December 2017 Long Range Disco

[bigtenfan]

47 minutes ago, osfan24 said:

Well if the JMA has a torch, it must be true. Seriously, has the JMA ever been right on anything, much less a forecast a month from now?

Actually the JMA had its 15 minutes of glory back in Feb 2006 when it was the first to sniff out the HECS that month that set what was at that time the record snowfall for NYC. Just goes to prove that a broken clock is right twice a day.

[Kmlwx]

37 minutes ago, BristowWx said:

No it has not.  One thing I am thankful for is as it appears right now this December will not be like last year.   That was a lesson in pain.  

bigtenfan is right. It sniffed out the Feb 2006 storm. 

It has absolutely had one or two times when it has sniffed something out at relatively long ranges before other models. However, it's likely more a case of a blind squirrel finding a nut every now and then. 

[dallen7908]

Well the first week of December may not be that different than last year.  Both the 6-10 day and 8-14 day CPC outlooks call for above normal temperatures and below-normal precipitation in MD. The good news is that forecast confidence is below average and the signal isn't that strong; 50-60% chance of above normal temperatures (3 categories). 

I could probably look this up but does anyone know the difference between the GFS ensemble mean and the GFS super ensemble mean. 

Weightings are tweaked from day to day but note the weighting given to operational runs (0%) and previous forecast cycle runs (30%) 


THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 20% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 20% OF  
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 20% OF YESTERDAY'S 12Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10, AND 10% OF TODAY'S 0Z CANADIAN  
ENSEMBLE MEAN CENTERED ON DAY 11  
 
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5,

[BristowWx]

First week we can punt..second week sure why not...but after 15 Dec the stakes get higher.  Would like a nice cold Xmas holiday week.  Not just that but if we have to punt December entirely then that just blows and doesn’t give much confidence for the rest of winter.  Not ready to punt anything.  

[CAPE]

Nothing has changed in the guidance with the pattern progression. GFS has looked too fast overall, and the last couple runs have delayed things just a bit, more in line with the EPS. The first week in December will likely be on the mild side, which has always looked like a high probability. Beyond that there should be a trough developing in the east and a generally colder pattern.

[Bob Chill]

1 hour ago, C.A.P.E. said:

Nothing has changed in the guidance with the pattern progression. GFS has looked too fast overall, and the last couple runs have delayed things just a bit, more in line with the EPS. The first week in December will likely be on the mild side, which has always looked like a high probability. Beyond that there should be a trough developing in the east and a generally colder pattern.

Yea man. There seems to be a disconnect with what guidance is showing and some of the posts around here. We're still a full week from the end of November. Very impressive blocking is showing up on all guidance. Our decent snow climo doesn't even really start for several weeks. The mild pattern showing up is only a downstream ridge response to troughing in the west. Pretty normal stuff. Everything else looks really good to me. 12z eps loses the AN heights in our hood by d15 and the gefs has been consistently faster. 

I see no reason to be negative about December at all. If anything we should all be more optimistic than at any time in the last 6 years. Imho- it's only a matter of time before the storm track starts looking ripe for areas south of 40N. 

[Rtd208]

DT (WxRisk) recently posted on Facebook confirming what others here have been saying. 1st week of December is mild with a pattern change to colder and stormier shortly after the 7th of the month which could set up a winter storm in the mid-atlantic/northeast around mid month. 

[Cobalt]

1 hour ago, Rtd208 said:

DT (WxRisk) recently posted on Facebook confirming what others here have been saying. 1st week of December is mild with a pattern change to colder and stormier shortly after the 7th of the month which could set up a winter storm in the mid-atlantic/northeast around mid month. 

That's what we've seen and it's also what we want to hear. I'd rather not blow a quick cold shot in early Dec to then warm up mid-late Dec like 2013

 

[Rtd208]

8 minutes ago, Cobalt said:

That's what we've seen and it's also what we want to hear. I'd rather not blow a quick cold **** in early Dec to then warm up mid-late Dec like 2013

Keeping it simple, past history has shown when the pattern evolves the way it seems to be evolving that usually leads to a good/great December cold and snow wise and also a good/great winter overall. Obviously there is more to it then just that but I am feeling very positive with where things are currently headed and I suspect we will see our first significant/major winter storm in the mid-atlantic/northeast before Christmas.

