Winter Speculation 17/18 -December Thread

[Carvers Gap]

Here are the individuals from the 12z GEFS.  One can see the assortment and clusters of the slp placements for storm 2.  Remember storm one is Saturday and is not our storm.

[Carvers Gap]

Still not there.  Until then, we wait.  The 12z Euro looks very similar to its 0z version and very similar to the CMC.  Weak area of slp riding the front to the mouth of the Chesapeake.  Energy transfer from Upper Mid-West.  Does not stall.  Odd to have the GFS amped and the Euro not.  Usually the GFS is progressive in nature.

 

[Holston_River_Rambler]

Maybe this is waaaayyyyyyy too nit picky, but I decided to try and see where the differences between the GFS  (right image) and Euro (left image) start for the mid week system (the one at roughly 130 - 144 hours we've been discussing). On the included image the blocking in the Davis Straits is about the same on both maps at 72 hours, but after playing them side by side, the difference seems to be in the northern energy I've pointed an arrow to on the GFS.  A bit of it quickly swings back into the upper low in the Pacific and the merged energy pumps up a ridge a little more quickly in the west, allowing the H5 low to dig a little further south and transfer further south (Cape Hatteras area).  The Euro seems to consolidate the initial energy a little more near the Great Basin. A piece breaks off and swings back, but is a little weaker and takes a little longer to create a ridge further west.  

Between 72 and 120 hours that little piece of energy seems to have big implications for how everything develops downstream.

Looking back at trends, when the GFS had that energy more consolidated (for example look at the 6z, Feb 26 run), its solution looks a lot more like the Euro. H5 low further north, frontal passage, then a wave develops in the south along that front. 

[Carvers Gap]

The EPS and GEFS are in two different camps.  On a global scale, they are not off by much.  But they are off just enough that what happens over coastal VA and NC is creating decent differences at the surface.  Maybe a case could be made that the Euro is moving a bit more in the GFS direction...but really two camps.  EPS is rolling right now.  The d9-10 frame also looks interesting.  Bout it.  But until the Euro is on board, not buying the GFS just yet.

[Carvers Gap]

MRX mentioning snow showers next Tuesday-Thursday.

A weak return flow Monday as well as we lose the upper ridge and the
pattern turns unsettled again as an upper low digs toward the area.
Air mass look cold enough for the possibility of snow showers at
times for parts of the area from Tuesday night through Thursday
morning.  Looks like toward the end of the period this trough will
be heading out and we will start to dry again.

[PowellVolz]

Might see several inches next week above 3k in the mountains.


.

[John1122]

Looking decent for places above 2000-2500 feet to see accumulating snow, probably 1-2 inches and increasing as you increase in elevation, before Mid-March.  I think valley areas may see flakes too but accumulation is very hard to come by after the huge warmth we've had unless we get a far more dynamic system than anything modeled. But it's always possible. NW Pa is getting that type of system tomorrow. 40-50mph winds forecast with 12-18 inches of snow.

[Holston_River_Rambler]

0z operational Euro at 240 hour was nice.  Big upper low rolling ESE through north Alabama and Georgia after digging through Missouri.  Snow develops in the Tri-Cities area and it looked to be changing the rain over to snow from Nashville south to norther Alabama.  The control and 6-7 members of the EPS (1 for the western forum areas) had what I would consider good hits (2 or more inches at this point, but 2 were big storms) and I stopped counting the smaller hits, but I'd say 15 or so had some snow in that time frame. Some had nothing.  

The CMC, in the same time frame had nice PNA ridge swelling into the Northwest Territories and two globs of energy, one digging through southern Utah and another aligned with it but separate, digging through the Dakotas. What that model shows at the surface at that time doesn't look so good, but I think it was heading to something very nice at 500 mb on that particular run.

The GFS is about 24 hours faster with the upper level energy than the CMC and has it in a similar place to the Euro, but much more strung out and progressive, so most of what falls is rain. But it still has a storm and that storm turns the corner and gives a nice hit to interior New England.  Almost all of the 6z GEFS have some sort of big storm in that time period, not necessarily for us, and not necessarily snow, but the energy is there. A few of them look quite a bit like the Euro's operational solution. 

