Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 36 minutes ago, PowellVolz said: That’s a cold rain for everyone outside the areas where a few hundred feet in elevation can make a huge difference. Indeed. Someone just shared w me that WxSouth has a nice write up on FB. Somebody in the NW quadrant of that look likely sees some snow even below 2500’. No idea if that look holds though. Link to comment Share on other sites More sharing options...
John1122 Posted March 8, 2018 Share Posted March 8, 2018 The GFS was pretty close but not quite there for anyone not at elevation in Tennessee. But for central Eastern Kentucky and SWVA and above 2500-3000 feet it's a hammer job. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted March 8, 2018 Share Posted March 8, 2018 UKMet had a beautiful Miller A track for its surface low at 0z, but the problem of cold enough air remains for lower elevations. I really think the key is how well the upper low at H5 holds together as it drops in and (IF we can get it to hold up) what track it takes. If we can get a favorable track of a intact and relatively wound up H5 low I think valleys can see some snow, even though accumulation will probably still be an issue (yesterday climbing un Mt. Cammerer really brought home how much difference even 1000 feet can make). As washed out as the potential vort H5 maps are on the GEFS there seems to be a good agreement that the vort takes a favorable track on its way here (at least for areas north of I-40, rolling down through Nebraska, eastern Kansas and toward Memphis where it starts to turn ESE and E. The vort looks a little west of the above track on the 0z UKMET's maps. 6z RGEM and NAM like a similar track to the GEFS. (The NAM also has a beautiful surface low track, but not enough cold air since the vort is near Kansas City) The track is similar on the 6z ICON, though the vort's evolution is a more little complicated. The CMC looks similar. 0z Euro has it in a similar place. Euro control is a bit further east. EPS seems to be in two camps: One is more like the control with a less distinct vort dropping in further east and the other is more like the operational with a more distinct vort further west and like the other models I listed above. I keep harping on this vort because I really think its dynamics are the best chance to see some snow, even if it doesn't amount to much outside of elevation, though will be happy to be proven wrong and see more! One problem that keeps popping up is that this vort seems to hit a wall around Arkansas and gets strung out. Outside of a small handful of EPS members, almost all models are showing this. The other problem seems to me to be the big upper low in the Canadian maritimes. It just isn't allowing enough ridging at 500 mb on its backside to help this vort get wound up. I also think we want to see trends for much more interaction between the H5 vort and the blob of moisture coming out of the Gulf. Although the 6z GFS has a wretched surface low track, it does show how this interaction can happen. Maybe it's useful to mention that the vort that passed overhead yesterday certainly over preformed and maybe since its March, the (at any other time than when we need it) evil SE ridge might flex enough to help the vort wind up a bit more as it drops in. Something else to think about though I'm not sure how much merit my version here has. Carvers mentioned sea surface temps in the Gulf a few posts back and I'll add that I bet if the UKMET, NAM, or Euro operational tracks verify, these temps might come into play in a different way, in the Gulf Stream. The 500 mb ridge o' heat we experienced to end Feb couldn't have done anything to cool the temps of the Carolina and Georgia coast down. Not saying it does much for us, but might be fun to watch if it rides up the coast. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Most, if not all, global models take the energy to our south now. The EPS is the most notable change. Some are Miller As. Some have Miller A characteristics and are sliders. Cold air is often an issue in March. We can be 15 degrees below normal for highs and it still not be enough. What we need is a storm that uses its own dynamics to build the cold. So, the weaker solutions are likely nothing for us. Positives overnight are that the system has room to strengthen now, because when it strengthens it will pull west. It now has room to do that. The surface models at least show a storm that is further south. Just based on the 0z/6z suites, I think that someone in the northwest quadrant will see a narrow band of moderate snow develop...again, Wxsouth had a good write-up about that on Facebook last night. The Euro is the path to no snow. The GFS/UKMET/ICON/CMC would likely have snow in portions NE TN and SW VA. The UKMET is likely wound-up too tight which is its bias, but it has had two straight nice runs. The 6z GFS seems reasonable, but I don't like hanging out in that camp. Cold rain is alway a possibility, but March storms are notorious for over performing. So, we will see. It has definitely been more interesting than anything that we have tracked(speaking only for myself in NE TN where we are well below snow norms) this winter. A trends that IMO that we want to see is a deepening storm. The weak solutions won't get it done. On a side note: I may try to work on a post-winter write-up on what worked and what did not. The fast flow made forecasting a bear. One of the nice things about the weekend system is that is is moving slow enough to track. Some systems this winter moved so quickly, that they gave little time for analysis...even the ones that gave snow to middle and west TN. