Winter Speculation 17/18 -December Thread

[Carvers Gap]

1 minute ago, John1122 said:

I find no reason to believe any models regarding path right now. There are just too many major swings from run to run. There is likely going to be a storm of some strength somewhere in the South between the 27th and 31st. That's about all that seems likely at this point. Probably not a cutter. 

I agree.

[John1122]

Looking through the massive thread in the Euro, I believe it was way too suppressed until about 24-36 hours out and I'm not sure it ever caught up.  At this range our I'm not sure if any showed snow reaching East Tennessee.

This was the Euro 3-4 days before that snow event happened. Keep in mind I believe it's area of heavier snow was all rain, there was 5-6+ inches in East Tennessee border counties and Asheville got 13 inches.

[tnweathernut]

I don't disagree the early December storm issues eventually coming northwest, but it seems this situation is a little different.  We all knew that one was comic northwest.  I think this one could potentially stay suppressed, unfortunately.  Hope I am wrong.

Seems we are slowly losing the ridging behind the system that was sending it further SE into the southern plains.  Without that, the energy is a late bloomer and a swing a miss for most in the TN Valley region.  If we can get it to dig more, the flow will be turned out of the WSW and precip would quickly develop.

Why anyone still calls the Euro the king is beyond me.  It flips and flips around as much as any model.  That said, if it's 12z run is close to accurate at 500, we have quite a bit of cold and dry ahead of us.  Since it's SO different in the extended I don't buy it. On to the next set of runs.

[jaxjagman]

Coldest run by far from the Euro

ECMWF Deterministic FORECAST FOR: BNA LAT= 36.12 LON= -86.68 ELE= 591 12Z DEC24 2 M 2 M 2 M SFC SFC 6 HR FROZN TOTAL MXT MNT TMP DEW WIND QPF PCP CLOUD (F) (F) (F) (F) (KTS) (IN) (IN) (PCT) SUN 12Z 24-DEC 39.9 34.9 07004 0.00 0.00 100 SUN 18Z 24-DEC 43.9 39.9 43.9 35.7 25008 0.00 0.00 100 MON 00Z 25-DEC 44.0 38.7 38.5 30.5 28010 0.01 0.00 85 MON 06Z 25-DEC 38.5 29.6 29.6 13.6 31009 0.01 0.00 84 MON 12Z 25-DEC 29.6 25.0 25.0 11.2 31005 0.00 0.00 98 MON 18Z 25-DEC 32.9 24.4 33.0 12.7 29004 0.00 0.00 96 TUE 00Z 26-DEC 34.1 31.7 31.6 19.8 08001 0.00 0.00 100 TUE 06Z 26-DEC 32.1 31.0 31.1 18.4 09003 0.01 0.01 100 TUE 12Z 26-DEC 31.1 30.0 30.0 19.7 03003 0.01 0.01 69 TUE 18Z 26-DEC 40.6 29.3 40.8 24.0 05004 0.00 0.00 0 WED 00Z 27-DEC 42.6 35.2 35.1 25.6 02006 0.00 0.00 18 WED 06Z 27-DEC 35.0 28.7 28.6 21.6 01006 0.00 0.00 24 WED 12Z 27-DEC 28.6 23.4 23.3 15.4 01007 0.00 0.00 56 WED 18Z 27-DEC 31.7 22.5 31.8 13.0 02007 0.00 0.00 2 THU 00Z 28-DEC 33.0 25.9 25.8 6.0 02006 0.00 0.00 36 THU 06Z 28-DEC 25.8 21.6 21.6 0.9 04006 0.00 0.00 86 THU 12Z 28-DEC 21.6 20.9 20.9 3.2 04006 0.00 0.00 63 THU 18Z 28-DEC 35.4 20.7 35.7 10.1 10003 0.00 0.00 94 FRI 00Z 29-DEC 37.7 33.8 33.9 22.0 07003 0.00 0.00 97 FRI 06Z 29-DEC 34.0 32.5 32.6 24.8 16003 0.00 0.00 65 FRI 12Z 29-DEC 33.7 32.0 33.7 29.1 16003 0.00 0.00 86 FRI 18Z 29-DEC 39.9 33.6 39.9 34.5 20003 0.00 0.00 99 SAT 00Z 30-DEC 40.0 37.9 37.9 36.1 20004 0.01 0.00 99 SAT 06Z 30-DEC 38.2 37.5 38.2 37.3 22005 0.00 0.00 100 SAT 12Z 30-DEC 39.0 36.7 36.8 34.8 30009 0.01 0.00 100 SAT 18Z 30-DEC 36.8 23.2 23.1 4.6 32013 0.04 0.04 59 SUN 00Z 31-DEC 23.7 15.5 15.3 -10.8 32012 0.00 0.00 0 SUN 06Z 31-DEC 15.3 8.4 8.3 -11.6 33010 0.00 0.00 0 SUN 12Z 31-DEC 8.3 4.6 4.5 -12.8 33008 0.00 0.00 0 SUN 18Z 31-DEC 14.6 4.3 14.9 -12.9 33007 0.00 0.00 0 MON 00Z 01-JAN 17.7 14.1 14.0 -13.1 34006 0.00 0.00 0 MON 06Z 01-JAN 14.0 10.8 10.7 -12.3 34005 0.00 0.00 0 MON 12Z 01-JAN 10.7 8.6 8.6 -10.4 35003 0.00 0.00 0 MON 18Z 01-JAN 20.8 8.2 21.0 -12.9 34003 0.00 0.00 0 TUE 00Z 02-JAN 23.2 17.8 18.0 -12.6 34002 0.00 0.00 8 TUE 06Z 02-JAN 18.2 14.3 14.2 -9.0 14002 0.00 0.00 14 TUE 12Z 02-JAN 14.8 12.9 13.6 -7.9 16004 0.00 0.00 1 TUE 18Z 02-JAN 33.1 13.5 33.4 -11.0 21004 0.00 0.00 0 WED 00Z 03-JAN 36.2 26.1 26.5 -2.6 20005 0.00 0.00 44 WED 06Z 03-JAN 27.0 22.8 22.8 -1.3 20004 0.00 0.00 40 WED 12Z 03-JAN 22.8 21.1 21.4 0.2 17004 0.00 0.00 100

