December 2019 Med/Long Range Disco

[packfan98]

5 minutes ago, Ralph Wiggum said:

6z GFS was a step in the right direction:

Definitely 

 

[poolz1]

4 minutes ago, Ralph Wiggum said:

6z GFS was a step in the right direction:

Amazing what such a minor shift can do.  I think PSU said it...it really reminds me of the storm last Dec that hammered places to our south.  That little whip rotating around the 50/50 providing confluence....  Maybe this year it breaks in our favor...Would be great to start a trend today.

[Ralph Wiggum]

It's a good look. Get this under 5 days and I think we would all be gooning. Almost there. Sure would make the Philly-Dallas / Giants-Redskins games alot of fun. 

[packfan98]

6z gefs has several members bullish for the MA.

[Ralph Wiggum]

2 minutes ago, packfan98 said:

6z gefs has several members bullish for the MA.

Member 3 with the 36"+ lollis ha! Some monsters in there. Cautious at this point. We've seen how much this has shifted around in only 6 hours from run-to-run.

Biggest takeaway from overnight runs...the big coastal storm idea seems more likely now. But there is going to be much fine tuning irt to track and evolution over the next few days. Plenty of small diffs at 500mb that could have huge impacts at the surface. Never liked trying to nail these down with the PV being close and trying to get involved.

[Buddy1987]

What a bomb on the 6z. Track like that I40 in NC up into VA and the DC guys would have a nice storm as it goes from MYR to inside Wilmington to RIC

[CAPE]

10 hours ago, psuhoffman said:

I agree completely with the first part. But I’m not sure I agree with the second. Since March of 2018 we haven’t had any real -NAO blocking. We had some bootleg transient ridges as a tpv lobe traversed a location to promote a short lived ridge there.  But what’s coming up seems like a classic west based -NAO episode. It also seems likely it gets muted for a while by as hostile a pac as we could have. 

The -NAO actually begins in only 24 hours as the current wave breaking near 50/50 builds a ridge over the top that links with the current epo side block.  By 48 hours it’s a classic west based -NAO with 50/50 low representation.

 

2 days later even a stronger west based -NAO representation.  And it is “blocking the flow”  despite a raging fast pac jet and gulf of Alaska vortex the next wave is being blocked under and is about to become the next 50/50 low.  That’s a classic evolution.  Lower heights exist in the means there because in a -NAO every wave gets forced under through that domain.  But one system doesn’t just sit there for weeks on end. If it did we would just be frigid cold and bone dry.  

 

A day later (now 4 days unto the -NAO) and we still have a classic ridge over low representation but the pacific problem is rearing its head.  That isn’t just a bad pac, it’s atrocious!  That gulf of Alaska vortex is pumping a ridge into central NAM.  The blocking isn’t breaking down but the central N Am ridge is going to merge and get absorbed which severely muted its effect.  

 

But even with that, it still manages to force the next wave under us!  With that pacific look that storm should cut to Hudson Bay!  If you want to know what our weather would look like without a -NAO with that pac just go back to December 2015.  The pattern over the east is blocked, that’s how a system gets suppressed south of us despite a vortex on the west coast.  It’s just not going to be able to completely offset a record pac jet in an awful alignment.  

 

At this point we’re 11 days unto the -NAO and the pac jet has cut underneath as soon as the vortex off the west coast relaxed some as is typical in a -NAO.  The pac is still bad just not the absolute dumpster fire it was.  This is still a classic west based -NAO with lower heights through the 50/50 space through the 11 days.  Who knows if it’s even right this far out but the representation is classic blocking regime imo.

 

Now at day 15 it’s evolved into an east based block.  Ironically the NAO index will be more negative now since its calculated at Iceland.  But again who knows if it’s right and the monster Scand ridge would imply we likely cycle back into blocking not break down.  

