Tennessee Valley 2019 Fall Speculation/Forecasting

[TellicoWx]

Need the lead system exiting the NE to act as a block and slow the pattern for the 11/12 piece of energy (0z Euro)...GFS is more progressive, and scoots it out to sea.

[Holston_River_Rambler]

Good thing we have the Euro on our side with that one. GFS has been moving more and more toward the Euro's solution for the later week system over the past few runs. I think we also want to see more of a sharp dig out of the piece coming out of Alberta to get us under a nice right entrance region. As Tellico pointed out the GFS is more progressive with it, so hopefully it will also end up with more of a dig. With some of the thoughts about a possible warm up mid month, it would make sense that we could have a chance at something beforehand. 

Also, check out the buckle over western North America at the end of the 0z Euro. That might force some energy pretty far south. 

As Carvers has been pointing out still some big highs helping all this along. I feel like a lot of those we saw last season seemed to weaken as we moved forward toward verification time, but new season, maybe new outcome. Along those lines the piece of energy that gives us a chance at hour 180 is currently over Siberia and according to both the GFS and Euro comes across the North Pole:

 

 

[Mr Bob]

17 hours ago, jaxjagman said:

To bad this isn't showing this 2-3 days out.Mr.Bob will probably pound me if he sees this..lol

OMG!!!!!!   Foul beast!  

These are useful in pattern discussions and it is the EPS afterall....We only object to the "Look at this 384 hr GFS. Wish this would happen" type silliness.....

 

 

[nrgjeff]

Cold chasing rain. You all know I fade everything though.

As for November, all cold does have a 70% continuation. Sure LY failed but that's the 30%. So, we'll see if we can get a cold Novie.

I'm trying to improve my winter attitude. Rather than dread cold short days, look fwd to Appalachian snow skiing! 

[Carvers Gap]

We'll see if this verifies...but Tuesday and Wednesday(next week) don't get above freezing at TRI on the 12z GFS.  Pretty sure there are some record lows in jeopardy if that is correct.  Long way to go, but another impressive run.  Let's see if the Euro backs it up.  FYI, I always forget that everything runs an hour earlier when we "fall back."

edit:  Looks like the GFS puts a bit of snow on the ground which skews that just a tad...but still looks like Tuesday would have trouble making it to freezing unless it was at midnight.  Super cold air mass that is 20-30 degrees below normals for max temps.

[Wurbus]

I'm not sure if this has been said yet, but Pivotal Weather is now providing free Euro model runs with precip and temps in real time.

[Holston_River_Rambler]

1 hour ago, Carvers Gap said:

Let's see if the Euro backs it up.

Indeed it does:

Still a little early for the close up maps though. 

[Wurbus]

Coldest map I see on the Euro from the Pivotal maps.

 

[Stovepipe]

9 minutes ago, Wurbus said:

Coldest map I see on the Euro from the Pivotal maps.

 

 

Welp, time to winterize the camper!

[Carvers Gap]

33 minutes ago, Holston_River_Rambler said:

Indeed it does:

Still a little early for the close up maps though. 

Yeah, it backs of just a bit with the Tuesday cold shot and that particular trough is shallower...and then it delivers a second and third shot during the next couple of days that are equally impressive.  The wind chills on Wednesday AM in the higher elevations are in the teens below zero.  The trend was slightly warmer(I mean are lower 30s for highs really that much warmer!?) for Tuesday and trended colder over most of the eastern 2/3 of NA for the following days.  The end of that run is cold...that would be cold even in January.   I hope it verifies.  Still about seven days out...but an impressive cold signal on the GFS and Euro for the 12z suite.  Death ridge for early fall, deep freeze for late fall...and then watch us go zonal all winter just to keep it even.  LOL

[nrgjeff]

ECMWF weeklies keep delaying the break-down of the blocking by a week. So, another week of cold is shown.

Nice having everything earlier with the time change. 

