even harder to predict at this hour since were over 72+ hours. Link to comment Share on other sites More sharing options...
Lookout Posted January 23, 2011 Share Posted January 23, 2011 Well, here's something you probably didnt see since i posted it in the middle of the night: Ok, here's what I was talking about. This is for KFQD(Rutherfordton, NC): This is through 6z wednesday: Temperature to start out with is 38º, 850's are at 0.5. Then temps fall to 0.5C at the height of the precip with the warmest 850 temp at 1.2C. .67 falls during the evening and early part of the night. From 6z wednesday on: The temperature is still at 33º with 850 temps of -2.1C. By then, an additional .31 has fallen during the late night/early morning hours. The temp does warm up to around 37 or 38 or so during the afternoon with .21 falling between 12z and 18z. It's almost like the euro is trying to tell us this is a rate dependent storm system. Interesting, thanks. Maybe they are close enough to the mountains to benefit. Rest of nc on the euro though surely isn't close. I do wonder if the deformation axis can be strong and persistent enough in any location that maybe..just maybe..something rare could happen and it could briefly reach the lower elevations for a few hours. But it has to be very intense with very strong lift for it to happen. It's a long shot though because surface/boundary layer temps are so warm but I can't completely rule it out. If the boundary layer started off just a few degrees colder it would be a much better shot..but 40? I wouldn't bet the farm on it. 12z gfs does offer some hope for some in nc, mainly rdu to gso as it shows a nearly isothermal profile in these locations. Would be an extremely wet snow with low ratios. Still looks too warm elsewhere though. Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted January 23, 2011 Author Share Posted January 23, 2011 12z GFS looks close but no cigar for those in the Western part of North Carolina (west of Hickory). Looking at the soundings for both Asheville and Morganton-Lenoir at 72 hours... from about 750mb to the surface it's anywhere from .5 to 1 degree above freezing. Then finally at 84 it crashes into the critical values but the precip is sliding out. Folks...this is painful to see how close it is. A 1 degree difference in that layer of the atmosphere would be a HUGE difference. Link to comment Share on other sites More sharing options...
packbacker Posted January 23, 2011 Share Posted January 23, 2011 Interesting, thanks. Maybe they are close enough to the mountains to benefit. Rest of nc on the euro though surely isn't close. 12z gfs does offer some hope for some in nc, mainly rdu to gso as it shows a nearly isothermal profile in these locations. Would be an extremely wet snow with low ratios. Still looks too warm elsewhere though. I keep forgetting that, the ratio's would be like 5 to 1, but it's better than nothing I guess. Link to comment Share on other sites More sharing options...
Cheeznado Posted January 23, 2011 Share Posted January 23, 2011 This is a good trend folks- if the next run is a bit deeper then from the northern part of ATL NE there could be a brief but intense period of heavy wet snow. Even with marginal temps the GFS snow product cranks out some accumulations: If the Euro comes in and is as deep or deeper, we have a shot at at least some snow. Link to comment Share on other sites More sharing options...
triadwx Posted January 23, 2011 Share Posted January 23, 2011 Wow, this is all painfully close. Better than yesterday evening, warm rain though. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 23, 2011 Share Posted January 23, 2011 UKMET takes LP up through north-central AL http://vortex.plymouth.edu/gifs/110123162339.gif Link to comment Share on other sites More sharing options...
FoothillsNC Posted January 23, 2011 Share Posted January 23, 2011 Yeah but the surface doesn't look good at all. Looks like low 40s and rain to me. I hope that's wrong! Even with dynamic cooling you'd still need surface temps to be within the ball park of freezing. I don't know if dynamic cooling can overcome such a warm start. The delay in the storm and the HP sliding out is what's killing it. I wouldn't trust those surface temps at all. We have high pressure to the north and northwest, low in south GA and due north winds at the surface. Even in October, thats 30's for us at the surface. Link to comment Share on other sites More sharing options...
WSNC Posted January 23, 2011 Share Posted January 23, 2011 Thanks Foothills. I was wondering why no one was discussing the weak highs to the north of the system. Looks like they are building in behind the departing GL low off the NE coast. I like the trends and expect them to continue. Link to comment Share on other sites More sharing options...
NEGa Posted January 23, 2011 Share Posted January 23, 2011 This is a good trend folks- if the next run is a bit deeper then from the northern part of ATL NE there could be a brief but intense period of heavy wet snow. Even with marginal temps the GFS snow product cranks out some accumulations: If the Euro comes in and is as deep or deeper, we have a shot at at least some snow. lol - just a most of us area getting pessimistic, cheez comes back with some optimism! one thing for sure, unlike the last storm anything that falls doesnt look to hang around too long for most folks Link to comment Share on other sites More sharing options...