[CAPE]

7 hours ago, Bob Chill said:

Yea man. There seems to be a disconnect with what guidance is showing and some of the posts around here. We're still a full week from the end of November. Very impressive blocking is showing up on all guidance. Our decent snow climo doesn't even really start for several weeks. The mild pattern showing up is only a downstream ridge response to troughing in the west. Pretty normal stuff. Everything else looks really good to me. 12z eps loses the AN heights in our hood by d15 and the gefs has been consistently faster. 

I see no reason to be negative about December at all. If anything we should all be more optimistic than at any time in the last 6 years. Imho- it's only a matter of time before the storm track starts looking ripe for areas south of 40N. 

The HL blocking eventually overwhelms. The western trough weakens, and the SE ridge gets beat down. Agree, it looks fine and the pattern is progressing in a favorable way. Just looked at the 0z EPS and things improve pretty quickly for us between day 12 and 15. Should be some cold fronts pushing through. Impressive change looking at the 850t anomalies for that period. If everything stays on track, mid to late month should be fun. Right when snow climo begins ramping up, and the days are short.

[showmethesnow]

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

The HL blocking eventually overwhelms. The western trough weakens, and the SE ridge gets beat down. Agree, it looks fine and the pattern is progressing in a favorable way. Just looked at the 0z EPS and things improve pretty quickly for us between day 12 and 15. Should be some cold fronts pushing through. Impressive change looking at the 850t anomalies for that period. If everything stays on track, mid to late month should be fun. Right when snow climo begins ramping up, and the days are short.

Can't understand the panic by some either. Progression looks fine and the only minor concern I have is the SW trough and that looks as if that is getting booted out. And looking at the EPS at the end of its run I can see how we get a nice East Coast storm with just a little adjustment in that time period.

[mitchnick]

It may have been Thanksgiving,  but it's still Thursday!  Weeklies folks, weeklies! 

http://www.phillywx.com/topic/894-cfs-ggem-jma-and-euro-weeklies-thread/?do=findComment&comment=82927

[CAPE]

59 minutes ago, showmethesnow said:

Can't understand the panic by some either. Progression looks fine and the only minor concern I have is the SW trough and that looks as if that is getting booted out. And looking at the EPS at the end of its run I can see how we get a nice East Coast storm with just a little adjustment in that time period.

I had the same thought when I looked at it. Can see scenario where some energy in the SW slides east and stays underneath. Hard to say how cold it would be at that time, but if the position/strength of modeled blocking is close to reality, it would be a possible period to watch.

[CAPE]

2 hours ago, mitchnick said:

It may have been Thanksgiving,  but it's still Thursday!  Weeklies folks, weeklies! 

http://www.phillywx.com/topic/894-cfs-ggem-jma-and-euro-weeklies-thread/?do=findComment&comment=82927

Yeah I just took a look. Pretty darn cold look overall beyond day 15 for the eastern US. Wow at the 12th through about the 23rd. Incredible HL blocking.. crazy -EPO. Big time cold dumping into central/eastern US. Mid month looks interesting for sure. NPAC looks favorable until the very end of the run, then it breaks down just a bit. Also looks like some relaxation in the HL on the Atlantic side- Neutral or weakly positive NAO at the end of December. Appears to be pretty brief though. But all that is way out there. The run looks solid through at least Xmas.  Hard to complain about what is being advertised.

[psuhoffman]

2 hours ago, showmethesnow said:

Can't understand the panic by some either. Progression looks fine and the only minor concern I have is the SW trough and that looks as if that is getting booted out. And looking at the EPS at the end of its run I can see how we get a nice East Coast storm with just a little adjustment in that time period.

I'm with you. Yourself, bob, wxusaf, cape and Mitch have been all over it.  I've been crazy busy but you all have had it covered.  I've been pessimistic on winter but where were sitting now has me feeling more hopeful. The large scale features we will need help from are actually lining up pretty good. I'm not sweating wasting some time in late November or early December. The progression we're looking at could break into a very favorable pattern come mid December which is right when we want it. I also suspect warming has hurt us on the edges so expecting snow from any pattern now is just not wise. Takes a fluke. Let's get this whole thing to evolve into a great pattern around December 10 and have it last through xmas. Nothing better then snow otg as we listen to holiday music. 

