December and January Pattern Discussion

[Carvers Gap]

0z GFS is colder. That is a positive in the long run. Not a lot to track, but IMO no way it stays that dry in a wet pattern.

[John1122]

There's about a 4 day warm-up in there but overall much better than last nights torchfest. It reminds me of the November pattern with cold down into Texas and temps about 30 degrees apart from NW TN to SE TN. Probably change a bunch by 12z but that look would lead to some ice possibilities in probably SW KY, far W TN and maybe NW Miss. 

[John1122]

Apparently the Euro is more moist for the Jan 2nd system....but surprise, surprise, it will be warm enough for rain most likely. Some more brief upslope potential Thursday night in the wake of the system.

[weathertree4u]

Anything on the GFS is gnna be warn..

Edit:sorry i put the wrong dates in

 

I don't think I have ever seen a model like the GFS be so consistently different from run to run for so many years; I mean, this has been going on for at least 5 years now. I used to get so upset when it would indicate a good snow for middle TN for several model runs, then suddenly it is gone! Personally, I try not to use it. The 0z run was good, perhaps believable, but then the 06z was back to the same old stuff huge warm up!

[Carvers Gap]

Mid-day thoughts...

1. I think the models are struggling (on the East coast) in the long term because the cold in Canada has been remarkably cold and the pattern has seen very little blocking over Greenland. The models have not been that bad out west where IMO they have accurately portrayed severe cold at times. We are just a small area of the globe. The models aren't "poor" just because the eastern seaboard is not handled well.

2. Two out of the last three GFS runs have not been warm, 0z and 12z, for North America.

3. CPC ensembles are slightly more favorable today. The NAO is hinting at going negative late in the period. The 0z Euro hinted at this at 240. The PNA is struggling to stay negative. As Jeff said, in this area we don't stay perpetually cold. The pattern has to reload which it will IMO.

4. Lastly, if you are going to disagree with an argument or a model's solution please provide some evidence. It is not good enough to say it's wrong...make your case. And it is no one person's duty to respond to every single post in this thread. Folks will quit posting if this happens....nobody wants a big rule book so it's much easier on us and the mods if we police ourselves. If someone is not following the rules, hit the report button. It works.

[Carvers Gap]

Thought this was an excellent write-up and provides some insights into why the ensembles are preferred...from HPC this AM.

EXTENDED FORECAST DISCUSSION

NWS WEATHER PREDICTION CENTER COLLEGE PARK MD

1049 AM EST SUN DEC 29 2013

VALID 12Z WED JAN 01 2014 - 12Z SUN JAN 05 2014

...SNOW AND BITTER COLD TO GRIP MUCH OF THE NORTHEAST LATE IN THE

WEEK...

RELIED ON THE 12Z/28 EUROPEAN CENTRE ENSEMBLE MEAN AS A SYNOPTIC

GUIDE THIS FORECAST. THAT PARTICULAR MEAN AFFORDS A SMOOTHER

TRANSITION FROM YESTERDAY'S MANUAL PROGS THAN THE 00Z/29

VERSIONS--ECENS, GEFS, CMCE. WHILE ALL OF THE GLOBAL NUMERICAL

MODELS AGREE ON A SHARP ARCTIC OUTBREAK FROM THE UPPER MIDWEST TO

THE INTERIOR NORTHEAST AFTER THE TURN OF THE YEAR, THE SOLUTION

SPREAD WITH REGARD TO THE SHORTWAVE INTERPLAY OVER THE EASTERN

STATES IS STILL LARGE--DISCONCERTINGLY SO GIVEN THE WINTER WEATHER

IMPACT THIS EVENT IS CAPABLE OF DELIVERING. IF THERE IS A TREND TO

BE GLEANED FROM THE LAST 24 HOURS OF GUIDANCE, IT WOULD BE THE

TIPPING OF THE SCALES TOWARD MILLER-B-TYPE CYCLOGENESIS--E.G.,

MULTIPLE LOW PRESSURE CENTERS DIVIDED BY THE APPALACHIAN MOUNTAIN

CHAIN. THE DENOTED COMPLEXITY OF MILLER-B-TYPE SYSTEMS MAKES

FORECASTING THE ATTENDANT HAZARDS FAR DICIER THAN

MILLER-A-TYPES--ONE LOW TRACKING FROM THE GULF OF MEXICO UP THE

ATLANTIC COAST. IN GENERAL, THE CLIMATOLOGY OF MILLER-B-TYPES

REVEALS INCREASING INCIDENCE OF HEAVY SNOWFALL NORTHWARD AND

EASTWARD ALONG THE ATLANTIC COAST--UNDER THE COMMA HEAD TRACK OF

THE COMPOSITE CYCLONE. THE SHORTWAVE ENERGY LIKELY TO COMPRISE THE

UPCOMING SYSTEM HAILS FROM BOTH SIDES OF THE SPLIT FLOW OVER

ALASKA AND THE YUKON. THE DATA DEARTH OVER THE NORTH PACIFIC AND

ARCTIC OCEANS IS MOST PROBABLY THE BIG MUDDLING FACTOR. THINGS

SHOULD COME INTO BETTER FOCUS ONCE THE ENERGY OF ORIGIN IS BETTER

READ.

