FoothillsNC Posted March 25, 2011 Share Posted March 25, 2011 I'm not saying its a definite, and the probabilities are still roughly 50% in my estimation, but I don't see any snow forecast for outside of VA, however if the NAM is right, its going to be extremely close for the northern mountains of NC on Saturday and Sat. Night. Right now its a little south of the GFS, but close to the ECMWF at those time ranges and all models are close on the 850 temps, the GFS slightly warmer thanks to a more north track of the 850 low. All in all, I thought its worth a mention for those folks above 4000 feet especially, and my main area of interest is Avery, Watauga and Ashe Counties in NC, but the adjoing ridges of ne Tn and possibly the higher mtns just northeast of AVL could get some snow or mix as well, early on. But the NAM has very strong damming and overrunning maximized right over the areas mentioned, in addition to Wva and central and southwestern VA, where the colder air is deeper, but NC's mtns are higher so it's offset. In my experience, if its a razor close call for snow versus rain in that area, the snow usually wins out, regardless of month, but not always. Time of day is def. a neg. factor. If the ultra tight 850 gradient on temps is off either way, just a little, the forecast would change drastically. The surface winds should become easterly, slightly ne, which helps with upslope cooling in the counties mentioned, esp. eastern ridges, and the temp profile from surface up to 850 are all close to freezing but slightly above at 850 except extreme nw NC near Ashe County, but the warm advection on NAM is neutral , with temps only getting to + 2 or 3 for the heart of the event, then +4 at the end, but by then over 1" liquid equivalent has fallen. So thats an extremely close call for a heavy wet snow above 4000 feet. None of the models handled the rain now in western TN and Ky well, but the NAM temps at 850 verified better and colder than the GFS during the 12z initializations. GFS just a degree or two too warm, and that could make a difference. Thought this was worth mentioning in case it does happen tomorrow, but no guarantees. Most will still see a very cold rain, even in the mountains but around 4k feet I think it could be a big wet snow, esp. in Watauga and Avery counties. Link to comment Share on other sites More sharing options...
Lookout Posted March 25, 2011 Share Posted March 25, 2011 Good post robert. This sort of all caught me by surprise because I haven't been following it that closely, other than quickly glancing precip totals on the ncep site. But The nam's 850mb temp gradient is amazing across the nc mountains with 0c in the areas you mentioned to plus 10c around asheville. As you said, the slightest change would either make it much much warmer or much colder in the mountains. Doesn't get much more tightly packed than this. Link to comment Share on other sites More sharing options...
Lee Posted March 25, 2011 Share Posted March 25, 2011 Dam* good post! Regardless what "others" apparently are thinking, this warrants attention for areas you mention without a doubt. It seems most every outlet is following the GFS with this by the looks of their outlooks(that along with personal bias, adjusting to climo,etc.). The Nam's continued depiction of this scenario,run after run, bears some respect,i.m.o.. AND, if it's depiction comes to fruition,AND, there is still the slight warm bias with it, some unexpected heavy snow will fall in the area's Robert mentioned . Link to comment Share on other sites More sharing options...
nchighcountrywx Posted March 25, 2011 Share Posted March 25, 2011 Thanks Robert. I would like to have one more snow before spring sets in. Lot of warm weather to work through before October. Link to comment Share on other sites More sharing options...
SnoJoe Posted March 25, 2011 Share Posted March 25, 2011 Bring it ! It's been a while since we've had several inches of that spring Carolina Cement. Mountain Mortar. Biscuit Batter. High Country Cake Mix. Gorge Goo. Appalachian Applesauce................... Ok, I'll stop. Link to comment Share on other sites More sharing options...
SnoJoe Posted March 26, 2011 Share Posted March 26, 2011 Bring it ! It's been a while since we've had several inches of that spring Carolina Cement. Mountain Mortar. Biscuit Batter. High Country Cake Mix. Gorge Goo. Appalachian Applesauce................... Ok, I'll stop. Peak Pudding.... ...Last one, promise. Link to comment Share on other sites More sharing options...
SnoJoe Posted March 26, 2011 Share Posted March 26, 2011 Foothill Fudge.......... ..............,...........C'mon, that's a good one, I had too. Link to comment Share on other sites More sharing options...
EmersonGA Posted March 26, 2011 Share Posted March 26, 2011 A little heavy on the single malt tonight Joe? Link to comment Share on other sites More sharing options...
SnoJoe Posted March 26, 2011 Share Posted March 26, 2011 A little heavy on the single malt tonight Joe? [/quote/] Scotch isn't a single malt, it's brewed with only one grain, barley! Jeez. Anyhow, Robert, I totally hijacked your thread and that's very inconsiderate and rude. I'm sorry. Link to comment Share on other sites More sharing options...