[AMZ8990]

19 minutes ago, jaxjagman said:

Coldest run by far from the Euro

ECMWF Deterministic FORECAST FOR: BNA LAT= 36.12 LON= -86.68 ELE= 591 12Z DEC24 2 M 2 M 2 M SFC SFC 6 HR FROZN TOTAL MXT MNT TMP DEW WIND QPF PCP CLOUD (F) (F) (F) (F) (KTS) (IN) (IN) (PCT) SUN 12Z 24-DEC 39.9 34.9 07004 0.00 0.00 100 SUN 18Z 24-DEC 43.9 39.9 43.9 35.7 25008 0.00 0.00 100 MON 00Z 25-DEC 44.0 38.7 38.5 30.5 28010 0.01 0.00 85 MON 06Z 25-DEC 38.5 29.6 29.6 13.6 31009 0.01 0.00 84 MON 12Z 25-DEC 29.6 25.0 25.0 11.2 31005 0.00 0.00 98 MON 18Z 25-DEC 32.9 24.4 33.0 12.7 29004 0.00 0.00 96 TUE 00Z 26-DEC 34.1 31.7 31.6 19.8 08001 0.00 0.00 100 TUE 06Z 26-DEC 32.1 31.0 31.1 18.4 09003 0.01 0.01 100 TUE 12Z 26-DEC 31.1 30.0 30.0 19.7 03003 0.01 0.01 69 TUE 18Z 26-DEC 40.6 29.3 40.8 24.0 05004 0.00 0.00 0 WED 00Z 27-DEC 42.6 35.2 35.1 25.6 02006 0.00 0.00 18 WED 06Z 27-DEC 35.0 28.7 28.6 21.6 01006 0.00 0.00 24 WED 12Z 27-DEC 28.6 23.4 23.3 15.4 01007 0.00 0.00 56 WED 18Z 27-DEC 31.7 22.5 31.8 13.0 02007 0.00 0.00 2 THU 00Z 28-DEC 33.0 25.9 25.8 6.0 02006 0.00 0.00 36 THU 06Z 28-DEC 25.8 21.6 21.6 0.9 04006 0.00 0.00 86 THU 12Z 28-DEC 21.6 20.9 20.9 3.2 04006 0.00 0.00 63 THU 18Z 28-DEC 35.4 20.7 35.7 10.1 10003 0.00 0.00 94 FRI 00Z 29-DEC 37.7 33.8 33.9 22.0 07003 0.00 0.00 97 FRI 06Z 29-DEC 34.0 32.5 32.6 24.8 16003 0.00 0.00 65 FRI 12Z 29-DEC 33.7 32.0 33.7 29.1 16003 0.00 0.00 86 FRI 18Z 29-DEC 39.9 33.6 39.9 34.5 20003 0.00 0.00 99 SAT 00Z 30-DEC 40.0 37.9 37.9 36.1 20004 0.01 0.00 99 SAT 06Z 30-DEC 38.2 37.5 38.2 37.3 22005 0.00 0.00 100 SAT 12Z 30-DEC 39.0 36.7 36.8 34.8 30009 0.01 0.00 100 SAT 18Z 30-DEC 36.8 23.2 23.1 4.6 32013 0.04 0.04 59 SUN 00Z 31-DEC 23.7 15.5 15.3 -10.8 32012 0.00 0.00 0 SUN 06Z 31-DEC 15.3 8.4 8.3 -11.6 33010 0.00 0.00 0 SUN 12Z 31-DEC 8.3 4.6 4.5 -12.8 33008 0.00 0.00 0 SUN 18Z 31-DEC 14.6 4.3 14.9 -12.9 33007 0.00 0.00 0 MON 00Z 01-JAN 17.7 14.1 14.0 -13.1 34006 0.00 0.00 0 MON 06Z 01-JAN 14.0 10.8 10.7 -12.3 34005 0.00 0.00 0 MON 12Z 01-JAN 10.7 8.6 8.6 -10.4 35003 0.00 0.00 0 MON 18Z 01-JAN 20.8 8.2 21.0 -12.9 34003 0.00 0.00 0 TUE 00Z 02-JAN 23.2 17.8 18.0 -12.6 34002 0.00 0.00 8 TUE 06Z 02-JAN 18.2 14.3 14.2 -9.0 14002 0.00 0.00 14 TUE 12Z 02-JAN 14.8 12.9 13.6 -7.9 16004 0.00 0.00 1 TUE 18Z 02-JAN 33.1 13.5 33.4 -11.0 21004 0.00 0.00 0 WED 00Z 03-JAN 36.2 26.1 26.5 -2.6 20005 0.00 0.00 44 WED 06Z 03-JAN 27.0 22.8 22.8 -1.3 20004 0.00 0.00 40 WED 12Z 03-JAN 22.8 21.1 21.4 0.2 17004 0.00 0.00 100

