Holston_River_Rambler Posted December 28, 2023 Share Posted December 28, 2023 Latest MRX on the system tomorrow and Saturday: On Friday night, upper-level closed low is forecast to be across KY with the upper-level trough axis shifting eastward across the Southern Appalachians by Saturday morning. Mid-level lapse rates will be steep across the region with a strong 150 kt upper jet contributing to some weak ascent across our area. Dynamics are weak, though, and the main contributor to precipitation will be weak orographic lift and weak CSI to support localized heavier showers. The temperature profile will be favorable for snow across the higher elevations of the plateau and mountains, but don`t expect much. A mix of rain showers and snow flurries is expected across the valley. There is so little moisture that significant snow accumulations are not forecast, and in fact, even the highest elevations of the mountains likely will not see more than 1 to 2 inches. Portions of the plateau will see a dusting to one-half inch with locally higher totals. Valley locations will not see accumulation with the exception of a localized brief dusting possible on some grassy surfaces. This system on Friday/Saturday is very weak. New term for me there, "Conditional Symmetric Instability (CSI)" 4 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 28, 2023 Share Posted December 28, 2023 Stole this from the MA (for the system the Euro depicted at 12z): TRI's in the same risk level as some of the lowest elevations of the Sierras!! 4 1 Link to comment Share on other sites More sharing options...
*Flash* Posted December 28, 2023 Share Posted December 28, 2023 20 minutes ago, Holston_River_Rambler said: Yeah that's the weird part of those runs. The only thing I can think of is that the higher resolution is doing something with RH from the still almost entirely unfrozen Great Lakes. The 18z NAM 3k has pretty good RH values up through 750mb and even in a few select locations in west and southern middle TN up to 500mb: Good points. I think if the system overachieves in the TN valleys tomorrow, this will be one of the reasons why. There was an event early January 2010 in which middle TN scored a surprise due to moisture fetch from the Great Lakes. It's not out of the realm of possibility. 5 Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 28, 2023 Share Posted December 28, 2023 13 minutes ago, Holston_River_Rambler said: Stole this from the MA (for the system the Euro depicted at 12z): TRI's in the same risk level as some of the lowest elevations of the Sierras!! Give me some of that. 1 Link to comment Share on other sites More sharing options...
tnweathernut Posted December 28, 2023 Share Posted December 28, 2023 18 minutes ago, Carvers Gap said: Give me some of that. That's the same period I have been watching for a few days now for the one I thought had good potential. Just hope as it comes into better view it's a legit shot at something we can track. I'm disappointed in the late week. From a couple of days ago I thought the energy coming off the lakes and rotating through would enhance snow showers for the mountains and give a decent shot at a light accumulation for the lower elevations from middle TN through the plateau and into northeast TN. 3 Link to comment Share on other sites More sharing options...
Itryatgolf70 Posted December 28, 2023 Share Posted December 28, 2023 I haven't seen it, but I've heard a pretty big continental trough past day 10 setting up with 12zeps increasing snow mean through day 16 but still early 5 Link to comment Share on other sites More sharing options...
PowellVolz Posted December 28, 2023 Share Posted December 28, 2023 MRX zone forecasts sometimes make no sense at all lol…for my location.“FridayA chance of rain and snow before 5pm, then a chance of rain. Mostly cloudy, with a high near 42. Southwest wind 5 to 10 mph. Chance of precipitation is 30%.Friday NightA chance of snow showers before 8pm, then a chance of rain and snow showers between 8pm and 9pm, then a chance of snow showers after 9pm. Mostly cloudy, with a low around 33. Southwest wind around 10 mph. Chance of precipitation is 30%.Rain/snow on Friday changes to all rain after 5pm (lol)Then at some point before 8pm it’s all snow but then Rain/snow between 8-9pm. . 3 5 Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 28, 2023 Share Posted December 28, 2023 37 minutes ago, Itryatgolf70 said: I haven't seen it, but I've heard a pretty big continental trough past day 10 setting up with 12zeps increasing snow mean through day 16 but still early Yes, that is what we we’re discussing yesterday. Maps today look very similar. How long does that trough hold? TBD. Maybe a slight uptick with the snow mean, but looks very similar to 0z. Models are going to take a few days to sort out the Greenland block, strat, and MJO. Agree, still early. I know this though. When @tnweathernutmentions a timeframe....it is worth watching. 3 Link to comment Share on other sites More sharing options...
