Ending out December with a Potential Pattern Change

[CoastalWx]

I should clarify and say the QBO is important, but I feel like some out there try to find analogs and then say things like "it's too negative" for this or that. I dunno...I fail to see the reason why and also think analogs for QBO are very hard to do since its oscillatory period is never static and I'm not sure we understand what a value of -19 means vs. a value of -9 or whatever.

[Damage In Tolland]

Indices are used far too much in forecasting. Toss them aside and go with how you learned to forecast

[N. OF PIKE]

Indices are used far too much in forecasting. Toss them aside if they don't look favorable and go with how your weenie taught you to forecast

words of wisdom from the rev

[CoastalWx]

Indices are used far too much in forecasting. Toss them aside and go with how you learned to forecast

 

Well they have value...lol. But yes, you need to know how to use them.

[CapturedNature]

Really? I thought New England was the cloudy one. BTV is one of the cloudiest cities in the lower 48. Rochester, Buffalo, Pittsburgh all are too. Right up there with Seattle and Portland. Way before the Midwest cities.

Maybe it's just those of us on the NW upslope and Lake effect clouds, but look up cloudiest cities or places to avoid if you like sun. Interior Northeast including PA/NY/NNE are right at the top with the Pacific NW.

Like this type of list...Alaska, PacNW, and the Northeast.

http://www.movoto.com/blog/opinions/top-10-u-s-cities-sun-worshippers-should-avoid/

 

I can't speak for BTV because I only lived in Lyndonville which can be a whole different sky but BTV is a pretty cloudy place in winter compared to SNE:

 

http://www.currentresults.com/Weather/Vermont/sunshine-by-month.php

 

http://www.currentresults.com/Weather/Connecticut/sunshine-by-month.php

 

I was talking more anecdotally but it has been my experience that it is generally overcast a lot more when we are in central Illinois in the winter than when we are home.  Several of those cities that you mentioned are on the eastern edge of the Midwest, FWIW.

 

It was also notable in the fact that people kept looking out our office windows and kept saying that it looked like rain or snow and were expecting it to rain or snow when in fact it was just another overcast day.  People just noticed the extra number of cloudy days that we had this month.

 

Those tables that only show the number of cloudy days in a whole year are kind of misleading though.  You could have clear skies for a month in Seattle in September but no one ever hears that.

[40/70 Benchmark]

Indices are used far too much in forecasting. Toss them aside and go with how you learned to forecast

Indecies are just like anything else...a piece of the puzzle, a tool that, when used correctly and supplemented with an extensive knowledge of how the atmosphere works, make pattern recognition a quicker and easier chore.

If one relies on them too heavily, then eventually they wil lead you astray.

 

The indecies are akin to an answer sheet, but if you don't know how the solution is arrived at, you're ultimately going to fail.

[Typhoon Tip]

I'm a little leery about precipitation chances once the onsetting -EPO/ +NP-EP  'esque pattern has arrived.  

 

The ridge out West is still too far West in my assessment.  Although ... I like Will's idea of overrunning being the best event type, for the D5-10 range.

 

The problem with a West-based +PNAP is the flow splits over the Rockies or thereabouts ...almost entirely a function of wave physics/instability in the numbers therein.  Meaning, it's hard to stretch a wave-length on Earth from 130W ... all the way to the longitude of the OV ... so the atmosphere (you'd have to go through the math to really see it...) naturally want's to "tuck" into the SW regions of the U.S..  

 

These/this are/is often seen as "Inside" or "Outside" sliders working there way down the West Coast.  Meanwhile, the northern component post the split meanders through southern Canada, with pockets both subtle and large of confluence creating sprawling polar highs from the NP-GL-NE ... which is pretty much a solid fit for most of these operational guidance types (although they may and do vary in details, of course...)   But, you will typically find that kind of cold southern Canada squeezed up against a SE ridge.

 

The geopotential heights immediately down stream of the southern component of the split are statically elevated, as the curvature/balancing of the flow around that southern jet pumps latent heat perpetually from the Gulf to off the SE U.S....  

 

The result is a very fast flow in the medium, prior to any S/Ws passing through.  

