Pattern Change thread

[nzucker]

Nate, the 00z ECM looks bad at 240h, I'm not disagreeing with you...but I'm just telling you it doesnt matter. Until we see some ensmble support for that crappy pattern, I do not buy it.

You obviously are getting married to your idea of bad patterns. A -PNA/-NAO pattern is generally good here...I'm not sure what you are describing. Yes of course if the NAO isn't powerful enough and we get some sort of monstrous PAC signal that destroys our setup then we won't see a good snow threat setup...but that isn't in the cards right now yet....except on your 00z ECM run right now at 240h.

Give me a reason why I should believe the 00z ECM OP run vs the ensembles at that time frame?

Can you show me a verification of the ensemble guidance versus the operational to see what the difference is in accuracy? Is that information available?

The 0z GFS also supports the OP ECM, which is why I give the pattern displayed a bit more faith...the GFS has been very consistent in showing that we'll see a strong +EPO regime and only a brief cold shot followed by normal to slightly warmer than normal temperatures in the long range, heading into early December. I like what I'm seeing from the Atlantic side with the west-based -NAO on steroids, but we need at least some cooperation from the Pacific. It's pretty early in the year to get snow if the pattern isn't particularly cold. I'd just like to see SOME model runs showing a decent Pacific, and that seems not to be happening, at least not as much as a few days ago when we had a semblance of a +PNA emerging in the long-range forecasts.

And we obviously have different perspectives. When I think of SNE, I'm talking more about BOS and the coastal plain since that's the only area I forecasted for in my winter outlook. I also am thinking about my home region, living at 350' elevation only 10 miles north from the NYC border. This is quite obviously a different climate from the hills of Worcester where you make home, so we have varying interpretations of how favorable the pattern might be. It definitely looks way better for you than for me, since there's always going to be a strong gradient in a -PNA/-NAO regime, and chances are that I end up on the warm side in a strong La Niña winter.

[nzucker]

Yeah I wasnt sure how fast they updated...looks like pretty quick tonight. They give ensemble mean out to 240....wsi gives us out to 360h...but beyond 240 is very iffy anyway.

You don't need to post the images, but what did the ECM ensembles show later on, like 276 and 300? Anything good? Still a GoA low?

[ORH_wxman]

Can you show me a verification of the ensemble guidance versus the operational to see what the difference is in accuracy? Is that information available?

The 0z GFS also supports the OP ECM, which is why I give the pattern displayed a bit more faith...the GFS has been very consistent in showing that we'll see a strong +EPO regime and only a brief cold shot followed by normal to slightly warmer than normal temperatures in the long range, heading into early December. I like what I'm seeing from the Atlantic side with the west-based -NAO on steroids, but we need at least some cooperation from the Pacific. It's pretty early in the year to get snow if the pattern isn't particularly cold. I'd just like to see SOME model runs showing a decent Pacific, and that seems not to be happening, at least not as much as a few days ago when we had a semblance of a +PNA emerging in the long-range forecasts.

And we obviously have different perspectives. When I think of SNE, I'm talking more about BOS and the coastal plain since that's the only area I forecasted for in my winter outlook. I also am thinking about my home region, living at 350' elevation only 10 miles north from the NYC border. This is quite obviously a different climate from the hills of Worcester where you make home, so we have varying interpretations of how favorable the pattern might be. It definitely looks way better for you than for me, since there's always going to be a strong gradient in a -PNA/-NAO regime, and chances are that I end up on the warm side in a strong La Niña winter.

Boston is pretty far north which matters more in a Nina then a Nino. Once again, you are obsessing over the PAC...last winter that was a -PNA/-NAO was 2008-2009...Boston had 65.9" of snow while you had like 40% of that.

I agree its very early in the season so Logan Airport may not do so well, but most of us do not live on a peninsula out in Boston Harbor....Ray can get 6" of snow while BOS gets a trace in this pattern and he doesn't live at 900 feet in the ORH hills.

[weatherwiz]

How would you classify this for the NAO? Such strong anomalies of opposite signs on each side of Greenland...

[ORH_wxman]

How would you classify this for the NAO? Such strong anomalies of opposite signs on each side of Greenland...

