February pattern discussion

[Typhoon Tip]

The key will be the relaxation of the predominant -EPO.  

 

I don't speak for the Euro based teleconnectors, but the GEFs derivatives have been flagging just such a relaxation for a few nightly runs as of late.  

 

The reason why that matters, ...in brief is that with on-going +NAO/diving PNA/ and +AO not helping, there isn't any flow construct that fits with those other, then losing the -EPO, and still supporting cold.  There just isn't -- anything else is spin/bargaining.  It would likely mean losing the ability to maintain cool anomalies, perhaps indistinguishable from spring do to timing...

 

The question is, when when when when when.  

 

Cisco mentioned in the Ext. range FD that the pattern change is lurking out there toward the end of next week, so NCEP appears to have taken notice.  He describes it as a loss of the seemingly endless steep latitude trajectories of the deep layer flow, into the N-tier/Lakes and our regions. ...Being replaced by Pac flow into the Pac NW.   Such a latter flow usually sets up a continental kadabatic warming scenario that starts over the Canadian front range and then works ESE through the remainder of N/A below the 50th (or so..) parallel.  It may not mean super warm, no... But it would definitely be a script flipper.  Melting and thawing and meaningful recovery would be well underway. 

 

However, caveat emptor:  The EPO (and I was afraid of this...) timing may be rushed in the GEFs; that's why the when is in question. Through yesterday, the EPO showed daily losses in negative magnitude, then going modestly positive by D10...  Now, that is pushed back. A kind of bulge/sagging out there between D8-12 is new, and may signal that a more truthful decay in the EPO blocking that's plagued the NE Pac/Alaska and NW Territories may take longer than a mere 10 days.  

[N. OF PIKE]

The key will be the relaxation of the predominant -EPO.  

 

I don't speak for the Euro based teleconnectors, but the GEFs derivatives have been flagging just such a relaxation for a few nightly runs as of late.  

 

The reason why that matters, ...in brief is that with on-going +NAO/diving PNA/ and +AO not helping, there isn't any flow construct that fits with those other, then losing the -EPO, and still supporting cold.  There just isn't -- anything else is spin/bargaining.  It would likely mean losing the ability to maintain cool anomalies, perhaps indistinguishable from spring do to timing...

 

The question is, when when when when when.  

 

Cisco mentioned in the Ext. range FD that the pattern change is lurking out there toward the end of next week, so NCEP appears to have taken notice.  He describes it as a loss of the seemingly endless steep latitude trajectories of the deep layer flow, into the N-tier/Lakes and our regions. ...Being replaced by Pac flow into the Pac NW.   Such a latter flow usually sets up a continental kadabatic warming scenario that starts over the Canadian front range and then works ESE through the remainder of N/A below the 50th (or so..) parallel.  It may not mean super warm, no... But it would definitely be a script flipper.  Melting and thawing and meaningful recovery would be well underway. 

 

However, caveat emptor:  The EPO (and I was afraid of this...) timing may be rushed in the GEFs; that's why the when is in question. Through yesterday, the EPO showed daily losses in negative magnitude, then going modestly positive by D10...  Now, that is pushed back. A kind of bulge/sagging out there between D8-12 is new, and may signal that a more truthful decay in the EPO blocking that's plagued the NE Pac/Alaska and NW Territories may take longer than a mere 10 days.  

 

Is there any reason to think the PNA ridge makes a comeback and gets heights back up over Rockies

[Typhoon Tip]

Is there any reason to think the PNA ridge makes a comeback and gets heights back up over Rockies

 

Not really ...  The WPO is also rising out in time and shows a complete neutralization. With the EPO also flat-lined, that means the entire North Pacific circulation medium is going away from AA (which correlates well with +PNA).  

 

There's that, and the MJO appears to want to strengthen on the cusp of Phase 2/3 over the next 10 days. Should that take place, what tropical forcing plays in might be constructively interfering with a neutral or even -PNA.  Seeing as the -PNA is progged anyway by both CPC/CDC (we're still just talking the American tele's), the two-week ending signal is on a warm(ing) curve.  Again, that would be hard to disconnect from season change, anyway ... as March often starts a lot different than it ends, anyway.  

 

Again, the EPO is not certain.  You can sustain cold into the 40th parallel E of the Rockies, in a -PNA, with a cutoff ridge near Alaska. But you were asking about the PNA...  

 

Also have to be mindful that a -PNA can still ridge over the Rockies.  Scott mentioned this yesterday and he's right... If the PNA domain is negative out near the dateline than it might tip the whole index negative, when in fact the N/A sector is out of phase.  It's just that it is less likely to be the case. 

 

[edit:  just checked; although there is a MJO wave signaled into the 2nd/3rd wave spaces, the signal is weak.]