THE FULL-LATITUDE SPLIT ALONG THE WEST COAST OF NORTH AMERICA WILL

CONTINUE TO KEEP THE SOUTHWESTERN UNITED STATES DRY. THE PACIFIC

NORTHWEST WILL BE GRAZED BY ENERGY WIGGLING THROUGH THE SPLIT.

LATE IN THE PERIOD, THE NEXT MAJOR SHORTWAVE INTERACTION SHOULD

OCCUR OVER THE GREAT PLAINS. FOR NOW, WILL RELY ON THE ROBUST

AGREEMENT AMONG THE VARIOUS ENSEMBLE MEANS THAT DEPICT CONTINUED

NORTHERN STREAM DOMINANCE.

[weathertree4u]

Mid-day thoughts...

1. I think the models are struggling (on the East coast) in the long term because the cold in Canada has been remarkably cold and the pattern has seen very little blocking over Greenland. The models have not been that bad out west where IMO they have accurately portrayed severe cold at times. We are just a small area of the globe. The models aren't "poor" just because the eastern seaboard is not handled well.

2. Two out of the last three GFS runs have not been warm, 0z and 12z, for North America.

3. CPC ensembles are slightly more favorable today. The NAO is hinting at going negative late in the period. The 0z Euro hinted at this at 240. The PNA is struggling to stay negative. As Jeff said, in this area we don't stay perpetually cold. The pattern has to reload which it will IMO.

4. Lastly, if you are going to disagree with an argument or a model's solution please provide some evidence. It is not good enough to say it's wrong...make your case. And it is no one person's duty to respond to every single post in this thread. Folks will quit posting if this happens....nobody wants a big rule book so it's much easier on us and the mods if we police ourselves. If someone is not following the rules, hit the report button. It works.

Part of the learning experience is to openly discuss things, with that being said, members are not always going to have verifiable proof regarding what they are stating, keep in mind, this is not a class room where we have to provide peer reviewed references for statements that are made, heck, the post I made this morning could be backed up with numerous mets that have said the same thing in an Online format but I don't have the time to chase down referenced material nor would I, again, this isn't a classroom; it is more of a brainstorming session on what the current patterns are doing. 

[Carvers Gap]

Part of the learning experience is to openly discuss things, with that being said, members are not always going to have verifiable proof regarding what they are stating, keep in mind, this is not a class room where we have to provide peer reviewed references for statements that are made, heck, the post I made this morning could be backed up with numerous mets that have said the same thing in an Online format but I don't have the time to chase down referenced material nor would I, again, this isn't a classroom; it is more of a brainstorming session on what the current patterns are doing.

This is a discussion about the upcoming pattern. It isn't a think tank but it isn't social media. It is a forum on weather. Look, I don't know you so I'll try to be diplomatic. I would be glad to continue this in the banter thread. Read Mr. Bob's post pinned to the top in regards to board rules. He is the mod. Argue with him. In fact IMO your post earlier was a good one. That is not what I was referencing. Folks don't have to write a thesis. But one liners about every model run and whether they like it or not is not what this forum is for. This is not Facebook or Twitter. If that continues, I think we will have a very short life as a region. A lot of us really had to tug and pull to get this region created within AmericanWx, so let's do things right way. I come here, as others do, to read about the weather. And yes, being able to support an idea with an argument or ask a good question is part of science. Sorry.

[tnweathernut]

I agree with both of you guys. I think the"heart" of Carvers post deals with civility in dealing with others. There are often arguments in other subforums and just a general "prickish" attitude at times toward other members. I don't want that to be a big part of the TN Valley subforum.

That doesn't mean we all have to hug and agree with one another all the time, but it does mean we should always try to treat each other with respect, even in areas where two members may disagree.

We are all here for similar reasons ......and its not really all that hard to get along.

On topic: I still like the looks on the various ensembles, but blocking in the Atlantic would be GREAT at some point, lol.

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[Carvers Gap]

The biggest thing is the total bombardment of posts by one poster in a thread. In some threads, I have to skip 5-6 posts per thread just to get to sensible wx talk. And if someone has the courage to call someone out on an argument, it is respectful to provide proof and be prepared to discuss your point...I do find it interesting that many who complain about this board are perfectly fine calling out someone else's thinking but turn right around and complain when that someone responds. Better have a thick skin on a wx board IMO.