This time period and piece of energy has been shown for several days now. It would be the third that we've been discussing and arriving between 3/10 and 3/11.  So to be clear what I'm talking about, there is the mid week storm (1) that may produce good upslope snow in the higher elevations (hopefully if it produces I will get some pics), another piece (2) that has occasionally amped up a bit as it forms on the front the earlier (1) storm lays out, and then the late next weekend energy (3). And it is this piece of energy (3) that I'm interested in. Although I'd be lying if I didn't say what the Euro was showing ATT made me happy all this is still a long ways out. So it's the time period that I'm interested in, no particular details just yet. Here are my reasons:

Hopefully there will be more of a trough carved by the previous fronts and energies regardless of what they do.   Jeff has mentioned that earlier cold shots (maybe the ones behind the front that swept through yesterday and the one next week) may underproduce, while later ones may overproduce. If I'm putting words in your mouth or mis-stating what you said, please just let me know. 

The energy has been consistently there and seems to be consistently there on several ensemble members. 

If this is going to work, I think the mid week system needs time to move to a 50/50 position to keep a nasty low out of the Great Lakes. Also the -NAO has weakened considerably by this point next weekend and as I noted in the historical thread and as others have mentioned, these storms like to sneak in as the -NAO decays. 

Still a week until it even comes into the mesoscale models' range, so expect lots of changes and all this may end up just being a whole lot of nothing.  This is all speculation, though I think I have some good reasons to be guardedly optimistic that at least higher elevations may be in for a treat the weekend of the 10th.  

[Carvers Gap]

Nice discussion by Jeff to continue w the cold as models have definitely cooled w d10-15 modeling overnight.  At d7, I think it was also wise not to buy the GFS as the Euro was not on board quite yet.  The GFS has moved some towards the Euro.  Still, with six days out...plenty can happen.  This is a truly changeable pattern for models.  And yes, then there is d10.  Very interesting to see the models handle the block in different ways.  Also, it was very interesting to see the Weeklies which were not warm...they weakened the block mid-month and followed it w another(shorter) episode of -NAO blocking.  Everything will have to be watched now at the models are really catching on to the influence of the block.  Several systems in the pipeline after this weekend's.  How that stalled system in the Atlantic finally verifies will have big impacts downstream.  

[nrgjeff]

Solar cycle recently updated data is trending with the Dalton Min. which is deeper/longer than the previous min. Currently the even more extreme Maunder Min. is considered off the table, but Dalton is enough to make winter interesting. It is really more a 18/19 and later winter topic, but fun to watch.

[Carvers Gap]

1 hour ago, nrgjeff said:

Solar cycle recently updated data is trending with the Dalton Min. which is deeper/longer than the previous min. Currently the even more extreme Maunder Min. is considered off the table, but Dalton is enough to make winter interesting. It is really more a 18/19 and later winter topic, but fun to watch.

Great find.  Do you think we are looking at several solar cycles like the current one?  I have always heard that the previous cycle gives hints to the strength of the next one.   I think that I have read that the next solar cycle might be even weaker.  I am certainly no solar expert.

[nrgjeff]

I'm not a solar guru either. My understanding is the coming cycle is supposed to be weak. Sometimes weak cycles come in groups. Current rate of descent is fast like the Dalton Min. We need to make winters interesting again. 

[Carvers Gap]

Just for kicks and giggles.  Go look at Tropical Tidbits at the 12zGFS on the precip/mslp toggle....that is one massive storm.  Takes up like half of the United States and stretches to the Yucatan.  

[Carvers Gap]

12z Euro...Well, the 0z was interesting and the 12z is no less interesting.  Textbook energy handoff.  Was slightly wonky at 500.  Changes from 0z is that it really is not a cutter.  It is hybrid A/B.  A slp begins in Louisiana and rolls through the perfect progression.  Another slp in tandem pushes into middle TN.  The MA had to like that look.  However, what will be interesting is this is well past d7 and is now on both the GFS and Euro operational....Is the Euro weakening the northern feature as it "sees" the block which might open the door for a more consolidated and dominant Miller A?  Possibly. Maybe it will just be a hybrid.  Most big winter storms have some shadow that goes west of the Apps.  We see the that often as the "warm nose."  Anyway, here is a graphic that shows the progression roughly of the two lows.  Still a LONG way to go, but it is not uncommon for the global models to see big systems this far out, and lose them, and get them back.  Verbatim, the thermal profile is rain for us.  So, no false advertising intended.  I am more of a track/intensity guy.  I will take track and intensity over all else.  I don't worry about snow maps at d9-10.  This could still go poof!  But this about all we have to watch.  So, watch we will.