Itryatgolf70 Posted December 28, 2023 Share Posted December 28, 2023 3 minutes ago, Carvers Gap said: Yes, that is what we we’re discussing yesterday. Maps today look very similar. How long does that trough hold? TBD. Maybe a slight uptick with the snow mean, but looks very similar to 0z. Models are going to take a few days to sort out the Greenland block, strat, and MJO. Agree, still early. I know this though. When @tnweathernutmentions a timeframe....it is worth watching. I know El Niños aren't notorious for alot of cold air, but we still have a ways to go to get a legit cold air source cold enough for snow and ice sleet here imo Link to comment Share on other sites More sharing options...
PowellVolz Posted December 28, 2023 Share Posted December 28, 2023 I know El Niños aren't notorious for alot of cold air, but we still have a ways to go to get a legit cold air source cold enough for snow and ice sleet here imoGetting some snow pack to our N/NW should help. Maybe not a lot of help but it won’t take much with highs around 40. . 1 Link to comment Share on other sites More sharing options...
tnweathernut Posted December 28, 2023 Share Posted December 28, 2023 Very probable a marginal airmass to work with around the timeframe we are discussing, and we'd likely have to thread the needle................ but when do we not? We have very few clean opportunities for snow in the midsouth. Just get a system tracking to our south in January, put someone on the northwest side and see what happens. Admittedly, it's an outside shot, but it's not a zero opportunity, IMO. 7 Link to comment Share on other sites More sharing options...
John1122 Posted December 28, 2023 Author Share Posted December 28, 2023 36 minutes ago, PowellVolz said: MRX zone forecasts sometimes make no sense at all lol…for my location. “Friday A chance of rain and snow before 5pm, then a chance of rain. Mostly cloudy, with a high near 42. Southwest wind 5 to 10 mph. Chance of precipitation is 30%. Friday Night A chance of snow showers before 8pm, then a chance of rain and snow showers between 8pm and 9pm, then a chance of snow showers after 9pm. Mostly cloudy, with a low around 33. Southwest wind around 10 mph. Chance of precipitation is 30%. Rain/snow on Friday changes to all rain after 5pm (lol) Then at some point before 8pm it’s all snow but then Rain/snow between 8-9pm. . Mine isn't far off but it's a random chance of rain mixing in between 9 and 10pm. Friday A 40 percent chance of snow, mainly after 2pm. Mostly cloudy, with a high near 37. Southwest wind 5 to 10 mph. Friday Night A chance of snow showers before 9pm, then a chance of rain and snow showers between 9pm and 10pm, then a chance of snow showers after 10pm. Mostly cloudy, with a low around 31. West wind around 10 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible. Saturday A chance of snow showers before 4pm, then a chance of sprinkles. Mostly cloudy, with a high near 38. West wind around 10 mph. Chance of precipitation is 30%. 3 Link to comment Share on other sites More sharing options...
PowellVolz Posted December 28, 2023 Share Posted December 28, 2023 Mine isn't far off but it's a random chance of rain mixing in between 9 and 10pm. Friday A 40 percent chance of snow, mainly after 2pm. Mostly cloudy, with a high near 37. Southwest wind 5 to 10 mph. Friday Night A chance of snow showers before 9pm, then a chance of rain and snow showers between 9pm and 10pm, then a chance of snow showers after 10pm. Mostly cloudy, with a low around 31. West wind around 10 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible. Saturday A chance of snow showers before 4pm, then a chance of sprinkles. Mostly cloudy, with a high near 38. West wind around 10 mph. Chance of precipitation is 30%.Kinda wild that the southern valley west of Chattanooga is in a better location than you. Maybe not better but in a more favorable location this go around. . 1 Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 28, 2023 Share Posted December 28, 2023 50 minutes ago, Itryatgolf70 said: I know El Niños aren't notorious for alot of cold air, but we still have a ways to go to get a legit cold air source cold enough for snow and ice sleet here imo Yeah, I think if/when we are going to see strong cold, it will have to come after the 20th. Storm track will work in January, though, even with marginal temps. Source regions are good by the second week of January FWIW. 4 Link to comment Share on other sites More sharing options...
