2016-2017 Great Tennessee Valley Winter Discussion

[John1122]

That Para is extremely unlikely of course, but man it's beautiful and kinda the idea that the GFS was throwing around when it had most of Tennessee under 15-25 inches of snow right around that time frame when I posted the maps for the 17th timeframe in banter a while back.

That solution is the solution I've been arguing for the past few days when the GFS keeps showing 1040+ highs with frigid air in great positions to dump snow/ice on us but lows just run north right into them and the cold doesn't penetrate. 

I don't know if that is the right solution, but it's what should happen with those players on the board in the positions they are shown.

 

[JayCee]

1 hour ago, dwagner88 said:

I don't understand this either. I know that I got about 4" of sleet and an inch of snow on top in the January storm. It is totally missing from KCHA records though. Best sledding I've ever done. Took forever to melt too. 

Sleet--the underrated winter precipitation.   

As far as the missing records...I'm clueless.  I don't understand why or how the records were lost or changed.  What would be the point?  I can't honestly believe they were lost in the modern era.  So why change them?  Sounds like something from the X-Files. 

[John1122]

I also think the para records all potentially frozen precip as snowfall on that map. It shows snow accumulating as mixed precip is depicted. It would be an epic winter storm either way, as 20s bank up to the Apps almost and moisture overruns the front that's hung up.

[nrgjeff]

Looks like a colder than normal 10 day period. Within the period look for a warm-up next weekend followed by more cold. Then 2-3 weeks of milder weather may come in for the Holidays. Bering sea ridge totally breaks down and that fast Pac jet returns. Possibly/hopefully the warm pattern is the temporary one. However no getting around the red tag jinx: hashtags like #clutch and #happening are bad luck.

Depending on how the MJO evolves we could get another cold pattern shortly after New Years. So, it is not a total loss. Pride is bruised a bit. Well, not really. It is a small price to pay for some possible storm chasing in the middle of winter.

It is still early in meteorological winter and calendar winter has not even started yet. I would not sweat it, unless dews get up to 65 and a tornado watch is valid overnight. Seriously mild holidays are no concern. The last 3 winters mild holidays were followed by cold in the core of winter.

Go storm chasing and then go skiing, noproblem! 

[Carvers Gap]

1 hour ago, nrgjeff said:

Looks like a colder than normal 10 day period. Within the period look for a warm-up next weekend followed by more cold. Then 2-3 weeks of milder weather may come in for the Holidays. Bering sea ridge totally breaks down and that fast Pac jet returns. Possibly/hopefully the warm pattern is the temporary one. However no getting around the red tag jinx: hashtags like #clutch and #happening are bad luck.

Depending on how the MJO evolves we could get another cold pattern shortly after New Years. So, it is not a total loss. Pride is bruised a bit. Well, not really. It is a small price to pay for some possible storm chasing in the middle of winter.

It is still early in meteorological winter and calendar winter has not even started yet. I would not sweat it, unless dews get up to 65 and a tornado watch is valid overnight. Seriously mild holidays are no concern. The last 3 winters mild holidays were followed by cold in the core of winter.

Go storm chasing and then go skiing, noproblem! 

Glad you are posting so often this season and are willing to put it out there on the line.  It is easy for many to use lots of language to minimize losses, but you shared your ideas clearly w no doublespeak.  You are right more times than not.  Bout all anyone could ask when trying to predict chaos.  Much respect, man.  And I agree, it might mean we can get cold when climo is coldest instead of a thaw.  Things have a way of working out.  Sugar Mtn has been blowing snow like crazy.  Slopes should be shaping up.  Thanks for the update.

[Daniel Boone]

6 hours ago, Carvers Gap said:

Edit...storm #1 I got around 6-8" with some ice at Papermill.  Could have been a bit more...(When I confronted MRX about the TRI data being wrong for that winter, they almost acted like it wasn't a big snow year.  I finally provided screenshots of NWS maps of the storm....then they said the records were lost.)Was a sharp cut-off for snow.  When I drove home a week or so later, I was shocked at how much metro missed.  

Carver's, that's the main reason of my somewhat dissing of NWS. Granted, some if not most of the flawed data is because of poor excuse observers from their official climate stations. This I witnessed myself as I spoke with the employees at, what was then, Pennington gap's official station at the water plant 1 mile south of town. They had a couldn't care less attitude of the data accuracy. The previous official penn. gap sites did a good job. kmrx said they needed someone at the time and the town offered. thankfully, I got mrx to drop them. However, not before they really screwed up records, climate normals and data for the area.

