Save the itchy algae! Posted December 10, 2019 Share Posted December 10, 2019 I feel like cold air moving at 110mph is something you’d see in the Day After Tomorrow movie 3 1 Link to comment Share on other sites More sharing options...
McMinnWx Posted December 10, 2019 Share Posted December 10, 2019 Is the front moving faster than anticipated? Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 10, 2019 Share Posted December 10, 2019 I'm not sure if that speed is accurate or not. Just my estimate at that time and was so unsure of it I didn't want to post it at first. Nothing to impede it on the Plains unlike here though and closer to the low/ high gradient there maybe? Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 After looking, the Rockies funnel cold air rapidly down the plains but as it spreads further from the Rockies it slows down. That's why you can see 50 degree temp drops in an hour there. Was reading about a place in Wisconsin that had mid 70s and tornadoes one morning in November, and the rescue efforts for the tornado victims took place in a blizzard. 2 Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 Looks like the NAM is going to NAM a lot of us again. Heavy snow streak from Arkansas through Memphis up through Nashville by around 1pm tomorrow. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 10, 2019 Share Posted December 10, 2019 Yeah, it's already got me in snow by 4 PM with 1.5" Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 The changeover on the NAM is way faster than forecast timing. My area changes to frozen by 2-3 pm on the NAM, but MRX forecast changeover here is 10pm. 1 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 10, 2019 Share Posted December 10, 2019 NAM listened to Holston on the speed lolSent from my SM-S767VL using Tapatalk 2 Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 Looks like two waves of snow on the NAM, the early one nails Mid Valley area with a snowblitz and give BNA 4 inches of snowfall. Southern Arkansas seems to get the benefit of both waves and close to 8 inches falls there. Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 Timing to frozen is similar on the 3k but the heavy snowfall isn't quite so heavy on it. Same narrow band of snow, but 1-3 inches instead of 2-5 inches on the 12k. Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 The NAM just books the precip through. It's ended before the MRX changeover time starts for most of us, Link to comment Share on other sites More sharing options...
TellicoWx Posted December 10, 2019 Share Posted December 10, 2019 00z RGEMSent from my SM-S767VL using Tapatalk 2 Link to comment Share on other sites More sharing options...
BlunderStorm Posted December 10, 2019 Share Posted December 10, 2019 Notably an encouraging uptick in totals from both the 3km and 12km NAM across the region. The first wave is certainly less dry. Link to comment Share on other sites More sharing options...
Wurbus Posted December 10, 2019 Share Posted December 10, 2019 00z HRRR was pretty pathetic on the snow totals. 2-4 inches in NE TN and nothing to a trace everywhere else. Link to comment Share on other sites More sharing options...
Kentucky Posted December 10, 2019 Share Posted December 10, 2019 00z GFS Positive Snow Depth through 42 1 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 10, 2019 Share Posted December 10, 2019 00z GFS sounding for Memphis, while somehow dropping 6" snow???Sent from my SM-S767VL using Tapatalk 1 Link to comment Share on other sites More sharing options...
jrips27 Posted December 10, 2019 Share Posted December 10, 2019 The difference between the GFS/RGEM and the NAM is truly remarkable for being 12-18 hours away at most. Pondering a drive up to the Crossville area tomorrow from Atlanta. The snow itch is real. so much uncertainty. 3 Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 18 minutes ago, TellicoWx said: 00z GFS sounding for Memphis, while somehow dropping 6" snow??? Sent from my SM-S767VL using Tapatalk It snows my column as below freezing from the top down tomorrow evening but says best guess precip type is rain. Confusing. Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 Ratio'd Canadian. Nothing to do now but sit back and see how right/wrong they all were. 3 1 Link to comment Share on other sites More sharing options...