Cold Indeed.

[Carvers Gap]

The 18z NAM has snow in TN at 42.

[ShawnEastTN]

9 minutes ago, Carvers Gap said:

The 18z NAM has snow in TN at 42.

The RGEM has been advertising the same thing I noticed today.  Also both the RGEM and the NAM show moisture coming into TX and LA at that same time frame while GFS has moisture staying in the Gulf until later frames.

[Mrwolf1972]

We got the cold comin just need the moisture 

[John1122]

1 hour ago, tnweathernut said:

I don't disagree the early December storm issues eventually coming northwest, but it seems this situation is a little different.  We all knew that one was comic northwest.  I think this one could potentially stay suppressed, unfortunately.  Hope I am wrong.

Seems we are slowly losing the ridging behind the system that was sending it further SE into the southern plains.  Without that, the energy is a late bloomer and a swing a miss for most in the TN Valley region.  If we can get it to dig more, the flow will be turned out of the WSW and precip would quickly develop.

Why anyone still calls the Euro the king is beyond me.  It flips and flips around as much as any model.  That said, if it's 12z run is close to accurate at 500, we have quite a bit of cold and dry ahead of us.  Since it's SO different in the extended I don't buy it. On to the next set of runs.

The Euro was suppressed on those runs for similar reasons. It was showing a lesser Pac NW Ridge that allowed the wave to be flatter and let it basically scoot out to sea with a whimper. Not saying it's not right this time, but it was having similar issues with the PNA region last time and it was effecting everything downstream. 

[ShawnEastTN]

Unrelated to the longer term discussion, but noticing some higher radar returns 30-40 dbz around Nashville.  Sleet?

[PowellVolz]

I’m liking the GFS.


.

[AMZ8990]

6 minutes ago, PowellVolz said:

I’m liking the GFS.


.

Is it trending the right direction???

[ShawnEastTN]

Is it trending the right direction???

It's not suppressed, holding fairly consistent last few runs.

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[ShawnEastTN]

If we could take the temps of the euro and the storm tracks of the GFS we'd be in really good business.

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[AMZ8990]

I just got a chance to look at the GFS.  Nice to see it pick back up onto to that piece of energy.  Hopefully that's a trend back our way.

[John1122]

The New Year's day storm on the 18z GFS is a great winter storm set up and track. The model is awful and always has been at handling gulf precip shields. I believe that would be a wide spread 3-6 inch type event for many of us. 

[J.C.]

2 hours ago, John1122 said:

The New Year's day storm on the 18z GFS is a great winter storm set up and track. The model is awful and always has been at handling gulf precip shields. I believe that would be a wide spread 3-6 inch type event for many of us. 

This is definitely something to keep an eye on.  If this storm happens anyone in this forum region could be hit hard.

[John1122]

GFS is weaker/more suppressed vs last run thru 90. 

[John1122]

Ends up with 1-2 inches in the eastern forum area. Much less than was shown in Georgia this run. I still won't be surprised if the GFS is 200 miles too far south and east. 

[John1122]

Canadian is suppressed as well. Amazing that there may be 2 major deep south winter storms in the same month. Places that get things like this once every few years for their entire winter may get another. Defies climo in a major way. 