LovingGulfLows Posted January 23, 2011 Share Posted January 23, 2011 This is a good trend folks- if the next run is a bit deeper then from the northern part of ATL NE there could be a brief but intense period of heavy wet snow. Even with marginal temps the GFS snow product cranks out some accumulations: If the Euro comes in and is as deep or deeper, we have a shot at at least some snow. That looks very similar to the swath of snow from March, 1st 2009. Link to comment Share on other sites More sharing options...
AirNelson39 Posted January 23, 2011 Share Posted January 23, 2011 12z GFS looks close but no cigar for those in the Western part of North Carolina (west of Hickory). Looking at the soundings for both Asheville and Morganton-Lenoir at 72 hours... from about 750mb to the surface it's anywhere from .5 to 1 degree above freezing. Then finally at 84 it crashes into the critical values but the precip is sliding out. Folks...this is painful to see how close it is. A 1 degree difference in that layer of the atmosphere would be a HUGE difference. I'll take my chances that this trends 1-2 dedgrees colder here in the foothills the next 2 days. I see an ever so slightly trend the last 24 hours. Link to comment Share on other sites More sharing options...
FoothillsNC Posted January 23, 2011 Share Posted January 23, 2011 The GFS is colder at the surface than I first thought. Here's Wednesday 72 hour, 78, and 84: Link to comment Share on other sites More sharing options...
Carvers Gap Posted January 23, 2011 Share Posted January 23, 2011 If the slp tracks where the models are projecting them(somewhere through the central south), there should be plenty of qpf in middle and east TN. It is truly unreal how wildly the models are varying. It's almost like they are waffling between a strung out system and an intense slp that bombs out of the GOM. Link to comment Share on other sites More sharing options...
triadwx Posted January 23, 2011 Share Posted January 23, 2011 If the slp tracks where the models are projecting them(somewhere through the central south), there should be plenty of qpf in middle and east TN. It is truly unreal how wildly the models are varying. It's almost like they are waffling between a strung out system and an intense slp that bombs out of the GOM. This is definitely going to be a nowcasting event, I hope all the time that I have watched this thing will actually not go to waste.. Link to comment Share on other sites More sharing options...
lilj4425 Posted January 23, 2011 Share Posted January 23, 2011 This is definitely going to be a nowcasting event, I hope all the time that I have watched this thing will actually not go to waste.. It will be rain just like always. These type of systems never work out in our favor. Link to comment Share on other sites More sharing options...
triadwx Posted January 23, 2011 Share Posted January 23, 2011 It will be rain just like always. These type of systems never work out in our favor. Thats what they said in March 09. Ended up with 9" in 6 hours. Im still going to watch, lol. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 23, 2011 Share Posted January 23, 2011 12z Canadian. Apps runner http://www.weatherof...ast/478_100.gif Link to comment Share on other sites More sharing options...
phil882 Posted January 23, 2011 Share Posted January 23, 2011 thanks. At 66 hours a pocket of 0 @850 develops over part of the NC mountains. I mentioned yesterday I think that models would see some dynamic and evap. cooling there so thats probably whats going on. If you look at the distance between the 0 and the +4 line, its a large distance , so many areas bound between I-20 and I-40 in the Southeast are around +2 to +3 at 850 for much of the event, thats not warm, its too warm generally for snow, but with elevation and some enhanced cooling, the mtns would be a good candidate for snow in that setup. Its hard to find the slp. in the NAM at 72 hours. Probably southeast GA. By then the nw section of the storm in TN and Miss. has turned to snow. The 5H still hasn't closed off. I don't recall if other runs closed it off fully though. Looking at BUFKIT, KAVL starts off as snow from 11pm Tuesday night... we switch over to rain at around 2-3am, but when the deformation band moves overhead, we switch back to snow at 12pm and NAM at that point drops about 8 inches here. Adiabatic Lift (which is a cooling process) is going to pay a very pivotal role in the mountains of NC, which can offset some of the WAA the 850mb low throws are way. That is largely what helped us during the early December snowstorm that you were spot on over here. My analysis on this NAM run: Its mostly a Gulf low that takes the traditional Winter storm track across FL panhandle to GA coast then Wilmington. Now, its unfortunate it doesn't have a lot of cold air, even on the west side. But this track will allow dynamic cooling. The 850 low track begins around eastern Alabama and crosses ATL then follows Interstate 85. That track, even with marginal temps, will pound northeast Alabama, northern GA and the mtns and foothills with heavy, wet snow, under a solid , rotating band of deformation snow. The temps are probably barely going to be cold enough, but as the suface low is at the coast, and the 5H system in a good spot in South GA and translates to a closed low crossing SC and to NC coast. This should allow just