FoothillsNC Posted March 26, 2011 Author Share Posted March 26, 2011 Foothill Fudge.......... ..............,...........C'mon, that's a good one, I had too. A little heavy on the single malt tonight Joe? [/quote/] Scotch isn't a single malt, it's brewed with only one grain, barley! Jeez. Anyhow, Robert, I totally hijacked your thread and that's very inconsiderate and rude. I'm sorry. thats ok, seeing how its not panning out. Whats your temps? The NAM looks like its erring on the cold side, the GFS is probably a safer bet, but I'd keep an eye on Monday for another slight chance, as the cold air may press just enough, still a long shot though. And late next week on the backend of whatever system comes through then. Enjoy your barley. Link to comment Share on other sites More sharing options...
NGTim Posted March 26, 2011 Share Posted March 26, 2011 I'm certainly hoping for the late week system. Was planning on doing a chase in late Feb or March, but didn't get the chance. A Friday scenario would work out great. Keep us posted. Link to comment Share on other sites More sharing options...
SnoJoe Posted March 26, 2011 Share Posted March 26, 2011 Been pretty well holding steady between 38 and 40 for the last 24 hours. Lots of mist and drizzle around. Makes for a nasty day. Link to comment Share on other sites More sharing options...
nchighcountrywx Posted March 26, 2011 Share Posted March 26, 2011 Was 30 to 32 above 5000'over here in Avery between 8am and 11 this morning but has risen to 34 to 35 now. Link to comment Share on other sites More sharing options...
FoothillsNC Posted March 27, 2011 Author Share Posted March 27, 2011 the first event came and went, without much except some sleet along the NC/VA border. Next up, is a much better chance. All models including SREF, GFS NAM have the colder air further south, and the moisture quickly returning overnight. This will be a faster mover, but once again probably a tight gradient in precip. I'm not sure even now how far north the strip of moisture will get, and if it doesn't get far enough north of I-40 into the colder air, again the snow won't occur. But theres enough evidence that it will get squarely into the northwestern third of NC, where the temps. profile through the column and the time of day, along with good rates and atleast some evap. cooling in the mid levels, will allow it to fall as snow. My best guess is the northern and central mtns of NC, northeast TN and into northwest piedmont and foothills of NC during the dawn to post-dawn hours. During the day this system rockets east, but it may be just cold enough anywhere north of 40 to bring snow, if all the factors come together, just about to the RDU area. The UVV's are impressive on RUC and theres'a weak 850 low circulation showing to develop right before dawn in between AVL and the GSP region, which is about the perfect position IF there is enough cold air, for a snow burst along the escarpment of the Apps from AVL Boone Lenoir Hickory to Winston. Beyond this, the circulation weakens quickly, but i'm not sure it will play out like that, couild be some terrain and lee trough play going on to cause that. Sometimes there is a good enhancement and strong snow rates for a few hours, which will further cool the column. The biggest unknowns now are more the placement of the QPF field, moreso than the temps. The NAM is the cold outlier again, having the 850 drop into the Upstate, but it does have a little support from the WRF model, which also is strong with a 850 low circulation ahead of the flat but stout 5H wave in Eastern TN. Still, pretty amazing to see snow outside the mountains of NC in late March, and I firmly believe there will in fact be snow, atleast falling if not accumulating, outside the mountains with this one. The model to watch now is RUC, and its moisture and temp placement so far through 18 hours is similar to NAM or a blend of GFS and NAM, which looks reasonable...again placing I-40 in NC, andpoints north , as the place to watch. The time of day and the location of the best moisture axis and rates, and thermal profile led me to believe just north of HKY to near INT and back toward Avery /Watauga counties as the best possible targets of real accum snow, but again the radar overnight will show how this plays out. Link to comment Share on other sites More sharing options...
phil882 Posted March 27, 2011 Share Posted March 27, 2011 Great discussion Robert! While I agree that the RUC is the model to watch at this point... note that it does not appear to be handling the precipitation very well currently developing across Arkansas. In fact, no model seems to have a clue with regard to the convective towers going up right now. RUC shows little convective development occurring for the next 3-6 hours, so if the current convection continues to persist and expand further, this should be a major red flag that we can expect heavier precipitation upstream. Deep convection like this produces latent heat which aids in cyclogenesis if widespread enough... a process that was a main factor is causing the January 2000 Carolina crusher. The models in that case significantly under-forecasted the amount of convective development that occurred over Georgia and Alabama around 12 hours before the even was underway for Raleigh, NC. Ultimately, this might prove to be the difference between having moderate precipitation that is not quite heavy enough to bring down those snow levels, or very heavy precip. that will produce enough melting aloft to get those snowflakes to the surface, even outside of the mountains. While this event is no Carolina Crusher... the positive feedback loop caused by convective development must be taken into account, especially when computer models seem to under forecast such an event. Link to comment Share on other sites More sharing options...
