December 2017 Mid-Long Range Disco

[eurojosh]

Hrs 42-54... can someone explain how it is raining continuously under a strong HP in southern TX?

[Jebman]

5 hours ago, supernovasky said:

Christmas night ice storm.

 

ICE is The Best! I'd go out on an EPIC, EPIC ice jebwalk.

I love ice even more than snow, I LOVE the sound of frantically spinning wheels on 2 inches of solid ice and I love to watch ppl try to walk on solid ice.

I am the only person in North America who can perform a jebwalk on a solid ice sheet and not fall. Everyone else would end up with a smashed hipbone.

[AfewUniversesBelowNormal]

Long term models are kind of bad at downwelling effects of a 10mb warming. This is really +PNA and -NAO tendency

[WhiteoutWX]

GFS looking to just dump the trough in the west and park it this run. Only slightly different than last run. Or the run before that. Absolutely no model consistency in the day 7-10 period. Wild swings run to run and model to model. 

[AfewUniversesBelowNormal]

29 minutes ago, WhiteoutWX said:

GFS looking to just dump the trough in the west and park it this run. Only slightly different than last run. Or the run before that. Absolutely no model consistency in the day 7-10 period. Wild swings run to run and model to model. 

begins here


Until this low pressure passes, long range is below average forecasting I think

[Amped]

22 minutes ago, StormchaserChuck said:

Long term models are kind of bad at downwelling effects of a 10mb warming. This is really +PNA and -NAO tendency

There is no warming to down-well.

[AfewUniversesBelowNormal]

16 minutes ago, Amped said:

There is no warming to down-well.

Just because the mountain is surrounded by water doesn't mean it's not a mountain. 

[Amped]

2 minutes ago, StormchaserChuck said:

Just because the mountain is surrounded by water doesn't mean it's not a mountain. 

 

 

Here

[AfewUniversesBelowNormal]

My guess is that Dec 26 will be totally different

[MillvilleWx]

2 hours ago, WhiteoutWX said:

GFS looking to just dump the trough in the west and park it this run. Only slightly different than last run. Or the run before that. Absolutely no model consistency in the day 7-10 period. Wild swings run to run and model to model. 

OPs are going to be swinging wild the next 5-7 days before we start seeing anything of consensus. Ensembles will be the way to go for the aforementioned time frame and just using the OP as one of the ensemble members. You can tell this is going to be a razor tight gradient over the Mid Atlantic and hopefully we can sit on the good side for some frozen. We'll probably get some transition type storms if high's to the north can work off the coast and increase the u-vector component of the wind in tandem with storms riding north along the baroclinic zone. Waters off coast are cooling, but still warmer than what we'd see during peak climo in mid-winter. This happened last March with our sleet storm as the high pulled east and screaming easterlies between 925 and 700mb pulled the thermal profile above 0C for the meat of the storm. Once the system pulled away, strong cold air advection funneled in from the northeast and changed the ptype the final hours. Would need the 500 pattern to shift the trough east toward the Tennessee Valley to stay straight frozen though. Back over Mississippi Valley will lead to warm intrusion and change to rain like what the current GFS is signaling. 

[CAPE]

4 hours ago, MillvilleWx said:

OPs are going to be swinging wild the next 5-7 days before we start seeing anything of consensus. Ensembles will be the way to go for the aforementioned time frame and just using the OP as one of the ensemble members. You can tell this is going to be a razor tight gradient over the Mid Atlantic and hopefully we can sit on the good side for some frozen. We'll probably get some transition type storms if high's to the north can work off the coast and increase the u-vector component of the wind in tandem with storms riding north along the baroclinic zone. Waters off coast are cooling, but still warmer than what we'd see during peak climo in mid-winter. This happened last March with our sleet storm as the high pulled east and screaming easterlies between 925 and 700mb pulled the thermal profile above 0C for the meat of the storm. Once the system pulled away, strong cold air advection funneled in from the northeast and changed the ptype the final hours. Would need the 500 pattern to shift the trough east toward the Tennessee Valley to stay straight frozen though. Back over Mississippi Valley will lead to warm intrusion and change to rain like what the current GFS is signaling. 