[whamby]

5 minutes ago, Daniel Boone said:

Carver's, that's the main reason of my somewhat dissing of NWS. Granted, some if not most of the flawed data is because of poor excuse observers from their official climate stations. This I witnessed myself as I spoke with the employees at, what was then, Pennington gap's official station at the water plant 1 mile south of town. They had a couldn't care less attitude of the data accuracy. The previous official penn. gap sites did a good job. kmrx said they needed someone at the time and the town offered. thankfully, I got mrx to drop them. However, not before they really screwed up records, climate normals and data for the area.

Interesting... I know there is a lot of missing data from the 1990s in CHA weather records. I always felt Morristown was covering too much area to do us in SE Tn justice. 

[Carvers Gap]

12z JMA on Tropical Tidbits looked interesting at 192.  LP slides south of the area.  Maybe it gets a bit strung out?

[jaxjagman]

2 hours ago, nrgjeff said:

Looks like a colder than normal 10 day period. Within the period look for a warm-up next weekend followed by more cold. Then 2-3 weeks of milder weather may come in for the Holidays. Bering sea ridge totally breaks down and that fast Pac jet returns. Possibly/hopefully the warm pattern is the temporary one. However no getting around the red tag jinx: hashtags like #clutch and #happening are bad luck.

Depending on how the MJO evolves we could get another cold pattern shortly after New Years. So, it is not a total loss. Pride is bruised a bit. Well, not really. It is a small price to pay for some possible storm chasing in the middle of winter.

It is still early in meteorological winter and calendar winter has not even started yet. I would not sweat it, unless dews get up to 65 and a tornado watch is valid overnight. Seriously mild holidays are no concern. The last 3 winters mild holidays were followed by cold in the core of winter.

Go storm chasing and then go skiing, noproblem! 

I concur with Carver and the rest here.Thanks for all your input.It's always nice to have some insight from a pro.

[John1122]

00z Canadian has a similar but less extreme version of the 12z GFS para. Temps in the -20s in Northern Indiana with a 1040+ hp over Ohio by 204. Temps are in the 20s here with overrunning freezing rain/sleet as the precip type. Looks like multiple waves over multiple days if it's solution were to verify. Plateau west has icing at hour 156. that lightens up but another wave forms 24 hours or so later with overrunning ice/snow in the area at 180. It goes away for a few hours and another wave over runs the area at 204 with the above mentioned very cold temps and great HP placement.  

 

This is what the Canadian spat out that run.

The 18z Para was a less extreme version of it's 06z that had Western Valley areas getting freezing precip, although synoptically it was very similar with waves of moisture and a HP in a good position to feed cold into the area but the storm placement was weaker and further south and it moved east faster, giving less time to wrap in cold air behind it.

[nrgjeff]

Thanks Carvers and Jax. I am still leaning that the warm-up is the secondary weather pattern. If cold comes back after the New Year or even the second week of January it would be the dominant pattern, week-by-week, Dec-Jan. Some of those years with wild swings, but plenty of cold, are reasonable comparisons.

Cold air will still lurk in western Canada, esp northwestern Canada, even when the mild Pacific jet stream starts. If the MJO convection in the Indian Ocean comes out to the Western Pacific, some Alaska ridging would pop up again. Sports metaphor time: Need to block out that jet stream like Anthony Davis stuffing the shooter in the NBA.

Right now we have a lot of convection over Indonesia. Perhaps the strong tropical cyclone making landfall in India, even farther west, is playing a role in the retrogression of the long-wave pattern and return of the SER. I am not really hypothesizing, just kicking it around. Lets see how things go once that cyclone spins down, and if Indonesia convection can scoot out into the West Pac.

Long as the wx pattern stays interesting I will be here. Anything from snow to severe interests me. Good to know the snowmakers are blowing up in the ski areas. Hopefully they can build up a base before that mild regime for the holidays. They count on a lot of revenue around the holidays.

[JayCee]

14 hours ago, nrgjeff said:

Looks like a colder than normal 10 day period. Within the period look for a warm-up next weekend followed by more cold. Then 2-3 weeks of milder weather may come in for the Holidays. Bering sea ridge totally breaks down and that fast Pac jet returns. Possibly/hopefully the warm pattern is the temporary one. However no getting around the red tag jinx: hashtags like #clutch and #happening are bad luck.

Depending on how the MJO evolves we could get another cold pattern shortly after New Years. So, it is not a total loss. Pride is bruised a bit. Well, not really. It is a small price to pay for some possible storm chasing in the middle of winter.

It is still early in meteorological winter and calendar winter has not even started yet. I would not sweat it, unless dews get up to 65 and a tornado watch is valid overnight. Seriously mild holidays are no concern. The last 3 winters mild holidays were followed by cold in the core of winter.

Go storm chasing and then go skiing, noproblem! 

I for one appreciate your candor.  Weather forecasting is far from an exact science, and I never fault a forecaster for not getting it right all the time.  If you were that good, I would ask you to give me some numbers for the lottery!!   Heck, even computer models change their thinking almost daily.  Props to you for calling it like you see it. 

