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Carvers Gap

Winter 'Tis the Season Banter Thread 2018-2019

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Here is what modeling has to contend with before or right after a system gets to MBY(and I am just talking stuff surrounding our continent):

1. Multiple mountain ranges (Sierra Nevadas, Rockies, Cumberland Plateau, and the Apps)

2. Four bodies of water(Pacific, Atlantic, Gulf of Mexico, and the Great Lakes)

3.  Air masses and precip systems which much travel over an entire continent before getting to our complex system of mountains, hills, valleys, etc

4.  A latitude where its default is rain and not snow for nine months out of the year.  The other three months...default is a mixed bag.

I really think on a larger scale the interaction of the Apps(especially the base of the southern Apps), warm/cold air masses rushing over the Plains, the Atlantic, and the GOM pose significant problems for even the best of sampled systems.   Timing is key.  Modeling the correct pressure at various levels of the atmosphere is also not easy.  By the time that system gets to our area, there are just a ton of variables which can change timing.  If the Apps were a lot longer(stretching to the GOM) or a lot shorter(ending in say PA), the steering currents which influence us would be much easier to model.  As it is, the base of the Apps causes systems to cut more sharply west at times.  Also, think if the Apps were not there.  Middle TN probably gets more snow because a system could actually cut where the Apps are now.  As is, the system has to go to one side if originating to the south.  There would be no CAD or downsloping.  Coastals would send much more precip our way.  I suspect winters would be a lot worse without the Apps.  One thing that wx models are much better at is actually identifying pieces of energy that will actually impact our region.  Wx models can spot wx in the western Pacific(see Jax's posts) and make pretty good guesses as to whether that impacts our weather.  Our AI is just not good enough to predict the chaos(butterfly effect stuff) that results down stream.  The are so much better than they used to be though.   And we need to remember, folks settled this area because the weather was not severe.  Winters are not as bad.  Summers are not as hot.  Plenty of precip though droughts in NE TN are not uncommon.  This region is requires mad skills and a thick skin, because it is easy to be wrong...a lot. 

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17 minutes ago, Carvers Gap said:

Here is what modeling has to contend with before or right after a system gets to MBY(and I am just talking stuff surrounding our continent):

1. Multiple mountain ranges (Sierra Nevadas, Rockies, Cumberland Plateau, and the Apps)

2. Four bodies of water(Pacific, Atlantic, Gulf of Mexico, and the Great Lakes)

3.  Air masses and precip systems which much travel over an entire continent before getting to our complex system of mountains, hills, valleys, etc

4.  A latitude where its default is rain and not snow for nine months out of the year.  The other three months...default is a mixed bag.

I really think on a larger scale the interaction of the Apps(especially the base of the southern Apps), warm/cold air masses rushing over the Plains, the Atlantic, and the GOM pose significant problems for even the best of sampled systems.   Timing is key.  Modeling the correct pressure at various levels of the atmosphere is also not easy.  By the time that system gets to our area, there are just a ton of variables which can change timing.  If the Apps were a lot longer(stretching to the GOM) or a lot shorter(ending in say PA), the steering currents which influence us would be much easier to model.  As it is, the base of the Apps causes systems to cut more sharply west at times.  Also, think if the Apps were not there.  Middle TN probably gets more snow because a system could actually cut where the Apps are now.  As is, the system has to go to one side if originating to the south.  There would be no CAD or downsloping.  Coastals would send much more precip our way.  I suspect winters would be a lot worse without the Apps.  One thing that wx models are much better at is actually identifying pieces of energy that will actually impact our region.  Wx models can spot wx in the western Pacific(see Jax's posts) and make pretty good guesses as to whether that impacts our weather.  Our AI is just not good enough to predict the chaos(butterfly effect stuff) that results down stream.  The are so much better than they used to be though.   And we need to remember, folks settled this area because the weather was not severe.  Winters are not as bad.  Summers are not as hot.  Plenty of precip though droughts in NE TN are not uncommon.  This region is requires mad skills and a thick skin, because it is easy to be wrong...a lot. 

