Next week's major storm and beyond

[OKpowdah]

There is some decent general agreement on a major trough diving into the Plains early next week, coinciding with a brief pulse in PNA ridging over western North America. In addition, there is *relative* agreement on a low cutting off in the southern U.S. somewhere between California and Mississippi.

How all the features on the table interact is sure to change over the week, as the GFS has aptly demonstrated in its last 6 runs. In particular, where that low cuts off will have ramifications on the extent of ridging in the east and the axis and amplitude of ridging out west, which then affects how the major trough evolves.

There is not one hint of blocking downstream over the western Atlantic, so I think it's safe to say we're looking at rain. However, depending on the details, maybe bookend light snow for higher elevations? One way or another I think part of the Great Lakes, Ohio Valley and Northeast are looking at a big precip and wind event.

Anyway, decent indications that we're looking at a significant storm in development. In addition, it clearly is integrated into the larger scale pattern, and a component of significant changes over North America by the end of next week. As the trough breaks northward, it will help pull/consolidate a part of the PV onto this side of the globe, with a decent dump of cold air into Canada and the northern tier of the U.S.

The other part of the PV dives into the trough sitting over Kamchatka, which amplifies ridging from the Aleutians northward to the pole, and bridging into Russia, giving us a solid channel of cold air into Canada. So in summary, we're shaking up the polar fields a bit.

NAO at least tends toward neutral. The PNA hangs out there too. So there is no mechanism to send that PV further south. We're looking at a classic gradient pattern evolving with tight height and temp gradients across the northern U.S. This doesn't leave much room for amplification, so I doubt if we see any significant storms in this period. Also which side of the gradient do we end up on? That's dependent on the states of the NAO and PNA. Neutral does us just fine. But we have to watch which way the gradient tilts as the upstream and downstream waves evolve.

[Ginx snewx]

Let's see if Scooter weenies him

Shabbs

Finally some blocking developing! Winter to arrive Jan 20th and likely run into Feb. some interesting weather finally!

[OSUmetstud]

pretty funny how different the GFS ensembles and Euro ensembles are on Allen's site.

[CoastalWx]

Sam's last paragraph sums it up.

[Damage In Tolland]

Who cares about big storms and amplification. Clippers and waves along fronts that give us 2-4 or 3-6 and ice/mix are fine

[Typhoon Tip]

Tough call on any pattern change there… The GEFs –derived teleconnectors (those pesky indices like the PNA, NAO, EPO…etc…) are in total offering some interesting aspect on things, but I’m not thinking a specific event does the deed this time.

• The NAO is …yeah, it’s falling off currently, but it only moves from +3SD (inferno) to a +.5 (smack in the face tease) and then slams to a halt, never actually slipping negative out to 2 or 3 weeks in the mean. I do like the overall 2SD drop, though.
  
• Meanwhile, the PNA is wavering up and down across 0.0SD (no skill) to whopping + or - .5 values over that same time span. Such small variances in a spatial domain that is truly massive (much of the eastern Pacific and western half of North America), could mean just about anything, but for me, it seems more likely more of the same because the signal for change there is intrinsically so weak.
  
• The EPO/WPO are the most encouraging (west Pacific and East Pacific) for winter weather enthusiasts. They are showing a much more discerned and obvious downward plunge …succeeding negative values by D7 and onward, at CDC’s (Climate Diagnostic Center) NCEP channel. The prevailing circulation on this planet is still west to east, and it thus stands to reason the WPO has a correlation with the EPO; therefore, having both descend may lend some confidence to that actually f* happening this time. It would mean the North Pacific et al is about to enter what is called the AB phase, which is a label for blocking … often extending up into Alaska. That would DEFINITELY dump cold into the 40^th parallel over N/A should that happen.
  
• Lastly, the GEFs AO (arctic oscillation) … plaguing in positive bias such that it has all season thus far, is at last showing the best signal for collapsing the index into negative thus far this season. The mean says it falls from +2.5 or +3 SD all the way to -1.5 by week ~ 2.5. There is somewhat better believability this time, too, because the variance among the individual members is not so extreme – in other words, if it were too much spread that would make any mean value less reliable. There has been talk about the recent (10 days and counting) Stratospheric warming event, which is all clad and so forth. However, since there is a significant 20+day lag before propagating substantive SSWs show correlation on the AO, and, it has yet to be determined if this event is even propagating, there’s little help from those observations for the time being. Point being, it is hard to say if the AO is falling for that or other reasons out in time. Takes some further analysis.
  