 

It gets complicated from there but just call it shear.  The S/Ws disappear.  You can actually already see that. It's what 86ed the big GL bomb idea the models had last week.  Much ... too much of the southern dynamics are now slopped back positively tilted, and that's really relfection of the SE ridge absorbing the wind velocity as the whole trough structure attempts to move through. 

 

Anyway ... it's not an absolute limitation of storminess.  I've explained all this in the past and folks seemed to respond as though it meant all or nothing.  No - it's an inhibitory factor.  Not a complete elimination of events.  

 

Re the Dailies... The Euro solution is suspect to me (more so than normal for the late middle range).  That is just about the only way to have an organized cyclogenesis on the EC in such a fast S/W mean-grinder, and seeing the model find the means to do so with 7 days to go is a bit lofty for hopers and dreamers.  We'll see... Whatever is organized beyond overrunning type events is going to be seriously hauling azz!  So that aspect of the run I agree with...

 

I'm curious as to why the western ridge has been so West biased now ...seemingly for over a week's worth of runs.  When we first sniffed out a pattern change, things looked a little kinder wrt to the standard model. Now we have this maddening split stream thing that's making deterministic ideas ... blurry.  

 

Temperatures being cold is probably in the 80+% confidence in the middle to extended range

Precipitation is probably < 40% during said time. 

 

Let's see... so far this cold season (which I'll include November, since Novie delivered a snow) has features a well timed typhoon recurvature/absorption into a hyper SPV result, ...jolt/snapping a wave configuration down stream.  This resulted in the record cold snap and GL effect storm ...eventually, vestigially laid the framework for a marginal event that would tip cold toward the TG Holiday. Shortly there after, the last gasp of the Pac forcing left, and we've been in somewhat warm biased, event starved thumb twiddler pattern ...waiting for just about anything interesting to happen.  Unfortunately, it's taken three weeks to get the interesting event to be an Xmas face smacker.  I have to admit, tho I don't feel the need to opine as loudly as the average SNE forum user ... I am not numb to the notion that this F*ING SUCKS relative to violating the affectation of the Holidays.  Actually, this 39F/mist unending grates upon anyone's nerves, snow regardless... Yuck.  Man, I was musing over the Intellicast p-type product, ...if you look around, it's like snowing virtually no where.  It's even raining below 6,000 feet in Montana!!   

 

Better luck next year...  But going forward, the "pattern change" is still obviously hugely apparent.  Right now, seems to favor a cold but drier biased one.   Again ...don't read this and think in terms of absolutes... I would not put all my money down on nothing happening at all, either. 

[RUNNAWAYICEBERG]

Cold and dry is the worst. Anything but that please.

[Damage In Tolland]

He's the only one saying that. Everyone else saying stormy period with plenty of chances

[Lava Rock]

I'm a little leery about precipitation chances once the onsetting -EPO/ +NP-EP  'esque pattern has arrived.  

 

The ridge out West is still too far West in my assessment.  Although ... I like Will's idea of overrunning being the best event type, for the D5-10 range.

 

The problem with a West-based +PNAP is the flow splits over the Rockies or thereabouts ...almost entirely a function of wave physics/instability in the numbers therein.  Meaning, it's hard to stretch a wave-length on Earth from 130W ... all the way to the longitude of the OV ... so the atmosphere (you'd have to go through the math to really see it...) naturally want's to "tuck" into the SW regions of the U.S..  

 

These/this are/is often seen as "Inside" or "Outside" sliders working there way down the West Coast.  Meanwhile, the northern component post the split meanders through southern Canada, with pockets both subtle and large of confluence creating sprawling polar highs from the NP-GL-NE ... which is pretty much a solid fit for most of these operational guidance types (although they may and do vary in details, of course...)   But, you will typically find that kind of cold southern Canada squeezed up against a SE ridge.

 

The geopotential heights immediately down stream of the southern component of the split are statically elevated, as the curvature/balancing of the flow around that southern jet pumps latent heat perpetually from the Gulf to off the SE U.S....  

 

The result is a very fast flow in the medium, prior to any S/Ws passing through.  

 

It gets complicated from there but just call it shear.  The S/Ws disappear.  You can actually already see that. It's what 86ed the big GL bomb idea the models had last week.  Much ... too much of the southern dynamics are now slopped back positively tilted, and that's really relfection of the SE ridge absorbing the wind velocity as the whole trough structure attempts to move through. 

