November Long Range Disco

[Bob Chill]

9 minutes ago, BristowWx said:

can’t remember did the weeklies predict the upcoming pattern with the blocking back in October?  

Nope. No seasonal model had it at all and it was first picked up by the GFS/GEFS. Transitioning from a +AO/NAO to a negative one is typically sudden. Not like overnight sudden but it usually magically appears on guidance inside of 2 weeks.

Take a look at the bottom graph. You can see how far off 14 day leads can be with the GEFS. EPS is no different at that lead:

 

 

Since the beginning of Oct, the GEFS was advertising a -AO but it never verified. Not one single time until the current transition showed up. For the first time since Oct 1st, the GEFS is going to "bust high" with the AO at 14 day leads. 

Now that it looks pretty much locked in and it's going to happen, don't stress on 14 day leads losing blocking because it's likely that the -AO/NAO regime will prove a bit stubborn. Not saying a strong -AO/NAO is locked and loaded for weeks on end. Just that once things get going it usually takes longer than what long lead models show when they are trying to relax things. 

I'm not worried about the Npac at all right now. Sure, the GOA trough will probably happen but it almost always comes and goes in late fall/winter. IMHO (and pretty much the only thing I care about) is how long the tendency for a -ao/nao will last. The longer it does, the better chances that Dec will also favor more blocking than less blocking. 

One thing I noticed on the EPS today is mean surface pressure over the pole and GL has trended upwards. The EPS was trying to bring back lower pressures and just recently changed it's mind and now has +MSLP anomalies showing near the pole and in the NAO region. If it holds and/or gets stronger as we move through time then we will prob enter Dec with a decent pattern in general. Somewhere between a very good one or one that doesn't need much work to be a very good one. 

[CAPE]

20 minutes ago, BristowWx said:

can’t remember did the weeklies predict the upcoming pattern with the blocking back in October?  

I dont recall. But basically the weeklies are only as good as the eps run they are based on, as the first 15 days are from that run, and it rolls that forward out to 46 days. When you look at the latest weeklies, it is based on the 0z eps run from early this morning(which was a pretty good run compared to the 12z).

[BristowWx]

10 minutes ago, Bob Chill said:

Nope. No seasonal model had it at all and it was first picked up by the GFS/GEFS. Transitioning from a +AO/NAO to a negative one is typically sudden. Not like overnight sudden but it usually magically appears on guidance inside of 2 weeks.

Take a look at the bottom graph. You can see how far off 14 day leads can be with the GEFS. EPS is no different at that lead:

 

 

Since the beginning of Oct, the GEFS was advertising a -AO but it never verified. Not one single time until the current transition showed up. For the first time since Oct 1st, the GEFS is going to "bust high" with the AO at 14 day leads. 

Now that it looks pretty much locked in and it's going to happen, don't stress on 14 day leads losing blocking because it's likely that the -AO/NAO regime will prove a bit stubborn. Not saying a strong -AO/NAO is locked and loaded for weeks on end. Just that once things get going it usually takes longer than what long lead models show when they are trying to relax things. 

I'm not worried about the Npac at all right now. Sure, the GOA trough will probably happen but it almost always comes and goes in late fall/winter. IMHO (and pretty much the only thing I care about) is how long the tendency for a -ao/nao will last. The longer it does, the better chances that Dec will also favor more blocking than less blocking. 

One thing I noticed on the EPS today is mean surface pressure over the pole and GL has trended upwards. The EPS was trying to bring back lower pressures and just recently changed it's mind and now has +MSLP anomalies showing near the pole and in the NAO region. If it holds and/or gets stronger as we move through time then we will prob enter Dec with a decent pattern in general. Somewhere between a very good one or one that doesn't need much work to be a very good one. 

Thank you.  It once again shows us that long leads are like dice rolling.  And to never get too enthused or discouraged beyond 10 days on the models.  I’ll have to keep that in mind before heading to the panic room.

[CAPE]

41 minutes ago, Bob Chill said:

Nope. No seasonal model had it at all and it was first picked up by the GFS/GEFS. Transitioning from a +AO/NAO to a negative one is typically sudden. Not like overnight sudden but it usually magically appears on guidance inside of 2 weeks.

Take a look at the bottom graph. You can see how far off 14 day leads can be with the GEFS. EPS is no different at that lead:

 

 

Since the beginning of Oct, the GEFS was advertising a -AO but it never verified. Not one single time until the current transition showed up. For the first time since Oct 1st, the GEFS is going to "bust high" with the AO at 14 day leads. 

