John1122 Posted January 26, 2017 Author Share Posted January 26, 2017 UK Met, this is only out to 72 and is before the more potent clipper arrives. Roughly .15 over East Tn. .08 or so in Middle. SWVA jackpots there. Link to comment Share on other sites More sharing options...
John1122 Posted January 26, 2017 Author Share Posted January 26, 2017 NAM was much more vigorous with the system at 18z and a little later, moves into the area around 1 pm. Still having precip type issues on it's output with rain, but I still don't believe we'd see rain because 850s are -5c even over the Memphis area. I think the precip would quickly change to snow if it started as rain. Any rain shown in East Tennessee is especially unlikely. 850s are -6c to -9c there with surface temps in the 30s. Link to comment Share on other sites More sharing options...
John1122 Posted January 26, 2017 Author Share Posted January 26, 2017 Link to comment Share on other sites More sharing options...
Coach B Posted January 26, 2017 Share Posted January 26, 2017 That look is far enough west for most of the state to at least keep an eye on it. Upper Cumberland and mountains look good. Would like to see it slow down and come in later in the evening for any potential minor accums in non-elevated areas. Have to take whatever we can get in a winter like this. Link to comment Share on other sites More sharing options...
John1122 Posted January 26, 2017 Author Share Posted January 26, 2017 MRX says dusting maybe up to 1/2 inch for non-mountain areas and that it will change to rain south of 40 and mix with rain north of there. Must be riding the NAM verbatim on it's p-type output maps. I have watched clippers here for many years, if they start out as snow, they don't change to rain then back to snow, especially with the aforementioned frigid 850 temps. Even 925 mb temps are at 0c or lower basically statewide. Link to comment Share on other sites More sharing options...
Mrwolf1972 Posted January 26, 2017 Share Posted January 26, 2017 18z GFS has dropped the snow amounts greatly Link to comment Share on other sites More sharing options...
BlunderStorm Posted January 26, 2017 Share Posted January 26, 2017 9 minutes ago, Mrwolf1972 said: 18z GFS has dropped the snow amounts greatly Perhaps bringing expectations to reality. Link to comment Share on other sites More sharing options...
whamby Posted January 26, 2017 Share Posted January 26, 2017 .4 in the Noog, is still pushing it. Link to comment Share on other sites More sharing options...
BlunderStorm Posted January 26, 2017 Share Posted January 26, 2017 My prediction. Hopefully it doesn't bust entirely... Potential for more in the valleys then shown here from Knox to TRI- and maybe less from Chatty to Knox. There may also be a shift westward. In which case areas west of the Cumberland plateau gain an inch more than shown and areas in the apps lose an inch. I see perhaps some flurries past us in the Piedmont but that's it. Just covering a few changes I may make to it later. Link to comment Share on other sites More sharing options...
John1122 Posted January 27, 2017 Author Share Posted January 27, 2017 GFS bumped totals slightly in the East, trough a little more east the last two runs results in less snow west and south. Still think it will be probably 12z Saturday before we get a really good idea on this one. I think, and even this isn't set in stone, that the Plateau and border counties in the east will see 1-2 inches. The mountains in SEKY/SWVA/ETN pick up 2-4. 1 or less in all non-elevation areas south or west of these areas. Link to comment Share on other sites More sharing options...
Daniel Boone Posted January 27, 2017 Share Posted January 27, 2017 I'm with you John on those areas and totals. It is possible, with track shown by Nam and Gfs, a little more could be realized. One thing I find unusual about the Gfs and the Nam to some degree, is it showing higher totals around the Morristown area than here, regardless of what track.?. Granted, we do get downsloped some from nw flow events but, even in those we get more than there. It is not only snowfall those models tend to do this but, rainfall as well. If we wound up with what they print out for us, we'd be about 15 to 20% less annually than what we receive. Link to comment Share on other sites More sharing options...