2 hours ago, mitchnick said:

It may have been Thanksgiving,  but it's still Thursday!  Weeklies folks, weeklies! 

http://www.phillywx.com/topic/894-cfs-ggem-jma-and-euro-weeklies-thread/?do=findComment&comment=82927

Weeklies were a thing of beauty. Week 1-2 are irrelevant since we know what that looks like. And by week 5-6 the skill is almost 0. But weeks 3-4 the evolution was exactly what we thought and hoped it would be. Gefs seems just a bit fast but weeklies confirm that's where the EPS thinks we're going also. Im encourages and cautiously optimistic. I said come the end of November if we were looking at a hostile pattern wrt the major drivers id be ready to call it on a bad winter. Well the look right now has me taking my hand away from the red button. 

[BristowWx]

Great insight and optimism.  It does look pretty sweet and so different from last winter.  

And I like the “red button” idea.  We need to add that to our meme’s like “it’s happening” and those kids at the birthday party.  It would be used only when things are really going down hill.  

[showmethesnow]

2 hours ago, C.A.P.E. said:

I had the same thought when I looked at it. Can see scenario where some energy in the SW slides east and stays underneath. Hard to say how cold it would be at that time, but if the position/strength of modeled blocking is close to reality, it would be a possible period to watch.

Nice seeing the position/strength of the blocking in the extended on the EPS but think we would have some play with that as far as any possible storm that may occur. Which is probably a good thing with it verifying poleward/eastward over modeling projections recently. Seeing the troughing/lower heights running through the 50/50 region (suggestive of a 50/50) through that time period would help over come somewhat a potentially not so great block and actually tweek an somewhat decent look into a good look for a possible storm. With a 50/50 we would probably see a much deeper drop of that trough into the Midwest then currently shown. Would also probably see the SE ridging, that completely gets suppressed on the run, actually have a portion of it get rotated NE in between the 50/50 and the trough dropping down. 

But really it is not so much about the possibility of seeing some snow but the possibility of seeing a storm itself. I look at the overall pattern in the extended and to me it has the earmarks of a possible pattern change storm for the east occurring. Taking us from a warm regime to a cold one. But it is 15 days away so this is nothing more then conjecture at this point and should be taken as such.

 

[MountainGeek]

For BristowWX....and perhaps we could link the image so if you click on it, it takes you directly to the Panic Room?

 

[mitchnick]

Fwiw,  last night's Euro had light snow for area at days 9-10. Light/flurries type.

[showmethesnow]

1 hour ago, psuhoffman said:

I'm with you. Yourself, bob, wxusaf, cape and Mitch have been all over it.  I've been crazy busy but you all have had it covered.  I've been pessimistic on winter but where were sitting now has me feeling more hopeful. The large scale features we will need help from are actually lining up pretty good. I'm not sweating wasting some time in late November or early December. The progression we're looking at could break into a very favorable pattern come mid December which is right when we want it. I also suspect warming has hurt us on the edges so expecting snow from any pattern now is just not wise. Takes a fluke. Let's get this whole thing to evolve into a great pattern around December 10 and have it last through xmas. Nothing better then snow otg as we listen to holiday music. 

Weeklies were a thing of beauty. Week 1-2 are irrelevant since we know what that looks like. And by week 5-6 the skill is almost 0. But weeks 3-4 the evolution was exactly what we thought and hoped it would be. Gefs seems just a bit fast but weeklies confirm that's where the EPS thinks we're going also. Im encourages and cautiously optimistic. I said come the end of November if we were looking at a hostile pattern wrt the major drivers id be ready to call it on a bad winter. Well the look right now has me taking my hand away from the red button. 