EPS has really moved in the wrong direction over the past 2 runs. The 500 mb pattern is retrograded- EPAC ridge axis too far west, trough parked out in the SW, and we have our unwelcome Xmas guest, the SE ridge .

[CAPE]

Ugly..

[MillvilleWx]

4 minutes ago, C.A.P.E. said:

EPS has really moved in the wrong direction over the past 2 runs. The 500 mb pattern is retrograded, EPAC ridge axis too far west, trough parked out in the SW, and we have our unwelcome Xmas guest, the SE ridge .

Yeah. There's not any good take aways in the ensemble runs and heck, the 6z GFS OP looking bleak too. Transitioning back to a strong SER and deep western troughing. I'm not happy because not only does that place us on wrong side of the baroclinic setup, it gives me more rough forecasts for my Western sites. There is nothing more debilitating than forecasting for snow and ice in Texas while I have light jacket, or jacketless afternoon's over here. Blah. Still think we're going to walk the line a lot end of the month, but if things don't change for the better, might be looking at the wrong side of the temp gradient. Still a ways away, so I expect some wholesale changes in the setup, but this was concern by everyone in here, and it's coming to light now approaching D10 with Christmas in sight. 

[CAPE]

27 minutes ago, MillvilleWx said:

Yeah. There's not any good take aways in the ensemble runs and heck, the 6z GFS OP looking bleak too. Transitioning back to a strong SER and deep western troughing. I'm not happy because not only does that place us on wrong side of the baroclinic setup, it gives me more rough forecasts for my Western sites. There is nothing more debilitating than forecasting for snow and ice in Texas while I have light jacket, or jacketless afternoon's over here. Blah. Still think we're going to walk the line a lot end of the month, but if things don't change for the better, might be looking at the wrong side of the temp gradient. Still a ways away, so I expect some wholesale changes in the setup, but this was concern by everyone in here, and it's coming to light now approaching D10 with Christmas in sight. 

Yeah we do have time for things to change. But yesterday morning at this time there was reason for optimism, as it appeared the ensembles were trending away from this look, and now they are going in the wrong direction again.

Personally, I will take whatever for the holidays- I have traveling to do so i just assume not have an ice storm. I can deal with a mild/warm Xmas (its become the norm) but it would be nice to see some indications that this is a fairly brief relaxation, and not the start of a wholesale pattern change as we move forward into January.

[showmethesnow]

As we have all seen over the last few days the models have been waffling on whether to throw a strong SW trough into the mix or not. Which would have a major impact on our weather through the coming Holidays. Thought I would look a little into why we may be seeing this occur. Not saying this is the cause but i think a strong argument could be made for it.

 

Below we see the 7 day change in SST. Notice we see fairly sharp drops off the southern portion of Baja (blue circle). Above that we see fairly strong warming (red circle). Warm SST's argue for ridging of which we see. With cold SST's you expect to see lower pressures and troughing gravitate into the region. This is what the models are probably keying on (steep drop in temps) when we see the strong SW trough on a run.

 

But look what the actual SST's are in that region. Though we have seen a fairly steep drop in temps the anomalies are still very warm (except for a very small cold pool). This look argues against the strong low pressures and troughing that the above SST map would suggest. This look would be more supportive of a weak SW trough.

 

Below is surface pressures associated with a run that does not lock in the SW trough. Notice that though we do see low pressures in Baja they are fairly weak. This look I think would be fairly representative of current SST anomalies (second map above).

 

 

Below is a surface map of a run with a locked in SW trough. Notice the pressures are much stronger then the previous map. This look is probably more reprentative of the SST 7 day anomalies change (first map above).

 

 

Below we see the 500mb map of a weak and somewhat transient SW trough. Notice the 564 line has not dug deep and is fairly flat. Also notice we have very weak neg anomalies (blue circle) connecting the upper portion of the trough to the lower portion. This is a fairly weak trough set up into the southwest so any re-surges of the trough out of Canada are able to progress eastward.

 

 

Now compare the above map to the one below. Notice how far south and sharp the 564 line is. Also notice the strong neg pressure anomalies (blue circle) connecting the lower portion of the trough to the upper portion. This is a strong and deep southwest trough. Any trough surges will be unable to escape to the east and will instead be sucked down into it reinforcing it for the next trough surge. 