Back to the weather, it does appear the ensembles are leading the way. Since this is the coldest time of the year, even if we can go average for temps we stand a chance at winter wx. WxSouth has often stated the pattern will remain a wet one. So, if we can sustain any type of cold the upper south should be in good shape at some point. Again, Jeff's post earlier in the thread has excellent insight on where we are in the terms of the current pattern and where it might lead. Hope to see another post from him soon.

[franklin NCwx]

The biggest thing is the total bombardment of posts by one poster in a thread. In some threads, I have to skip 5-6 posts per thread just to get to sensible wx talk. And if someone has the courage to call someone out on an argument, it is respectful to provide proof and be prepared to discuss your point...I do find it interesting that many who complain about this board are perfectly fine calling out someone else's thinking but turn right around and complain when that someone responds. Better have a thick skin on a wx board IMO.

Back to the weather, it does appear the ensembles are leading the way. Since this is the coldest time of the year, even if we can go average for temps we stand a chance at winter wx. WxSouth has often stated the pattern will remain a wet one. So, if we can sustain any type of cold the upper south should be in good shape at some point. Again, Jeff's post earlier in the thread has excellent insight on where we are in the terms of the current pattern and where it might lead. Hope to see another post from him soon.

12z euro matches its ensembles at day 9 10 now. Looks chilly after the cutter.

[franklin NCwx]

Ukmet and jma both have a snowstorm. Southern low is dominant and stays to our south. Looks like the cmc is a split between the jma/ukmet camp and euro gfs camp.

[Carvers Gap]

Ukmet and jma both have a snowstorm. Southern low is dominant and stays to our south. Looks like the cmc is a split between the jma/ukmet camp and euro gfs camp.

That is good to hear. Just took a look at the 12z Euro. I am somewhat skeptical as all models have been flip flopping some. But the Euro seemed to see the westward injection of cold into the pattern sequence first...a few days ago. So, I give it some merit and its ensembles have been portraying this as well. Certainly, days 8-10 show an excellent evolving pattern for eastern winter wx enthusiasts. Will it show that tomorrow? IDK. Potentially(said that too many times this winter), a colder pattern is now depicted on most models after day 8, GFS and Euro especially. Some minor support from the CPC ensemble teleconnectors, very minor in terms of today's trends.

[tnweathernut]

That is good to hear. Just took a look at the 12z Euro. I am somewhat skeptical as all models have been flip flopping some. But the Euro seemed to see the westward injection of cold into the pattern sequence first...a few days ago. So, I give it some merit and its ensembles have been portraying this as well. Certainly, days 8-10 show an excellent evolving pattern for eastern winter wx enthusiasts. Will it show that tomorrow? IDK. Potentially(said that too many times this winter), a colder pattern is now depicted on most models after day 8, GFS and Euro especially. Some minor support from the CPC ensemble teleconnectors, very minor in terms of today's trends.

Good post. We have had a TON of potential showing past day 7. I just hope we can reel that potential inside day 5 at some point in the near future....

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[tnweathernut]

Euro ensembles are bullish on cold from shortly after 168 through the end of the run (240)

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[jaxjagman]

Anomalies are much better today on the 12z

[John1122]

Right now the models seem to be in two camps for Thursday. GFS is drier and colder, the Euro and others are warmer and wetter. So, I don't know that rooting for either is good at this point. Right now I'm hanging my personal hat on picking up some upslope snow showers Thursday night and Friday. 

 

Not surprisingly, now it looks like the weekend will see precip again, but not a major system. Just a frontal passage with rain to snow again. As everyone has lamented, the cold won't stay around until we get a blocking. It's a roller coaster until then and when we get in roller coaster situations that's almost always cold chasing moisture for the entire Tennessee Valley region. It only ever really does much in the way of wintry weather for the upslope areas outside of a few flurries or snow showers. 

[tnweathernut]

The Euro control is almost comical. After two events.... ...... 2nd and the 6th (rain with lows from the southern plains/west TN to the OH valley) followed by cold blasts of air, it stays cold and dry until a beautiful Miller A on Jan 11th, however this storm is also rain as there is ZERO cold air to work with.......followed by yet another Miller A that runs from The gulf coast (Louisiana) straight north to Michigan (also rain with 0 cold air). Don't worry though, we look primed to get more arctic air AFTER that system on the 11-12th.....lol....

At least the Ensembles still look good.....you have to think we at least have a legit threat at some point between days 5-10.. But I am a glass half full kind of guy.

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[valkhorn]

18Z GFS gives TN a great 2-4" and up snow for most of the state around hour 183, but what the 18z giveth the 00z will take away.