Just had a chance to look at them. No complaints on my part whatsoever. As you say weeks 3-4 you couldn't ask for more. And as far as weeks 5/6 the look does degenerate where they begin showing periods of higher heights in the east. But as long as I see the trough located in the east as well I won't sweat that too much. At the very end of the run where we have hints of a GOA trough as well as hints of a SW trough, the overall pattern would probably suggest them to be somewhat transitory in nature. But as you said the skill level is low so it isn't really worth the effort to worry about it.

[frd]

Well, in regards to the weeklies, at least there is a progression that starts to put the wheels into motion to a patten in the East near and after December 10 th that we want to see. 

 

 

[frd]

This really encourages me the most, the lastest few days keeps the AO neagative.  

Also, Bluewave in the NY thread model thread a few days ago mentioned something very interesting,  that the record low sea ice at this date may act to

reinforce the magnitide of the coming drop in the AO.   

 

[dallen7908]

...would be even more encouraging if 14-day forecasts of a negative AO weren't so common ...

 

The CPC released their 3-4 week outlook this afternoon.  They also call for big changes during week 3 (high amplitude riding, North Atlantic blocking, anomalous troughing etc.) but only cool east coast temperatures to near normal due to how mild week 2 is expected to be and due to "lack of MJO support for widespread negative temperature anomalies until Week-4". [Stephen Baxter] 

[Bob Chill]

Decent ens consensus now for BN temps to settle into most of the conus by d14-15. H5 pattern is ripe on all 3 global ens. Something could sneak in before that because the nao block is well established but the real deal winter wx pattern is starting to come into focus by the end of the first week of Dec. 

If the ao drops again after a brief trip towards neutral over the next few days then this Dec seems to be following a similar progression as previous years were the -ao locks in for an extended period. My gut tells me that it's the real deal. The flip from the +ao earlier this month is already happening in real time. Hedging with persistence is a decent odds proposition. 

 

[BristowWx]

10 minutes ago, dallen7908 said:

...would be even more encouraging if 14-day forecasts of a negative AO weren't so common ...

 

The CPC released their 3-4 week outlook this afternoon.  They also call for big changes during week 3 (high amplitude riding, North Atlantic blocking, anomalous troughing etc.) but only cool east coast temperatures to near normal due to how mild week 2 is expected to be and due to "lack of MJO support for widespread negative temperature anomalies until Week-4". [Stephen Baxter] 

Week 4 is Xmas week or the week before.  That works.  Don't want it now.  I would take is wall to wall but that's not our reality.  

[dallen7908]

Yes it does sound encouraging ... CPC is hedging ... and being "conservative" with their call. http://www.cpc.ncep.noaa.gov/products/predictions/WK34/

[CAPE]

48 minutes ago, Bob Chill said:

Decent ens consensus now for BN temps to settle into most of the conus by d14-15. H5 pattern is ripe on all 3 global ens. Something could sneak in before that because the nao block is well established but the real deal winter wx pattern is starting to come into focus by the end of the first week of Dec. 

If the ao drops again after a brief trip towards neutral over the next few days then this Dec seems to be following a similar progression as previous years were the -ao locks in for an extended period. My gut tells me that it's the real deal. The flip from the +ao earlier this month is already happening in real time. Hedging with persistence is a decent odds proposition. 

 

Yeah it's pretty impressive how similar the 3 global ensembles look at day 15.

Like you, I have been pretty focused on the AO, and it appears the -AO will have some staying power. Love seeing the persistence on all the guidance now.

Its happening!!?

[BristowWx]

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

Yeah it's pretty impressive how similar the 3 global ensembles look at day 15.

Like you, I have been pretty focused on the AO, and it appears the -AO will have some staying power. Love seeing the persistence on all the guidance now.

Its happening!!?

Yes...Time to pull out the it’s happening guy...sure we might regret it later but isn’t that what we do best

[Interstate]

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

Yeah it's pretty impressive how similar the 3 global ensembles look at day 15.

Like you, I have been pretty focused on the AO, and it appears the -AO will have some staying power. Love seeing the persistence on all the guidance now.

Its happening!!?

15 Days huh... Just like Thanksgiving weekend and the Sunday/Monday after Thanksgiving

[CAPE]

Just now, RidingTheModelWithMostSnow said:

15 Days huh... Just like Thanksgiving weekend.

What exactly did you expect to happen this weekend?