 

The look past day 5 could be BS.  But what we see on guidance is classic -NAO imo.  It’s muted by other hostile factors. We went through a similar problem towards the start of the last great blocking period in Feb into Mar 2018.  We suffered a perfect track rainstorm then a couple near misses due to an imperfect trough axis because of a less ideal Pac.  Then a storm got suppressed. It was during the second cycle or pulse of the NAO that we finally got a nice snowstorm in late March.  No idea how this will play out. But I do think this is finally a real -NAO. But that doesn’t mean we get snow.  We had a real -NAO most of the winter of 2000/2001 without much to show because of a not ideal pac.  December 2001 had a great NAO block the pac ruined.  It’s hapoened before. 

tl;dr (lol)

You could have saved yourself a lot of unnecessary explanation had you seen this post-

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

Outside of lucking into something with perfect timing, we really need a legitimate (sustained) -AO/-NAO to overcome the unfavorable EPAC. No idea how long that will persist. I hope it is fairly transient but we just cannot know. And IMO we are not seeing strong signs of real/legit/sustained HL blocking on the means- yet. Not raging + either, but neutral-ish probably wont get it done if the PAC remains fairly hostile.

eta- Looking at the EPS at h5 and also the teleconnections, the period(as advertised) between the 16th and the 22nd, would qualify as a modest period of blocking. That window does look interesting, esp towards the 22/23rd(when NA ridging looks to break down). We have seen some nice op runs lately, but ofc the Pac is less than ideal. Definitely worth monitoring.

The period I was specifically referring to in the post to which you replied was irt to Bob's post, and is a few days after Xmas(18z GFS). Not a block as advertised.

The broader point I was making is, overall on the means, we are not seeing strong indications of sustained HL blocking going forward  (-AO/NAO).

[CAPE]

EPS isn't too enthused about the pre-Xmas potential yet. Actually looking through the members, there is a stronger signal for the period just after.

[BristowWx]

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

EPS isn't too enthused about the pre-Xmas potential yet. Actually looking through the members, there is a stronger signal for the period just after.

I clicked back all the way to ec 9th 18z which was the first op run on GFS to see some type of storm at that time and it really hasn’t wavered.   I find that remarkable.  

[Ralph Wiggum]

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

EPS isn't too enthused about the pre-Xmas potential yet. Actually looking through the members, there is a stronger signal for the period just after.

EPS has been following along late with the last few coastal storms if that matters here. Who knows which will cave?

[psuhoffman]

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

tl;dr (lol)

You could have saved yourself a lot of unnecessary explanation had you seen this post-

The period I was specifically referring to in the post to which you replied was irt to Bob's post, and is a few days after Xmas(18z GFS). Not a block as advertised.

The broader point I was making is, overall on the means, we are not seeing strong indications of sustained HL blocking going forward  (-AO/NAO).

I read that before the ETA I think. Sorry. That does clear things up. The difference though is important going forward. Last year we never had legit blocking. Even early it was just luckily timed transient ridges. This year there has been a real tendency for blocks in the AO space. We’ve had 4 so far. 2 EPO blocks that migrated up over the pole, one short lived but legit -NAO late November that forced a damn perfect H5 cutoff low under us but did us no good because of a crap antecedent airmass, and now another NAO that looks to last about a week and will force another couple waves under us.

That’s important imo because the QBO and the North Atlantic SST both argued for a more favorable look up top then last year but I wanted to see some evidence of it.   Last years the pac was mediocre imo. It wasn’t good enough without any AO/NAO help. But we still managed a decent number of frozen events. And several good storms missed just north because of no blocking. This year I’ve already counted 3 systems that were blocked under us and maybe 2 more coming. They did us no good because we’ve frustratingly lacked timing lining other factors up. 

What does disturb me right now is the pacific. I have believed it was temporary but it’s starting to look more permanent than I expected across guidance. None of this will matter if the pac transitions to a Nina look with that current raging jet.  It doesn’t make much sense that it would do that. But nothing last year made much sense either. It’s very possible the raging fire that is the oceans right now has altered typical climo response to certain anomalies.  But I am confident we will get more help up top this year. Whether it will do is any more good wrt snow is yet to be made clear. 

[psuhoffman]

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

EPS isn't too enthused about the pre-Xmas potential yet. Actually looking through the members, there is a stronger signal for the period just after.

Euro favors bombing the first low to out northeast but that vortex then sets the table for the next wave. 

[CAPE]

2 minutes ago, Ralph Wiggum said:

EPS has been following along late with the last few coastal storms if that matters here. Who knows which will cave?

Yeah and the op has had a coastal storm for several runs, last 2 runs destroy SNE, and there are  EPS members that have it, but very few are snow producers for the MA. That can change.

[CAPE]

4 minutes ago, psuhoffman said:

I read that before the ETA I think. Sorry. That does clear things up. The difference though is important going forward. Last year we never had legit blocking. Even early it was just luckily timed transient ridges. This year there has been a real tendency for blocks in the AO space. We’ve had 4 so far. 2 EPO blocks that migrated up over the pole, one short lived but legit -NAO late November that forced a damn perfect H5 cutoff low under us but did us no good because of a crap antecedent airmass, and now another NAO that looks to last about a week and will force another couple waves under us.

