Historic Christmas Cold & maybe snow?! Dec 23rd-30th

[TellicoWx]

6 minutes ago, Scottie16 said:

0Z NAM seems to be following suite with the GFS.

3k looks 100x better west of the plateau

[John1122]

I'm not sure why the NAM loses the dynamics of the storm as soon as it hits the western Plateau. It looks healthy as all get out then just dies out. 

[fountainguy97]

1 minute ago, John1122 said:

I'm not sure why the NAM loses the dynamics of the storm as soon as it hits the western Plateau. It looks healthy as all get out then just dies out. 

I think the nam has issues long range with de-amping storms. It used to be the opposite but they gutted it and seems it's now too far the other way. It usually doesn't "catch-up" precip wise until inside 60 hrs. 

[John1122]

RGEM wasn't good at all. Just bone dry except for a small bullseye around the central plateau. Barely gets .2 total qpf for most areas. 

[ShawnEastTN]

RGEM wasn't good at all. Just bone dry except for a small bullseye around the central plateau. Barely gets .2 total qpf for most areas. 

I'm riding the GFS until this time tomorrow. Then I'll start hugging the meso models in particular the RGEM, but I'm a bit unnerved at the RGEM really want to see it come around because it used to score well inside 48 hours in particular.

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[Stovepipe]

19 minutes ago, fountainguy97 said:

I think the nam has issues long range with de-amping storms. It used to be the opposite but they gutted it and seems it's now too far the other way. It usually doesn't "catch-up" precip wise until inside 60 hrs. 

Long range NAM clowns, particularly of the Earl Barker variety (if I'm remembering his name correctly) were high quality entertainment in years past.

[Daniel Boone]

25 minutes ago, John1122 said:

RGEM wasn't good at all. Just bone dry except for a small bullseye around the central plateau. Barely gets .2 total qpf for most areas. 

That's somewhat disturbing to say the least. 

[John1122]

Just now, Daniel Boone said:

That's somewhat disturbing to say the least. 

Hopefully it improves by this time tomorrow. If not, I expect the GFS will head its way. 

[Silas Lang]

Looks like the cold air is a lot slower to get here on the RGEM as well. 

[Vol4Life]

Gfs looks like it held serve! 

[Jed33]

GFS looks faster with the cold another 25mi faster east move like it was doing yesterday.

[ShawnEastTN]

Long range NAM clowns, particularly of the Earl Barker variety (if I'm remembering his name correctly) were high quality entertainment in years past.

Oh the DGEX model!!! I had forgotten that all together until you said Earl Barker. That thing put out insane clowns. I miss those, they used to get folks so worked up!!

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[ShawnEastTN]

GFS looks faster with the cold another 25mi faster east move like it was doing yesterday.

Yeah it actually looks better than previous runs to me. Moisture looks deeper and more of a SW fetch over the local region than previous runs. Odd looking even with that shape of the precip shield over Tennessee but a good look.

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[mempho]

43 minutes ago, Stovepipe said:

Long range NAM clowns, particularly of the Earl Barker variety (if I'm remembering his name correctly) were high quality entertainment in years past.

It’s Baker!!!

 

[BlunderStorm]

39 minutes ago, Vol4Life said:

Gfs looks like it held serve! 

Even more of a negative tilt if anything, the slp is 40 miles west and 2 mb deeper at 54. A better run for west and central TN, though it sputters out over the great valley.

[Stovepipe]

36 minutes ago, ShawnEastTN said:

Oh the DGEX model!!! I had forgotten that all together until you said Earl Barker. That thing put out insane clowns. I miss those, they used to get folks so worked up!!

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It was the symbology of the maps that really hyped the weenies.  No cotton candy gradients, Earl rocked a serious contrasting color scheme.  We were like “I’m right on the edge of brown and white!  Between 14 and 18 inches bruh!”

[mempho]

21 minutes ago, BlunderStorm said:

Even more of a negative tilt if anything, the slp is 40 miles west and 2 mb deeper at 54. A better run for west and central TN, though it sputters out over the great valley.

Look at the map carefully.  Some of that is lake effect.  

[John1122]

Euro was slightly better but not by a lot. 

[John1122]

The NAM is working towards the GFS. The 12k is getting snow into East Tennessee now. 

[BlunderStorm]

06z NAM is solid and an improvement from 0z. Notably the valley snowhole SE of Knoxville to Chatty is still there but smaller.

