December Discussion

[mreaves]

7 minutes ago, OSUmetstud said:

Yeah. This is from our climate consultant at the office. 

My parents live on the Bras d’Or Lakes about a mile from the Seal Island Bridge (where Wood has an RWIS station). They sent me the attached pictures this morning of the storm surge and related flooding and damage they are currently experiencing. The winds are northeasterly, meaning they are funneling down through from the open ocean, resulting in a direct hit on their property.

 

The water is about 3-4 feet above the high-water mark – the highest we have ever seen it since our family bought the property in the 1960’s. It has washed out cribbing along the shore that my dad and I installed when I was 12yo (not yesterday but it’s held up pretty well until now). We have been reinforcing the shoreline with large granite boulders over the past few years, which seem to be holding up, but a lot of the shoreline is still exposed and inundated about 15-20 feet inland (more in some places). And the winds are expected to continue at least throughout the day.

 

 

[OSUmetstud]

1 minute ago, Typhoon Tip said:

The hyperbolic commentary is cute in that ... how does wind "funnel" across "open ocean"  - nice. 

But yeah, almost scary lookin' ... cold deathly N. Atlantic November witch water engulfing the land...  

Well there's a complex inlet between Cape Breton County and Victoria County in that area he's discussing that gets gap wind contributions from the NE (and SW) since there's higher elevations on either side of the Seal Island Bridge area. 

 

[40/70 Benchmark]

I saw all of the recent posts and was hopeful that some piece of guidance had trended favorably, only to discover a slew of posts chronicling se Canada's travails in the wake of this latest system.

Splendidly picture perfect-

[HIPPYVALLEY]

1 hour ago, RUNNAWAYICEBERG said:

We ride the cmc.

 Always do in the winter!  I can't tell you how much CMC fantasy snow I have shoveled over the years.

[OSUmetstud]

2 minutes ago, 40/70 Benchmark said:

I saw all of the recent posts and was hopeful that some piece of guidance had trended favorably, only to discover a slew of posts chronicling se Canada's travails in the wake of this latest system.

Splendidly picture perfect-

Wave spacing issue is real but there's potential. Not too much more to say than that. 

[40/70 Benchmark]

3 minutes ago, OSUmetstud said:

Wave spacing issue is real but there's potential. Not too much more to say than that. 

Yes, but when you work during the day and step away, usually an increase in post frequency is an auspicious indicator.

Hey, at least I know which islands in the maratimes are most prone to wind funneling....and its not OT because it happens in December, I guess.

[USCAPEWEATHERAF]

3 hours ago, Typhoon Tip said:

James ... there are glaring differences between these two ... just to help you out.

I sense that you may be identifying just the locations of (+) and (-) nodes in your comparison, and then leaping to passionate conclusions (heh, so to speak..). If so, that approach is not seeing crucial aspects with the interstitial relationships/limitations in between those nodes.  It's alright. Folks don't come along with that knowledge necessarily built into their filters, so don't take this as chiding.  

First and for most, ...the flow is too fast in the lower panel.  Look over Old Mexico to Bermuda: when you see that entire axis is in a 'laminar' construct ....with lots of isotachs smashed together and smooth, that means the flow is highly compressed. Compression = high velocity.  You don't want that ... A January 2005 redux would intrinsically require a slower field, which if you look at the geopotential height gradient tapestry of that top panel, the flow is much slower  ... key: outside of individual wave/spaces/impulses identifiable in the flow, the winds are lighter.  That aspect is important for both slowing systems down .. giving them time and space to maximize.   Another way to think of it: the total torque budget of the system is conserved at the S/W scale...and not borrowed by torque already used up in L/Ws ... screaming along like Jovian wind bands - mind you...I'm speaking in hyperbolic terms there, but just to help visualize the point.

Secondly, the individual wave spacing/morphology is not even in the same ilk really, even if the flow of the lower panel were slackened off...  Wrt to the targeted impulse in your comparison, I'm assuming to be the fast open-wave structure over the lower Ohio Valley area, vs the compact(er) mechanics diving through Wisconsin of the top.   It "might" be that the structure of the S/W is different partially due to the compression differences ... but, open wave mechanics in a progressive field isn't really in the same ball-park of cyclogenesis type --> evolution.  Point being ... you can have open waves in weaker overall gradients and vice versa.  There is a bit of mastery in knowing/learning to recognize which wave structures are 'heading' toward a negative/closure, but.. the baseline requirement is not having over say... 80 kts of wind outside of S/W spaces. 

Having pointed that out... yes, you can have powerful flat waves in high velocity saturation that create fast moving robust storm ... They snow prodigiously along < 500 mile wide corridors... Essentially, Dec 2005, or November 1987 are variants of that...But those are not analogs for Jan 2005.    

Another aspect/difference, which is more systemic in nature:  Notice that 'hook' low you see just west of California? Commonly referred in met parlance as an "outside" slider (yes there are 'inside' sliders, but both function similarly), that feature is a positively feed-back to the compression E of the 100th latitude(s). It's existence in space and time ... by exhausting latent heat down stream of it circulation, that is helping to rise heights from Texas throughout the Gulf/Florida and adjacent SW Atlantic Basin.  The flow down there can have elevated heights anyway, but the hook look is only adding to that circumstance. 

There may be other limiting factors, but these in total make analog ratio between those two charts, very far from 1

Thanks for the explanation John, much appreciated

[USCAPEWEATHERAF]

The latest three GFS runs have gone way south with the shortwave and way underperforming, I was wrong to jump the gun yesterday.