It is possible that 3^rd and 4^th bullet points may (eventually) reflect a pattern change of sorts (should the NP switch to AB mode succeed … I think we’ve seen that hinted yet failed a few times in the means since autumn). Not to be overly tedious, but to be clear, any event next Thursday wouldn't actually trigger the change. Reason? Any NP influence on altering the circulation over N/A would by very nature be arriving from a progressive “reset”, where NP changes then force the N/A hand. Any event mid-late next week might have more affect – if any – on the North Atlantic, though. That could cause a pattern shift of sorts as a retrogressive action, but therein is a kind of conflict – it would mean a train wreck, with retrogression vectors colliding with those arriving. Interesting.

[Tropopause_Fold]

end of the euro is cold...all over NA.

[dryslot]

Euro is cold after next thurs cutter

[Typhoon Tip]

end of the euro is cold...all over NA.

You didn't ask... but imo the Euro model sucks ass. These recent D4-5-6 debacles and having been embarrassed by the GFS are exposing the model as overrated - at least relative to the handling of events embedded in the current pattern, that is definitely true. If we change the pattern and the Euro suddenly improves in the middle range, so be it ...

The GEFs teleconnectors argued against all these recent phantom Euro storms and won that argument each time...well, the last 2 times anyway; we'll see if the weekend thing sneaks back or not. For now I am not buying any Euro solution beyond D3.5 until further notice.

[CoastalWx]

The pattern is changing...I don't think there is much question on that. The questions to be answered have to do with gradient positioning, which will be driven by AO domain things like ridging in extreme nrn PAC and also the PNA. I'll take my chances with this pattern over what we had, any day...but it also may not be a glorious, snowy pattern.

[Tropopause_Fold]

You didn't ask... but imo the Euro model sucks ass. These recent D4-5-6 debacles and having been embarrassed by the GFS is exposing the model as overrating - at least relative to the handling over events embedded in the current pattern, that is definitely true.

well yeah anything post day 5 or 6 is sorta grain-of-salt type stuff anyway.

overall though, i think the ensembles are showing a move similar to the general idea of what the euro just showed. if/when/where exactly we see the arctic dislodge onto this side of the globe i don't know.

[dryslot]

The pattern is changing...I don't think there is much question on that. The questions to be answered have to do with gradient positioning, which will be driven by AO domain things like ridging in extreme nrn PAC and also the PNA. I'll take my chances with this pattern over what we had, any day...but it also may not be a glorious, snowy pattern.

Will see, If Jan fails, I will throw it in as it won't matter what Feb and March does around here

[snowNH]

You didn't ask... but imo the Euro model sucks ass. These recent D4-5-6 debacles and having been embarrassed by the GFS is exposing the model as overrating - at least relative to the handling over events embedded in the current pattern, that is definitely true. If we change the pattern and the Euro suddenly improved in the middle range, so be it ...

The GEFs teleconnectors argued against all these recent phantom Euro storms and won that argument each time...well, the last 2 times anyway; we'll see if the weekend thing sneaks back or not.

Nope. Everyone told me this morning that I was crazy for saying the gfs has been schooling the euro. Everyone else is right, we are wrong.

Everyone else will probably agree now cause you said it and not me.

[Tropopause_Fold]

Nope. Everyone told me this morning that I was crazy for saying the gfs has been schooling the euro. Everyone else is right, we are wrong.

Everyone else will probably agree now cause you said it and not me.

like nails on a chalkboard.

[Typhoon Tip]

well yeah anything post day 5 or 6 is sorta grain-of-salt type stuff anyway.

overall though, i think the ensembles are showing a move similar to the general idea of what the euro just showed. if/when/where exactly we see the arctic dislodge onto this side of the globe i don't know.