[CoastalWx]

I think John is right about the GEFS pushing back the break down of the -EPO. It seems like it's on its own with that which throws off the teleconnections. I still like the overall idea of a which into Bering Sea or western AK, perhaps a -PNA response a gradient-like pattern here. The GEFS now of GOAk troughing so they are trying to cancel winter. I don't buy it.

[N. OF PIKE]

Not really ...  The WPO is also rising out in time and shows a complete neutralization. With the EPO also flat-lined, that means the entire North Pacific circulation medium is going away from AA (which correlates well with +PNA).  

 

There's that, and the MJO appears to want to strengthen on the cusp of Phase 2/3 over the next 10 days. Should that take place, what tropical forcing plays in might be constructively interfering with a neutral or even -PNA.  Seeing as the -PNA is progged anyway by both CPC/CDC (we're still just talking the American tele's), the two-week ending signal is on a warm(ing) curve.  Again, that would be hard to disconnect from season change, anyway ... as March often starts a lot different than it ends, anyway.  

 

Again, the EPO is not certain.  You can sustain cold into the 40th parallel E of the Rockies, in a -PNA, with a cutoff ridge near Alaska. But you were asking about the PNA...  

 

Also have to be mindful that a -PNA can still ridge over the Rockies.  Scott mentioned this yesterday and he's right... If the PNA domain is negative out near the dateline than it might tip the whole index negative, when in fact the N/A sector is out of phase.  It's just that it is less likely to be the case. 

Thanks John.

[N. OF PIKE]

I think John is right about the GEFS pushing back the break down of the -EPO. It seems like it's on its own with that which throws off the teleconnections. I still like the overall idea of a which into Bering Sea or western AK, perhaps a -PNA response a gradient-like pattern here. The GEFS now of GOAk troughing so they are trying to cancel winter. I don't buy it.

Scott, you have probably mentioned it several times, what things can help push the gradient in a "gradient pattern" further South so that SNE does better than they have in other "gradient patterns, that ended up lousy" and too far to our North. Is that what makes the Polar Vortex positioning further SW key to get confluence in such a pattern that helps us stay colder when precip arrives.

[Ginx snewx]

At some point Pickles, winter will end

[CoastalWx]

Scott, you have probably mentioned it several times, what things can help push the gradient in a "gradient pattern" further South so that SNE does better than they have in other "gradient patterns, that ended up lousy" and too far to our North. Is that what makes the Polar Vortex positioning further SW key to get confluence in such a pattern that helps us stay colder when precip arrives.

 

Two things. A high amplitude ridge preferably east of the dateline. This helps dump the cold into Canadan and allows for deeper penetration ito the US. Also, any sort of weak -NAO ridging (even into NE Greenland) will help push the PV further SW into Quebec and that also allows for confluence to our north. You can also have a combo of these..you don't necessarily have to have both. BNut basically, anyone of these serves to beat down the SE ridge a bit.

[Go Kart Mozart]

What do the euro weeklies say about this?

[snowman19]

The key will be the relaxation of the predominant -EPO.

I don't speak for the Euro based teleconnectors, but the GEFs derivatives have been flagging just such a relaxation for a few nightly runs as of late.

The reason why that matters, ...in brief is that with on-going +NAO/diving PNA/ and +AO not helping, there isn't any flow construct that fits with those other, then losing the -EPO, and still supporting cold. There just isn't -- anything else is spin/bargaining. It would likely mean losing the ability to maintain cool anomalies, perhaps indistinguishable from spring do to timing...

The question is, when when when when when.

Cisco mentioned in the Ext. range FD that the pattern change is lurking out there toward the end of next week, so NCEP appears to have taken notice. He describes it as a loss of the seemingly endless steep latitude trajectories of the deep layer flow, into the N-tier/Lakes and our regions. ...Being replaced by Pac flow into the Pac NW. Such a latter flow usually sets up a continental kadabatic warming scenario that starts over the Canadian front range and then works ESE through the remainder of N/A below the 50th (or so..) parallel. It may not mean super warm, no... But it would definitely be a script flipper. Melting and thawing and meaningful recovery would be well underway.

However, caveat emptor: The EPO (and I was afraid of this...) timing may be rushed in the GEFs; that's why the when is in question. Through yesterday, the EPO showed daily losses in negative magnitude, then going modestly positive by D10... Now, that is pushed back. A kind of bulge/sagging out there between D8-12 is new, and may signal that a more truthful decay in the EPO blocking that's plagued the NE Pac/Alaska and NW Territories may take longer than a mere 10 days.