BlunderStorm Posted December 10, 2019 Share Posted December 10, 2019 The ICON believe it or not has shown signs of improvement Plateau and east albeit still very underwhelming. 2 runs ago it had only portions of the plateau and SWVA barely catching a dusting. I'm wondering if the cold air arrives sooner than MRX is expecting especially with what the NAM did. Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 The Euro stepped up significantly from 12z and is closer to the GFS/Canadian models. 1 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 10, 2019 Share Posted December 10, 2019 The ICON believe it or not has shown signs of improvement Plateau and east albeit still very underwhelming. 2 runs ago it had only portions of the plateau and SWVA barely catching a dusting. I'm wondering if the cold air arrives sooner than MRX is expecting especially with what the NAM did.Noticed on all the 00z modeling there is decent lift from Nashville east to the Smokies (for a couple hours while before the layer gets dry slotted)..00z Euro increased across this area as well. If that is how it unfolds..could see a nice 1-3 plateau (1-1.5 valley) area underneath the higher rates. The OPRH is supportive of the band. Sent from my SM-S767VL using Tapatalk 1 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 10, 2019 Share Posted December 10, 2019 00z NAM...the energy continues east to the mountains, with surface temps right around freezing. It would definitely be threading the needle, with a small window to put down some moderate snow.Sent from my SM-S767VL using Tapatalk Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 05z RAP hits Northern middle down to Nashville with around 1 inch. Northern Plateau from Jamestown to Cumberland Gap with 2-3 stretching into Kentucky. Still some snow happening in eastern areas at that point. Not much going on south of 40 on the RAP, especially eastern areas. But it's out there at the edge if its range still. That said the last few runs have been focusing on SEKy and the Northern areas for accumulation. It's a much better model out to about hour 6 to 8 vs 15+ 1 Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 The front is roughly from Louisville, Ky to Jackson, Tn. The freezing weather is about 75 miles behind the front. 54 in Louisville and 29 in Southern Illinois just west of Louisville. Link to comment Share on other sites More sharing options...
Runman292 Posted December 10, 2019 Share Posted December 10, 2019 In MRX's latest discussion, the short version is that they will not be issuing any winter weather advisories due to their thinking that the road surfaces will be too warm and the snow won't be heavy enough to stick around on the roads. Their current thinking is 1-1.5 inches in the plateau, 1-3 in the higher elevations in the smokies and Northeast TN/SW Virginia, and maybe a dusting in the valley, all on grassy surfaces. Link to comment Share on other sites More sharing options...
John1122 Posted December 10, 2019 Author Share Posted December 10, 2019 MRX has a terrible track record with issuing winter products. Their logic on this one is questionable imo. They apparently don't understand that moderate snow falling in mid December with such a low sun angle, and after dark, will stick to roads. Especially since the forecast low for my area is 23 degrees. Now it might not snow very much and that's one thing, but the seem confident that actual snow depth will exceed winter weather advisory criteria in the area. It has been modestly warm for 36 hours, but we had sub-freezing lows every day of December except the 1st and the 9th. If the snow comes as modeled and as forecast and hits around 4-9 pm, I-75 will get messy and dangerous here, especially since it gets to about 2500 feet near here. 1 Link to comment Share on other sites More sharing options...
Utvols235 Posted December 10, 2019 Share Posted December 10, 2019 Nashseverewx and NWS aren’t seeing this one pan out at all. Saying snow chances are dismal. 1 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 10, 2019 Share Posted December 10, 2019 The rain/ snow line is getting close to Nashville. I know many of you know about the correlation coefficient, but if you are wondering what in the world this weird looking radar is, it's part of a dual polarization radar that can help identify rain and snow because of how it scans what's falling through the air. First you can see the front pass south of Nashville and then the brighter colors show the transition to snow. When it is in a circle around a radar site at a pretty uniform distance it is usually because the radar is not aimed straight out, but at an angle up and it is seeing the transition to snow, but waaaaayyyyy up. Notice here how it starts to crawl in to Nashville as the loop continues. That is the rain/snow line creeping closer and down in the atmosphere. I'm not sure exactly how high it is right now, but it is moving in. There is still some moisture lingering back that way too and I bet those enhanced echoes north of Nashville over s. KY are some bright banding as the snow is melting in the atmosphere. 3 1 Link to comment Share on other sites More sharing options...
weathertree4u Posted December 10, 2019 Share Posted December 10, 2019 Just now, Holston_River_Rambler said: The rain/ snow line is getting close to Nashville. I know many of you know about the correlation coefficient, but if you are wondering what in the world this weird looking radar is, it's part of a dual polarization radar that can help identify rain and snow because of how it scans what's falling through the air. First you can see the front pass south of Nashville and then the brighter colors show the transition to snow. When it is in a circle around a radar site at a pretty uniform distance it is usually because the radar is not aimed straight out, but at an angle up and it is seeing the transition to snow, but waaaaayyyyy up. Notice here how it starts to crawl in to Nashville as the lop continues. That is the rain snow line creeping closer and down in the atmosphere. I'm not sure exactly how high it is right now, but it is moving in. There is still some moisture lingering back that way too and I bet those enhanced echoes north of Nashville over s. KY are some bright banding as the snow is melting in the atmosphere. Some of that is sleet; I am northeast of Nashville and we have sleet mixing in here 2 3 Link to comment Share on other sites More sharing options...
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