Wurbus Posted December 31, 2021 Share Posted December 31, 2021 Plumes had an uptick from 9z to 15z across most Eastern area's. Knoxville only had 1 plume above 4 inches and now has 6 over 4 inches. 2 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 31, 2021 Share Posted December 31, 2021 18z NAM says fine then...I will join the party lol 2 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 31, 2021 Share Posted December 31, 2021 18z NAM 1 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 31, 2021 Author Share Posted December 31, 2021 Yeah, the NAM looks better than 12z for sure: Still not as good as 12z GFS, but better than it was. 2 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 31, 2021 Share Posted December 31, 2021 Glancing at the 12z GEFS...still quite a bit of spread between nothing and a decent little event 1 Link to comment Share on other sites More sharing options...
Wurbus Posted December 31, 2021 Share Posted December 31, 2021 18z RGEM brought it! Nice increase forum wide, besides those 2 pesky snow holes. 2 1 3 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 31, 2021 Author Share Posted December 31, 2021 Beat me to the punch! The vort pass made me breathe heavily: 3 3 2 Link to comment Share on other sites More sharing options...
Reb Posted December 31, 2021 Share Posted December 31, 2021 GFS looking beefy 2 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 31, 2021 Author Share Posted December 31, 2021 I'm sure some of you already ready MRX's disco, but I thought I'd post it here for posterity due to the topic points: 1) Severe. Very warm day is expected with a strong low level jet out of the southwest to the south of the frontal boundary. This will help to pump in warm, unstable air, along with good speed shear. Directional shear component is not as impressive, but with these strong winds helping to increase low level shear of 30+ knots in the eastern TN Valley, the chance for a possible tornado is present. Biggest question looks like it will be how much instability is available for storms to tap into. As usual the NAM is the most bullish with MLCAPE while most other forecast soundings showing a more moderate 300-500 J/kg, but all of these are pretty high for New Years Day. Think the biggest threat with possible severe weather will be strong straight line winds as this fast moving system makes it`s way through, but a quick isolated spin up of a tornado can`t be ruled out along the QLCS line. Think the main line will move onto the Cumberland Plateau around 00z, and quickly push east of the mountains by around 06/07z. 2) Flooding. This system will also have a good amount of moisture to work with as the jet helps to pull in Gulf moisture, and PWAT values rise above 1 inch in the Valley. This will help produce heavy showers and thunderstorms that could quickly dump a moderate amount of rain ahead of the line with isolated storms, and as the main line moves thorugh. High resolution models and Plumes indicate that 0.5-1.5 inches of rain are expected on Saturday which could lead to flooding of low lying and poor drainage areas by Saturday evening into early Sunday. But hopefully with this system quickly moving through the QPF amounts and flooding will be somewhat mitigated. 3) Snow. By Sunday we should get a brief break in precipitation chances as the line is to the east of the mountains, and the surface low begins to move through the Tennessee Valley. This will bring with it a strong shot of cold air Sunday night into Monday morning quickly dropping temperatures below freezing. With the 12z model runs some of the operational models are now indicating that the system will be stronger and slower than previous model runs. If this verifies it would mean that colder air and higher QPF amounts would be likely leading to more snow in the southern Appalachians and eastern TN Valley. Operational GFS has gone MUCH higher on snowfall amounts overnight, and in general most models have increased snowfall amounts overnight. Have bumped up official snow amounts in the Valley, but have been much more tame with amounts ranging from a dusting to quarter inch around Chattanooga, up to around an inch or more in the Tri-Cities... Higher amounts closer to 2+ inches can be expected in the higher elevations of the southern Appalachians and northern Cumberland Plateau. Have stayed closer to GEFS plumes which show a much lower amount compared to the operational models. Think that snowfall totals may need to be bumped up if models continue the trend of slower and stronger with the low, but would like to see multiple runs of the stronger/slower solution, and would also like to see ensemble members in better agreement with the slightly higher snow amounts. Have also undercut some guidance because ground temperatures are still going to be very warm (highs in the 70s/60s the days before) so snow will hit the ground quickly melt... Snow totals on the snow board will be much higher than what people actually see on the ground and on the roads (which is what most people actually care about). Weather quiets down by Monday afternoon and we get into a more mild and seasonable pattern thorugh the middle of the work week. Another trough will begin to swing through the eastern half of the US by the end of the work week... Temperatures are expected to be warm enough that most of the precipitation that falls Thursday into Friday will be all liquid, but in the overnight hours we could switch over to light snow in the Valley... But this is still a ways off and confidence will likely increase after we past this weekend system. 1 Link to comment Share on other sites More sharing options...