Now that it looks pretty much locked in and it's going to happen, don't stress on 14 day leads losing blocking because it's likely that the -AO/NAO regime will prove a bit stubborn. Not saying a strong -AO/NAO is locked and loaded for weeks on end. Just that once things get going it usually takes longer than what long lead models show when they are trying to relax things. 

I'm not worried about the Npac at all right now. Sure, the GOA trough will probably happen but it almost always comes and goes in late fall/winter. IMHO (and pretty much the only thing I care about) is how long the tendency for a -ao/nao will last. The longer it does, the better chances that Dec will also favor more blocking than less blocking. 

One thing I noticed on the EPS today is mean surface pressure over the pole and GL has trended upwards. The EPS was trying to bring back lower pressures and just recently changed it's mind and now has +MSLP anomalies showing near the pole and in the NAO region. If it holds and/or gets stronger as we move through time then we will prob enter Dec with a decent pattern in general. Somewhere between a very good one or one that doesn't need much work to be a very good one. 

I noticed this too. I made a post a couple days ago about the AO possibly trending towards neutral heading into December, based on the latest EPS runs at that time. It would be a big help if the -AO does hold and then maybe strengthens(again) as we head into mid December. I am probably a bit more "worried" about the influence of the GOA trough on the overall pattern than you are, lol. It seemed like we kept discounting it last winter, or thinking other features could overcome it, but it was a pretty persistent hindrance. Now if in fact we can maintain a largely -AO/NAO regime for the balance of met winter, then there certainly will be times when a less than ideal NPAC can be overcome, and there will also likely be occasions when things will reshuffle out west and become more favorable at times.

[showmethesnow]

Normally don't look at the JMA except for occasional glances but yesterdays 12Z was kind if fun to look at.

Wall to wall blocking up top from western Canada to Europe at day 8.

 

 

Also showed a somewhat interesting setup heading into day 9/10. Have a piece of the pv in the North east that has been trapped underneath of the blocking, slowed to a crawl because of previous energy slowly working its way through the 50/50 region. We also see a short wave running through Kansas being driven southeast because of the pv in the NE. To further complicate the setup we also see some energy diving down from central Canada that looks as if it would merge with that shortwave in a day or two. 

A somewhat a convoluted setup and how that all would play out at day 9/10 is probably dependent on what the pv in the NE does. If it moves out fairly quickly after this time period there is a decent chance we see a moderate/strong storm somewhere in the east/eastern seaboard as that shortwave amplifies. If the pv stays planted or continues to crawl we probably see the shortwave move somewhat harmlessly out to sea. Considering we are seeing the blockage if front of the NE pv breaking down at this time and seeing the ridging building between the the NE pv and the shortwave I would probably lean towards an east coast storm solution (where and what I wouldn't want to hazard a guess).

 

 

 

[BristowWx]

42 minutes ago, showmethesnow said:

Normally don't look at the JMA except for occasional glances but yesterdays 12Z was kind if fun to look at.

Wall to wall blocking up top from western Canada to Europe at day 8.

 

 

Also showed a somewhat interesting setup heading into day 9/10. Have a piece of the pv in the North east that has been trapped underneath of the blocking, slowed to a crawl because of previous energy slowly working its way through the 50/50 region. We also see a short wave running through Kansas being driven southeast because of the pv in the NE. To further complicate the setup we also see some energy diving down from central Canada that looks as if it would merge with that shortwave in a day or two. 

A somewhat a convoluted setup and how that all would play out at day 9/10 is probably dependent on what the pv in the NE does. If it moves out fairly quickly after this time period there is a decent chance we see a moderate/strong storm somewhere in the east/eastern seaboard as that shortwave amplifies. If the pv stays planted or continues to crawl we probably see the shortwave move somewhat harmlessly out to sea. Considering we are seeing the blockage if front of the NE pv breaking down at this time and seeing the ridging building between the the NE pv and the shortwave I would probably lean towards an east coast storm solution (where and what I wouldn't want to hazard a guess).