Daniel Boone Posted December 29, 2023 Share Posted December 29, 2023 2 hours ago, PowellVolz said: MRX zone forecasts sometimes make no sense at all lol…for my location. “Friday A chance of rain and snow before 5pm, then a chance of rain. Mostly cloudy, with a high near 42. Southwest wind 5 to 10 mph. Chance of precipitation is 30%. Friday Night A chance of snow showers before 8pm, then a chance of rain and snow showers between 8pm and 9pm, then a chance of snow showers after 9pm. Mostly cloudy, with a low around 33. Southwest wind around 10 mph. Chance of precipitation is 30%. Rain/snow on Friday changes to all rain after 5pm (lol) Then at some point before 8pm it’s all snow but then Rain/snow between 8-9pm. . Yeah, sadly not a very professional forecast at all. 1 Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 2 hours ago, PowellVolz said: Kinda wild that the southern valley west of Chattanooga is in a better location than you. Maybe not better but in a more favorable location this go around. . From Western Cumberland south down the Western Plateau looks best for now. That's just how it goes with upper level energy. 2 Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 GFS has a nice little Eastern areas 40 and north/Northern Plateau thumper at 147-156. Consistent storm signal there but this whole fall and winter most storms have under performed on QPF with a couple of exceptions. Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 Canadian also has it in suppressed fashion. Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 The Canadian follows up the suppressed storm with a perfect Southern slider that would make the whole forum pretty happy. 2 Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 Just a beast of a winter storm on the Euro again this run. Great run for areas along and south of 40 in middle and western areas, with the Plateau and Mountains getting crushed along with SE Ky and SWVa. 2 Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 The Euro is loading up for a second storm just about 48 hours later. 1 Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 That said, probably time for one of you guys to crank up a January thread. My pending trip to Chattanooga seems to have fired winter on all cylinders. 1 Link to comment Share on other sites More sharing options...
John1122 Posted December 29, 2023 Author Share Posted December 29, 2023 The second storm takes a perfect track but isn't too strong, which would help with WAA. Nice run for south of 40 especially for that storm. But generally 1.5 to 4 inches across most of the forum with a two storm total of 4-10 inches being fairly widespread. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 29, 2023 Share Posted December 29, 2023 I'll take a stab at a January thread. Link to comment Share on other sites More sharing options...
matt9697 Posted December 29, 2023 Share Posted December 29, 2023 7 hours ago, John1122 said: The Canadian follows up the suppressed storm with a perfect Southern slider that would make the whole forum pretty happy. Yea been a while since we have had an I-40 special Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 29, 2023 Share Posted December 29, 2023 Some great model runs for the timeframe before the 10th, and we had better hit. The new GEFSext MJO plot doesn't even get the MJO out of phase 5 until Jan 28th. It is conceivable that the entire month of January could be spent in warm phases of the MJO - and still not even rotate into 6 which is the warmest. Now, I am not convinced this is what occurs, but that plot is the worst case scenario - and that is the eastern ridge hooking into the NAO scenario likely. That said, notice the MJO is not out of phase 8 yet, and most modeling didn't have the current stall in 8. However, seeing the MJO stall out in 5 would be a surprise to me......but the plot below would basically wipe out out best climatology from Jan 15th to roughly Feb 7th. Again, it is possible this is completely wrong, and I will probably look at that scenario later. Think last year where the MJO wouldn't leave the warm phases....this winter, it should really not want to go there. The CFSv2 seasonal this morning has flipped January to warm. Basically, the CFS is banking on the second half of January being very warm. Most LR modeling is flirting with a western Atlantic ridge which is hooked into the NAO for an undetermined duration after Jan 10th. That is a huge problem. Let's hope that is in error. Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 29, 2023 Share Posted December 29, 2023 I do think we are probably going to need to track the system on Jan 4th. The 6z GFS looked like a decent past for eastern areas. That is in addition to a good Euro run at 0z Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 29, 2023 Share Posted December 29, 2023 Winter Weather Advisories have been posted for portions of the Plateau. URGENT - WINTER WEATHER MESSAGE National Weather Service Nashville TN 205 AM CST Fri Dec 29 2023 TNZ011-032>034-065-066-078>080-292100- /O.NEW.KOHX.WW.Y.0005.231230T0000Z-231230T1200Z/ Pickett-Putnam-Overton-Fentress-White-Cumberland-Warren-Grundy- Van Buren- Including the cities of Byrdstown, Cookeville, Livingston, Jamestown, Allardt, Sparta, Crossville, McMinnville, Altamont, Coalmont, and Spencer 205 AM CST Fri Dec 29 2023 ...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM CST THIS EVENING TO 6 AM CST SATURDAY... * WHAT...Snow expected. Total snow accumulations of one inch with locally higher elevations up to two inches possible. * WHERE...Portions of Middle Tennessee. * WHEN...From 6 PM CST this evening to 6 AM CST Saturday. * IMPACTS...Plan on slippery road conditions. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 29, 2023 Share Posted December 29, 2023 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 29, 2023 Share Posted December 29, 2023 I'm getting some flurries here in Morgan County. Not a terrible radar, we'll see how well it holds together: 1 Link to comment Share on other sites More sharing options...
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