It makes me think that at some point in the future (maybe the way way off future) mets are going to look back on the how, the methods, we are currently trying to apply and wonder what we were thinking.  I'm not sure the methods we are relying on are realistically capable of doing it.  I don't want anyone to misinterpret what I am trying to say, I am constantly amazed at what mets and many others on here are currently able to do using what we have now.  Just can't help thinking that at some point we will gain a different perspective, insight or understanding that will change the way we view and understand the atmosphere.  I am a teacher and nothing excites me more then to have a student who shows a genuine, internal interest in weather/meteorology and to wonder if she or he may play a roll in that process.

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I think a lot of the problem is our expectations of how accurate a weather model should be. The advancements of modern technology have probably contributed to a lot of people expecting too much from weather models.  There’s no such thing as a perfect model, especially when you are dealing with the chaotic nature of the atmosphere. Computer models have improved over time, but I don’t expect any drastic changes to their accuracy in the foreseeable future. It seems to be a problem of diminishing returns.

That doesn’t mean the current state of weather modeling is “bad”. As my mathematical modeling professor once told me, “there’s no such thing as a bad model”.  Even the most simple weather model could provide you with useful information about the evolution of the atmosphere.  That’s pretty much the best we can do for now. Using models as a guide for how the atmosphere might evolve over time and combine that with our knowledge of how the weather in this area typically behaves during various conditions. It certainly isn't perfect, but at least  there is a decent level of predictability (unlike the perception that forecasts are "never right" based on social media comments). 

On the idea of using knowledge of our local climate, it is truly amazing how much collective knowledge this forum has about local weather patterns.  I think we all have great interest in learning how the local terrain impacts our weather. I'm constantly learning something new from this forum.

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11 minutes ago, Math/Met said:

I think a lot of the problem is our expectations of how accurate a weather model should be. The advancements of modern technology have probably contributed to a lot of people expecting too much from weather models.  There’s no such thing as a perfect model, especially when you are dealing with the chaotic nature of the atmosphere. Computer models have improved over time, but I don’t expect any drastic changes to their accuracy in the foreseeable future. It seems to be a problem of diminishing returns.

That doesn’t mean the current state of weather modeling is “bad”. As my mathematical modeling professor once told me, “there’s no such thing as a bad model”.  Even the most simple weather model could provide you with useful information about the evolution of the atmosphere.  That’s pretty much the best we can do for now. Using models as a guide for how the atmosphere might evolve over time and combine that with our knowledge of how the weather in this area typically behaves during various conditions. It certainly isn't perfect, but at least  there is a decent level of predictability (unlike the perception that forecasts are "never right" based on social media comments). 

On the idea of using knowledge of our local climate, it is truly amazing how much collective knowledge this forum has about local weather patterns.  I think we all have great interest in learning how the local terrain impacts our weather. I'm constantly learning something new from this forum.

I think this is very close to the idea I was trying to express.  As with any scientific arena, advances are sometimes fast sometime slow.  I agree completely with the common idea that as technologically advanced as we are now, people expect that to carry over to forecasting the atmosphere.

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It was not a hard forecast with models. Some of the snow output did not make sense. Using a good old fashioned thickness QPF chart, the timing looked suspect. Always felt like cold chasing rain. I halved consensus. Worked out OK in northeast Tenn. Just forgot to go zero CHA.

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I think it would be cool if models had the ability to adjust certain parameters on the fly based off of previously digested real time data that had been analyzed versus what the model had originally forecasted at different times prior to an actual event.  Albeit it would take some time to get enough data too actually make it work properly, not to mention the sheer amount of data that would create.  Essentially I’m talking about an AI model (lol) though.   It would in theory be consistently learning and adapting based off of what it initially forcasted versus what actually happened in real time.  It would take awhile to get the data to make it work properly but once you had the data in place it sounds pretty cool, IMO.  Just a wild thought I had.  

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3 hours ago, Hilton01 said:

It makes me think that at some point in the future (maybe the way way off future) mets are going to look back on the how, the methods, we are currently trying to apply and wonder what we were thinking.  I'm not sure the methods we are relying on are realistically capable of doing it.  I don't want anyone to misinterpret what I am trying to say, I am constantly amazed at what mets and many others on here are currently able to do using what we have now.  Just can't help thinking that at some point we will gain a different perspective, insight or understanding that will change the way we view and understand the atmosphere.  I am a teacher and nothing excites me more then to have a student who shows a genuine, internal interest in weather/meteorology and to wonder if she or he may play a roll in that process.