enough cold air to be dynamically cooled with extreme lift (the vort is top of the chart!), so if it doesn't snow hard in a line from Ne Ala/se TN and points northeast across the Southern Apps, I'd shred my Met diploma. But, this all based on this run of the NAM, it does resemble the Euro for several runs, and where I am leaning as far as the overall setup. Its a very slow mover, good precip producer, and for some folks in Ms,Tn, Al, Ga Sc, NC and VA mostly north and west of the 850 low, there will be both heavy rain and then heavy snow. If this run of the NAM is close to right, a (maybe) devastating heavy wet snow would hit some areas of the Srn. Apps region roughly anywhere from Ne. Ala/est TN/extreme N. GA/Wrn Carolinas/VA. The comma head showing up is harsh , and may stretch into the piedmont of NC. Again, this is my analysis of the NAM. It looks reasonable, and jives with the Euro. I am particularly concerned about the Southern Appalachians... the December 18th-19th storm here last year was devastating, and even that pales in comparison to the massive dump we got on January 27th, 1998. Both events had pretty high SLC with ratios around 6:1 to 10:1. This even looks very similar, and with such heavy precipitation rates, I'm very concerned about falling trees. The GFS is very close to NAM through 84 hours, except its a smidge warmer. As with these types of systems, they're probably harder to forecast than any other. If you say "no snow" in a certain spot, then usually the opposite happens, you just can't pinpoint where. But strong dynamics usually do this very thing, play havoc on forecasts. Oddly, this GFS run doesn't get much qpf to Tenn, except the very eastern part. If temps were colder, it would be a heck of a lot easier, but as it is now, you have to be on the northwest part of the upper low at 850 to even have a chance, so atleast we can nail that part down probably. It goes from central Al to roughly south of ATL to near CAE to eastern NC, on most models. Next, the models probably aren't handling dynamic cooling enough yet, but there's hints at it with the pockets of sub zero 850's but overall this is a slightly warmer than normal cutoff low, even for January, which is odd. So, not every place to the northwest of the 850 low is going to get snow, but it will probably come down to 1) elevation and 2) rates. The NAM and GFS have strong UVV crossing in tandem with the cooling 850's across the extreme N. Ga mtns and the western Carolinas, so my area for the greatest chance of snow would still probably in general go from ne Alabama to the mtns of NC, with a safety net from Shreveport to CHA to CLT to RDU line, but once east of the mountains its even harder to predict at this hour since were over 72+ hours. The NCEP maps don't paint the whole picture with the GFS. There are a lot of locations just to the west of the 850mb low that rapidly fall below freezing by 78 hours. Per the plymouth maps, folks in GSP, HKY, up to Winston-Salem seem to changeover as the heaviest deformation band precipitation moves overhead. Link to comment Share on other sites More sharing options...
weatherheels Posted January 23, 2011 Share Posted January 23, 2011 Northern ATL, snow? There is no way, it is not even close. I don't see anyone east of INT getting more than a passing flake at the very end, and even that is unlikely. The GFS snowfall map does not correspond well at all to the locations that are cold enough for snow, when investigating the soundings. For example, ATL is never even close to snow while there is sufficient saturation in the column, nor is GSP, CLT, GSO, or even HKY. As a MET you shouldn't use phrases like "there is no way", because people take you literally. There is always a chance, even if it is only very slim. But I personally would like to thank you for keeping it real. I haven't read much from you but it seems like you cut through the bs to the heart of what is more than likely going to happen. I look forward to your disco and forecast in the future and I'm excited to see if this one turns out like you think it will, I hope not Link to comment Share on other sites More sharing options...
FoothillsNC Posted January 23, 2011 Share Posted January 23, 2011 Thats what they said in March 09. Ended up with 9" in 6 hours. Im still going to watch, lol. were you in Shelby for that one? It was forecast to change to snow, pretty far in advance, but don't recall 9" being forecast. Upper lows have suprises everytime. Looking at BUFKIT, KAVL starts off as snow from 11pm Tuesday night... we switch over to rain at around 2-3am, but when the deformation band moves overhead, we switch back to snow at 12pm and NAM at that point drops about 8 inches here. Adiabatic Lift (which is a cooling process) is going to pay a very pivotal role in the mountains of NC, which can offset some of the WAA the 850mb low throws are way. That is largely what helped us during the early December snowstorm that you were spot on over here. the worst part about chances east of the mountains is probably time of day. I know its only January, but with temps mid 30's at the surface it will really have to come down in buckets to accumulate, and thats going to be hard to forecast this far out. But atleast the NAM and GFS have that band, I just wish they showed it to start much earlier. Link to comment Share on other sites More sharing options...