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Just so folks don't think I am the only one discussing the potential for winter weather with this, I just read this from the AM disco by MRX.... Through Saturday, isentropic lift and moisture will be increasing across the area as a low pressure system tracks east across the Red River Valley with a warm front extending across the TN/KY border. Precip will be light initially until the 850 mb low moves into west TN/northern MS and a coupled jet structure provides strong QG forcing over our area Saturday night. The NAM is much further south with the surface low track than any other model, and since it generates convection along the Gulf Coast, it has less QPF in our area as a result. Will lean toward the more northern solutions of the GFS/SREF/ECMWF, which suggest rain amounts Saturday night and Sunday morning in the range of 0.5 to 1 inch. As the surface low tracks to the NC/SC coastline, the models diverge in the handling of its track and intensification, and thus how much moisture and forcing remain across our area. The GFS is much more bullish on coastal cyclogenesis, and shows a midlevel deformation zone over East TN/SW VA Sunday night. If this pans out, northern areas could see several inches of snow. However, the ECMWF is much drier. Will lean the forecast toward the GFS by having likely PoPs north Sunday night and holding a chance of rain/snow into Monday morning. The rest of the forecast period will feature a closed upper low over the Great Lakes and New England that will keep a cold NW flow over our area. Weak disturbances tracking around this low may bring light precip at times for Monday through Wednesday, but timing is too uncertain at this time to mention any significant precip chances. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted March 8, 2018 Share Posted March 8, 2018 And I'll throw Blacksburg's (more pertinent for those in NE TN and SW VA) in for good measure: .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 530 AM EST Thursday... Major focus will be on potential significant winter storm during the later half of the weekend into Monday. The GFS has been consistent from one-to-run to the next in advertising the potential for a significant winter storm with snowfall amounts consistently in the 4-8+ range, by tracking the surface low in a fairly classic Miller A position. However, while the ECMWF, Canadian, and NAM suggest a similar, albeit slightly more southern track, they have trended toward the GFS, so that is a concern. Bottom line is that we still cannot hone in on a specific forecast, but winter precipitation appears likely Sunday into Monday regardless of which model you follow. The position of the upper jet during the event, mainly across GA/SC, suggests that the farther southern solutions such as the ECMWF may be more accurate. But again, any of these scenarios will result in a threat of winter weather across much, if not all, of the CWA during the late weekend/early next week period. Simply put, all interests should watch the weather forecasts in the coming days closely as this could be one of our more significant snow storms we have seen this winter, then again it may not be. Stay tuned! At any rate, temperatures will remain below normal through the period as mean troughing remains in place across the eastern U.S. along with northwest flow. Temperatures will average about 10 degrees below normal with lows mostly in the 20s and highs in the 30s and 40s. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 The 12z NAM(warning...take w a grain of salt at this range) is a pure Miller A and is northwest of 0z and 6z. Almost a perfect track. What we need is for the storm to be strong so precipitation backs over the Apps. Not saying that happens, but that is a really good look including the trend to bring it back northwest. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Pretty crazy how the models had this on the coast, shifted to the Ohio Valley, and have slowly pushed this to the point that we are looking at a Miller A. And now the potential problems that we have to watch are where the storm is too far to the south and/or east. Right now, I don't mind having it a little east. Sure, it could miss. But we need a strong inland runner and this gives it room to strengthen and come back. GFS rolling now. I think this will eventually come back north some...so, we need room for that to happen. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Well, the 12z GFS has some energy transfer this run. Still a wide range of solutions being portrayed on multiple models. Miller A hybrid and Miller A. Middle and west TN get some action this run. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 12z CMC will be a Miller A it appears through 78. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted March 8, 2018 Share Posted March 8, 2018 After looking at 12z GFS I liked its trend to more interaction between my H5 energy and the initial energy that taps Gulf moisture, but this came with the tradeoff of the H5 energy being so progressive its pops a surface low near Memphis that cruises west to east just south of the TN border. Now will be interesting to see if the GFS is being to progressive with the northern stream energy (or maybe that's just me wishcasting). If we can get the interaction between the two features a little more west and south (and there is a gif in the SE forum's long range thread that shows this has been a trend, at least on the GEFS) we can get a surface low to pop further south and then turn northeast. That's close to the CMC's depiction at 12z. The 12z ICON shows something similar to the CMC, but the midwest energy is a little too late. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Have to think the 12z GFS is out on a limb now. We will see what the Euro rolls with at 12z. The 12z GFS is the only model with a solution that far north and west. Now, it may be actual verification gets there after northern jogs are completed. However, the UKMET just slides right off the eastern seaboard. The CMC is a Miller A. The NAM(notably at range) is a Miller A. The ICON is a Miller A. A ton of options still on the table, but the 12z GFS run seems to be an outlier. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Yep. The 12z GEFS says to toss the 12z GFS. The GEFS is more of a souther slider that takes the mean slp across the northern areas of the Gulf states. 2-5" for NE TN w the higher amounts in the extreme NE corner. I still think there is a decent chance that this gains latitude as it gets past our longitude. I also think there is a decent chance that it gains in strength on modeling. IF we are going to get snow, we need this to our south and to let it trend back. May or may not happen, but we need it south first which the GEFS does. Link to comment Share on other sites More sharing options...
John1122 Posted March 8, 2018 Share Posted March 8, 2018 The 12z GFS was a nice run for most of the forum, so I guess it shouldn't shock that it's probably toss worthy. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 15 minutes ago, John1122 said: The 12z GFS was a nice run for most of the forum, so I guess it shouldn't shock that it's probably toss worthy. No doubt. I was thinking the same thing. I still think this comes further north than the southern cluster of modeling. However, like you, I think there is only so much room for this to move north while west of the Apps. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 LOL. The 12z Euro and GFS operationals are far, far, far apart to put it mildly. Far. One goes poof and the other tries to make a run across the TN Valley. I suspect that the EPS will not support the operational. But who knows? Link to comment Share on other sites More sharing options...
nrgjeff Posted March 8, 2018 Share Posted March 8, 2018 Euro does not make a lot of sense. Either transfer the energy or keep it back. The vanishing act does not compute. I'd transfer but have something at elevation / northeast. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 So are we saying the 12z NAVGEM is a good compromise between the GFS and Euro operationals? Not completely joking, not completely serious. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted March 8, 2018 Share Posted March 8, 2018 Yeah the H5 energy looks good on the 12z Euro as it drops down the front range, until it hits around Denver and then it unravels. Looking back over the Euro's last 3 runs at H5 it has trended more west with the vort, so maybe splitting the difference of the more progressive GFS with the Euro holding the energy back isn't to bad of an idea for the general evolution at this point? NAVGEM for a general, ballpark, 500mb setup, but maybe not specific details? Also of note, the UKMET really jumped south from what it had been showing. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Here are the analogs to the anomalous 12z GFS run...more for fun, but an interesting site. Found this on the MA forum. This has some of the interesting stalled NE TN wx systems totals that @tnweathernut and I always talk about. http://www.eas.slu.edu/CIPS/ANALOG/DFHR.php?reg=SE&fhr=F084&rundt=2018030812&map=thbCOOP72 Link to comment Share on other sites More sharing options...
