tnweathernut Posted March 8, 2017 Author Share Posted March 8, 2017 4 minutes ago, Mrwolf1972 said: Colder air will move in behind the front, then models show an upper trough swinging across the area and a weak surface low moving by to our south late Saturday through early Sunday. While the system may initially start out as rain, thermal profiles suggest a quick changeover to snow after sunset Saturday night. Accumulating snow will be possible, especially north of I-40 and in the mountains. Areas south of I-40 may see some accumulating snow, but confidence is much too low at this point to indicate anything more than a rain/snow mix. It appears that the last few runs of the GFS and ECMWF have trended cooler, indicating a better potential for snow in our forecast area, but there`s still plenty of time for finer details to change. Keep in mind, this event is still 4 days out. that's from Knoxville nws. Can't disagree with anything they said, except it being 4 days away. It's just beyond three. Maybe they are rounding up? lol Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 The NAM outside of 48 hours is iffy...but that is generally a good look. Lots of cold on the map and more than one piece of energy late in the run. Looks like a lot depends on how strong that hp is...and where the precip rates are heaviest. Link to comment Share on other sites More sharing options...
John1122 Posted March 8, 2017 Share Posted March 8, 2017 It's still snowing from Nashville to the NETn/SWVA areas at this point. Surface temps are hovering around freezing around Knox, just below freezing around Nashville, upper 20s on the Plateau/SEKY and SWVA, around 30 in the Tri-Cities area. Link to comment Share on other sites More sharing options...
John1122 Posted March 8, 2017 Share Posted March 8, 2017 NAM also depicts some small areas with heavy freezing rain approaching a half an inch. I don't believe this aspect of it, I think it'll either be rain or snow but I guess it's possible. Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted March 8, 2017 Share Posted March 8, 2017 id say by tomorrow or Friday the nam will come in line with the rest I don't think the nam will be the only right model when the rest are coming in agreement as of right now. Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted March 8, 2017 Share Posted March 8, 2017 gfs at 74 snow totals at 90 Link to comment Share on other sites More sharing options...
rbowman Posted March 8, 2017 Share Posted March 8, 2017 I'd sure feel better about this if that 540 line would sink on down south to about the Alabama border. Sent from my LG-H918 using Tapatalk Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted March 8, 2017 Share Posted March 8, 2017 ice in southern valley Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 Yeah, the NAM has a bias of being overly amped. So, sometimes it can be a bit overdone which has led to the coining of a forum phrase known as getting "nammed." As an additional note...during this past winter, models consistently overestimated how far south the cold would get. In this case (up to now), they have been strengthening the hp which is pushing the snow axis south. On the GFS, it has shifted the axis from Canton, OH, to the TN Valley. All of the usual upper south woes still apply...down sloping in certain areas, snow holes, the warm nose, marginal temps, jog north, etc. Time of day will now be important. If you are lucky enough to have it arrive at night...much better chances of accumulation obviously. Just looked at the 18z GFS...appears to hold serve and might be ever so slightly north. Really just looks like the snow line is about 20 miles north of 12z. Precip shield looks pretty similar in placement. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 To clarify, the track held serve...the system was a bit weaker which lessened amount in the southern areas of middle TN. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 That second system is interesting as it's center has shifted from Missouri to Arkansas at 120. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 Yep, that second piece of energy will have to be watched. It digs more to our west and sharpens the trough over the EC. The resulting LP is significantly closer to the coast. Could add an upslope event after the first wave....it got its act together a bit late, but that is a blizzard for the NE. That would drive very cold air down into the most of the forum area. Also, if it gets its act together a bit earlier...changes the narrative. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 Low temps for Weds. Freezing line reaches the FL border. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 Check out the NE snow totals. Pretty sharp upturn. 18z 12z Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 8, 2017 Share Posted March 8, 2017 18z GFS 16 day snow map should be a weenie run of the year contender. What a run! Link to comment Share on other sites More sharing options...
John1122 Posted March 9, 2017 Share Posted March 9, 2017 The level of cold and orientation of 500mb features are pretty much perfect for wintry weather threats for the next 10 days or more. We're dealing with a mid January type air mass with the potential energy of spring systems. It's hard to get excited after the way this winter has gone, but this may be the best month of the cold season if the next 10-15 days work out as well as they look right now. Link to comment Share on other sites More sharing options...
dwagner88 Posted March 9, 2017 Share Posted March 9, 2017 FWIW, the data from the 18Z does not support the clown at all. It's above freezing at KCHA for essentially the entire event. No way 3-4" of snow accumulates in March at 33 degrees. Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted March 9, 2017 Share Posted March 9, 2017 0z nam a tick south bit snow sagged south to Link to comment Share on other sites More sharing options...