TellicoWx Posted December 31, 2021 Share Posted December 31, 2021 18z GFS looks aloy like the RGEM 1 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 31, 2021 Author Share Posted December 31, 2021 1 minute ago, Holston_River_Rambler said: Snow totals on the snow board will be much higher than what people actually see on the ground and on the roads (which is what most people actually care about). #Imchasingthedeckpic Link to comment Share on other sites More sharing options...
TellicoWx Posted December 31, 2021 Share Posted December 31, 2021 18z GEFS has some 2" means back into MS/AL 2 Link to comment Share on other sites More sharing options...
*Flash* Posted December 31, 2021 Share Posted December 31, 2021 So basically, if the models were songs on an Adele playlist, we have the RGEM/GFS/SREF with 'Rolling in the Deep', the NAM/GEFS/ECMWF with 'Easy on Me', and a few ensemble members with 'Chasing Pavements'. Seems like the latter is the outlier at the moment. Not bad. 2 3 Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 31, 2021 Share Posted December 31, 2021 TIMS model doing the work so far... 3 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted January 1, 2022 Author Share Posted January 1, 2022 18z Euro a little deeper and little slower with the energy. Gif with the 12z run and the 18z run: Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted January 1, 2022 Author Share Posted January 1, 2022 No precip type maps yet, but the qpf does seem a little south IMO: Link to comment Share on other sites More sharing options...
TellicoWx Posted January 1, 2022 Share Posted January 1, 2022 Not even sure the 0z NAM is going to squeeze out a flurry lol Link to comment Share on other sites More sharing options...
Wurbus Posted January 1, 2022 Share Posted January 1, 2022 5 minutes ago, TellicoWx said: Not even sure the 0z NAM is going to squeeze out a flurry lol HRRR was the same way. Hopefully, this isn't a trend for the rest of the models. 1 Link to comment Share on other sites More sharing options...
John1122 Posted January 1, 2022 Share Posted January 1, 2022 Rgem wasn't bad at all. Not quite 18z but a good forum wide event. 3 Link to comment Share on other sites More sharing options...
John1122 Posted January 1, 2022 Share Posted January 1, 2022 GFS remains in the thumper category. Looks like the NAM may be on an island on the North American modeling. Of course the NAM beyond 36-48 hours isn't great. 2 Link to comment Share on other sites More sharing options...
Daniel Boone Posted January 1, 2022 Share Posted January 1, 2022 Just now, John1122 said: GFS remains in the thumper category. Looks like the NAM may be on an island on the North American modeling. Of course the NAM beyond 36-48 hours isn't great. I remember last year similar thing happened. The hrrr is dry too. It was terrible here last winter. Link to comment Share on other sites More sharing options...
John1122 Posted January 1, 2022 Share Posted January 1, 2022 Euro wasn't very enthusiastic. The 06z NAM bounced back from 00z a but. The 48hr HRRR at 06 was pretty good for quite a but of the area. Link to comment Share on other sites More sharing options...
John1122 Posted January 1, 2022 Share Posted January 1, 2022 06z 3k is pretty nice for roughly the eastern half of the valley region from just east of Nash and points east. Brings some snow to most everyone though. Way better than it's lower res version put out. Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted January 1, 2022 Author Share Posted January 1, 2022 6z GFS kind followed the 6z NAMs in that it resolved the energy as a little bit better, but still not as good as some of the runs yesterday. The last few runs: Link to comment Share on other sites More sharing options...
TellicoWx Posted January 1, 2022 Share Posted January 1, 2022 12z NAM already looks better @33 Link to comment Share on other sites More sharing options...
Reb Posted January 1, 2022 Share Posted January 1, 2022 Yup fixing to get NAM’d Link to comment Share on other sites More sharing options...
TellicoWx Posted January 1, 2022 Share Posted January 1, 2022 Yep looks correct...snow hole right over @nrgjeffhouse lol jk 4 1 Link to comment Share on other sites More sharing options...
TellicoWx Posted January 1, 2022 Share Posted January 1, 2022 3k was alot better for western and Middle areas 4 1 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted January 1, 2022 Author Share Posted January 1, 2022 I love the RGEM. It's such a happy little model. 4 Link to comment Share on other sites More sharing options...
Uncle Nasty Posted January 1, 2022 Share Posted January 1, 2022 Yep looks correct...snow hole right over [mention=2545]nrgjeff[/mention]house lol jkSame here. Maybe we can get lucky and at least see a good snow shower in Ooltewah. I'm not holding my breath but it would be a nice surprise.Sent from my moto z4 using Tapatalk Link to comment Share on other sites More sharing options...
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