[Carvers Gap]

The 0z CMC and GFS both suppress the storm...but the CMC hammers portions of the northern forum area w the one behind it on New Years.

[John1122]

Canadian with a second storm for new years that buries the border counties, Southern KY and SWVA. A 3rd event is gathering in Texas. 

[John1122]

2nd wave on the GFS is perfect again. This would be a nice event for most of the forum. 

 

[Carvers Gap]

Confluence....for the first system it is almost too far to the east and trending that way more each day.  The second system on December 31...its confluence is more west of the forum area.    One is a glancing blow and the others is a solid winter storm.  Still not sold that the first storm is just a glancing shot....it would not take much to pull that storm back.

[Carvers Gap]

Compared to the previous run...The 0z UKMET is north w its energy at 60. The 6z NAM has come north as well.  The 0z Euro almost has zero precip over the forum area for the next ten days.  The GFS is weaker w each system.  I think we see this trough pull a bit north if no storm is there to drive it further south....Much like these clippers that we see when is is cold, the clipper almost always pulls well north within the last 72 hours.  It seems to me that the short range models have begun a trend to pull the first wave north.  It could be a NAM bias at play....but the pattern looks way too suppressed.  Trend is weaker for sure....but in no way do I trust the models after what happened a week ago w the models and where they verify today.   

[AMZ8990]

55 minutes ago, Carvers Gap said:

Compared to the previous run...The 0z UKMET is north w its energy at 60. The 6z NAM has come north as well.  The 0z Euro almost has zero precip over the forum area for the next ten days.  The GFS is weaker w each system.  I think we see this trough pull a bit north if no storm is there to drive it further south....Much like these clippers that we see when is is cold, the clipper almost always pulls well north within the last 72 hours.  It seems to me that the short range models have begun a trend to pull the first wave north.  It could be a NAM bias at play....but the pattern looks way too suppressed.  Trend is weaker for sure....but in no way do I trust the models after what hapeened a week ago w the models and where they verify today.   

No doubt, this time last week we were expecting a blow torch Christmas.  Now my forecast says I won't get over 38 today.  If anything, the weather and forecasting it is keeping us all on our toes.

[Carvers Gap]

42 minutes ago, AMZ8990 said:

No doubt, this time last week we were expecting a blow torch Christmas.  Now my forecast says I won't get over 38 today.  If anything, the weather and forecasting it is keeping us all on our toes.

I was sure then that the models, almost all of them, were wrong when they depicted the EPO w a weirdly configured trough under it.  They made no sense.   Now suppression can be legit...it could fit the pattern where cold high pressure squashes everything.  That has actually happened before many times. It looks more and more likely that might be correct...but the bone dry Euro is suspicious to me, even the EPS. I would say it is an outlier but many models are trending to it.  The 12z NAM at 33 already looks a bit different at the surface.  Again, I don’t buy the wall-to-wall dry look of the Euro...but I am out on a limb much more so than I was with the feaux trough under the EPO....

[Carvers Gap]

The trough/ridge configuration is trending flatter...that is not allowing any storms to dig and form a storm here...now, at some point if it trends flat enough it will allow storms to track further north as sliders IMO.  The track will shift north.  The 6z NAM (edit) was a good example...the very first wave was further north.  That is not a good setup for the NE...but if it gets flat enough it could help us.  Right now it is in between being not sharp enough and not flat enough...thus, the dry look.  I suspect if the ridge and trough continue to flatten to more of a flatter trough, we will see future runs slide along it.  Even the NAM has began building snow back in the TX Panhandle over several runs...it is there between hours 33-36.  To me that is a sign of a weaker trough/ridge configuration.  Prob won’t help w the first storm but it might w subsequent storms.  

[AMZ8990]

22 minutes ago, Carvers Gap said:

I was sure then that the models, almost all of them, were wrong when they depicted the EPO w a weirdly configured trough under it.  They made no sense.   Now suppression can be legit...it could fit the pattern where cold high pressure squashed everything.  That has actually happened before many times. It looks more and more likely that might be correct...but the bone dry Euro is suspicious to me, even the EPS. I would say it is an outlier but many models are trending to it.  The 12z NAM at 33 already looks a bit different at the surface.  Again, I don’t buy the wall-to-wall dry look of the Euro...but I am out on a limb much more so than I was with the feaux trough under the EPO....

It's gonna stink if we get this cold air to lock in place, but then it's bone dry.  Then again that's life in Tennessee I guess.

[Carvers Gap]

4 minutes ago, AMZ8990 said:

It's gonna stink if we get this cold air to lock in place, but then it's bone dry.  Then again that's life in Tennessee I guess.

True.  Hopefully, the thaw is not the beginning of the end...and is just a break.  Looks like it arrives around Jan 10.  I still think the trough verifies more shallow and storms track further north...again, just using past experience and am on shaky ground given overnight model trends.