That’s important imo because the QBO and the North Atlantic SST both argued for a more favorable look up top then last year but I wanted to see some evidence of it.   Last years the pac was mediocre imo. It wasn’t good enough without any AO/NAO help. But we still managed a decent number of frozen events. And several good storms missed just north because of no blocking. This year I’ve already counted 3 systems that were blocked under us and maybe 2 more coming. They did us no good because we’ve frustratingly lacked timing lining other factors up. 

What does disturb me right now is the pacific. I have believed it was temporary but it’s starting to look more permanent than I expected across guidance. None of this will matter if the pac transitions to a Nina look with that current raging jet.  It doesn’t make much sense that it would do that. But nothing last year made much sense either. It’s very possible the raging fire that is the oceans right now has altered typical climo response to certain anomalies.  But I am confident we will get more help up top this year. Whether it will do is any more good wrt snow is yet to be made clear. 

Yeah I mentioned the EPO/WPO as a good example of recent blocking when the question was brought up in banter. Hopefully we see something more sustained on the NA side as we get deeper into winter. If we continue to see the QBO trend towards negative/low solar/atmospheric Nino behavior(debatable at this point), there is a decent chance blocking episodes become more prevalent and of longer duration going forward. Wrt the Pac, if it stays in crap mode for an extended period then probably the only way to overcome it for our region would be persistently strong HL blocking.

[showmethesnow]

This isn't a hateful look whatsoever. This is the 06Z GEFS days 7-15 and besides some minor differences this is a pretty accurate depiction of what the GEFS has been throwing up for awhile now.  

 

 

Now compare the 00Z euro for that same period of time. Very similar to the GEFS except for how it is handling the PAC in particular in the NW and Alaska (black circle) and the corresponding response with the ridging in the central US. It is not as aggressive with the PAC ridging and we see lower heights over spreading Alaska from the PV to its north. This difference is why we are seeing such discrepancies with the temp maps below. Now I want to point out one thing I have an issue with. Notice we are seeing a pretty stout west based -NAO as well as  corresponding lower pressures through the 50/50 region as lows pass through. What doesn't jive is the lack of backing we are seeing with the flow. I can understand to a point how an overwhelming PAC flow can mitigate the response we should be seeing from the blocking but this is probably over kill. In my mind we should be seeing more troughing in the east then currently depicted as well as better ridging in the NW. Those plus height anomalies should be stretching farther east (red circle). And if you haven't caught on by now, if you do show the better backing of the flow we end up with a very similar look as the GEFS.

 

Now if you look at the GEFS temps anomalies you can see the better cold in the northern tier as well as seasonal to slightly below draped down the east coast. Pretty much a signiture of the better backing we are seeing with the GEFS.

 

EPS on the other hand is showing very little backing and you can see what the response is as we see the CONUS flooded with warm anomalies.

 

 

Now to show you the potential that the GEFS has to offer, here is the snow map for days 8-15 (just after the possible coastal we have been tracking). Keeping in mind that this map (Guess it is supposed to be a mean map) is most times grossly underdone in the extended when it comes to individual member output this is fairly impressive. Also note the southward extension of these snows. This is hardly the look of a shutout pattern. EPS actually has some interest during this period of time as well as there are enough members (1/4 to a 1/3) in play to suggest the possibilities.

 

 

So the question is, which is right/more right? Know many/most on here are putting their money on the EPS. I'm not at this time. Knowing the very similar looks (as to the current GEFS depiction) that have been thrown at us up around Alaska/NW this last month/month and a half I fully expect that it will gravitate back once again though it may be rushing it a touch. Also I am not a big fan of the lack of backing we are seeing with the EPS as explained above. Also seeing some support within the EPS members helps as well. So my money is riding on the GEFS. Of course after losing the house last winter in Vegas maybe I should just quite betting.  

[JakkelWx]

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

If we continue to see the QBO trend towards negative

Interestingly enough the QBO has entered the negative phase

[psuhoffman]

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

Yeah I mentioned the EPO/WPO as a good example of recent blocking when the question was brought up in banter. Hopefully we see something more sustained on the NA side as we get deeper into winter. If we continue to see the QBO trend towards negative/low solar/atmospheric Nino behavior(debatable at this point), there is a decent chance blocking episodes become more prevalent and of longer duration going forward. Wrt the Pac, if it stays in crap mode for an extended period then probably the only way to overcome it for our region would be persistently strong HL blocking.