Daniel Boone Posted January 27, 2017 Share Posted January 27, 2017 Meant to mention that the GGEM is more accurate and precise as it shows the amounts in relation to the true terrain setup. I have been researching this and have conclusions as to the cause of the Gfs and Nam problems regarding this. May detail later as keep get knocked out and have to sign back into amwx. Link to comment Share on other sites More sharing options...
weathertree4u Posted January 27, 2017 Share Posted January 27, 2017 9 minutes ago, flash43 said: 12z GFS lookin' better than prior runs. Even at 50% reduction, I'll take a poor man's inch at this point. I just want to see snow falling out of the sky again/for winter to feel like winter. Worst case, I'll probably just set sail for Jamestown or somethin'. Desperate times call for desperate measures. Looking good north of Nashville on this run. Would like to see the same basic thing the next couple runs before jump on the wagon. Link to comment Share on other sites More sharing options...
Carvers Gap Posted January 27, 2017 Share Posted January 27, 2017 I am not a big fan of clippers because so often they pull north at the last minute. We had some awesome ones during the 80s here. Also, it pays to be on the upslope. JC will often see a couple of inches and we(in Kingsport) see barely a flake here due to the Plateau's rain shadow. Very tricky systems to quote Bob Chill. Might not know until the last minute. Time of day will matter as well. I am always cautious as they rarely live up to expectations here...kind of like those long range -NAOs. Ha! Really though, prob will won't be a decent forecast until within 24 hours. The strength of that cortex and where it goes is tough to gauge at this point. I will take my 3" of snow though...but truly expect less than an inch. Folks at elevation view clippers with enthusiasm and well they should. As a valley dweller, snow from a clipper is a bonus. Link to comment Share on other sites More sharing options...
BNAwx Posted January 27, 2017 Share Posted January 27, 2017 1 hour ago, flash43 said: 12z GFS lookin' better than prior runs. Even at 50% reduction, I'll take a poor man's inch at this point. I just want to see snow falling out of the sky again/for winter to feel like winter. Worst case, I'll probably just set sail for Jamestown or somethin'. Desperate times call for desperate measures. Yeah, the northern part of the Plateau is a good place to be with these clipper systems. Wouldn't mind having a little getaway up there. Link to comment Share on other sites More sharing options...
John1122 Posted January 27, 2017 Author Share Posted January 27, 2017 Special Weather Statement National Weather Service Morristown TN 322 PM EST Fri Jan 27 2017 TNZ012>018-035>047-067>074-087-VAZ001-002-005-006-008-280500- Scott TN-Campbell-Claiborne-Hancock-Hawkins-Sullivan-Johnson- Morgan-Anderson-Union-Grainger-Hamblen-Northwest Cocke- Cocke Smoky Mountains-Northwest Greene-Southeast Greene- Washington TN-Unicoi-Northwest Carter-Southeast Carter-Roane- Loudon-Knox-Jefferson-NW Blount-Blount Smoky Mountains- North Sevier-Sevier Smoky Mountains-Southeast Monroe-Lee-Wise- Scott-Russell-Washington- Including the cities of...Oneida...La Follette...Tazewell... Sneedville...Rogersville...Kingsport...Bristol...Mountain City... Wartburg...Clinton...Oak Ridge...Maynardville...Rutledge... Morristown...Newport...Cosby...Greeneville...Cedar Creek... Johnson City...Erwin...Elizabethton...Roan Mountain...Kingston... Lenoir City...Knoxville...Dandridge...Maryville...Cades Cove... Sevierville...Gatlinburg...Coker Creek...Jonesville...Wise... Norton...Gate City...Lebanon...Abingdon 322 PM EST Fri Jan 27 2017 ...SNOW ACCUMULATIONS POSSIBLE ALONG THE NORTHERN CUMBERLAND PLATEAU...SOUTHWEST VIRGINIA...NORTHEAST TENNESSEE...AND THE HIGHER ELEVATIONS OF THE EAST TENNESSEE MOUNTAINS SUNDAY THROUGH MONDAY MORNING... SCATTERED LIGHT SNOW SHOWERS WILL BE POSSIBLE ACROSS THE AREA SUNDAY MORNING BEFORE TRANSITIONING TO RAIN SUNDAY AFTERNOON. SNOWFALL ACCUMULATIONS THROUGH THE MORNING WILL RANGE FROM A DUSTING IN THE VALLEY...TO HALF OF AN INCH IN SOUTHWEST VIRGINIA AND HIGHER ELEVATIONS OF THE EAST TENNESSEE MOUNTAINS. AS THE TEMPERATURE DROPS BELOW FREEZING SUNDAY EVENING...RAIN SHOWERS ARE EXPECTED TO TRANSITION TO SNOW...WITH SCATTERED SNOW SHOWERS THROUGH MONDAY MORNING. ADDITIONAL SNOWFALL ACCUMULATION TOTALS RANGE FROM HALF OF AN INCH TO TWO AND A HALF INCHES ALONG THE NORTHERN CUMBERLAND PLATEAU AND NORTHEAST TN...WITH AN ADDITIONAL 3 TO 6 INCHES EXPECTED THROUGHOUT SOUTHWEST VIRGINIA AND THE HIGHER ELEVATIONS IN THE EAST TENNESSEE MOUNTAINS. Link to comment Share on other sites More sharing options...