 

 

 

It’s really tough to imagine we don’t get some slow monster storm develop out of a pattern like that I’m not saying snow but something with high impactI

[showmethesnow]

Looking over the overnight runs and I am getting a little more interested in a potential east coast storm now roughly centered around day 10. Though weak initially with the signal GEFS has been consistent and has steadily strengthened and improved the look over 4-5 days of runs. I also like the lower heights and troughing showing up in the general 50/50 region which is suggestive of a possible 50/50 low that would back up the flow. Gem has also been suggestive of a possible east coast storm through this period but nowhere to the degree that the GEFS is. EPS hasn't been consistent during this time period so it is hard to say. Flashes hints one run and then takes them away the next. One other thing I have liked seeing is that we are now seeing storms pop up on different op runs as well as some of the ensemble members during this time period.

Still roughly 10 days away so it is really not worth getting worked up about it yet. 

 

[showmethesnow]

15 minutes ago, BristowWx said:

It’s really tough to imagine we don’t get some slow monster storm develop out of a pattern like that I’m not saying snow but something with high impactI

I could see that happening but I could also see that pv stay planted and drive everything underneath us without giving it any chance to amplify. All I know is I wouldn't want to try to forecast off what it shows. IMO there are just to many solutions/outcomes that are possible.

[showmethesnow]

12 minutes ago, losetoa6 said:

Interesting the  day 5 trough depicted by the Euro is much shallower then the Gfs, Gefs, Ukmet, ,and CMC.  Day 9/10 as well. Curious if it's picking up on something the others aren't.  I mean..  120 hours is mid range not fantasy.  Heck even comparing eps and Gefs at day 6 there's decent differences.

What you are seeing there is most likely smoothing on the EPS. With 51 members on the EPS vs the GEFS 15 it plays a big part in how the mean is depicted. With timing issues between all the members on the EPS this spreads out the different solutions so they somewhat cancel each other out dampening the signal (or in this case the depth of the trough). Look at how broad the EPS trough is to the sharper trough depicted on the GEFS this signals that there is a good chance smoothing is occurring.

[showmethesnow]

Just now, losetoa6 said:

I understand the smoothing esp past day 10 ..but  at only day 6? That's mid range.  Maybe your right ..it just caught my eye though 

If you have access to the ind members look at them during day 5/6. I would bet better then even money that there is quite a bit of spread on how they depict that trough, even at day 5/6. Which is kind of understandable considering the chaotic nature up top. But really, the shallower and broader trough compared to other guidance is normally a high probability tip off that smoothing is occurring.

[BristowWx]

Did you guys see hour 240 on the GFS OP 6z for black Friday?  I think I got my Christmas goose early.  Yes, its digital snow but that is what we need 500mb to look like all the time. 

[showmethesnow]

26 minutes ago, losetoa6 said:

I understand the smoothing esp past day 10 ..but  at only day 6? That's mid range.  Maybe your right ..it just caught my eye though 

Just realized what you were comparing, the 06Z GEFS to the 00Z EPS. I was looking at the trough in the midwest at day 5 for the 00Z GEFS vs the 00Z EPS when I was replying to you which looked like pretty obvious smoothing. 

[CAPE]

14 minutes ago, losetoa6 said:

I understand the smoothing esp past day 10 ..but  at only day 6? That's mid range.  Maybe your right ..it just caught my eye though 

Look at the N Pacific view. Pretty significant differences that impact the downstream trough strength and position. That blocking ridge is a monster on the EPS compared to the GEFS at 144. 

[CAPE]

13 minutes ago, BristowWx said:

Did you guys see hour 240 on the GFS OP 6z for black Friday?  I think I got my Christmas goose early.  Yes, its digital snow but that is what we need 500mb to look like all the time. 

That is the third run out of the last 6 or so that the GFS op has had some snow in the MA for Friday-Saturday after Tday.

[showmethesnow]

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

Look at the N Pacific view. Pretty significant differences that impact the downstream trough strength and position. That blocking ridge is a monster on the EPS compared to the GEFS at 144. 

You are right, that is probably the major reason we are seeing a difference with the trough. Though I still contend there is some smoothing occurring. 

[CAPE]

32 minutes ago, showmethesnow said:

You are right, that is probably the major reason we are seeing a difference with the trough. Though I still contend there is some smoothing occurring. 

There has been a noticeable trend on the last few runs of the EPS to be less impressive with the upcoming cold period. And of course most of it has to do with our Nina nemesis- the big Aleutian ridge/AK vortex combo not cooperating lol.

[mitchnick]

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

There has been a noticeable trend on the last few runs of the EPS to be less impressive with the upcoming cold period. And of course most of it has to do with our Nina nemesis- the big Aleutian ridge/AK vortex combo not cooperating lol.

What period? 

[CAPE]

1 minute ago, mitchnick said:

What period? 

