December 2020 Medium/Long Term Pattern Discussion.

[TellicoWx]

4 minutes ago, BlunderStorm said:

GL low looking more wound up on the 0z GFS. 

And somehow still manages to produce for middle and east TN..will give it this, no matter how much it changes the 500 up.. it still produces (so far). Don't trust anything outside 60-72 hrs on any Op tho.

[jaxjagman]

I'm starting to get the feeling towards the new year into the first of the new year it could get bone chillin cold.Some hints the AO could really drop with troughs coming out of East Asia with even some hints of a possible strenghten +PNA,even the Euro is giving a hint at this in of the long range with a polar high sort of speaking,even if you look at the NAO,all signs are pointing at this possibly

[John1122]

1 minute ago, jaxjagman said:

I'm starting to get the feeling towards the new year into the first of the new year it could get bone chillin cold.Some hints the AO could really drop with troughs coming out of East Asia with even some hints of a possible strenghten +PNA,even the Euro is giving a hint at this in of the long range with a polar high sort of speaking,even if you look at the NAO,all signs are pointing at this possibly

There's been some super negative AO looks on the ensembles. Several guys like Ventrice have been talking about early January looking icy. Glad you know the East Asian stuff. 

[John1122]

17 minutes ago, BlunderStorm said:

GL low looking more wound up on the 0z GFS. Not as potent cold is brought south but more of it though. The front seems more progressive and enters at less of an angle leaving less of a chance for a second southeastern low to develop in time to bump the totals for the forum region.

It often seems to be around but Eric Webb I believe swears it doesn't prevent southern snow storms at all. 

[TellicoWx]

12z vs 00z 500...both still produce areas of 6+ across the forum..GFS keeps honking about something lol

[jaxjagman]

10 minutes ago, John1122 said:

There's been some super negative AO looks on the ensembles. Several guys like Ventrice have been talking about early January looking icy. Glad you know the East Asian stuff. 

Definite troughs coming out of east East Asia,in the mid to long range,just got to figure out the teleconnections but sure seems to me it could be a decent cold snap upcoming

[jaxjagman]

[TellicoWx]

00z CMC

[John1122]

Canadian went a bit weird that run. Reminded me of the solution models were throwing out a few times in the early December storm.  Much slower than the GFS and it snows basically all day Christmas day. 

[TellicoWx]

00z GEFs looks better than 18z

[John1122]

Not the GFS but this is way better than it's 12z clown map. 

 

[TellicoWx]

1 minute ago, John1122 said:

Canadian went a bit weird that run. Reminded me of the solution models were throwing out a few times in the early December storm.  Much slower than the GFS and it snows basically all day Christmas day. 

Yeah def a weird run...closes it off and drives it south while taking its time at 500..meanders across the forum

[TellicoWx]

00z Euro

[TellicoWx]

Dr No strikes again lol

[Wurbus]

4 minutes ago, TellicoWx said:

Dr No strikes again lol

We definitely have 2 camps and we will just have to wait and see which model caves first. I believe Euro caved to GFS during the last system so we shall see. My guess is we wind up with a blend of the two.

[John1122]

5 minutes ago, TellicoWx said:

Dr No strikes again lol

Fortunately the Euro has been pretty bad at this range to date in December. Usually in the opposite direction with it showing big events while the GFS didn't. 

[TellicoWx]

UKie/Euro/CMC (even with it's meandering run which gives the snow) are consolidating the energy along the southern end = cutter city...GFS is kinda on an island, but has taken steps toward the others (went from initial low up into Canada to winding up over the GL)...bias maybe, but "if" toward the tail then need it to keep digging to our south.

[Holston_River_Rambler]

It's SEC championship Saturday, and you know what that means...

Happy Hour GFS is at 6z!

 

On a half way more serious note, guess which model had that more wound up/ cut off southern solution yesterday at 12z???

J

 

 

M

 

 

A

 

 

Although I have to say the Canadian had a similar solution for a while, but for a different reason. The 0z CMC has a triple phaser, just a wee bit too far west and north to be optimal for us. 

 

 

Man the overnight Euro was ugly, like y'all said. It even gives us a tiny little bit of CAPE and a lot of shear:

 

 

 

Hopefully the Euro is overamping that initial push of energy (although following weather weenie rule 35 tnweathernut reminded me of yesterday, probably not). But it has overamped some systems in this range in the past month. I can't find the images, but at one point the Euro had, in this time frame (around hour 120), a wound up storm dumping snow on middle TN. It ended up less wound up, but that doesn't mean it will this time.  

 

It's actual depiction of the energy looked closer to a better solution and if you discount the wound up energy heading to the lakes, it isn't too far from the GFS or CMC:

 

Notice the piece of energy I circled. It closes off a secondary piece of energy to our south. Of course the same rule I applied to the first piece that closes off (above) could also be applied to this piece. If it is overampy, maybe it is overamping both. 