[jaxjagman]

It's still long range but the system next weekend is looking more severe.If the system were to go into the OV like the GEFS shows this would be a more wide spread severe threat,with more chances of supercells before the boundary comes though .Either way ,both the Euro and GFS shows a severe threat next weekend though the Euro is more severe in the deep south,Here's the Showalter before the front passes though even if it dont go into the OV,still looks nasty on the 18z run.Mid Valley into the east

[jaxjagman]

Pretty soon the Euro is going to be in the GOM or already showing it,if there was cold air it would be something to get excited about

[Holston_River_Rambler]

Regardless of whether or not there ends up being any snow for MBY (or even the Smokies), I'm excited that this system keeps looking so powerful even over a week out. 

 

[Holston_River_Rambler]

Man even though as Jax says there doesn't seem to be a lot of cold air (and he's right), I really like where the Euro seems to be headed with H5 potential vorticity (included image).  This is still at day 10 and maybe that's where it will stay, but as Carver's said yesterday there isn't much else right now, so we'll watch.  A piece of energy rolling east from Texas and another strong vort diving SSE out of Saskatchewan into the Dakotas and Nebraska and already interacting a little over Colorado.  These pieces were on the Euro at 12z yesterday too, but it was all shifted slightly east.  The GFS and CMC also have both pieces of energy, but the more southerly one is in different places on each model. Oddly enough all three seem to agree with the more northern vort's placement in it dropping out of central Canada and that it will interact in some way with the southern one. Still a looooooooooooooong ways to go but I'm getting excited for now because wintry or no, this one keeps showing up and as I said above looks dynamic.  Speaking only for myself, after this winter I'm ready to go out with a bang, whether it be snow or thunder!

[Carvers Gap]

Marginal temps in March is the game we play.  Need the system at night and wound-up.  The 12z GFS is almost a weenie run.  The comma head that forms on the d8-9 storm is impressive.  Plenty of opportunities IF that run is correct.  I would not be surprised to see convection regardless of precipitation type.  

[Carvers Gap]

You can see the Miller A.  I am sure there is a bit of energy hand off.  What was interesting about this run is that the northern stream dives into the slp over Hatteras.  You can see that energy over the upper Midwest.  Nice comma head look.  Thermal profile would be ok IF that look verified.  Anyway, again something to watch...could go poof or consolidated with any model run.  The 0z Euro did have a similar look.  Bout all we can ask for at this range.  This is one of several options on the table.

[Carvers Gap]

Day 7-9 storm.  The 0z CMC and GFS show a similar storm...the CMC is a beauty, but trying to think of the last time it led the way.  So grain of salt, but nice snow map.  The 12z EPS looked decent as well.  

[Carvers Gap]

Overall, the track for the d7-9 storm still has two camps - cutter and hybrid Miller A.  The 6z GFS actually takes a track that is good for middle TN.   The Euro cuts to the Lakes, w probably some energy transfer to the coast.  Now here is what is interesting, the EPS is not in agreement w the 0z run.  The EPS takes the slp across the mid-South, turns the corner and is and inland runner.  Likely there is some energy west of the Apps.  How much is the question?  The 6z GFS and 0z EPS look very similar.   All of this said, this system is barely in focus.   It looks a lot like many of the systems that hit middle TN during the past few winters...Temp profiles are still marginal.   Really hope much of this falls at night and hope someone in the forum area can see at least some March winter weather.

[jaxjagman]

The storm a couple years ago in Mid Tn just had the perfect track,couldn't ask for anything better here,plus it was in the heart of winter

[jaxjagman]

[Carvers Gap]

The 12z Euro is much closer to the rest of 12z guidance.  Energy transfer from a slp that pushes into middle TN and then jumps to the EC.  The backside snow slides through most of easter KY and southwest Virginia.  It is still very much open to debate how much energy is west of the Apps and where it is (east or middle TN).    To me, looks like a hybrid system.  The 12z GEFS had a hefty 16 day mean.  Most models are now fighting fair w usual biases in play.  The Euro is a bit more wound up and the GFS/CMC are slightly more progressive.  Seven days out, plenty of room for many options.   I think the cutter solution just does not make sense...It may try to cut and then that is where the energy transfer occurs.  This could be a Miller A.  Or it could go well south like 12z CMC.  The 0z CMC was decent looking, but I don't trust the Canadian model to lead the way - but it does show how it could snow here.  But the Euro went from a snow shield in Cleveland to one over easter KY and southwest VA stretching to Maine.  Higher elevations in TN do decently well.  Again, plenty of time to see several scenarios still in modeling before things consolidate...The GFS has a few light chances before that.