That is a huge east based -NAO

[weatherwiz]

That is a huge east based -NAO

Thanks!

Sometimes when I see images like that I'm not sure what to do...should I just pay attention to the anomalies that are located just east of Greenland then?

[CoastalWx]

You don't need to post the images, but what did the ECM ensembles show later on, like 276 and 300? Anything good? Still a GoA low?

It had a GOA low but not in a bad spot and not particularly strong. In fact, there ensembles hinted at trying to pop a +pna. They'll be fluctuations. The 00z ensembles were a bit warmer, but still cold. 00z yesterday did the same..and then 12z came in with a mega -nao and also colder. We'll see minor fluctuations in the ensembles.

I mentioned yesterday that even the 12z gfs ensemble members had inside runners after Thanksgiving weekend, but it goes to show you how volatile the pattern is. Besides, some of the coldest patterns will still have ensemble members showing warm solutions that far out, so I take the individual members fwiw. It seems like a pretty good cold signal...not arctic, but colder than normal for sure. Maybe it means I flip to rain..I don't know and nobody does at this time range. All we can do is to make sure some of the big pieces of the puzzle are there. At the very least, I'd feel pretty good just away from the coast, but even I have hope with -6 to -8C 850 temps.

[Tropopause_Fold]

Can you show me a verification of the ensemble guidance versus the operational to see what the difference is in accuracy? Is that information available?

The 0z GFS also supports the OP ECM, which is why I give the pattern displayed a bit more faith...the GFS has been very consistent in showing that we'll see a strong +EPO regime and only a brief cold shot followed by normal to slightly warmer than normal temperatures in the long range, heading into early December. I like what I'm seeing from the Atlantic side with the west-based -NAO on steroids, but we need at least some cooperation from the Pacific. It's pretty early in the year to get snow if the pattern isn't particularly cold. I'd just like to see SOME model runs showing a decent Pacific, and that seems not to be happening, at least not as much as a few days ago when we had a semblance of a +PNA emerging in the long-range forecasts.

And we obviously have different perspectives. When I think of SNE, I'm talking more about BOS and the coastal plain since that's the only area I forecasted for in my winter outlook. I also am thinking about my home region, living at 350' elevation only 10 miles north from the NYC border. This is quite obviously a different climate from the hills of Worcester where you make home, so we have varying interpretations of how favorable the pattern might be. It definitely looks way better for you than for me, since there's always going to be a strong gradient in a -PNA/-NAO regime, and chances are that I end up on the warm side in a strong La Niña winter.

looks bad from about dobbs ferry points SW

[Damage In Tolland]

I think we could actually slip above average if you extrapolate the 0z ECM out past Day 10...the trough over our region is lifting out because there's a 516dm trough over the GoA and a minor weakness in the jet stream over the Pacific Northwest; this is allowing for zonal flow to control the pattern over the CONUS as heights are rapidly increasing in the Plains and Midwest. We do have a nice NAO block, but I wouldn't underestimate the influence of the Pacific regime in this case, especially since it occurs at a time when we will have a strengthening Niña and lack of favorable tropical forcing. I am pretty disappointed in this run....just a few days ago, the ECM was showing an epic +PNA forming in combination with the NAO block, but we've totally lost that. I'm just a bit distraught about the fact that we seem unable to sustain any cold anomalies and are launching into the typical La Niña pattern so early in the winter. We know we'll see some strong cold fronts in a strong La Niña; that's virtually guaranteed with Canada being colder than last winter and much lower global temperatures along with good NH snow cover coming in. But we need to have a long period of cold anomalies to allow us to take advantage of a storm, especially down towards the coastal plain where average temperatures are still in the mid-upper 40s during this period. It's a different story when we get into late December-late February as this NAO block would probably be sufficient at a climatologically colder time.

[weatherwiz]

Before we transform into a more winter like pattern looks like we will have one more convective/heavy rain/wind threat.

[CoastalWx]

The other thing to remember, is that when most talk about the country warming or showing signs of torch...etc, it can be a different ball game north of 41N. We may be in our own little world, so when people talk about warming, remember where they live or what areas they are talking about. That can be a bias. Sometimes we are guilty here in our own backyards, talking about a storm that looks iffy at the coast, but classic for the interior...and vice-versa.