It also blew one at D4 ...had snowy thermal fields and we got rain.

yeah yeah, we'll see. Personally, I feel the pattern is changing due to the NP relay thing I discussed much above, anyway... If winter is all that matters to the reader here, you may want to wait on that -

[NorEastermass128]

The pattern is changing...I don't think there is much question on that. The questions to be answered have to do with gradient positioning, which will be driven by AO domain things like ridging in extreme nrn PAC and also the PNA. I'll take my chances with this pattern over what we had, any day...but it also may not be a glorious, snowy pattern.

Exactly...we just cannot be sure what side of the gradient we are going to be on this far out. Hopefully, within the next 7-10 days, we will start to get a better sense of where the AO/NAO/PNA are trending.

Until then, we wait. Maybe we get a 'gravy snow event before the Jan 15-20 timeframe, maybe we don't. I feel like anything will be better than the current pattern though. Since 10/29, I have had one period of flurries on 12/25. Insane!

[CoastalWx]

Will see, If Jan fails, I will throw it in as it won't matter what Feb and March does around here

I would certainly feel better where you are. As I said to Kevin, I'm still unsure of where the gradient sets up so I'm not ready to proclaim 1994 is here. It still could be messy for us. However, if I lived in NNE..I would feel better for now.

[Typhoon Tip]

Nope. Everyone told me this morning that I was crazy for saying the gfs has been schooling the euro. Everyone else is right, we are wrong.

Everyone else will probably agree now cause you said it and not me.

Woa woa wooooa - Nice shootin', tex!

Over the long haul I'd still put my coins in the Euro ante any day. The heavy handed point was simply to say that currently, the Euro is suspect more than usual.

[dryslot]

I would certainly feel better where you are. As I said to Kevin, I'm still unsure of where the gradient sets up so I'm not ready to proclaim 1994 is here. It still could be messy for us. However, if I lived in NNE..I would feel better for now.

Like i said we will see, I will feel much better once we see results, Open water and brown grass in Jan here does not leave anyone warm and fuzzy it reminds me of 06-07, It looks like we may be heading that way to some extent, Where the pattern flipped mid month that winter, Maybe not the same but will see, Caution for now..

[Tropopause_Fold]

It also blew one at D4 ...had snowy thermal fields and we got rain.

yeah yeah, we'll see. Personally, I feel the pattern is changing due to the NP relay thing I discussed much above, anyway... If winter is all that matters to the reader here, you may want to wait on that -

i think it blew one inside of 36 hours, honestly. i agree it has had a rough go of it here and there vs. our expectations on the model in recent history.

obviously you know this, but i think sometimes we either 1) over-emphasize what the models do/are and 2) expect the euro to *always* be right and the GFS to *always* be wrong.

they all have their respective values, strengths, weaknesses blah blah.

[Ginx snewx]

This gradient talk after the change is wrong IMHO, we are not heading into a gradient setup after the AO tanks.

[CoastalWx]

i think it blew one inside of 36 hours, honestly. i agree it has had a rough go of it here and there vs. our expectations on the model in recent history.

obviously you know this, but i think sometimes we either 1) over-emphasize what the models do/are and 2) expect the euro to *always* be right and the GFS to *always* be wrong.

they all have their respective values, strengths, weaknesses blah blah.

Exactly, it's guidance like anything else.

[CoastalWx]

This gradient talk after the change is wrong IMHO, we are not heading into a gradient setup after the AO tanks.

It definitely is gradient until the NAO goes negative.

[Tropopause_Fold]

This gradient talk after the change is wrong IMHO, we are not heading into a gradient setup after the AO tanks.

hopefully you are right...but i'd be hesitant to do away with the SE ridge. it could go away briefly but i guess i'd be surprised if it didn't show itself again.

[Typhoon Tip]

i think it blew one inside of 36 hours, honestly. i agree it has had a rough go of it here and there vs. our expectations on the model in recent history.

obviously you know this, but i think sometimes we either 1) over-emphasize what the models do/are and 2) expect the euro to *always* be right and the GFS to *always* be wrong.

they all have their respective values, strengths, weaknesses blah blah.

Not just blah blah, though. This is fundamentally the most important aspect to remember in model interpretation "art" (if you will...).