BlunderStorm Posted January 27, 2017 Share Posted January 27, 2017 interesting...and MRX is generally somewhat conservative. Link to comment Share on other sites More sharing options...
John1122 Posted January 27, 2017 Author Share Posted January 27, 2017 They say the forecast could vary greatly between now and then. But their model of choice is the GFS. I still don't see the rain aspect coming to pass, especially north of 40. I am often baffled as to why WFO often act as if it doesn't snow with temps above 32 degrees. When the upper atmosphere is right, it will snow at the surface unless it's extremely warm. Unless something changes, the -6 to -9 850s and 0 to -2 925s should keep this all snow even if the surface gets into the mid 30s. Link to comment Share on other sites More sharing options...
John1122 Posted January 27, 2017 Author Share Posted January 27, 2017 Looking to see the RGEM get into range. It had a lot of skill handling clippers last year. Blew the NAM off the face of the earth among the shorter range models. As of now, it's much more moist and further west than the NAM, which has went bone dry. Link to comment Share on other sites More sharing options...
BlunderStorm Posted January 27, 2017 Share Posted January 27, 2017 Heh, if you have snow on the ground already and it's above freezing it will still accumulate up to 35F given moderate snowfall. Link to comment Share on other sites More sharing options...
John1122 Posted January 27, 2017 Author Share Posted January 27, 2017 The precip streak in Central Missouri on the RGEM may hold some hope to those in Middle/West Tennessee. Far better angle than the NAM. The event doesn't get rolling over the eastern half in decent fashion until beyond the range of the RGEM. Link to comment Share on other sites More sharing options...
John1122 Posted January 27, 2017 Author Share Posted January 27, 2017 4 minutes ago, BlunderStorm said: Heh, if you have snow on the ground already and it's above freezing it will still accumulate up to 35F given moderate snowfall. I'm not even referring to accumulation, they seem to always imply that flakes won't fall from the sky once it's above 32. The surface is honestly far less important to snowfall than the upper atmosphere. That's why it can rain and be 15 degrees at the surface (this happened here once), or snow with temps in the 40s at times. Link to comment Share on other sites More sharing options...
weathertree4u Posted January 27, 2017 Share Posted January 27, 2017 22 minutes ago, John1122 said: I'm not even referring to accumulation, they seem to always imply that flakes won't fall from the sky once it's above 32. The surface is honestly far less important to snowfall than the upper atmosphere. That's why it can rain and be 15 degrees at the surface (this happened here once), or snow with temps in the 40s at times. I would think this would be a Advisory level event for areas along and east of I-65 and I-40 north especially but probably safer to issue it area wide, have seen these things overperform, especially if it comes in overnight Sunday into Monday morning. Link to comment Share on other sites More sharing options...
tnweathernut Posted January 27, 2017 Share Posted January 27, 2017 I really think timing is the key for this event. Sunday afternoon wouldn't interest me, but the bulk coming in after sunset would at least have the potential to create a pretty scene in some places Monday morning. Even better if light snow continues after daybreak..... Link to comment Share on other sites More sharing options...