I'm with you as far some cold returning.  Even the great winter two years ago came after a pretty mild and uneventful December. 

[tnweathernut]

I agree with those on the board regarding Jeff.  Your postings are always solid and MUCH appreciated.

Taking a glance at the models I hate we are in the go cold and dry then warm and wet cycle, BUT I am loving the rain if I am being honest.  I don't think the bulk of Tennesseans knew just how dry it was until the Gatlinburg fires occurred.  ANY rains are welcomed and needed!  There is still a chance for something wintry before the cold lifts in a more meaningful way, but living in the south and scoring a "winter" event always seems to be a challenge.  The overnight Euro depicts the same type of setup as seen on other modeling, an arctic front that presses through and a low develops on that boundry.  

I do think NC probably has a better chance with this if that low were to develop, with possible CAD, and it's so far out there it's still not worthy of doing anything but taking quick glances at the overall pattern to see how it might happen. That said, that last high is COLD, so even those in TN should keep an eye on it.  Moisture tends to overperform on the northern edges of any low pressure in the south without blocking (what's that, right?)  In the words of Dumb and dumber, "so you're saying there's a chance"?

 

 

[JayCee]

Agree with you tnweathernut.  Since we can't have snow, let it rain, let it rain, let it rain!

[Carvers Gap]

12z CMC 240hr total ice accumulation.  What is the Euro looking like?

[jaxjagman]

Not much at all really,it's ZR or IP no snow

[Carvers Gap]

The 6z GFS op had very little warm-up in the LR.  The weeklies (last night ) had 2-3 weeks where it was warm in the mean, maybe weeks 2-4.  Then, they flip very cold.  The control basically continues the same pattern we are in.  I am noticing more volatility with controls and OPs during the past 24 hours.  That might indicate that the ensembles are smoothing things out a bit too much.  

[nrgjeff]

Unfortunately volatility may rule the balance of winter, not unusual in La Nina. Though the index is weak, the tropical Pacific atmosphere is in full Nina mode. OLR outgoing long-wave radiation is classic Nina. I am starting to favor 4 week patterns, fairly even as opposed to dominant and secondary patterns.

If you go back to the week of Thanksgiving, next week we will conclude a 4-5 week cold pattern. A 4 week warm pattern is forecast by the Euro; CFS says just 3. More broadly however, they both have trough west with SER for about 3-4 weeks starting late next week through about January 10. The La Nina background state would favor SER deeper in the January. The MJO could have something to say though. MJO can and usually does have more influence in La Nina years.

Another noticeable trend is forecasts calling for the polar vortex tighten up again for a few weeks. This is the real PV, not the media polar pig. Tighter PV keeps the arctic air locked up more. If you want it to get cold again, look for MJO help to disrupt the developing mild Pacific jet stream.

[Carvers Gap]

Jeff, I was thinking as well that the we might be nearing the end of the current pattern as time had simply run out a bit early.  We burned a week or two just cooling-off NA, so we did not get the full effects of the cold.  As for volatility, I actually like it over a stable pattern sometimes, even a cold pattern.  For me, volatility equals a ton of chaos that gives models problems as well. The 12z GFS is similar to what I have in mind.  It has a SER that is active, but at times it gets pushed back by the cold to our north.  IMO, I think where the models might be in error is trying to warm-up all of NA.  The controls and OPs have depicted this at times.  I have a suspicion that western Canada may stay cold, and that we may still have a source region.  Weak Ninas here in TN are only second to weak Ninos for me in terms of favorite wx patterns.  Seems like weak Ninas are not cold on average but have severe cold outbreaks.  If we can score an outbreak in January, I think we are all happy.  Also, the GOM is open on the 12z GFS.  That might make things interesting.  Forgot to mention, the 46 day weekly precip mean was way above normal for the forum area which is great news.  I saw where officials have installed a special flood monitor for the Little Pigeon above Gatlinburg due to burned-out areas flooding more easily.  Jeff, when you say the SER is favored deeper into Jan, are you saying the currently projected ridge might last longer...or it may appear again after the current episode in late Jan?

 

Also, I am noticing the CMC and GFS both now advertise multiple frozen precip events in middle and west TN during the previously discussed time range.  Man, the 12z GFS is mainly cold throughout.  Heckuva way to run a warm-up.  

[Carvers Gap]

On 12/11/2016 at 5:47 PM, John1122 said:

I also think the para records all potentially frozen precip as snowfall on that map. It shows snow accumulating as mixed precip is depicted. It would be an epic winter storm either way, as 20s bank up to the Apps almost and moisture overruns the front that's hung up.

What do you think?  Is some portion of the forum are going to get frozen precip during the next ten days? Nice set-up shaping-up for the Plateau. 