You made some great comments that made me think.  Glad that you shared them....was just responding to those.  

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1 hour ago, nrgjeff said:

It was not a hard forecast with models. Some of the snow output did not make sense. Using a good old fashioned thickness QPF chart, the timing looked suspect. Always felt like cold chasing rain. I halved consensus. Worked out OK in northeast Tenn. Just forgot to go zero CHA.

I really wanted to laugh at that last sentence...but didn't want you to think I was laughing at the rest of it.  You all are on a bad streak down there.

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27 minutes ago, ShawnEastTN said:

Screw it I'm moving to a more wintry location like Shreveport Louisiana.

Sent from my SM-G965U using Tapatalk
 

And it's only 10 days away. Yeah right...

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1 hour ago, Holston_River_Rambler said:

 

giphy.gif 

giphy.gif   

 

 

It’s more likely we find a real life version of the 2nd picture before we ever get what the 1st picture shows.  Lol

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The Fv3 is awesome. It not only gives us storms within 15 days, but often within 10 days. If we could get an even awesomer color scheme for it's wild snow maps, that would be great! 

I want a happy clown, not a sad clown, with yellows, oranges, and reds, before blues and greens. 

Is it really just the NAM run out to 15 days? 

 

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Any want to start guessing how long the Fv3 will try to trail us along before it evaporates? I bet we get within 3 days on the Fv3 before it trends to Missouri/ IL. If you can't beat 'em, join 'em. 

I'm calling this the Fouke Monster Storm.

giphy.gif 

giphy.gif 

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43 minutes ago, Holston_River_Rambler said:

Any want to start guessing how long the Fv3 will try to trail us along before it evaporates? I bet we get within 3 days on the Fv3 before it trends to Missouri/ IL. If you can't beat 'em, join 'em. 

I'm calling this the Fouke Monster Storm.

giphy.gif 

giphy.gif 

I bet we get to within a day and a half before it trends away from us.  FV3 loves to tease!

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With the stout ridge going up in the eastern NA...pretty much figure the PV is going to take a beating.  Last winter, the impact on the troposphere was quick unlike the January event that we just had.  No two PV splits are the same.  Last year we were dealing with La Niña, and it was not a stormy pattern.  This spring will likely feature plenty of rainy systems.   March is always iffy at lower elevations...but get a PV split and that ups the chances for a spring winter storm.   If we get a couple of cold weeks to end the month, and then a chance or two in March.  Who knows?  This is why I don’t like backloaded winters. So, we scored a system a couple of days ago.  If we manage a couple more, tough to ask for much more.  Also, around TR or F of next week, some slight mischief possible.  

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With the wx being less predictable than normal this winter, hard to say what spring will look like.  What "should" happen has rarely happened this winter.  I suspect the same unpredictability continues as long as the MJO is abnormally amped.  I will take a few 70s during March, but it seems when spring gets warm early....that summers tend to get really hot.  I will save the 80s for late April and May.  LOL.  The crazy thing is this cool, cloudy wx(not talking BN temps)....that has been a constant this winter during a winter of inconsistent forecast models.  I doubt that stops anytime soon either.  Again, the reason I don't like Nino winters is because winters often arrive about the time everyone is pretty much over winter.  They are also fairly dreary....not big extremes in terms of temps, but the real feel is cool because of the high humidity.  

Lastly, (I think Jeff mentioned this possibility) without the past PV split during early January, we likely don't see a return of cold during January.  IMHO, and I differ with others, I think the abnormal convection in the western Pac and Indian Oceans is suspect #1.  Without the PV splitting, I think we would have had a blowtorch.  The cold right now fits with the 2-3 week lag that PV splits have in regards to cold in the East.  The temps in Chicago IMHO are likely due to that split.  There will be plenty of debate about all of that....That said, for those calling for a backloaded winter...they have already pocketed minor nice snow event here in E TN north of I-40, one in DC, and record cold in the Chicago region.  There will be a relaxation it appears, but if winter returns again....then I think the backloaded winter idea had some real merit.