Tip, NYC area guy here, but it's pretty clear we are about to go into a -pna, +epo/wpo, +nao, +ao, SE ridge pattern come March. Once the RNA pattern kicks in, nyc south would be done as far as winter weather, correct? I know you guys up in New England would be ok, but I read that RNA is the kiss of death from nyc south, especially in March

[Mikehobbyst]

Tip, NYC area guy here, but it's pretty clear we are about to go into a -pna, +epo/wpo, +nao, +ao, SE ridge pattern come March. Once the RNA pattern kicks in, nyc south would be done as far as winter weather, correct? I know you guys up in New England would be ok, but I read that RNA is the kiss of death from nyc south, especially in March

Mets with the -EPO likely continuing through most of March as the models seem to hint, I think we keep some severe cold through the equinox and no signs of spring until the last 4-5 days at March.  Sorry for the bad news, but it is what it is.  I wonder if some Mets are going to come to this same conclusion about 30-35 more days of severe cold and snow chances.

[Typhoon Tip]

Tip, NYC area guy here, but it's pretty clear we are about to go into a -pna, +epo/wpo, +nao, +ao, SE ridge pattern come March. Once the RNA pattern kicks in, nyc south would be done as far as winter weather, correct? I know you guys up in New England would be ok, but I read that RNA is the kiss of death from nyc south, especially in March

 

I don't think the vision of a +EPO/+WPO is really all that clear when utilizing the GEFs -derived products.  Conditions could certainly turn out that way, but the timing and magnitude of paradigm shift are in question, just as they were yesterday, when we stressed that concept (I don't employ the GGEM, or Euro -based products, because I do no have access to those at the present time. These other guidance types might indicate a faster more obvious change).

 

Last night's GEFs run has now pushed the EPO sign change back out to March 7; the previous night, also had pushed ... The trend is thus to delay the onset of a +EPO domain in the GEFs.  Additionally, the sign change is at the farthest time interval of the extended (so less confident), but also suggests that the whole phase change in general may have been rushed -- not an uncommon behavior.    

 

If the EPO does at last neutralize/go positive, then there would be pretty much no stopping an on-rushing warmth ... if perhaps masked by the assumption of seasonal change. The Meteorological first of which begins at the end of 7 days from now.  

 

To digress for a moment ... there isn't anything spectacular about March 1 in the climate (that I am aware) that argues Mar 1 needs to be delineated as the first day of spring. Perhaps numerically it makes more sense to break the annum into four equal parts, and I guess it's easier to do that with whole months...  I'm not sure why the real reason is that March 1 has to be "the Meteorological first day of spring). I guess must be too hard to do with Dec 22 to Mar 21; Mar 22 to June 21;  Jun 22 to Sept 21 .... etc?  If so, that's troglodyte thinking...  You could righteously argue that Mar 1 is statistically warmer than Feb 1, by a bigger margin than Feb 1 is compared to Jan 1; perhaps that's why, and thus I contradict myself a little.  But at our latitude, that part of the curve is a very obtuse slope, and if I were gambler I'd probably have a fire-bet down on cold and snowy patterns on that particular date.  

 

Anyway, back to present ... As has been the case all along, the EPO is everything right now.  The other mass fields would certainly balance out a flatter, more SE ridge appeal, but the wave-spacing required for a -EPO phase state is causing the N-stream to perpetually incur a parabolic "dent" if you will.  It's why the flow has been unusually fast over recent weeks, as well..   

[Typhoon Tip]

Mets with the -EPO likely continuing through most of March as the models seem to hint, I think we keep some severe cold through the equinox and no signs of spring until the last 4-5 days at March.  Sorry for the bad news, but it is what it is.  I wonder if some Mets are going to come to this same conclusion about 30-35 more days of severe cold and snow chances.

 

Relative to season you mean?  "Severe cold" gets harder and harder as March goes on..  Also, not sure what "snow chances" has to do with anything.  -EPO pertains to temperature anomaly distribution -- yeah, you need cold for snow... but yes and no. March is a fickle month.  ...Actually, right through mid April for that matter.  Some of the highest QPF, blue snow monsters happen at 32.5 F and it can be in the mid 50s by the end of the week.   

[Clinch Leatherwood]

Absolutely love your posts John, some of the most thorough and informative to read on the forum.  That said I wish there was a cliff notes button!

 

I think the pattern is already undergoing change. 

[N. OF PIKE]

At some point Pickles, winter will end

I wonder if you will call the early spring should the EPO flip. . .the BDF will be lovely in E mass this spring.

[Ginx snewx]

I wonder if you will call the early spring should the EPO flip. . .the BDF will be lovely in E mass this spring.

if my Aunt had balls she'd be my Uncle, at some point winter will end

[weathafella]

Well.....February has a shot to out do 1934 especially with whats coming Monday onward. That said, yes it has to end. Does it do it 1961 style with a 2 footer?

