Winter Pattern Discussion 2014-2015 (December/January)

[GaWx]

I think many folks remember the non-winters of the 90s. Might be why many get nervous, that and our latitude. Rarely do we get snow before Christmas in Kingsport of any major significance. Seems like a winter forecast is such a difficult task when a La Niña or Niño is not raging. I don't usually throw in the towel until February. Many winters have been saved in February. So, we have a solid 10 weeks before things move to spring. I think last January spoiled folks with almost wall to wall cold. El Niño winters, not matter what the strength, are often wet and chilly. The strength of the Niño defines the precip type. The lack of snow cover in Canada does concern me some,but that can change quickly. Things can and will change quickly here as well. It is winter. I would be completely shocked if many don't cash in on this. May just be this winter is one of a few big events instead of several small ones.

Our best shot at a cold winter is when La Niña or El Niño is not raging. I assume you realize that. High end neutral positive to weak to low end mod niño winters have produced the coldest on average when there is also a +PDO and -NAO. Even with just one of these two along with a weak to low end mod Niño, quite cold winters have occurred though having both is much better for those chances.

[Carvers Gap]

Our best shot at a cold winter is when La Niña or El Niño is not raging. I assume you realize that. High end neutral positive to weak to low end mod niño winters have produced the coldest on average when there is also a +PDO and -NAO. Even with just one of these two along with a weak to low end mod Niño, quite cold winters have occurred though having both is much better for those chances.

 

Oh yeah, understand that.  Just saying that producing a winter forecast is easier when  a moderate to strong Nino or Nina is present.  For us, the winters with greater snow amounts are weak Ninos and Ninas for sure.  But...they are difficult to predict due to the variability of the pattern as things are less certain. 

 

The 12z Euro banks the cold up against the Rockies on this run.  Has more of a cutter scenario where most energy through ten days goes west of the Apps.  Definitely a valid scenario and is yet another solution produced by the Euro...and probably not a pattern most of us who like snow would want.  So, on to the next run and hope the trough centers a bit more east.  The 0z seemed to center the trough so that we actually needed a ridge.  The 12z sets the axis further west and places too much of a ridge.  Almost looks like this winter that we are going to have to have a system that cuts, drags down cold air, and then a trailing system plows into the fresh, cold air.  Was hoping for a better solution on the 12z Euro, but it is what it is.  Hopefully, the Euro is up to its old tricks of holding the cold back.  The GFS seemed to want to bring the cold East.  However, the GFS has bowed down to the Euro on the Christmas system w/ the stronger cutter.  The GFS had just a weak wave for quite some time.  The 12z GFS seems to be in agreement w/ the 12z Euro that the cold will center in the Plains w/ a slight ridge in the SE.  Not a bad pattern in that there is southern stream energy w/ cold air sitting to its northwest.  Based on today's runs only, that is probably a better set-up for the mid-west than the upper south.  Lots of energy though and plenty of cold though. 

 

It is looking more, and more this winter that instead of looking at several small systems that we may be looking at a few very large systems.

[Carvers Gap]

Well, so much for the warm CFSv2 Jan fcast. It has solid cold in the E US now and the coldest anomalies on the planet. 1939-40 type winter still possible based on this!

Day by day evolution of Jan fcast as it got colder over last week:

http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/images/summaryCFSv2.NaT2m.201501.gif

It also has drier than normal for the SE outside of SE GA and FL though it often takes only one major winter storm to make it a memorable winter for much of the SE US and cold is much more crucial than wet based on history. Example: Feb. of 1895 was quite dry in ATL with only 2". Yet, it is the snowiest month in ATL history with 11.6" from three storms!

http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/images/summaryCFSv2.NaPrec.201501.gif

 

I don't think CFS2 has been supremely terrible...but suspect for sure.  It depicted a warmer December than many had, and probably will be correct in many areas.  However, it just seems to be too extreme when the pattern is set to be above average.  One can watch the trends on it and get good info.  It was cooling January off as early as November on the model.  I think I even mentioned that in the first post in this thread.  So, it has been useful in that it signaled that January should be normal for temps.  I have a hard time believing things will be remotely dry w/ this Nino going on.  We have rarely seen the sun here for like three weeks.  But overall, it does not hold a candle to the Euro Weeklies.  Appreciate you stopping by from time to time.  Have a great weekend.

[jaxjagman]

 

To bad the CFS isn't reliable

[jaxjagman]

[John1122]

The GFS keeps flipping around on a potential New Years time frame storm. It is pretty consistent with the cold coming though. The intensity of the cold is the big question at this point. Some runs show sub zero, others show highs in the 20s/30s and lows in the high single/mid teens across the Valley.