A great teacher and I once discussed years ago how the models merely offer paradigms for which it is then up to the user to decide what aspects to glean off them as being veracious and which ones to ignore. It is not (philosophy here) the models fault; it's always up to the reader. I like to go from the outside in with these models. I look at the canvas - if it's not designed for oil, I use acrylic - haha. Seriously though, (trend+persistence+teleconnectors) = the X factor, and the X factor almost always wins over any particular model run's design. Sometimes you get run from a guidance type and it sleeps squarely with X, and then you've really got something. Sometimes you get a, b, c, and d guidance types in that same sack and then it's a party!

1993 was a party. 1997 friendly gathering with a couple or two that said they couldn't make it. 2005 was one nighter between the NAM and reality and all the other's were wicked jealous because she was the best looking babe in class.

I think this is all spelled out pretty clearly in Chapter 3 of Synoptic ...

lol

[OKpowdah]

John,

1- As depicted by model guidance this is a clear pattern change. It doesn't always have to affect the domain of all your indices. Right now, the change is simply shifting the zonal mean zonal wind maximum equatorward, by a possible split and displacement (at the very least, distortion) of the polar vortex. As you say, we're still in a zonal pattern, but we're shifting the continental-mean gradient south. The NAO and PNA fields will do what they're going to do, and will dictate the evolution of the next several weeks *within* this new base state. If anything, the base state will help to decrease the NAO to near neutral (as the ensembles show).

2- I never said the event next week triggers the pattern change. I said it's a component of the pattern change ... First, the trough amplifies as upstream ridging punches into the vortex over Alaska. Second, as the trough breaks northward, it pulls / consolidates PV energy southward over Canada,

[snowNH]

Woa woa wooooa - Nice shootin', tex!

Over the long haul I'd still put my coins in the Euro ante any day. The heavy handed point was simply to say that currently, the Euro is suspect more than usual.

And that's what I simply was implying as well, but everyone shot me down cause I'm snowNH and I know squat.

All models have been bad, but no models have been consistently showing amped coastals like the euro has, maybe ggem. I agree, it is the best model, but it should be taken as with a grain of salt right now that is all.

I know that everyone on here feels the same way too, cause yesterday it showed 12-15 for CNE and no one even talked about it cause they knew the euro is sucking a** right now.

All of this probably goes back to what you said yesterday, people are starting to focus on the "why it can't snow" instead of the " why it could snow"

This pattern sucks so bad the optimistic will is turning into Ryan.

Welp last post until tomorrow morning.. later doobies.

[Ginx snewx]

It definitely is gradient until the NAO goes negative.

hopefully you are right...but i'd be hesitant to do away with the SE ridge. it could go away briefly but i guess i'd be surprised if it didn't show itself again.

I expect a pattern like the 240 Euro shows (LOL I know) but the PV drops south, a neg NAO sets up. That is what I expect would be a pattern flip. Of course it could be rushed a tad on the Euro but it is showing today the type of pattern I would expect once the PV splits, -epo sets up shop and a semblance of -NAO sets in again. Blocking is coming back JMHO.

[Tropopause_Fold]

And that's what I simply was implying as well, but everyone shot me down cause I'm snowNH and I know squat.

All models have been bad, but no models have been consistently showing amped coastals like the euro has, maybe ggem. I agree, it is the best model, but it should be taken as with a grain of salt right now that is all.

I know that everyone on here feels the same way too, cause yesterday it showed 12-15 for CNE and no one even talked about it cause they knew the euro is sucking a** right now.

All of this probably goes back to what you said yesterday, people are starting to focus on the "why it can't snow" instead of the " why it could snow"

This pattern sucks so bad the optimistic will is turning into Ryan.

Welp last post until tomorrow morning.. later doobies.

[CoastalWx]

I expect a pattern like the 240 Euro shows (LOL I know) but the PV drops south, a neg NAO sets up. That is what I expect would be a pattern flip. Of course it could be rushed a tad on the Euro but it is showing today the type of pattern I would expect once the PV splits, -epo sets up shop and a semblance of -NAO sets in again. Blocking is coming back JMHO.

I expect the +NAO vortex to be surrounded on 2-3 sides, but remain steady. The traditional -NAO of ridging poking into the Davis Straits imo, won't occur for at least 2-3 more weeks.