[BlunderStorm]

06z 3kNAM Kuchera map on Pivotal sure is a beaut for most.

[Met1985]

32 minutes ago, John1122 said:

The NAM is working towards the GFS. The 12k is getting snow into East Tennessee now. 

Yeah a big jump in snowfall on this side of the mountain for sure. Hopefully a last minute trend towards recognizing more moisture behind the front. 

[fountainguy97]

Looks like models mostly held serve at 0z. Atleast GFS has some NAM support at 6z.  
 

06z gfs holds serve. Ticking north a touch a 500mb but nothing major. It and NAM are lock step. Euro still north.

[PowellVolz]

I won’t know what to do if the GFS had this or had something like this 10 days ago.


.

[Carvers Gap]

MRX morning discussion....

Key Messages:

1. Extreme cold that has not been seen in this area for decades
will build into the area on Thursday night and continue through
Saturday.

2. Expected impacts from this extreme event will be gusty winds
that may cause power outages, potentially hazardous road
conditions from snow/ice, and dangerous wind chills.

The arrival of an extremely cold air mass continues to be the big
story for this period. From 00Z Fri to 12Z Fri, most of the area
will see around a 30-40 degree drop in temperatures. The cold
front will move through quickly, from around midnight to 4 AM, and
dry air aloft builds in a few hours after surface fropa. So there
will only be a small window when there will be potential for snow
accumulation, which appears to be from 06Z to 12Z. For the most
part, the SREF and NBM members have mostly settled on snow
amounts from about a quarter inch to one inch for the Valley, with
up to 2 inches in the higher elevations and SW VA, and the
forecast amounts will fall in this range. Outside of some light
snow showers or flurries adding a tenth or so in the mountains and
SW VA, accumulating snowfall will mostly end by 12Z. As we have
been emphasizing the past few days, despite the light snow
amounts, travel in the area may be impacted by the rapid drop in
temperatures causing any moisture on roads to quickly freeze. Icy
road conditions may persist through Friday and potentially through
Saturday as well, since max temperatures will be in the teens and
20s.

With the frontal passage will come a sharp increase in winds, with
sustained winds expected to be in the 15-30 mph range with gusts
in the 40s, and near 50 mph in the mountains. A concern with these
winds will be the potential for downed trees and power lines
leading to power outages when temperatures will be getting
extremely cold. Wind chill values on Friday will be below zero
for the entire area through Friday and Friday night, and -15 to
-25 in the mountains, Cumberland Plateau, and SW VA. Therefore, a
Wind Chill Watch will be issued for the entire area from 09Z Fri
through 18Z Sat. The TN Valley may end up in a Wind Chill
Advisory, but at this point, will have a blanket Watch and let
later shifts divide it by topography for an Advisory/Warning.

Bottom line, this will be an impactful, extreme cold event that
has not been seen in this area for decades.

The rest of the forecast period will be dry with a gradual warming
trend.

 

[Carvers Gap]

The power outage potential due to high winds is concerning.  MRX reiterated this on social media a few hours ago.

[fountainguy97]

Hrrr pumping out good totals. NWS across the state are going to be forced to acknowledge these meso-models soon. 

[Icy Hot]

41 minutes ago, Carvers Gap said:

MRX morning discussion....

Key Messages:

1. Extreme cold that has not been seen in this area for decades
will build into the area on Thursday night and continue through
Saturday.

2. Expected impacts from this extreme event will be gusty winds
that may cause power outages, potentially hazardous road
conditions from snow/ice, and dangerous wind chills.

The arrival of an extremely cold air mass continues to be the big
story for this period. From 00Z Fri to 12Z Fri, most of the area
will see around a 30-40 degree drop in temperatures. The cold
front will move through quickly, from around midnight to 4 AM, and
dry air aloft builds in a few hours after surface fropa. So there
will only be a small window when there will be potential for snow
accumulation, which appears to be from 06Z to 12Z. For the most
part, the SREF and NBM members have mostly settled on snow
amounts from about a quarter inch to one inch for the Valley, with
up to 2 inches in the higher elevations and SW VA, and the
forecast amounts will fall in this range. Outside of some light
snow showers or flurries adding a tenth or so in the mountains and
SW VA, accumulating snowfall will mostly end by 12Z. As we have
been emphasizing the past few days, despite the light snow
amounts, travel in the area may be impacted by the rapid drop in
temperatures causing any moisture on roads to quickly freeze. Icy
road conditions may persist through Friday and potentially through
Saturday as well, since max temperatures will be in the teens and
20s.