FoothillsNC Posted March 28, 2011 Author Share Posted March 28, 2011 the NAM and GFS have blown the forecast badly from just 6 to 12 hours out, in areas around Mississippi, Arkansas and western Tenn. Here's the current radar, where not much should be. It looks like the models were/are too late in developing the precip, a sure sign or a more energetic system. Downstream, for NC and VA, I won't be surprised at all if by dawn snow is falling extremely heavily in my shaded white zone. But the convection is always the X factor, esp. east of the Apps, for example last night when thunderstorms were abundant in the 42 degree air. If youre in the snow threat zone, keep an eye on the radars tonight and early AM. Any elevated convection can turn the rain to snow in a real hurry, in and around the area that is currently threshold. NAM event total: Link to comment Share on other sites More sharing options...
ncjoaquin Posted March 28, 2011 Share Posted March 28, 2011 I'll be up at 1:15 AM, so if the snow makes it this far west, I will be up to see it. I hope it snows east of here, but I would hate to miss probably(but who knows) the last chance of the year. Link to comment Share on other sites More sharing options...
NavarreDon Posted March 28, 2011 Share Posted March 28, 2011 I'll be up at 1:15 AM, so if the snow makes it this far west, I will be up to see it. I hope it snows east of here, but I would hate to miss probably(but who knows) the last chance of the year. Good luck to those that want snow! Looks like we may be on the outside looking in. Link to comment Share on other sites More sharing options...
Weather Czar Posted March 28, 2011 Share Posted March 28, 2011 Good luck to those that want snow! Looks like we may be on the outside looking in. Maybe until Friday, that system looks interesting. Link to comment Share on other sites More sharing options...
phil882 Posted March 28, 2011 Share Posted March 28, 2011 I'll be up at 1:15 AM, so if the snow makes it this far west, I will be up to see it. I hope it snows east of here, but I would hate to miss probably(but who knows) the last chance of the year. Good luck to those that want snow! Looks like we may be on the outside looking in. How are you guys looking temperature wise... I'm stuck now at 43.2 degrees and it hasn't budged for the last hour or so. Once again the folks already in the upper 30's with the low 30's dewpoints are sitting much better in my opinion. Link to comment Share on other sites More sharing options...
NavarreDon Posted March 28, 2011 Share Posted March 28, 2011 How are you guys looking temperature wise... I'm stuck now at 43.2 degrees and it hasn't budged for the last hour or so. Once again the folks already in the upper 30's with the low 30's dewpoints are sitting much better in my opinion. 42.6 here Phil. My wet bulb is 40.2 last wind dir was wnw. I am def. not an expert but imo it doesn't look good for us. I haven't looked at the Fri. system Weather Czar posted about so maybe there is some hope left. May is coming quick will you be leaving Asheville after that? Link to comment Share on other sites More sharing options...
calculus1 Posted March 28, 2011 Share Posted March 28, 2011 It seems we have two threads for the same system. Which one are we using? Link to comment Share on other sites More sharing options...
phil882 Posted March 28, 2011 Share Posted March 28, 2011 42.6 here Phil. My wet bulb is 40.2 last wind dir was wnw. I am def. not an expert but imo it doesn't look good for us. I haven't looked at the Fri. system Weather Czar posted about so maybe there is some hope left. May is coming quick will you be leaving Asheville after that? It all depends on those coveted grad school assistantships. If I get one... I'm likely not staying in Asheville. However, if its not to be... I just might look for a job at NCDC or within the NWS. So no guarantee I'm heading out of Asheville just yet Link to comment Share on other sites More sharing options...
NavarreDon Posted March 28, 2011 Share Posted March 28, 2011 It all depends on those coveted grad school assistantships. If I get one... I'm likely not staying in Asheville. However, if its not to be... I just might look for a job at NCDC or within the NWS. So no guarantee I'm heading out of Asheville just yet Good Luck for sure! If you go you will have to keep up with Asheville weather & throw us a bone every so often. Link to comment Share on other sites More sharing options...
FoothillsNC Posted March 28, 2011 Author Share Posted March 28, 2011 The 00z NAM continues to miss the rain thats developed since this afternoon. Its totals look too light based on whats developing. Still think north of 40 is the best spot for the best chance of snow with this in the morning. Any convection could radically change things locally. Link to comment Share on other sites More sharing options...
phil882 Posted March 28, 2011 Share Posted March 28, 2011 Well the nam certainly looks off now... first the WRF and now RUC is ramping precipitation amounts way up! Link to comment Share on other sites More sharing options...
msuwx Posted March 28, 2011 Share Posted March 28, 2011 6z RUC prints out 0.37" in GSO with an all-snow sounding. Link to comment Share on other sites More sharing options...
phil882 Posted March 28, 2011 Share Posted March 28, 2011 6z RUC prints out 0.37" in GSO with an all-snow sounding. Yea I'm thinking from KHKY to KGSO is really in for a surprise this morning just going off the latest radar trends. The only saving grace will be the warm temperatures, but I imagine their soundings will be able to go isothermal pretty quickly with the current CAA in place. Link to comment Share on other sites More sharing options...
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