 

The 18z brings a southern slider by on New Years eve and puts down a 3-5 inch swath from basically extreme N.Alabama up to Nashville and points east. 

 

That'll change a lot in the next few days but hopefully the idea of cold and a storm meeting stays on the table.

[jaxjagman]

 

Euro is showing the MJO going into 6 at the end .Before this it looks like the NAO is going to go + the AO isn't as strong as the past couple days and the EPO is exrtemely negative looking

 

The Pv is getting hit hard at 10hpa on the GEFS mean,D11

 

 

[jaxjagman]

The GFS keeps flipping around on a potential New Years time frame storm. It is pretty consistent with the cold coming though. The intensity of the cold is the big question at this point. Some runs show sub zero, others show highs in the 20s/30s and lows in the high single/mid teens across the Valley.

 

The 18z brings a southern slider by on New Years eve and puts down a 3-5 inch swath from basically extreme N.Alabama up to Nashville and points east. 

 

That'll change a lot in the next few days but hopefully the idea of cold and a storm meeting stays on the table.

Yeah not a bad look,like you said though it will change over and over.That run it was much colder on the 18z,.42 qpfs all snow for BNA

[jaxjagman]

gefs  18z still looks good to me towards the New Year and beyond,2m temps in the 20's to lower 30's,we don't want to see teens in the single digits  if that was the case we'd be looking at dry air and no storms,i like the looks

[John1122]

gefs  18z still looks good to me towards the New Year and beyond,2m temps in the 20's to lower 30's,we don't want to see teens in the single digits  if that was the case we'd be looking at dry air and no storms,i like the looks

Very true, January was frigid last year but not as productive for non-upslope areas of the Valley as February was once it warmed up a little bit. The main thing January did was chill the ground temps.

[Carvers Gap]

Very warm phases of MJO if it verifies. We will see what the impacts are here.

[jaxjagman]

 

 

 

Wave 2 which i figured would show up toniight

 

 

Nothing showing poleward

 

 

 

 

[Carvers Gap]

I am having a hard time remembering when the Euro has been so inconsistent. Last night's run is yet another variation of the pattern(I am not even speaking of particular wx events). Very much moves to the MJO status Jax posted last night. No more than a few days of passing cold and nothing on the horizon after that. Wow. Either the pattern change is significant causing all of this flip flopping....or the Euro is moving towards a pattern that produces very little winter wx for most of NA.

[Carvers Gap]

The GFS continues to show cold after Christmas and then the cold retreats late, somewhat similar to the Euro but holds onto the cold longer. Burns said in the SE thread that maybe something unusual is getting ready to unfold and is causing the model chaos. I am probably in agreement. Before January's cold last season, the models went into a funk and the GFS seemed to sniff it out first. I am definitely not saying that is going to repeat itself. I also do not like where the models are leaning this AM, but hey...it will be different tomorrow.

[tnweathernut]

I am having a hard time remembering when the Euro has been so inconsistent. Last night's run is yet another variation of the pattern(I am not even speaking of particular wx events). Very much moves to the MJO status Jax posted last night. No more than a few days of passing cold and nothing on the horizon after that. Wow. Either the pattern change is significant causing all of this flip flopping....or the Euro is moving towards a pattern that produces very little winter wx for most of NA.

I haven't looked at an OP run past day 3/4 in the last 5 days. All I am looking at are the ensembles. 12z Euro ensembles continue to look pretty good to 240. Once the pattern changes I might look at the OP's. Until then, it's pure folly IMO.

[jaxjagman]

I haven't looked at an OP run past day 3/4 in the last 5 days. All I am looking at are the ensembles. 12z Euro ensembles continue to look pretty good to 240. Once the pattern changes I might look at the OP's. Until then, it's pure folly IMO.

I agree.looking at the GEFS,we could be looking at some fun times ahead

[Carvers Gap]

I haven't looked at an OP run past day 3/4 in the last 5 days. All I am looking at are the ensembles. 12z Euro ensembles continue to look pretty good to 240. Once the pattern changes I might look at the OP's. Until then, it's pure folly IMO.

Actually, I am not so sure that the OP won't eventually get out ahead of the ensembles. Folly insinuates foolishness on my part. I don't think that was your intention, but that is the definition of the word. Personally, I think looking at the OP gives us a different lens with which to view the ensembles. Often, they will tell us where the ensembles are leaning. I think the ensembles have a tendency to produce a type of statistical group think.