jaxjagman Posted January 27, 2017 Share Posted January 27, 2017 33 minutes ago, John1122 said: The precip streak in Central Missouri on the RGEM may hold some hope to those in Middle/West Tennessee. Far better angle than the NAM. The event doesn't get rolling over the eastern half in decent fashion until beyond the range of the RGEM. This would be good for you with the upslope flow.On a side note, they started to treat our roads this morning,they didnt learn from the last little snow with all those accidents in our area treating the roads to soon. Link to comment Share on other sites More sharing options...
bearman Posted January 28, 2017 Share Posted January 28, 2017 MRX had this to say this morning about the Sunday clipper. For the life of me I don't understand their obsession with the idea that we are going to see a change over to rain. We just don't see this happen under these circumstances. Looking forward to the coming snow potential, the 12Z NAM and the 06Z GFS have some large differences in amounts in the TN Valley. The GFS seems to be an outlier with its higher amounts, and the SREF supports the NAM. The main difference appears to come on Sunday morning, when the GFS has colder surface temps than the NAM, allowing more snow to accumulate that period. Since temps are expected to be above freezing in the Valley in both models during that time, the lower amounts of the NAM/SREF appear more realistic. Will await the 12Z GFS before issuing any W/W/A products, but given the long time period of snow accumulation (> 24 hours), an advisory will likely be the most appropriate product for the northern half of the area. Link to comment Share on other sites More sharing options...
John1122 Posted January 28, 2017 Author Share Posted January 28, 2017 JKL's thoughts on the clipper for their CWA. Quote As previous discussion mentioned...periods of heavy snow are possible and cannot rule out some thundersnow. This type of scenario usually produces one or more bands of snow that overachieve and approach or exceed warning criteria. However, trying to pinpoint where that is going to happen at this time frame is not possible with any degree of confidence and do not expect it to be widespread so will not issue a Winter Storm Watch. We will continue to advertise locally higher amounts than the general 1 to 3 inches that is expected and I anticipate winter weather headlines being posted later on today. Link to comment Share on other sites More sharing options...
John1122 Posted January 28, 2017 Author Share Posted January 28, 2017 Right now the biggest issue for snow accumulation may be temps. The NAM never gets anyone below about 35 at the surface when precip arrives, the 925 temps are +2c for a good portion of East Tn and surface temps warm into the mid 40s in the central Valley areas on it. The GFS and RGEM are 5 degrees or so colder. The 850s are -5 to -7 over most of the area throughout. The 540 line is something like 50/50 snow chance below 1000 feet in elevation. The 528 or even 522 line is over the area during this time. There are certain times when that can produce rain, but it's really really rare once it's down in the 520s. Link to comment Share on other sites More sharing options...
Daniel Boone Posted January 28, 2017 Share Posted January 28, 2017 John, those are valid points that make complete sense, imo. That is precisely what I was referring to awhile back regarding Kmrx that I think some took as me bashing them. That was not the intent, by no means as I know and like several of the mets there. There is one thing that has happened recently that is one probable reason for the rather "should know, but not knowing" attitude in their outlooks ; Several retirements of which have been replaced with newbies of which may be, at least partly , interns. Although, you'd think even the interns know it can snow above 32 as long as temps are colder higher up, let alone having all the tools you mention that show expected temp. profiles. Sad, really. It all may come down to the fact that some people are just there for the Job and may not really like what they do and basically have a "could care less" attitude, unfortunately. Link to comment Share on other sites More sharing options...
John1122 Posted January 28, 2017 Author Share Posted January 28, 2017 MRX goes with WWA above 2500 and in SWVA. Thinks rain/too warm for more than an inch in the Plateau/lower elevations per disco. JKL goes WWA for all their counties including border of TN counties. Says 1-3 with some 4+ areas in potential bands/thundersnow. There will be one of two scenarios here at my place. This will start as snow and stay snow, especially if there are remotely decent rates, or it will start as rain and stay rain. It will not start as snow and switch to rain in the afternoon. Cold air advection begins in the afternoon per JKL so if anything it will be getting cooler as the day goes on into early evening. Link to comment Share on other sites More sharing options...
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