[ski MRG]

looks bad from about dobbs ferry points SW

lol, almost spit coffee on my keyboard. Simple but effective.

[Tropopause_Fold]

The other thing to remember, is that when most talk about the country warming or showing signs of torch...etc, it can be a different ball game north of 41N. We may be in our own little world, so when people talk about warming, remember where they live or what areas they are talking about. That can be a bias. Sometimes we are guilty here in our own backyards, talking about a storm that looks iffy at the coast, but classic for the interior...and vice-versa.

good point and a positive for the sub-forum thing.

[Tropopause_Fold]

lol, almost spit coffee on my keyboard. Simple but effective.

well Tubes is becoming rainstorm in the tropics thread.

[MaineJayhawk]

well Tubes is becoming rainstorm in the tropics thread.

lol ... winter is going down the Tubes.

[CoastalWx]

lol ... winter is going down the Tubes.

Nice new addition to the Rev Kev stuff...lol.

[Tropopause_Fold]

I'm not sure HM; the ridge axis around Thanksgiving looks like it's still a bit too far west and would lead to a storm being more of a cutter/redeveloper than a classic coastal. Heights over FL are still near 588dm which usually isn't a good sign for an I-95 event.

The pattern gets a little better after that, although we're losing the arctic connection due to the +EPO. It's still probably cold enough if we get the right s/w however, as the NAO blocking is through the roof.

[CoastalWx]

It's not the fact that it could be something like a coastal hugger, then cold, then coastal hugger again.....it's using a deterministic model at d10 and extrapolating afterwards. His ideas are as valid as anything, but I just don't understand extrapolating out an op model past d10.

[Tropopause_Fold]

It's not the fact that it could be something like a coastal hugger, then cold, then coastal hugger again.....it's using a deterministic model at d10 and extrapolating afterwards. His ideas are as valid as anything, but I just don't understand extrapolating out an op model past d10.

100% agreement.

[Tropopause_Fold]

It's not the fact that it could be something like a coastal hugger, then cold, then coastal hugger again.....it's using a deterministic model at d10 and extrapolating afterwards. His ideas are as valid as anything, but I just don't understand extrapolating out an op model past d10.

yeah the specifics of the whole thing could end up such that we are dry and cold or like you said, an unfavorable track to the systems that develop and they end up huggers or inland runners. certainly possible. but that's just details. the overall picture remains the same with a regime shift...that's still a massive area of high heights over greenland. of course that doesn't specifically equate to snow falling X number of days later in SNE, but you have to like the odds vs. the opposite. and i think that's all we've been saying now for days.

if mid-december rolls around and no one has received a wintry event, that doesn't mean the thinking was wrong.

[CoastalWx]

yeah the specifics of the whole thing could end up such that we are dry and cold or like you said, an unfavorable track to the systems that develop and they end up huggers or inland runners. certainly possible. but that's just details. the overall picture remains the same with a regime shift...that's still a massive area of high heights over greenland. of course that doesn't specifically equate to snow falling X number of days later in SNE, but you have to like the odds vs. the opposite. and i think that's all we've been saying now for days.

if mid-december rolls around and no one has received a wintry event, that doesn't mean the thinking was wrong.

Exactly. The details are to be determined, but I like what I see so far. I don't think anybody is locking in big snow during this time, but the pattern seems favorable for many to see their first snow and obviously the interior is favored this time of year.

[CoastalWx]

-22F in northern Saskatchewan right now.

[mahk_webstah]

In my opinion, the pattern doesn't look good as all; there's a two-day cold shot after Thanksgiving that's pretty legitimate, but the trough is quickly moving out of the Northeast. You can see that there's zonal flow across the entire CONUS with almost everyone in the country being above average...heights in the Northern Plains have gone from 522dm during the upcoming cold shot to over 550dm. We also have a 980mb low developing in the GoA which is blasting warm air into North America and attempting to scour out our troughing. Even with a solid west-based -NAO, the Pacific is winning the battle, and this makes sense given that the Niña will be rapidly intensifying at this point with strong trade winds, low AAM, and an incoherent MJO. Everything about the ECM is a typical Niña pattern where we get a big cutter, then a short-lived but intense cool down followed by a return to above average temperatures. This would set the stage for a poor beginning to December in my opinion.