[jaxjagman]

I have attached an article by Scott Sabol of WJW-TV in Cleveland OH. This is an important read because Professor Jin-Yi Yuh of the University of California has written a definition of various types of El Nino episodes. Dr. Yuh feels that the current brand of +ENSO is of a "Central Pacific" type, and not a "Modoki" version. That said, the "CP" stamp has been associated with fairly severe winters featuring widespread cold and snow, the most recent case being 2009-10. The incredible warming of waters along the entire West Coast of North America is likely to be one of the main factors in aiding the formation of blocking ridges, as long as a sub-Aleutian vortex returns to prominence.

All of that aside, there have been more than a few who are not buying the cold winter scenario that the numerical models have been forecasting to return over the next week to the eastern two-thirds of North America. The main point of contention is the Madden-Julian Oscillation, which some insist is in a very unfavorable position (Phase 4) to aid amplification of the polar westerlies. But the MJO is clearly in an incoherent state now, with widespread convection all the way from the lower Arabian Sea to below the Hawaiian Islands. Most importantly, tropical forcing is linked with, and is energizing, both the northern and southern branches of the westerlies. In effect, you get cold air advection chances with frequent and powerful storms.

That is the gist of my forecast through the first ten days of January. The analog method has worked very well so far (even in December, with its mild first 2/3 and shift to colder at the end). Comparison tests suggest that broad ridge formation from Alaska into Greenland will press very cold air into much of the U.S., with a threat for two significant winter weather events over the eastern third of the nation between New Year's Eve and January 5 - 6. There is a high likelihood of a January Thaw between the 10th and 19th, followed by another very cold period from January 20 - 31. Note that the temperature forecast includes a ten day thaw.

One more thing I need to point out is that subtropical ridging stays over the Greater Antilles and Sargasso Sea through January 5. This position is not a warm teleconnection for the southern and eastern tiers of the U.S., this despite what the 12z December 20 ECMWF ensemble spread might indicate. Instead, this is a "fuel pump" anticyclone scenario where storms tracking through the Old South or up the East Coast are able to dump high amounts of precipitation.

This is going to be a rough ride. You did not really believe that a relatively mild period at the end of calendar fall was how the entire winter season would play out, did you?

Prepared by Meteorologist LARRY COSGROVE

[jaxjagman]

http://sabolscience.blogspot.com/2014/12/the-different-faces-of-central-pacific.html

[tnweathernut]

Actually, I am not so sure that the OP won't eventually get out ahead of the ensembles. Folly insinuates foolishness on my part. I don't think that was your intention, but that is the definition of the word. Personally, I think looking at the OP gives us a different lens with which to view the ensembles. Often, they will tell us where the ensembles are leaning. I think the ensembles have a tendency to produce a type of statistical group think.

Not calling you foolish, but I do think during periods of major pattern changes the OP models spit out foolishness regularly (as evidenced multiple times just in the last week). That was my point.

The ensembles have been very bullish (especially when you remove anticipated bias from the various versions) on a very nice look at H5 coming and a major pattern change. Once we reel that in, I think the OP runs will begin to hone in and consolidate around a specific threat. Until then, I really don't think they will have a clue.

All this said, it's science and I am sure there are a lot of different methods and lenses one can look through to draw conclusions. I enjoy seeing them all, even when they don't agree with me.

Hope you have a great finish to your weekend Carvers....thanks for your input here.

[Carvers Gap]

Looking down the road...Mr Bob says the weeklies fail to lock in a cold pattern. The MJO is in the wrong phase. We have a weak Nino. Looks exactly the same as the beginning of December. Some good cases out there for a great winter, some not. To end December and begin January, I think we get 7-10 days of cold and then more cold, rainy wx. When the cold comes back is anyone's guess. It really looks like this winter will be accentuated by big storms with tranquil patterns in between. With December in the books, and 1/3 of the winter in the books for those outside of elevation...we have yet to get out of the gates. I still think this is a good(not great by any means) winter for many in terms of snow. I see no evidence outside of analogs of cold locking in. Looks transient throughout winter as the Nino-ish Pacific will unseat it in an active pattern. But that same fly in the ointment may produce a memorable storm for the TN Valley (or two) with an active jet. Ninos can drop big snows here. Seems a window for a good storm(and I am certainly not the first to say this) will open shortly after Christmas and close around the 10th. Let's just hope we don't have three weeks of tranquil wx to follow like December. Though it may seem I am pessimistic about our chances, 95-96' looms in the back of my mind as one of those winters where overall temps were not impressive but two great snow storms made that winter if I recall. Some excellent cold was found in spots. Might that be how this winters turns out?