[Cold Miser]

Absolutely love your posts John, some of the most thorough and informative to read on the forum.  That said I wish there was a cliff notes button!

 

I think the pattern is already undergoing change. 

This.

[Typhoon Tip]

Not sure what was so hard to understand about any of that.. 

[40/70 Benchmark]

Monster day 8 storm on the EURO. Tracks the low through New England but big snows in the deep interior.

That's the type of event that'll help us catch BOS's snowfall total haha.

Yes, long range EURO amplitude has been the way to lean this winter.

 

I'm also not sure why people keep focusing on the fact that the "tide is going to turn" with regard to the EPO/PNA, but why doesn't that apply to the polar fields???

Flawed logic.

[CoastalWx]

Yes, long range EURO amplitude has been the way to lean this winter.

 

I'm also not sure why people keep focusing on the fact that the "tide is going to turn" with regard to the EPO/PNA, but why doesn't that apply to the polar fields???

Flawed logic.

 

What do you mean?

[40/70 Benchmark]

I think John is right about the GEFS pushing back the break down of the -EPO. It seems like it's on its own with that which throws off the teleconnections. I still like the overall idea of a which into Bering Sea or western AK, perhaps a -PNA response a gradient-like pattern here. The GEFS now of GOAk troughing so they are trying to cancel winter. I don't buy it.

Think back to when we were entering this record shattering orgy from the abyss of that wretched Dec/first half of January regime....we were originally supposed to be rocking and rolling by xmas, at the latest....and it ended up pushed back by a few weeks.

Why shouldn't that happen here??

 

I'd love to hang onto this for the first two weeks of March, then blast it all to hell because by then, it's elevation season, anyway.

[40/70 Benchmark]

What do you mean?

What I mean is the whole "this has to end sometime" seems to only apply to the semi permanent -EPO/+PNA....well, aren't the polar fields about to to flip??

I mean, are we going to maintain a +NAO/AO tandem forever? 

Ok, long range guidance is only flagging a change with regard to the Pacific....fine, but the obnoxious Atlantic and Arctic regimes have to be on borrowed time, as well....otherwise, these epic snows and cold have simply belied what has been an enormous failure on the part of Cohen.

[CoastalWx]

What I mean is the whole "this has to end sometime" seems to only apply to the semi permanent -EPO/+PNA....well, aren't the polar fields about to to flip??

I mean, are we going to maintain a +NAO/AO tandem forever? 

Ok, long range guidance is only flagging a change with regard to the Pacific....fine, but the obnoxious Atlantic and Arctic regimes have to be on borrowed time, as well....otherwise, these epic snows and cold have simply belied what has been an enormous failure on the part of Cohen.

 

The +NAO/AO shows no sign of stopping..lol. I think our focus should remain on the Pacific right now. I don't see any signs of the Ao or NAO changing overall base states other than some wobbles here and there. Those wobbles are important too.

[40/70 Benchmark]

The +NAO/AO shows no sign of stopping..lol. I think our focus should remain on the Pacific right now. I don't see any signs of the Ao or NAO changing overall base states other than some wobbles here and there. Those wobbles are important too.

Well, hopefully the Pacific change keeps getting shoved back....akin to the blocking modeled during seasons like 2001-02 and 2011-12.

Always 10 days away!!

 

This "has to end sometime" logic goes both ways....seasonal progression aside, of course.

I know climo will warm, but I mean the pattern in-and-of itself.

[CoastalWx]

I also noticed a few posters getting perhaps a little defensive when stating that we are going to undergo a few changes. It doesn't mean no snow..lol. The ridge retros which naturally opens up the door to a different storm track. It may mean rapid fire moderate events, or some taint..we don't know. It's still an active and overall BN pattern.

[ORH_wxman]

The ensembles have shown a deep -PNA in the 11-15 for like a week now and it gets muted every time....the EPO reloads keep happening and they seem to be far enough east that they don't allow the deep trough to dominate the PAC NW.

[TalcottWx]

I mean it's almost march. It's a given we get changes now...

[40/70 Benchmark]

I mean it's almost march. It's a given we get changes now...

I mentioned climo.....not what I mean.

You misunderstood.

[40/70 Benchmark]

The ensembles have shown a deep -PNA in the 11-15 for like a week now and it gets muted every time....the EPO reloads keep happening and they seem to be far enough east that they don't allow the deep trough to dominate the PAC NW.

Yes, this is basically what I'm getting at.

 

We see just the opposite in terrible seasons with modeled relaxation of the Pacific jet....always modeled, but just never happens.

 

I wouldn't be surprised if we keep seeing that.

At least hold off through the first half of march because by then climo is ready to crash the party, anyway...as Jay alluded to.