 

 

So the problem we are seeing now with the models may very well be due to them not knowing whether to key on 7 day SST temp drops or to actually key on what the current anomalies are. My best guess, which isn't worth much, is this will come down to what we see in the next 7 days or so with the SST temps off Baja. If we continue to see a drop with these temps I favor a solution of a strong SW trough. A leveling out of SST temps or even an increase probably means I would favor a weak and/or transient SW trough.

 

[Cobalt]

He seems to be on board for cold in the East. Seems alone at the moment, but I see where he's coming from. 

[mattie g]

4 minutes ago, Cobalt said:

He seems to be on board for cold in the East. Seems alone at the moment, but I see where he's coming from. 

If there's ever a time when he's *not* on board for cold and/or snow in the East, then you know that winter is f***ed.

[mappy]

13 hours ago, Bob Chill said:

This is acceptable. Weather it happens or not, a triple phaser during christmas week would fun

not sure if done on purpose, but if so... well played. 

[BristowWx]

15 minutes ago, Cobalt said:

He seems to be on board for cold in the East. Seems alone at the moment, but I see where he's coming from. 

What does he mean feedback fairy?  Just curious 

[Thanatos_I_Am]

16 minutes ago, Cobalt said:

He seems to be on board for cold in the East. Seems alone at the moment, but I see where he's coming from. 

Yeah don’t put too much stock into what this guy says. I’ve never seen him predict warm, boring weather. 

[BristowWx]

4 minutes ago, Thanatos_I_Am said:

Yeah don’t put too much stock into what this guy says. I’ve never seen him predict warm, boring weather. 

He does like to hype.  But still an experienced met so I respect that.  He seems to reference the GFS a lot.  His next tweet could have been stick with the EPS which is more likely to verify.  He likes to give hope to the weenie fan base.

[showmethesnow]

10 minutes ago, losetoa6 said:

Real nice writeup @showmethesnow

Thank you.

[mitchnick]

Second run Gfs has looked like this at the end of the run.

 

[Ralph Wiggum]

Ugly..

Discussing in another thread, while 500mb maps scream warm SW flow, surface maps suggest plenty of sprawling strong Arctic HP along the Canadian border seeping South. Probably not what many would expect if just looking at H5:

[usedtobe]

The GFS and Euro ensemble means sure look ugly around Christmas.  Have to hope that some of the disagreeing ensembles are right.  The esnemble means certainly have stepped back over the last two days. 

[poolz1]

I could be wrong with this but it seems to me that a lot hinges on the location of the trough near Hawaii.  Notice the op runs that keep the trough back near HI allow the trough to dig down the west coast, pushing the ridge east and the continuing to dig into the SW.  With a trough pushed further east/ne of HI, this pumps the ridge enough to deflect the trough and send it down east of the rockies. ENS show this to a certain extent as well.

18z run yesterday with a positive outcome for us..

 

00z run with an unfavorable outcome.

 

 

[Ralph Wiggum]

Even when you go out to day 12. The se ridge really isn't prolific . 3 or 4 look a little crappy but the majority  are somewhat acceptable and workable  imo

 

 . 

 

I dont think there is any denying the SER is coming in the LR, one form or another. It is going to come down to how it aligns itself, strength, and how much impact the PV will have on it in attempt to push it back periodically. It would be nice to see some blocking in the NAO region but not really seeing signs of that. -AO is around at least, so there's that.

 

Eta: Im not suggesting the ens looks with the SER will have staying power the remainder of winter. Most here knew coming in tho with the Nina we would have to deal with this feature at times during the winter (some periods longer than others).

[BTRWx's Thanks Giving]

So it's either wxwatcher's happy place

or MoJO

or a little of both

[RobertRath]

this SER talk has me bummed! I’ve got a ski trip planned to snowshoe WVa just after Christmas. Sure looks “today” like it’s gonna be a warm trip. Anybody here from W VA? How bad does the SER affect that area? Thanks 

[showmethesnow]

8 minutes ago, BTRWx's Thanks Giving said:

So it's either wxwatcher's happy place

or MoJO

Not that I have been watching MJO closely but compared to others that have been posted over the last few days this is actually pretty crappy. Just barely broaches 7 before it takes a nosedive back into the COD