[John1122]

1989 had similar November cold.  I can remember going deer hunting and it was 13 degrees with flurries when I left.  That led into the extremely frigid December but of course 1990 broke warm. 

[TellicoWx]

Key piece to me is the piece of energy on 6z and prior GFS is weaker on 12z GFS, allowing Atlantic ridge to build back to Greenland quicker in allowing a deeper trough...12z GFS and Euro doesn't have it beating on western edge of the ridge. (6z vs 12z GFS)

[Carvers Gap]

2 hours ago, John1122 said:

1989 had similar November cold.  I can remember going deer hunting and it was 13 degrees with flurries when I left.  That led into the extremely frigid December but of course 1990 broke warm. 

My first semester at UT.  Pretty much froze.  Second semester, I think the opened the outdoor pool in like January.  LOL.  

Just seems like right now that the trough really wants to go into the East.  Really pulling for that November -> winter correlation to work out.  Great start here for a cold month to be realized.

[Mr. Kevin]

5 hours ago, Carvers Gap said:

My first semester at UT.  Pretty much froze.  Second semester, I think the opened the outdoor pool in like January.  LOL.  

Just seems like right now that the trough really wants to go into the East.  Really pulling for that November -> winter correlation to work out.  Great start here for a cold month to be realized.

Carver, i think people would want it to be cold during winter. Shorter wavelengths can allow it to be colder, but we will see if the longer wavelengths allow that or not.

[John1122]

The Euro and GFS keep the flake chances next Sunday. The Euro is more aggressive than the GFS, especially from Nashville to Eastern Kentucky with 3/4ths inch over the Northern middle Tn areas, 1.5ish into Kentucky. The GFS would just be some flakes in the area. The Canadian has a western Valley ice event centered Eastern Arkansas to Jackson. 

 

Stiff coldfront and it's not warm before it arrives.  Temps are in the mid 40s ahead of the front on the EURO,  mid 10s to low 20s behind it 24 hours later.  The Euro looks like the cold squeezing moisture in the form of snow with anafrontal snow behind the front. 

[TellicoWx]

12 minutes ago, John1122 said:

The Euro and GFS keep the flake chances next Sunday. The Euro is more aggressive than the GFS, especially from Nashville to Eastern Kentucky with 3/4ths inch over the Northern middle Tn areas, 1.5ish into Kentucky. The GFS would just be some flakes in the area. The Canadian has a western Valley ice event centered Eastern Arkansas to Jackson. 

Decent day for the Ensembles: Measurable (1+), for my area. Any flakes in November here is a win lol.

GEFS:

6z 1/21 (0)

12z 1/21 (1)

18z 6/21 (2)

00z 13/21 (7)

EPS: since 12z yesterday

12z 8/51 (2)

00z 19/51 (4)

12z 21/51 (6)

Still waiting on tonight's 0z EPS. 0z GEFS also had a sharp drop for the mean high, closer to the EPS now in the mid 30's.

[TellicoWx]

Some increase in the mean so far on the 0z EPS:

12z vs 0z

[ShawnEastTN]

My point forecast from Morristown now includes rain & snow showers Thursday night, and slight chance snow showers Friday morning.

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[Carvers Gap]

I would guess that maybe the GFS and other LR modeling are possibly missing some small scale features embedded in the northern stream next week.  Tuesday and Wednesday next week are super cold on the 12z GFS.  I wouldn't rule out some northern stream feature slipping into the picture at the last minute.  That is normally a late Dec/January flaw in modeling, but this airmass being modeled is January level cold(not severe by January norms...but severe by November standards).   That type of cold is about a month and a half early.  Modeling has had some frozen precip during that time frame from time to time on various runs.  At this point, climatology very much frowns on valley systems that feature measurable frozen precip other than passing flurries or snow showers.  However, with the GOM being slightly more active and cold roaring through....doesn't hurt to watch things.  Probably the best option would be snow coming in along the Arctic front.  Low probability at this point, but chances are not zero either.   I will say this...anytime that much cold air gets into the forum area, has to be watched for shenanigans.  Some type of upslope event would likely not be out of the question either as lake effect snow is probably going to be a part of these big, cold highs.  

edit:  What I am looking for is of the slider variety as true confluence is probably in New England so that makes a coastal less probably.  