With the frontal passage will come a sharp increase in winds, with
sustained winds expected to be in the 15-30 mph range with gusts
in the 40s, and near 50 mph in the mountains. A concern with these
winds will be the potential for downed trees and power lines
leading to power outages when temperatures will be getting
extremely cold. Wind chill values on Friday will be below zero
for the entire area through Friday and Friday night, and -15 to
-25 in the mountains, Cumberland Plateau, and SW VA. Therefore, a
Wind Chill Watch will be issued for the entire area from 09Z Fri
through 18Z Sat. The TN Valley may end up in a Wind Chill
Advisory, but at this point, will have a blanket Watch and let
later shifts divide it by topography for an Advisory/Warning.

Bottom line, this will be an impactful, extreme cold event that
has not been seen in this area for decades.

The rest of the forecast period will be dry with a gradual warming
trend.

 

Am I missing something? They say "cold not seen in decades." We've been to -4 at least 3 times within the last 10 years in NETN. Are they just not looking at historical data anymore?

[Carvers Gap]

5 minutes ago, Icy Hot said:

Am I missing something? They say "cold not seen in decades." We've been to -4 at least 3 times within the last 10 years in NETN. Are they just not looking at historical data anymore?

I was thinking about this as well.  I think the wind chills make this unique and maybe the overall coverage of the cold.   We actually have a shot to break some record lows and probably record high mins, especially in Chattanooga and TYS.  I think it was 2018(December) when the North Fork of the Holston froze here.  Likely, they are talking about the air mass in general as Montana may well set the hp record for North America.   But certainly you are correct in saying we have had bouts of severe cold of late, especially December.  This "might" be a tier colder though.  Excellent catch as usual.  

[Daniel Boone]

55 minutes ago, Carvers Gap said:

MRX morning discussion....

Key Messages:

1. Extreme cold that has not been seen in this area for decades
will build into the area on Thursday night and continue through
Saturday.

2. Expected impacts from this extreme event will be gusty winds
that may cause power outages, potentially hazardous road
conditions from snow/ice, and dangerous wind chills.

The arrival of an extremely cold air mass continues to be the big
story for this period. From 00Z Fri to 12Z Fri, most of the area
will see around a 30-40 degree drop in temperatures. The cold
front will move through quickly, from around midnight to 4 AM, and
dry air aloft builds in a few hours after surface fropa. So there
will only be a small window when there will be potential for snow
accumulation, which appears to be from 06Z to 12Z. For the most
part, the SREF and NBM members have mostly settled on snow
amounts from about a quarter inch to one inch for the Valley, with
up to 2 inches in the higher elevations and SW VA, and the
forecast amounts will fall in this range. Outside of some light
snow showers or flurries adding a tenth or so in the mountains and
SW VA, accumulating snowfall will mostly end by 12Z. As we have
been emphasizing the past few days, despite the light snow
amounts, travel in the area may be impacted by the rapid drop in
temperatures causing any moisture on roads to quickly freeze. Icy
road conditions may persist through Friday and potentially through
Saturday as well, since max temperatures will be in the teens and
20s.

With the frontal passage will come a sharp increase in winds, with
sustained winds expected to be in the 15-30 mph range with gusts
in the 40s, and near 50 mph in the mountains. A concern with these
winds will be the potential for downed trees and power lines
leading to power outages when temperatures will be getting
extremely cold. Wind chill values on Friday will be below zero
for the entire area through Friday and Friday night, and -15 to
-25 in the mountains, Cumberland Plateau, and SW VA. Therefore, a
Wind Chill Watch will be issued for the entire area from 09Z Fri
through 18Z Sat. The TN Valley may end up in a Wind Chill
Advisory, but at this point, will have a blanket Watch and let
later shifts divide it by topography for an Advisory/Warning.

Bottom line, this will be an impactful, extreme cold event that
has not been seen in this area for decades.

The rest of the forecast period will be dry with a gradual warming
trend.

 

I hadn't been thinking clear on this upcoming cold and thought was coldest since feb 96 but, then I remembered feb 20 2015. -16 Jonesville. - 20 Pennington gap morning lows. I recorded a high of 12.