And the QBO...it went positive and the NAO has been reluctant to turn strongly negative after modeling has repetitively tried to do so.  I think that changes soon, but I do think that index gains some more clout after this winter.  As duely noted, one index/teleconnection does not make a forecast... 

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Great post Carvers! Might fit in a more technical thread than Banter. 

1. Change of QBO is likely much more important than a static value. QBO was rising, so far winter has been mild. Last time QBO was falling going into winter (+ in fall going toward -) it was cold. I believe QBO is useful when using its change with time.

2. The clouds have definitely been an El Nino signature. Southern stream active is too. However that darn Indonesia convection is Nina/mild.

Separately I think this year PV split was traditional top down from the strato. MJO mess followed. Last year one could argue it was bottom up; hence, even more MJO disruption. Either way the PV is just one or many variables. 

In keeping with Banter, the other X factor is Southern Discomfort.

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Well, not seeing much to hang my hat on with the operational models overnight. Hard to believe that we are having yet another winter as the past several. Oh well, at the end of the day, not much if anything we can do but to roll with the changes - after all - will be down right Springish first part of the week, near 70 degrees!

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No snow in Chattanooga. Patriots in the Superbowl. SSDY

Kansas hoops needs to get back on track this weekend, or our Big 12 streak will be in real jeopardy. I figure Tennessee will win. Vols are a machine!

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On 1/31/2019 at 9:59 AM, Carvers Gap said:

With the wx being less predictable than normal this winter, hard to say what spring will look like.  What "should" happen has rarely happened this winter.  I suspect the same unpredictability continues as long as the MJO is abnormally amped.  I will take a few 70s during March, but it seems when spring gets warm early....that summers tend to get really hot.  I will save the 80s for late April and May.  LOL.  The crazy thing is this cool, cloudy wx(not talking BN temps)....that has been a constant this winter during a winter of inconsistent forecast models.  I doubt that stops anytime soon either.  Again, the reason I don't like Nino winters is because winters often arrive about the time everyone is pretty much over winter.  They are also fairly dreary....not big extremes in terms of temps, but the real feel is cool because of the high humidity.  

Lastly, (I think Jeff mentioned this possibility) without the past PV split during early January, we likely don't see a return of cold during January.  IMHO, and I differ with others, I think the abnormal convection in the western Pac and Indian Oceans is suspect #1.  Without the PV splitting, I think we would have had a blowtorch.  The cold right now fits with the 2-3 week lag that PV splits have in regards to cold in the East.  The temps in Chicago IMHO are likely due to that split.  There will be plenty of debate about all of that....That said, for those calling for a backloaded winter...they have already pocketed minor nice snow event here in E TN north of I-40, one in DC, and record cold in the Chicago region.  There will be a relaxation it appears, but if winter returns again....then I think the backloaded winter idea had some real merit.

And the QBO...it went positive and the NAO has been reluctant to turn strongly negative after modeling has repetitively tried to do so.  I think that changes soon, but I do think that index gains some more clout after this winter.  As duely noted, one index/teleconnection does not make a forecast... 

The December QBO reading, plus how it is trending, coupled with the ENSO state has a good indication for a base value for the winter as a whole on US temp avg. With this December's QBO and ENSO state setup, only roughly 20% of the time produced a winter national avg of BN. If we had been in a La Nina with the same setup, that pct jumped to a more neutral state (50% of the time produced a BN avg). To me its why each Nino/Nina is a different animal, they react differently each time depending on the QBO combo. Once you have the base state as a nation, then a winter forecast can start adding in all the other indices based off that %. To override the warm state combo, we needed the other ones to be moderate values and working in unison (since weak values would only tend to get us to near normal with the QBO/ENSO combo). I completely agree with John, the Pacific is our driver, not just here but as a nation as a whole. My order of weight is QBO/ENSO, EPO, PNA, AO, MJO, NAO..from most weight to least (only caveat is the MJO, depends on amplification. Some data suggests its influence falls off if it in a low state closer to the COD and easier to overcome the warm phases). The whole setup is like a recipe, takes all the ingredients combined to get an outcome.

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