 

There has been almost no consistency with the GFS lately.

[John1122]

I honestly wouldn't be a bit surprised to see this be a nearly exact depiction of what will happen. For whatever reason we're in multi-year cycles of this kind of cold chasing moisture as storms ride up West of the Apps on a consistent basis. this was the basically the Jan 2006 til March 2009 pattern as well. Not sure why the pattern has evolved into an all or nothing scenario in the 2000s. But it seems that it has,

The Euro control is almost comical. After two events.... ...... 2nd and the 6th (rain with lows from the southern plains/west TN to the OH valley) followed by cold blasts of air, it stays cold and dry until a beautiful Miller A on Jan 11th, however this storm is also rain as there is ZERO cold air to work with.......followed by yet another Miller A that runs from The gulf coast (Louisiana) straight north to Michigan (also rain with 0 cold air). Don't worry though, we look primed to get more arctic air AFTER that system on the 11-12th.....lol....


At least the Ensembles still look good.....you have to think we at least have a legit threat at some point between days 5-10.. But I am a glass half full kind of guy.


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[Carvers Gap]

I will take my chances with an active southern jet and Arctic air intrusions. At some point, IMO, someone on the East coast should get walloped. That cold high over the Hudson has been present during many great TN winters. Have to think it won't be wasted. At some point I might actually be concerned with ice over the Valley with it in that position.

[franklin NCwx]

Man, gfs ensembles all over the map from one run to the next.

[John1122]

Man, gfs ensembles all over the map from one run to the next.

This is likely why so many WFO's are generally ignoring it or giving it little weight. JKL mentioned in their AFD that the GFS suite was quite an outlier vs basically all other models.

[1234snow]

0z GFS drops the trough out in the west again before 180 and we are right back to where we started a few weeks ago. This winter has been another frustrating one.

[tnweathernut]

Extreme high (1060+) shows on 0z again. Just a matter of time before one drops in on us in the TN Valley. Looks to be aimed further west initially, but if its a little quicker and a little further east initially (like most ensembles) I think next weekend/early following week could be highly changeable.......with a good opportunity for ice/snow.

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[tnweathernut]

0z GFS drops the trough out in the west again before 180 and we are right back to where we started a few weeks ago. This winter has been another frustrating one.

Most ensembles disagree and mostly keep the trough in the east......time will tell.......if the op is in error it would have HUGE differences in our weather here.

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[1234snow]

Most ensembles disagree and mostly keep the trough in the east......time will tell.......if the op is in error it would have HUGE differences in our weather here.

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Yes the GFS has had a lot of trouble handling things in the mid/long range so there is still a wide range of where the trough will drop down. It's just been hard to break that pattern down except here recently.

[Clarksville Snowman]

I'm just waiting for the op to catch on to the ensembles, the ensembles looking good. Have hope we can cash in sometime in the first 10 days of Jan., would be nice to get a big snow. Bring on WINTER!!

[John1122]

The GFS is so nuts right now that anything happening wouldn't surprise me. I will possibly give slightly more credence to the GFS showing a big Western trough because it's happened already this late fall/early winter.  Still, it basically shifts that trough by 1000 miles almost every run. 

[John1122]

From JKL this morning.

 

 

 

FORECAST MODELS THEN START TO GET INTERESTING BY NEXT WEEKEND. A
LARGE RIDGE APPEARS TO BUILD UP THE WEST COAST OF NORTH AMERICA ALL
THE WAY NORTH INTO THE BEAUFORT SEA. THIS OPENS UP A DEEP TROUGH
OVER THE CENTRAL U.S. CREATING A FUNNEL FOR ARCTIC AIR OVER CANADA
TO SURGE SOUTH. MODELS CURRENTLY AGREE ON THE DEVELOPMENT OF A STORM
SYSTEM ON THE POLAR FRONT OVER THE CENTRAL U.S. DURING THE WEEKEND
AND THIS IS CURRENTLY PROGGED TO BEGIN AFFECTING EAST KENTUCKY BY
SUNDAY. LOTS OF UNCERTAINTY WITH THIS DEVELOPING PATTERN BUT WILL
ADVERTISE A CHANCE OF BOTH RAIN AND SNOW TO CLOSE OUT THE PERIOD ON
SUNDAY. WE WILL THEN HAVE TO PAY CLOSE ATTENTION TO WHERE THE ARCTIC
AIR MASS SLOSHES NEXT WEEK...WHETHER IT STAYS TO OUR WEST AS HAS BEEN
THE CASE MUCH OF THIS EARLY WINTER OR WHETHER IT BREAKS TRADITION
AND HEADS MORE SOUTH AND EAST AND PAYS US A VISIT.