 

edit:  95-96' I think is a weak Nina year.  So, maybe not a great analog.  My thinking is still similar.  Without those two great events, nobody would remember it.  That may be where we are heading this year.  It certainly appears, though the pattern is bland, that we are seeing storms make a run up the coast.  Many of them have only produced Apps snows so far.  But for here, it only takes one of those to reach normal.

[Carvers Gap]

I don't know that I agree w/ this, but looks like CPC is banking on a cold last 2/3 of winter.  Their January forecast is for normal.  Are they implying February will be cold?  I have no idea.  However, this was just made, so I thought I would share.  Precip is normal and maybe on the dry side for KY.  I think we stay damp all winter.

 

[Carvers Gap]

Significant shift on the 0z NAM for Christmas.  Doesn't really change the outcome, cold rain.  But the low is in a different, more eastward position.  Saw that mentioned on the SE board.  Thought I'd share.

[jaxjagman]

Significant shift on the 0z NAM for Christmas.  Doesn't really change the outcome, cold rain.  But the low is in a different, more eastward position.  Saw that mentioned on the SE board.  Thought I'd share.

The NAM would be all by itself with that track

[Carvers Gap]

The NAM would be all by itself with that track

 

The 0z GFS shifted as well...not as much, but some eastward initially.  Really there is very little HP to push this down and east.  Should be a cutter.  We will know in the AM if the NAM run was just a hiccup.  Memphis is not that far from at least needing to watch the system.  You all have a good evening.

[Carvers Gap]

The NAM would be all by itself with that track

 

Not exactly.  Go checkout Burger and Delta talking about it in the SE forum.  More separation between the two streams is evident.  Probably signifies nothing...but it might give us hints w/ future systems if the medium range models are being too bullish w/ interaction between the two streams.

[jaxjagman]

The 0z GFS shifted as well...not as much, but some eastward initially.  Really there is very little HP to push this down and east.  Should be a cutter.  We will know in the AM if the NAM run was just a hiccup.  Memphis is not that far from at least needing to watch the system.  You all have a good evening.

Definite to warm at the lower levels for sn on the GFS 0z tonight for BNA,Would believe towards the cumberland east would have a shot though for some

 

Edit:This would be the X-Mas eve system

[1234snow]

Significant shift on the 0z NAM for Christmas. Doesn't really change the outcome, cold rain. But the low is in a different, more eastward position. Saw that mentioned on the SE board. Thought I'd share.

There has been some wild variations for the Christmas storm on all the major models since the storm came into range(Hour 180). The para GFS was the first to sniff out a storm and then the next day the GFS and Euro had the Superbomb solution. Then after that the models kept pumping up the ridge on west coast more and more on each run. This let the trough dig more over the Southern Plains and we still got cutter solutions but they were weaker.

I saw the 18z and 0z runs of the NAM about an hour ago but I didn't bring it up because the NAM has been awful lately (It had up to an inch of QPF for our busted storm a few days ago when all other models had caved to a no storm solution). The 18z run looked east of the GFS/Euro and the 0z run was even further east taking the low up the eastern side of the apps.

I don't think we have seen the final outcome at all with the Christmas storm. I would think snow chances would go up slightly especially for western Tennessee if the southern part of the trough can get more separation and pinch/cut off from the larger trough. Just something to keep an eye on.

12z Euro has a light snow event for east TN around Hour 174 and a big but wet storm at Hour 240. I think we can sneak in a shot while we have the ridge holding serve out in the west sometime in the 7-10 day time frame.

[1234snow]

Today's CFS2 run was much warmer than a few days ago but the teleconnections was a different story. Has a solid -NAO/AO and +PNA pattern through the 16th of January.

I would post photos but it is not letting me upload files.

[Carvers Gap]

Today's CFS2 run was much warmer than a few days ago but the teleconnections was a different story. Has a solid -NAO/AO and +PNA pattern through the 16th of January.

I would post photos but it is not letting me upload files.

In my thinking, I have toyed with the idea that the late month cold will be significantly blunted. The projected MJO phases, the Euro weeklies, the NINO not being a Modoki, and the general pattern shown on the models the last few days now lead me to believe the cold shot will be significantly blunted both in severity and duration. That evidence is getting harder to shove aside. The ensembles have already miscalculated storm chances for this past weekend and this current week, thus showing a lack of reliability. The OPs have produced some wild solutions but seem to be settling on a cool, wet basin-wide Nino-like pattern with very little, if any, Arctic air involved for the TN Valley. We will still have chances for snow, but IMO it is time to take the severely cold winter possibility off the table. We still could have a typical, cool winter...just not severe. Looks like our next decent chances for sustained cold and snow are after Jan 15.