phil882 Posted January 23, 2011 Share Posted January 23, 2011 Looking at the soundings for GSP, they are never supportive of snow. At 78 hours, GSP has a 950 temp of 2.7C, and a surface temp of 2.5C. At 84, the column is no longer saturated in the dendritic growth zone or below. I don't know if you are looking at the same sounding I am, but I believe the GFS soundings might be erroneousness near the surface... falsely portraying drying when there should be none at 78 hours. If the lower level temps wet bulb down, this is close to a wet snow sounding. With all the diabatic cooling due to melting snow aloft, this could easily turn into heavy snow. P.S.... what in the world is going on with the hodograph... looks like some kid just doodled circles. Are the winds really going to be that chaotic? Link to comment Share on other sites More sharing options...
triadwx Posted January 23, 2011 Share Posted January 23, 2011 were you in Shelby for that one? It was forecast to change to snow, pretty far in advance, but don't recall 9" being forecast. Upper lows have suprises everytime. Yep, I lived in Shelby 9 years before moving here back in August. That was one hell of a storm. Link to comment Share on other sites More sharing options...
eyewall Posted January 23, 2011 Share Posted January 23, 2011 With the date in mind and the horrible timing / setup I am dubbing this one the Carolina Crusher of Dreams for now (for those east of the mountains). I just think it is not be with this for much of the same reasons bnmdjm has been pointing out. It is frustrating as hell to accept that but that is reality. I think it is time to look ahead and see what February might bring for the most part. Link to comment Share on other sites More sharing options...
NCBlizzard Posted January 23, 2011 Share Posted January 23, 2011 Thats what they said in March 09. Ended up with 9" in 6 hours. Im still going to watch, lol. Yea I ended up with 8" and it changed to snow in the blink of an eye. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 23, 2011 Share Posted January 23, 2011 I keep noticing the HP's building out to the W and NW on the GFS. I wonder what would happen to surface temps if we keep slowing down. Link to comment Share on other sites More sharing options...
NavarreDon Posted January 23, 2011 Share Posted January 23, 2011 Looking at BUFKIT, KAVL starts off as snow from 11pm Tuesday night... we switch over to rain at around 2-3am, but when the deformation band moves overhead, we switch back to snow at 12pm and NAM at that point drops about 8 inches here. Adiabatic Lift (which is a cooling process) is going to pay a very pivotal role in the mountains of NC, which can offset some of the WAA the 850mb low throws are way. That is largely what helped us during the early December snowstorm that you were spot on over here. I am particularly concerned about the Southern Appalachians... the December 18th-19th storm here last year was devastating, and even that pales in comparison to the massive dump we got on January 27th, 1998. Both events had pretty high SLC with ratios around 6:1 to 10:1. This even looks very similar, and with such heavy precipitation rates, I'm very concerned about falling trees. Phil, I was just telling some co-workers this storm could be similar to the Dec. 18-19 storm. After the flow I ended up with 17". From the initial we got 14.5". There were alot of weak branches & trees that came down. My road looked like a war zone. Lost power for 3 days with no generator. Looks like from the bufkit we are going to have a longer period of rain with this one. One to watch in the Mnts. for sure! Link to comment Share on other sites More sharing options...
triadwx Posted January 23, 2011 Share Posted January 23, 2011 Yea I ended up with 8" and it changed to snow in the blink of an eye. I remember looking up and all of the sudden seeing white, then it hit the ground. No mix, it went from rain to snow. Link to comment Share on other sites More sharing options...
NCBlizzard Posted January 23, 2011 Share Posted January 23, 2011 I remember looking up and all of the sudden seeing white, then it hit the ground. No mix, it went from rain to snow. Yea it was heavy rain and then all of a sudden everything was white. It was the heaviest snow i've ever seen, but it came through late evening into the night whereas this one looks to come through through the early afternoon. Link to comment Share on other sites More sharing options...
chapelhillwx Posted January 23, 2011 Share Posted January 23, 2011 Yea it was heavy rain and then all of a sudden everything was white. It was the heaviest snow i've ever seen, but it came through late evening into the night whereas this one looks to come through through the early afternoon. I would expect the onset to delay by at least a few more hours. Remember, this storm was initially modeled as a Monday-Tuesday system. Link to comment Share on other sites More sharing options...
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