 

Anyway ... it's not an absolute limitation of storminess.  I've explained all this in the past and folks seemed to respond as though it meant all or nothing.  No - it's an inhibitory factor.  Not a complete elimination of events.  

 

Re the Dailies... The Euro solution is suspect to me (more so than normal for the late middle range).  That is just about the only way to have an organized cyclogenesis on the EC in such a fast S/W mean-grinder, and seeing the model find the means to do so with 7 days to go is a bit lofty for hopers and dreamers.  We'll see... Whatever is organized beyond overrunning type events is going to be seriously hauling azz!  So that aspect of the run I agree with...

 

I'm curious as to why the western ridge has been so west biased now ...seemingly for over a week's worth of runs.  When we first sniffed out a pattern change, things looked a little kinder wrt to the standard model. Now we have this maddening split stream thing that's making deterministic ideas ... blurry.  

 

Temperatures being cold is probably in the 80+% confidence in the middle to extended range

Precipitation is probably < 40% during said time. 

 

Let's see... so far this cold season (which I'll include November, since Novie delivered a snow) has features a well timed typhoon recurvature/absorption into a hyper SPV result, ...jolt/snapping a wave configuration down stream.  This resulted in the record cold snap and GL effect storm ...eventually, vestigially laid the framework for a marginal event that would tip cold toward the TG Holiday. Shortly there after, the last gasp of the Pac forcing left, and we've been in somewhat warm biased, event starved thumb twiddler pattern ...waiting for just about anything interesting to happen.  Unfortunately, it's taken three weeks to get the interesting event to be a Xmas face smacker.   Man, I was musing over the Intellicast p-type product, ...if you look around, it's like snowing virtually no where.  It's even raining below 6,000 feet in Montana!!   

 

Better luck next year...  But going forward, the "pattern change" is still obviously hugely apparent.  Right now, seems to favor a cold but drier biased one.   Again ...don't read this and think in terms of absolutes... I would not put all my money down on nothing happening at all, either. 

This is what I worry about.

[40/70 Benchmark]

It's definetly not a pattern favorable for major events, but as John intimated, we can still see these sheared out swfe type deals.

[CoastalWx]

One thing I noticed is that guidance (particularly EC ensembles) seems to want to develop ridging near N Pole and up over northern Greenland. This will be key to our future as the ridge in AK maintains, but split flow may develop as heights neutralize over the US West Coast.  So basically this further enhances the idea of a gradient pattern.

[40/70 Benchmark]

He's the only one saying that. Everyone else saying stormy period with plenty of chances

I think he's saying it's possible. 

[RUNNAWAYICEBERG]

It's definetly not a pattern favorable for major events, but as John intimated, we can still see these sheared out swfe type deals.

Why would they get sheared out? They get put threw the meat grinder, the PV?

Can we get decent swfe stuff in this pattern?

[Ginx snewx]

I wonder how it ever snowed in 1994

[Typhoon Tip]

This is what I worry about.

 

"...I would not put all my money down on nothing happening at all, either. "

[CT Rain]

I wonder how it ever snowed in 1994

 

huh?

[Typhoon Tip]

I wonder how it ever snowed in 1994

 

That year was special for eastern New England... hugely augmented totals from a lot of persistent onshore flow, resulting from repeating nascent polar highs migrating N of our latitude.  

 

This also set up overrunning events as the primary event type (similar to discussed above).  But the combination of those two in the means allowed for above to much above normal snowfall/wintry type precipitation events.  If you look at the distribution of the anomalies, one might notice a focusing of the along the coastal plain, and with some pockets of less, inland, "sort of" opposite typology.  

[40/70 Benchmark]

Why would they get sheared out? They get put threw the meat grinder, the PV?

Can we get decent swfe stuff in this pattern?

 In this pattern, we want them sheared out imo....you don't want major cyclogenesis without ATL blocking.

The paradox here is that the very issue he is identifying as a threat to our snow chances is also what saves them.

 

The key is to keep the PV at bay, far enough n, imo....not too far n, but near HB...

[40/70 Benchmark]

That year was special for eastern New England... hugely augmented totals from a lot of persistent onshore flow, resulting from repeating nascent polar highs migrating N of our latitude.  