So long as the QBO continues a slow decent and doesnt have a reversal with temporary secondary spike (that happens sometimes) it’s fine. When the QBO has been descending and below 5 in winter months they have usually had a favorable AO. We were already at 5 for November so assuming no reversal we should be ok wrt qbo. 

[Weather Will]

JB mentions the potential this weekend in his Raging Weather Bull.  Looks at the UK and the EURO changes for support.  Potential Carolinas Northward.

[BristowWx]

5 minutes ago, Weather Will said:

JB mentions the potential this weekend in his Raging Weather Bull.  Looks at the UK and the EURO changes for support.  Potential Carolinas Northward.

Like Bob told us before the idea of too much blocking doesn’t come up that much as something to worry about..or words to that effect..I am sure we are not finished with multiple solutions being presented.  

[stormtracker]

I think we're looking at a mirage on the 6z GFS.  If we get some 12z confirmation from it AND the other other models, maybe it's worth a "hmm".   But that's about it until we get this thing under 144 at least.  I dunno

[WinterWxLuvr]

7 minutes ago, stormtracker said:

I think we're looking at a mirage on the 6z GFS.  If we get some 12z confirmation from it AND the other other models, maybe it's worth a "hmm".   But that's about it until we get this thing under 144 at least.  I dunno

The potential is huge

[midatlanticweather]

10 minutes ago, WinterWxLuvr said:

The potential is huge

For the GFS to be really wrong... Yes! 

 

[Bob Chill]

21 minutes ago, BristowWx said:

Like Bob told us before the idea of too much blocking doesn’t come up that much as something to worry about..or words to that effect..I am sure we are not finished with multiple solutions being presented.  

If the only thing standing in the way at d4 is too much confluence/blocking then it gets really interesting. Right now the entire existence of the storm is in question so no sense overthinking the track of a storm that may or may not exist.

It's an attention worthy setup so I'm not poo pooing anything. It's one of those random setups that could blow up in an otherwise naso good regime. How lucky we feelin?

[showmethesnow]

By hour 126 NE Suppression is pulling out a little quicker with stronger/quicker heights builds in the east. Should be coming north. Let's see how far though.

[JakkelWx]

GFS run is Dr. No. The only thing that messes the storm up is the PNA ridge out west is flatter this run, and there's hardly any northern stream involvement.

[showmethesnow]

7 minutes ago, showmethesnow said:

By hour 126 NE Suppression is pulling out a little quicker with stronger/quicker heights builds in the east. Should be coming north. Let's see how far though.

  And this is why I don't make the big bucks when it comes to weather forecasting.

[psuhoffman]

6 minutes ago, showmethesnow said:

By hour 126 NE Suppression is pulling out a little quicker with stronger/quicker heights builds in the east. Should be coming north. Let's see how far though.

Naw the issue is with the upper level progression of the trough. 6z achieved a hit by phasing a northern feature with the southern one. This run went back to having the northern piece slide by to the north and the southern gets burried again.  The euro is all northern stream and so it bombs late to our north. We need the in between idea. Strong enough southern feature that it is the inception of east coast cyclogenesis but enough northern stream phasing to pull it north. Actually I’m not sure the northern vort is really a true NS feature but same concept.  

[psuhoffman]

Just now, showmethesnow said:

  And this is why I don't make the big bucks when it comes to weather forecasting.

You were right about the confluence. Had the gfs taken the same trough progression as 6z it would have climbed the coast more.  But it had a completely different idea this run. 

[showmethesnow]

Just now, psuhoffman said:

Naw the issue is with the upper level progression of the trough. 6z achieved a hit by phasing a northern feature with the southern one. This run went back to having the northern piece slide by to the north and the southern gets burried again.  The euro is all northern stream and so it bombs late to our north. We need the in between idea. Strong enough southern feature that it is the inception of east coast cyclogenesis but enough northern stream phasing to pull it north. Actually I’m not sure the northern vort is really a true NS feature but same concept.  

Yeah I saw that. My mistake for posting anything from just a quick glance. A newbie moment on my part. 

[stormtracker]

1 hour ago, WinterWxLuvr said:

The potential is huge

And just like that, poof.  From double digit snow to smoking cirrus.   It's gonna change again, but this run was more Euro-esque