1234snow Posted March 9, 2017 Share Posted March 9, 2017 0z NAM clown map. Someone pinch me. Edit: Tapatalk is not showing my uploads. Here is a link but Mr. Wolf has got me covered. http://www.tropicaltidbits.com/analysis/models/?model=namconus®ion=seus&pkg=asnow&runtime=2017030900&fh=81 Link to comment Share on other sites More sharing options...
John1122 Posted March 9, 2017 Share Posted March 9, 2017 Ratio'd NAM really hammers the border areas over to SWVA but has that sharp cut-off south and west. Link to comment Share on other sites More sharing options...
John1122 Posted March 9, 2017 Share Posted March 9, 2017 Would be a brutal ice storm if true in that area of Middle Tennessee. I personally believe that is more likely to be a rn/sn transition area. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 9, 2017 Share Posted March 9, 2017 Yes, that snow bullseye is directly over Ol Carvers' house. I will enjoy my fifteen minutes of wx model fame and would kindly like to cash-in my 12-14" of electronic dendrites for the real McCoys. Thank you. Thank you. Link to comment Share on other sites More sharing options...
BlunderStorm Posted March 9, 2017 Share Posted March 9, 2017 It is pretty good shot up here in the New Garden area (Lebanon, SwordsCreek, Honaker, Raven, Big A mountain, Richlands, etc) as well but surely it is too good to be true. Link to comment Share on other sites More sharing options...
1234snow Posted March 9, 2017 Share Posted March 9, 2017 Ratio'd NAM really hammers the border areas over to SWVA but has that sharp cut-off south and west.Literally my house is in the bullseye for a clown map for the first time ever. On March 12th after a blowtorch winter. You can't make this up. I do think that the totals even without the Kuchera method are probably a little overdone on the NAM. Maybe a realistic number would be to take 75% of the 10:1 ratio numbers. I think we are seeing a locked in solution and I do not see many major changes in the track anyways especially with a strong high pressing down and confluence in the NE. If anything the rain/snow line could move south a little more. Link to comment Share on other sites More sharing options...
John1122 Posted March 9, 2017 Share Posted March 9, 2017 Everything seems to be lining up at 500 just where it needs to be, the ridge in the west is nice, the low in NE means this cannot go north, the flow is straight from Central Canada where temps are in the -30 to -50 degree range. It even arrives late afternoon into the overnight hours rather than arriving at 10 am and trying to snow through the afternoon. Link to comment Share on other sites More sharing options...
1234snow Posted March 9, 2017 Share Posted March 9, 2017 Yes, that snow bullseye is directly over Ol Carvers' house. I will enjoy my fifteen minutes of wx model fame and would kindly like to cash-in my 12-14" of electronic dendrites for the real McCoys. Thank you. Thank you.Best model run ever for us? I'll probably stick that one in the iPad archive. I know that won't happen but I feel fairly confident in an accumulating snow around and north of I-40. We have had 1 full day of fairly consistent model runs which is almost unheard of. Link to comment Share on other sites More sharing options...
Carvers Gap Posted March 9, 2017 Share Posted March 9, 2017 23 minutes ago, 1234snow said: Best model run ever for us? I'll probably stick that one in the iPad archive. I know that won't happen but I feel fairly confident in an accumulating snow around and north of I-40. We have had 1 full day of fairly consistent model runs which is almost unheard of. LOL. That and the 16 day 18z GFS/GEFS are going into the archive. Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted March 9, 2017 Share Posted March 9, 2017 0z GFS @84 Link to comment Share on other sites More sharing options...
John1122 Posted March 9, 2017 Share Posted March 9, 2017 GFS is just drier than the NAM by a good bit, colder, but drier. I have said this a million times, it often has trouble with showing too little precip and not getting the northern edge far enough north in these set ups. The NAM often over amps things. I could see a compromise between the two working out. Link to comment Share on other sites More sharing options...
BlunderStorm Posted March 9, 2017 Share Posted March 9, 2017 GFS is slipping north a little over the past 2 runs watch the model trend. Admittably it is also slipping a little south as well. Link to comment Share on other sites More sharing options...
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