[John1122]

1 hour ago, Carvers Gap said:

What do you think?  Is some portion of the forum are going to get frozen precip during the next ten days? Nice set-up shaping-up for the Plateau. 

I'll be shocked if North Central Tennessee to NW Tennessee and a lot of Southern Kentucky don't manage icy weather. Further east of there it's up in the air. I will say that these Arctic air masses almost always sink further south and east than models indicate.

[John1122]

The 12z runs of the Canadian and GFS basically line up with each other on the ice area develops for the first time.  The GFS had actually mostly been keeping it out of Tennessee. We will have a few more days to watch and I'm sure they'll flip all over the place, but it's getting close to the timeframe when accuracy scores are much higher. 

 

 

[JayCee]

If nothing else, it sounds like we'll be drowning the drought with above normal rainfall over the next few months.  That is great news. 

As far as the ZR maps above, I don't mind it missing my backyard.  When you live in the woods, ice is the enemy.  If I can't have snowflakes or sleet pellets, I'm good with plain rain. 

[John1122]

I live in the woods and in a very prone area to get icing due to cold getting trapped right over my area with the steep ridges on every side of me. Living in a bowl makes for interesting weather. It's most noticeable in icing events and clear calm mornings. I'm usually 5-8 degrees colder on most clear mornings than areas at 2500 feet or so. Sometimes 10 or more. I've went up 500 feet in elevation before and went from 25 degrees to 40 degrees.  The opposite happens in snow set ups. They are usually 2-3 degrees colder than me and that makes a lot of difference here in changeover times and amounts. It's crazy how small a distance north to south and an elevation difference of 4 or 500 feet make.

[Carvers Gap]

1 hour ago, JayCee said:

If nothing else, it sounds like we'll be drowning the drought with above normal rainfall over the next few months.  That is great news. 

As far as the ZR maps above, I don't mind it missing my backyard.  When you live in the woods, ice is the enemy.  If I can't have snowflakes or sleet pellets, I'm good with plain rain. 

Plenty of moving parts...Arctic boundary and timing of precip and number of waves.  

[ShawnEastTN]

2 minutes ago, Carvers Gap said:

Plenty of moving parts...Arctic boundary and timing of precip and number of waves.  

Yep, while the plateau is a good barrier to blocking low level cold in situations like this I also recall every so often the cold makes it over into the valley and catches everyone off guard even forecasters.  It will be interesting to watch.

[Carvers Gap]

13 minutes ago, ShawnEastTN said:

Yep, while the plateau is a good barrier to blocking low level cold in situations like this I also recall every so often the cold makes it over into the valley and catches everyone off guard even forecasters.  It will be interesting to watch.

Not that I actively seek ice storms in the Valley, but IMO in the east you want the precip to move in over cold and lock it into place creating a temperature inversion.  Then, you rely on evaporational cooling and low dew points to drop temps on the ground.  The models are sort-of depicting several waves riding a cold frontal boundary.  That makes it tricky.  In East TN, we prob don't want cold chasing rain.  We would want for the cold to press over the Plateau between a lull....or for the models to miss how far south the cold air pushes.

[ShawnEastTN]

1 minute ago, Carvers Gap said:

Not that I actively seek ice storms in the Valley, but IMO in the east you want the precip to move in over cold and lock it into place creating a temperature inversion.  Then, you rely on evaporational cooling and low dew points to drop temps on the ground.  The models are sort-of depicting several waves riding a cold frontal boundary.  That makes it tricky.  In East TN, we prob don't want cold chasing rain.  We would want for the cold to press over the Plateau between a lull....or for the models to miss how far south the cold air pushes.

Definitely don't want ice either...  I live probably about 8 miles as the crow files from the Escarpment and just like you say if it can spill over in a lull between those waves we could have a problem.  I've seen where counties just along the edge of the plateau in the valley got surprise ice this way, actually just a few years ago even.

[John1122]

18z just plasters the Plateau with ice again. Frontal boundary sinks south and east of the area. Cold comes in, front moves back up a little and moisture overruns the cold air. I'd keep a wary eye a row or two of counties East of where it's showing the ice now. Cold seems to always sag just a little further in these situations. 

[Carvers Gap]

13 minutes ago, John1122 said:

18z just plasters the Plateau with ice again. Frontal boundary sinks south and east of the area. Cold comes in, front moves back up a little and moisture overruns the cold air. I'd keep a wary eye a row or two of counties East of where it's showing the ice now. Cold seems to always sag just a little further in these situations. 

 Yep.  I think everybody ought to keep a close eye on it.  Been there several runs now.  Seeing a 1044 hp trailing the initial ice gets my attention.  Seems like a possibility that the cold bottles up against the west side of the Apps vs the Plateau....but everybody Plateau and westward should watch the system.  John, the GFS again show very little warm-up.  If anything, it is very cold much like the control on the EPS.