[jaxjagman]

1 hour ago, Carvers Gap said:

The 12z Euro is much closer to the rest of 12z guidance.  Energy transfer from a slp that pushes into middle TN and then jumps to the EC.  The backside snow slides through most of easter KY and southwest Virginia.  It is still very much open to debate how much energy is west of the Apps and where it is (east or middle TN).    To me, looks like a hybrid system.  The 12z GEFS had a hefty 16 day mean.  Most models are now fighting fair w usual biases in play.  The Euro is a bit more wound up and the GFS/CMC are slightly more progressive.  Seven days out, plenty of room for many options.   I think the cutter solution just does not make sense...It may try to cut and then that is where the energy transfer occurs.  This could be a Miller A.  Or it could go well south like 12z CMC.  The 0z CMC was decent looking, but I don't trust the Canadian model to lead the way - but it does show how it could snow here.  But the Euro went from a snow shield in Cleveland to one over easter KY and southwest VA stretching to Maine.  Higher elevations in TN do decently well.  Again, plenty of time to see several scenarios still in modeling before things consolidate...The GFS has a few light chances before that.

The Control run isn't that bad and it's not far off from the Euro.It's how they both handle the shortwave trough.The Control has a neutral shortwave that goes positive tilt into Arkansas and the Euro doesn't do this until it gets into the Central parts of the Valley,this is why you have a stronger system showing up on the Control.

Give you credit though Carver,you never gave up on winter..lol...kudos to you

[jaxjagman]

Clown map of the Control

[John1122]

I have a trip to Lexington next Sunday, the GFS dropped about 6-8 inches there and 2-4 from my area up 75 through Kentucky on that particular run. The Euro was a blockbuster run for the same areas. Hammer job for the Plateau/Kentucky and mountains. Sadly it's a week away and the models have been absolutely horrid at this range this year with showing big snows and losing them.

[Holston_River_Rambler]

One thing that I've found to be somewhat consistent with the day 7ish storm has been a powerful vort. at 500mb dropping down out of Saskatchewan.  Not only has that feature consistently been modeled, but it consistently drops south of the TN River.  Then, instead of rolling on through as a bowling ball,  (which it looks like it wants to do in the Euro frame I have included from potential vorticity at 500 mb) it gets strung out while interacting with another chunk of energy that came out ahead of it from the west.  Regardless, its this vort that helps develop a swath of snow (as of 0z Euro) from Nashville east and gradually lifting out from about 1 am next Monday through late Monday morning and into the afternoon in the far Northeast sections. I will also add that the amount of energy on the included map has been consistently high in the Euro's depiction in that there seems to be energy all over the place in the SE.

The same vort is at almost the same place over Kansas City on the 6z GFS at 144 hours, so about 10 hours faster.  

The vort. looks potent and will be interesting to see what it produces if it is shows up as modeled and how the Hi-Res models handle it once they get in range. Euro even has a smidge of surface based CAPE over portions of the Great eastern Valley and SW VA.  Not sure if it is enough to get much in the way of thunder though. And I really don't know how to interpret T-Storm data on the models, so kinda hoping thunderstorm savy folks can help teach me here. 

It seems to me the system has evolved to have 3 parts. (1) Some light rain for most of the  eastern TN Valley and SW VA from isentropic lift (though maybe some snow from Wytheville, VA north and east) as early as Friday night into Saturday morning. (2)Then a large chunk of energy rolls through from the west and this is the one that has all the big questions of track. Miller A? Miller B? hybrid? All this is next Saturday into Sunday.  (3) The dynamic vort. I'm talking about above for next Sunday night and into Monday. 

Of course all these pieces are not discrete in how they interact and each can and will have impacts on the other. Nice to have something so interesting and possibly dynamic to track!

[Holston_River_Rambler]

Something else I've been trying to learn more about are the trend maps available on Tropical Tidbits.  I have attached one in hopes that someone can help me if I'm using these incorrectly. This is at 500mb and shows the GEFS 500mb heights as black lines, but also includes Z500 vorticity trends?  If that's the case its interesting that the 500mb trough on the GEFS looks overall more positively tilted, but the 48 hour trend of vorticity looks a little more neutral or even negative as everything rolls from the Mississippi eastward. Again all still a ways off, but thought I'd use this opportunity to try and learn a bit.