I say let's go for the WPC's idea, for now:

"While the amplifying evolution is a consistent and agreeable theme in the guidance, the details are still fairly uncertain. If anything the new 00Z guidance is lowering confidence somewhat given a return to more spread for exactly how Eastern Pacific shortwave energy reaching the West evolves in the short range/early medium range time frame, with the 00Z UKMET/CMC not comparing particularly well with recently established consensus. To some degree these issues feed through the rest of the period. Interaction from Canadian flow provides added complexity. Among the 12Z/18Z solutions the GFS/ECMWF/CMC clustered fairly well in principle, suggesting steady progression of the northern tier system and then one or more waves (possibly with fairly strong development) embedded along the trailing front that crosses the eastern U.S. Another surface low could form in the vicinity of the Great Lakes (or elsewhere nearby) based on these solutions closing off an upper low. Ensembles show greater spread including hinting at some potential for slower shortwave energy such as what the new UKMET/CMC suggest, while keeping the overall upper trough open. For the purposes of a single deterministic forecast, preference sided with an operational 12Z/18Z model blend (more emphasis on the GFS/ECMWF) for about the first half of the period and then some inclusion of the 18Z GEFS/12Z ECMWF means to tone down the GFS/ECMWF/CMC specifics given the detail uncertainties farther out in time."

 

 

 

 

[Looking to the skies]

King Euro against American GFS.  Sort of like the old country song Cut across Shorty, we want the GFS to win this one!!  Faster and more cold on backside.  

[weathertree4u]

32 minutes ago, Holston_River_Rambler said:

It's SEC championship Saturday, and you know what that means...

Happy Hour GFS is at 6z!

 

On a half way more serious note, guess which model had that more wound up/ cut off southern solution yesterday at 12z???

J

 

 

M

 

 

A

 

 

Although I have to say the Canadian had a similar solution for a while, but for a different reason. The 0z CMC has a triple phaser, just a wee bit too far west and north to be optimal for us. 

 

 

Man the overnight Euro was ugly, like y'all said. It even gives us a tiny little bit of CAPE and a lot of shear:

 

 

 

Hopefully the Euro is overamping that initial push of energy (although following weather weenie rule 35 tnweathernut reminded me of yesterday, probably not). But it has overamped some systems in this range in the past month. I can't find the images, but at one point the Euro had, in this time frame (around hour 120), a wound up storm dumping snow on middle TN. It ended up less wound up, but that doesn't mean it will this time.  

 

It's actual depiction of the energy looked closer to a better solution and if you discount the wound up energy heading to the lakes, it isn't too far from the GFS or CMC:

 

Notice the piece of energy I circled. It closes off a secondary piece of energy to our south. Of course the same rule I applied to the first piece that closes off (above) could also be applied to this piece. If it is overampy, maybe it is overamping both. 

I say let's go for the WPC's idea, for now:

"While the amplifying evolution is a consistent and agreeable theme in the guidance, the details are still fairly uncertain. If anything the new 00Z guidance is lowering confidence somewhat given a return to more spread for exactly how Eastern Pacific shortwave energy reaching the West evolves in the short range/early medium range time frame, with the 00Z UKMET/CMC not comparing particularly well with recently established consensus. To some degree these issues feed through the rest of the period. Interaction from Canadian flow provides added complexity. Among the 12Z/18Z solutions the GFS/ECMWF/CMC clustered fairly well in principle, suggesting steady progression of the northern tier system and then one or more waves (possibly with fairly strong development) embedded along the trailing front that crosses the eastern U.S. Another surface low could form in the vicinity of the Great Lakes (or elsewhere nearby) based on these solutions closing off an upper low. Ensembles show greater spread including hinting at some potential for slower shortwave energy such as what the new UKMET/CMC suggest, while keeping the overall upper trough open. For the purposes of a single deterministic forecast, preference sided with an operational 12Z/18Z model blend (more emphasis on the GFS/ECMWF) for about the first half of the period and then some inclusion of the 18Z GEFS/12Z ECMWF means to tone down the GFS/ECMWF/CMC specifics given the detail uncertainties farther out in time."

 

 

 

 

Overall, I like the look of the next few days. Not really seeing anything like the last several seasons, which, even if dont get a good snow, is so refreshing!

[Carvers Gap]

Again, have said if for days...very LOW confidence right now.  Think about this, models originally had a total torch(and I mean raging torch) beginning on the 18th.  As for the potential Christmas event, all of the normal model biases are in play.  I do not buy the models which are holding too much energy back.  Not sure I buy the models that are too quick either.  Right now, this reminds me(in some ways) very much of the early December track which hammered the Midwest.   One important piece is that the GFS brings a much colder (and bigger) air mass.  It is an outlier in this regard.  However, we know the Euro has a bias of not "seeing" cold air masses and their deepening troughs.  I don't have a ton invested right now.  Our last major snow was over two years ago IMBY.  So, I don't hold my breath too much. If we get the Christmas storm great, if not....historically always a long shot to get big snows on Christmas at lower elevations.  And right now this pattern is a good one for higher elevations, and not so much for lower elevations at this latitude.  My gut tells me there will be a storm, but likely rain in the far eastern areas(low elevations) with more wintery precise the further west one goes from I75...again, just a guess.