The GFS also shows the change to an unfavorable Pacific in the longer range with more of a +EPO look coming into play...I'm not impressed with any pattern that features 516dm heights in the Gulf of Alaska. Here is Day 11 from the 0z GFS and it seems similar to the ECM with the cold air starting to fade:

Perhaps I am being a little regional and imby but I kinda likes that setup...looks active and cold enough

[dryslot]

Perhaps I am being a little regional and imby but I kinda likes that setup...looks active and cold enough

I am not worried, Look at the setup we had back in 07-08, We got by up here with a marginal setup, I think i remember the Nao being positive that winter......

[CT Rain]

It had a GOA low but not in a bad spot and not particularly strong. In fact, there ensembles hinted at trying to pop a +pna. They'll be fluctuations. The 00z ensembles were a bit warmer, but still cold. 00z yesterday did the same..and then 12z came in with a mega -nao and also colder. We'll see minor fluctuations in the ensembles.

I mentioned yesterday that even the 12z gfs ensemble members had inside runners after Thanksgiving weekend, but it goes to show you how volatile the pattern is. Besides, some of the coldest patterns will still have ensemble members showing warm solutions that far out, so I take the individual members fwiw. It seems like a pretty good cold signal...not arctic, but colder than normal for sure. Maybe it means I flip to rain..I don't know and nobody does at this time range. All we can do is to make sure some of the big pieces of the puzzle are there. At the very least, I'd feel pretty good just away from the coast, but even I have hope with -6 to -8C 850 temps.

I dunno the Euro Ensemble mean is definitely not as exciting as it was a couple days ago... GOA low comes back and the -NAO doesn't have a whole lot of staying power.

[CT Rain]

Nate, the 00z ECM looks bad at 240h, I'm not disagreeing with you...but I'm just telling you it doesnt matter. Until we see some ensmble support for that crappy pattern, I do not buy it.

You obviously are getting married to your idea of bad patterns. A -PNA/-NAO pattern is generally good here...I'm not sure what you are describing. Yes of course if the NAO isn't powerful enough and we get some sort of monstrous PAC signal that destroys our setup then we won't see a good snow threat setup...but that isn't in the cards right now yet....except on your 00z ECM run right now at 240h.

Give me a reason why I should believe the 00z ECM OP run vs the ensembles at that time frame?

Good post, Will. The ensembles obviously look much better than the op run and through 360 hours even though the -NAO begins to fall apart we get saved by a +PNA to keep the cold dislodged from the Pole and placed in Quebec to remain in place.

I'm a little worried with signs of the -NAO ridge falling apart after day 10 that if we don't see the +PNA pop we could be in trouble.. but right now still game on for an impressive cold shot and snow chances for the 5 or 6 days after Thanksgiving.

[CoastalWx]

I dunno the Euro Ensemble mean is definitely not as exciting as it was a couple days ago... GOA low comes back and the -NAO doesn't have a whole lot of staying power.

It's fluctuated a little with the strength of the -nao over the last few runs, but I think the question is how long does it last. 00z yesterday was just a hair weaker, than 12z was ridiculous and now 00z slightly weakened a little. I'm not surprised 00z weakened since the 12z run was off the charts with the -nao. Usually, a massive block like that dampens out at the end of the run anyways, but I think the question is whether or not is pulses back up again..or does it continue to weaken. I certainly wouldn't be shocked if it weakens...I think that is the consensus, but there are other factors like whether or not heights lower in the west at all, or does the GOA low come back with vengeance. Maybe it's something where higher than normal heights hang around and then it pulses back up again?

The other thing was that models tried to bring another surge of cold south into central Canada at the end of the runs.

[H2Otown_WX]

Nothing too impressive about the cold on the GFS. It looks like the SE ridge is getting a little more potent with each run since yesterday.

[CoastalWx]

Oh oh. GFS has something up its sleeve on Wednesday next week.

[alex]

Oh oh. GFS has something up its sleeve on Wednesday next week.

Ohhh do tell do tell