[Carvers Gap]

@John1122, I think the possibilities of you getting a cold November are increasing quite a bit.  I have my fingers crossed.   Last November flipping on modeling has me a bit gun shy.  However, looks like temps through mid-month will be well BN.  Maybe some decent signs that the second half will be seasonal to BN.  One could make an argument that my warm December idea is even in jeopardy.  The eastern trough is looking fairly steady right now.  Hopefully, that holds as we settle into early winter in a few weeks....changing wavelengths do make me nervous as the current ones are a bit short.  That said, the ensembles do have more of a stable wave pattern for the northern hemisphere which look a bit more winter like in nature(meaning longer wavelengths)...I may be getting ahead of myself on that, though.

[Carvers Gap]

LOL.  Ya'll need to me to talk more about New England confluence and sliders being the main potential.  The CMC has a Miller A @174.  

[Carvers Gap]

Typhoon Halong is probably factoring into East coast weather next week.  BIG storm.  As mentioned in the MA forum, that is the type of system that resets what would otherwise be a good pattern.  Could be both a blessing(short term) and a curse type deal(long term w/ pattern reset and doing more damage than needed to the PV this earl).  

[ShawnEastTN]

LOL.  Ya'll need to me to talk more about New England confluence and sliders being the main potential.  The CMC has a Miller A @174.  

I'll take what the crazy canuck is selling!

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[PowellVolz]

Icon likes the CMC


.

[Carvers Gap]

Watching the 12z Euro roll right now...the 12z UKMET had a monster high rolling in from Canada with a sip over the TX Panhandle around the Tuesday/Weds timeframe of next week.  Then the run ended.  So, that is three models with some potential, but need one of the major global models on board(GFS or Euro).   Still is interesting for sure.  Big, cold highs our of Canada have been an ingredient in many big EC coastal storms.  Just kicking things around, but interesting.  

[ShawnEastTN]

Watching the 12z Euro roll right now...the 12z UKMET had a monster high rolling in from Canada with a sip over the TX Panhandle around the Tuesday/Weds timeframe of next week.  Then the run ended.  So, that is three models with some potential, but need one of the major global models on board(GFS or Euro).   Still is interesting for sure.  Big, cold highs our of Canada have been an ingredient in many big EC coastal storms.  Just kicking things around, but interesting.  

12z Euro seems to want a bit of moisture stretched along that boundary at hours 168 and 174, but not the monster the CMC is depicting.

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[Carvers Gap]

Looks like the 12z Euro held back its energy in the southern stream and buried it over west TX.  Sometimes it is right with that, sometimes not.  The northern stream energy did pop a coastal.  The CMC had the wave continue out of SW Louisiana and continue up through the Piedmont.  Pieces are there...timing on that run was not.  GFS was too progressive.  Euro held energy back.  Both are biases.  I would think there is a decent signal for an EC storm...may not help us here, but maybe for folks from West Virginia to inland NE.  But who knows...that set up could yield an inland runner or just be sheered out with nothing.  Interesting to see for sure.

[Carvers Gap]

And looking a little more closely at the 12z Euro, it has the wave on Tuesday in SE GA.  It just lacked precip.  So, just guessing the phase missed or was a weak phase.  Honestly, that setup with no changes probably has more precip over the TN valley.  So, really at seven days out....that is still fairly astounding agreement among many models for surface feature placements over just one small area of the globe.  

[Mr. Kevin]

I am kevin from ne Arkansas. I do have a question. What do we need to watch for to see if December and rest of the winter will be cold? I think most are curious about what.