 The LR is growing more uncertain with each day - after showing a promising pattern for several weeks.  I think the uncertainty of the MJO is disrupting modeling.  I think we are entering a time frame of great uncertainty - much more so than a normal year.  I think we will have our chances during January and maybe later this month.  This pattern is far more active than I thought it would be, and that is a good thing.

[bearman]

 

Quote

Carver, I am very glad you put this all in perspective.  I have so much respect for your input and knowledge.   The   in me however wants to revolt.

 

[AMZ8990]

3 hours ago, Holston_River_Rambler said:

It's SEC championship Saturday, and you know what that means...

Happy Hour GFS is at 6z!

 

On a half way more serious note, guess which model had that more wound up/ cut off southern solution yesterday at 12z???

J

 

 

M

 

 

A

 

 

Although I have to say the Canadian had a similar solution for a while, but for a different reason. The 0z CMC has a triple phaser, just a wee bit too far west and north to be optimal for us. 

 

 

Man the overnight Euro was ugly, like y'all said. It even gives us a tiny little bit of CAPE and a lot of shear:

 

 

 

Hopefully the Euro is overamping that initial push of energy (although following weather weenie rule 35 tnweathernut reminded me of yesterday, probably not). But it has overamped some systems in this range in the past month. I can't find the images, but at one point the Euro had, in this time frame (around hour 120), a wound up storm dumping snow on middle TN. It ended up less wound up, but that doesn't mean it will this time.  

 

It's actual depiction of the energy looked closer to a better solution and if you discount the wound up energy heading to the lakes, it isn't too far from the GFS or CMC:

 

Notice the piece of energy I circled. It closes off a secondary piece of energy to our south. Of course the same rule I applied to the first piece that closes off (above) could also be applied to this piece. If it is overampy, maybe it is overamping both. 

I say let's go for the WPC's idea, for now:

"While the amplifying evolution is a consistent and agreeable theme in the guidance, the details are still fairly uncertain. If anything the new 00Z guidance is lowering confidence somewhat given a return to more spread for exactly how Eastern Pacific shortwave energy reaching the West evolves in the short range/early medium range time frame, with the 00Z UKMET/CMC not comparing particularly well with recently established consensus. To some degree these issues feed through the rest of the period. Interaction from Canadian flow provides added complexity. Among the 12Z/18Z solutions the GFS/ECMWF/CMC clustered fairly well in principle, suggesting steady progression of the northern tier system and then one or more waves (possibly with fairly strong development) embedded along the trailing front that crosses the eastern U.S. Another surface low could form in the vicinity of the Great Lakes (or elsewhere nearby) based on these solutions closing off an upper low. Ensembles show greater spread including hinting at some potential for slower shortwave energy such as what the new UKMET/CMC suggest, while keeping the overall upper trough open. For the purposes of a single deterministic forecast, preference sided with an operational 12Z/18Z model blend (more emphasis on the GFS/ECMWF) for about the first half of the period and then some inclusion of the 18Z GEFS/12Z ECMWF means to tone down the GFS/ECMWF/CMC specifics given the detail uncertainties farther out in time."

 

 

 

 

Of course West Tennessee gets left out. Smh

[Wurbus]

Man. E3 on the 6z GEFS is a sight to behold.

[tnweathernut]

The GFS at 12z remains extremely consistent in its presentation of rain changing to a heavy quick thump of snow.  Of course it could also easily be consistently wrong too.

Chattanooga gets in on the action so we can probably toss...  just ask Jeff, lol.

speaking for the eastern 2/3 of the state.  West TN is still getting the shaft.  :-(

[Wurbus]

Most GEFS members agreeing with the GFS. I count about 75% of the members showing roughly the same thing as the GFS.

CMC is showing some light snow across most of the forum area after the front moves through, but not as quick of a changeover as the GFS.

[BlunderStorm]

The ICON as of the last 2 runs has evolved towards are more favorable solution from last night. It does away with the weak low in the midwest wandering into our back yard and returns to a low in the Canadian shield introducing more cold and advancing the front more quickly with a low developing along the front further south. It still is a mostly rain event on there but I'll take an Appalachian runner with a shot of cold over what it was showing. 

[Holston_River_Rambler]

UKMET handles the energy very differently from its 0z run. Result is better for central and western areas. 

 

 

[Holston_River_Rambler]

Result in accums, for those interested:

[1234snow]

I know that our focus is the snow but check out the 2m Temp anomaly on Tropical Tidbits from the 12z GFS. Wild watching the cold front plow thru the Gulf of Mexico and Southeast states. One thing seems to be guaranteed is that this is a potent cold shot.

12z GFS was a fun run in general. Plenty of opportunities to track on that run after Christmas storm.