 

This also set up overrunning events as the primary event type (similar to discussed above).  But the combination of those two in the means allowed for above to much above normal snowfall/wintry type precipitation events.  If you look at the distribution of the anomalies, one might notice a focusing of the along the coastal plain, and with some pockets of less, inland, "sort of" opposite typology.  

Exactly. 

 

Boston and the s shore had a much greater positive sf anomaly than I.

The year of the oes circle jerk.

There was also a secondary maxima in the ORH hills, which is not at all out of the ordinary, as late season elevation deals permit.

[RUNNAWAYICEBERG]

In this pattern, we want them sheared out imo....you don't want major cyclogenesis without ATL blocking.

The paradox here is that the very issue he is identifying as a threat to our snow chances is also what saves them.

The key is to keep the PV at bay, far enough n, imo....not too far n, but near HB...

But not too far south either? Such a delicate pattern....can go either way.

[Typhoon Tip]

It's definetly not a pattern favorable for major events, but as John intimated, we can still see these sheared out swfe type deals.

 

Yep.

 

Also... if that western ridge gets bumped farther E...we'd observe less splitting.  less splitting would eventually erode the SE ridge and allow for deeper plumbing S/W... That would all change the playing field.  It is just a bit more difficult to run a solid coastal noreastern set up with it being modeled the way it is now...

[Typhoon Tip]

He's the only one saying that. Everyone else saying stormy period with plenty of chances

 

 

Saying WHAT exactly?  

 

Do us a favor:  demonstrate a modicum of comprehension and paraphrase what all that meant -

[40/70 Benchmark]

But not too far south either? Such a delicate pattern....can go either way.

Yes. 

Hence don't get too invested in day 6 threats....not only do we have an envelope of favorability with regard to the position of players on the field, so to speak, but we are also dealing with SWs moving at ludicrous rates of speed owed to the compressed geopotential medium that John alluded to. There is no atlantic blocking to counter that, either.

A favorably positioned PV and a compressed flow can save us from the system running bodily west of us, but this comes at the cost of said SW getting sheared out and moving at a high rate of speed.

If you want to salvage an event, temper expectations.

5-10" is about the max impact in this regime.

[RUNNAWAYICEBERG]

I feel like we are entering last winters pattern...to some extent. That's what I'm gathering from some posts.

[Typhoon Tip]

Exactly. 

 

Boston and the s shore had a much greater positive sf anomaly than I.

The year of the oes circle jerk.

There was also a secondary maxima in the ORH hills, which is not at all out of the ordinary, as late season elevation deals permit.

 

Yeah, ...and I also would add: there were some aspects about the large-scale circulation medium that were rather unusual ...  The NAO was infact positive much of the time, but it was really weirdly positive... It was like a "west-based positive NAO", if that's possible.

 

I remember the charts up at school looking that way more so than not, much of the time. The SPV became so large that although the NAO was positive, we got the cold lower troposphere into our lat/lon.  

[Ginx snewx]

Point being fast flow out of the SW over polar air equates to multiple fast overrunning chances. Last night's Euro is a dead ringer.

[Damage In Tolland]

Saying WHAT exactly?

Do us a favor: demonstrate a modicum of comprehension and paraphrase what all that meant -

Well the vast majority of us don't have time to read your War and Peace posts so we just skim them. (Hint) In summary.. You are favoring a mostly cold and dry period while not ruling out smaller light 1-3 inch events

[Typhoon Tip]

I feel like we are entering last winters pattern...to some extent. That's what I'm gathering from some posts.

 

There are some similarities, indeed.  Last year we had a predominate -EPO/+NAO arc across the Canadian Shield... 

 

And that's pretty much what we see heading into the middle and extended range...  I am not sure about the split-flow characteristic/how much the same that is... But seasons are like snow-flakes ...

[40/70 Benchmark]

Yeah, ...and I also would add: there were some aspects about the large-scale circulation medium that were rather unusual ...  The NAO was infact positive much of the time, but it was really weirdly positive... It was like a "west-based positive NAO", if that's possible.

 

I remember the charts up at school looking that way more so than not, much of the time. The SPV became so large that although the NAO was positive, we got the cold lower troposphere into our lat/lon.  

This is a great illustration of why UNDERSTANDING the atmosphere is necessary when using indexes. 

It harkens back to my index/answer sheet analogy...