John1122 Posted March 8, 2018 Share Posted March 8, 2018 It won't be as extreme but that 1-30-2010 analog was similar to the 12z GFS clown map. The map on the analog site is not quite right either. It's showing 2-4 inches in Campbell County and I received 13 inches from that storm. Link to comment Share on other sites More sharing options...
Stovepipe Posted March 8, 2018 Share Posted March 8, 2018 59 minutes ago, Carvers Gap said: Here are the analogs to the anomalous 12z GFS run...more for fun, but an interesting site. Found this on the MA forum. This has some of the interesting stalled NE TN wx systems totals that @tnweathernut and I always talk about. http://www.eas.slu.edu/CIPS/ANALOG/DFHR.php?reg=SE&fhr=F084&rundt=2018030812&map=thbCOOP72 Whoa, now that is an interesting site. Thanks for the new bookmark! Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted March 8, 2018 Share Posted March 8, 2018 I think I found one of the differences in why the Euro is suppressing the energy so much. The image I have included is 500mb relative vorticity (I know, imagine that ) from Euro 12z. The black arrow is pointing towards a large vort that is just blazing down from Canada towards the Great Lakes. The Euro has this vort. much faster and further south than the GFS. The blue lines are ridging? that the large vort is pushing and pulling up as it plows on south. This ridging seems to be just slamming the energy that we want to be a little more amplified down and south and not giving it much room to breath and grow. You can see this at Tropical Tidbits on the GFS at 78 hours on the 500mb vort setting. The GFS has the large vort still near Hudson's Bay while the Euro has it almost to Lake Superior. Looking through the EPS, there were still some members that had the vort we want to amplify hanging on and rolling on down through the plains into our area, but the EPS members that didn't had the lower 500mb heights indicative of that large vort pressing in fast from the north. There was some talk of this in the MA forum last night, but suppression for them doesn't have to mean suppression for us so I didn't give it much thought at the time. Definitely NOT rooting for this, but something to think about. And if this is all wrong, PLEASE let me know! Man though, if that larger chunk of energy could trend to coming out a little quicker and west... Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Because I am bored and am not totally buying the run by Dr No....here is the 18z NAM. It moved significantly northwest...not south as it rolled through MS, AL, and GA. It is also the NAM at range which immediately puts any solution up for debate. The temps west of the Apps are 34F. That is likely snow in NE TN. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted March 8, 2018 Share Posted March 8, 2018 I'll add, to play devil's advocate to my own post, that the 18z, 12k NAM at 500mb vorticity looks a lot more like the Euro in that it has the larger energy close to Lake Superior. Yet we still get the nice surface solution Carvers has just posted. And the 3k NAM looks like it might be headed to something even better. It seems like everything I've every watched any of you track has some sort of NW trend in the run up and it's March, so I would guess that might be even more pronounced? and suppression should normally not be too much of a worry. John has also often mentioned that the precip. shields on these Miller As northwest sides are undermodeled. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 18z ICON looks nice as well...marginal temps, nice track. Nice look w energy diving into the back of the storm. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 It is pretty incredible the differences that are left between the GFS and Euro. The 18z GFS will likely hold serve to its 12z run. -NAO climo says this storm(not referring to the NAM...just the storm) should slide across and then makes a turn up the coast. Not sure of the track, but I hold to that idea. Very tough to suppress a storm during March...ton of energy in most of those storms. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Wow. The 12z Euro goes OTS with a whimper and the 18z GFS is cutting west of the Apps. This is at 72 hours...not five days out. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 I will likely get burned...but I do not buy the Euro operational right now. Proceed at your own risk in buying that opinion. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2018 Share Posted March 8, 2018 Areas of middle TN are going to get thumped w this run of the GFS. Southwest Virginia crush job. edit: LOL. Yes, they are. Link to comment Share on other sites More sharing options...
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