[mitchnick]

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

Well, I thought you were talking about day 6, but when I go to Tropical Tidbits and look at the 850 anomalies from last night for the NE, and then compare to previous runs, there is so little difference imho, you may be talking about a different period.

[BristowWx]

1 minute ago, mitchnick said:

Well, I thought you were talking about day 6, but when I go to Tropical Tidbits and look at the 850 anomalies from last night for the NE, and then compare to previous runs, there is so little difference imho, you may be talking about a different period.

GEFS gets a little better each time.  If the period we are talking is t-day week/weekend.  I am not going to sweat it too much.  still looks chilly especially compared to last year.  I think Thanksgiving was quite warm...and I think Xmas was warmer than Thanksgiving which is just insane.

[CAPE]

Just now, mitchnick said:

Well, I thought you were talking about day 6, but when I go to Tropical Tidbits and look at the 850 anomalies from last night for the NE, and then compare to previous runs, there is so little difference imho, you may be talking about a different period.

I was referring to the general period of interest, which is basically next week. If you go back and look at say the last 4 runs of the EPS from about Sunday 12z the 19th to the following Sunday, there are noticeable differences at h5 and 850t. For the same period, GEFS continues to look colder in general. And I am using WB, so it might be more difficult to see with the 24 hr jumps if you are looking at the EPS on TT.

[pasnownut]

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

Look at the N Pacific view. Pretty significant differences that impact the downstream trough strength and position. That blocking ridge is a monster on the EPS compared to the GEFS at 144. 

yeah, i saw that and thought the same.  Enough difference to hold em on this round of bets...

at 500 im still nervous at the EPS midwest buldge, and hope that the blocking depicted up north continues to suppress that warm nose.  Id take what the GEFS is serving though.

EPS 500 seems to lose the pronounced ridge out west after Turk day weekend and go more zonal, but still not a bad look for northern stream clippers.

 

Nut

[CAPE]

12 minutes ago, BristowWx said:

GEFS gets a little better each time.  If the period we are talking is t-day week/weekend.  I am not going to sweat it too much.  still looks chilly especially compared to last year.  I think Thanksgiving was quite warm...and I think Xmas was warmer than Thanksgiving which is just insane.

Yeah that is what I am looking at. And like I said, I am fine with a chilly T-day. I don't expect to see snow lol. But the GFS op runs have been hinting lately for just after, so who knows. Be interesting to see if the EPS sticks to the stronger NPAC block/vortex idea.

[BristowWx]

Just now, C.A.P.E. said:

Yeah that is what I am looking at. And like I said, I am fine with a chilly T-day. I don't expect to see snow lol. But the GFS op runs have been hinting lately for just after, so who knows. Be interesting to see if the EPS sticks to the stronger NPAC block/vortex idea.

Yes.  I saw that on the EPS on TT.  looks less favorable at 500mb on EPS than even the previous run and certainly different than GEFS.  Don't like but cant change it.  will see what this fine day brings to us.  I do like that the GEFS is holding firm at 500mb.   

[mitchnick]

Well, I'll say this much. Once you get to 150 hrs. on the GEPS, it holds blocking/ridging over Greenland through 384 hrs. along with a trough in varying locations over us/east coast. What a pleasant change from last year. 

[pasnownut]

55 minutes ago, mitchnick said:

Well, I'll say this much. Once you get to 150 hrs. on the GEPS, it holds blocking/ridging over Greenland through 384 hrs. along with a trough in varying locations over us/east coast. What a pleasant change from last year. 

do you have the link to the skill scores of the ensembles?

 

d10 GEPS looks quite simialr to EPS at 500.  GEFS is paddling its own canoe with the sharpness of the trough.  Will be fune to see who wins...or dow we already know who the king is?

 

Nut

[midatlanticweather]

56 minutes ago, mitchnick said:

Well, I'll say this much. Once you get to 150 hrs. on the GEPS, it holds blocking/ridging over Greenland through 384 hrs. along with a trough in varying locations over us/east coast. What a pleasant change from last year. 

I just hope it is not perpetually day 10+

[mitchnick]

8 minutes ago, midatlanticweather said:

I just hope it is not perpetually day 10+

starts at 150 hours, sooooooo......

[Cobalt]

GFS coming in warmer all around

[CAPE]

9 minutes ago, Cobalt said:

GFS coming in warmer all around

Is it?

Looks pretty much the same through 156. Maybe a tad colder.