[dryslot]

10 minutes ago, HIPPYVALLEY said:

 Always do in the winter!  I can't tell you how much CMC fantasy snow I have shoveled over the years.

It starts with what some call an Oh.

[OSUmetstud]

9 minutes ago, 40/70 Benchmark said:

Yes, but when you work during the day and step away, usually an increase in post frequency is an auspicious indicator.

Hey, at least I know which islands in the maratimes are most prone to wind funneling....and its not OT because it happens in December, I guess.

Stop being a bitch

[MJOatleast7]

3 hours ago, Typhoon Tip said:

James ... there are glaring differences between these two ... just to help you out.

I sense that you may be identifying just the locations of (+) and (-) nodes in your comparison, and then leaping to passionate conclusions (heh, so to speak..). If so, that approach is not seeing crucial aspects with the interstitial relationships/limitations in between those nodes.  It's alright. Folks don't come along with that knowledge necessarily built into their filters, so don't take this as chiding.  

First and for most, ...the flow is too fast in the lower panel.  Look over Old Mexico to Bermuda: when you see that entire axis is in a 'laminar' construct ....with lots of isotachs smashed together and smooth, that means the flow is highly compressed. Compression = high velocity.  You don't want that ... A January 2005 redux would intrinsically require a slower field, which if you look at the geopotential height gradient tapestry of that top panel, the flow is much slower  ... key: outside of individual wave/spaces/impulses identifiable in the flow, the winds are lighter.  That aspect is important for both slowing systems down .. giving them time and space to maximize.   Another way to think of it: the total torque budget of the system is conserved at the S/W scale...and not borrowed by torque already used up in L/Ws ... screaming along like Jovian wind bands - mind you...I'm speaking in hyperbolic terms there, but just to help visualize the point.

Secondly, the individual wave spacing/morphology is not even in the same ilk really, even if the flow of the lower panel were slackened off...  Wrt to the targeted impulse in your comparison, I'm assuming to be the fast open-wave structure over the lower Ohio Valley area, vs the compact(er) mechanics diving through Wisconsin of the top.   It "might" be that the structure of the S/W is different partially due to the compression differences ... but, open wave mechanics in a progressive field isn't really in the same ball-park of cyclogenesis type --> evolution.  Point being ... you can have open waves in weaker overall gradients and vice versa.  There is a bit of mastery in knowing/learning to recognize which wave structures are 'heading' toward a negative/closure, but.. the baseline requirement is not having over say... 80 kts of wind outside of S/W spaces. 

Having pointed that out... yes, you can have powerful flat waves in high velocity saturation that create fast moving robust storm ... They snow prodigiously along < 500 mile wide corridors... Essentially, Dec 2005, or November 1987 are variants of that...But those are not analogs for Jan 2005.    

Another aspect/difference, which is more systemic in nature:  Notice that 'hook' low you see just west of California? Commonly referred in met parlance as an "outside" slider (yes there are 'inside' sliders, but both function similarly), that feature is a positively feed-back to the compression E of the 100th latitude(s). It's existence in space and time ... by exhausting latent heat down stream of it circulation, that is helping to rise heights from Texas throughout the Gulf/Florida and adjacent SW Atlantic Basin.  The flow down there can have elevated heights anyway, but the hook look is only adding to that circumstance. 

There may be other limiting factors, but these in total make analog ratio between those two charts, very far from 1

This seems like two seasons ago ('16-17) when we had weeks of fast laminar flow south of 40N owing to high heights in the tropics that just wouldn't budge for most of the winter, over a wide swath longitude. I remember many posts from you about how we couldn't get any digging or slowing of the flow. You think we're setting up for a similar thing this go-round?

[ORH_wxman]

Ukie popped the Dec 5th low for the first time....but its still too far SE. But at least it's much better looking.

 

 

[TheCloser24]

FWIW, FV3-GFS shows major noreaster 12/8-9.

[OSUmetstud]

3 minutes ago, TheCloser24 said:

FWIW, FV3-GFS shows major noreaster 12/8-9.

I already like this version better. 

[Typhoon Tip]

2 minutes ago, TheCloser24 said:

FWIW, FV3-GFS shows major noreaster 12/8-9.

Not to be a douche ...but, not much more than any guidance saying yes or not to that event/time range - 

All these guidance types have been taking turns.  

Nick was just saying that wave spacing is an issue and he's right. I commented on that myself a while ago - the flow is festooned with S/W's, any one of which could get the job done but when the flow is fast and their hunched together (for lack of simple way to say it) they don't have time to engineer the gig ...

[cny rider]

39 minutes ago, USCAPEWEATHERAF said:

Thanks for the explanation John, much appreciated

Agree, that was a great, informative post.

[OSUmetstud]

6 minutes ago, Typhoon Tip said:

Not to be a douche ...but, not much more than any guidance saying yes or not to that event/time range - 

All these guidance types have been taking turns.  

Nick was just saying that wave spacing is an issue and he's right. I commented on that myself a while ago - the flow is festooned with S/W's, any one of which could get the job done but when the flow is fast and their hunched together (for lack of simple way to say it) they don't have time to engineer the gig ...

I think things are a bit better for the 7th to 9th than the 5th for SNE. 

[tamarack]

1 hour ago, Typhoon Tip said:

The hyperbolic commentary is cute in that ... how does wind "funnel" across "open ocean"  - nice. 

But yeah, almost scary lookin' ... cold deathly N. Atlantic November witch water engulfing the land...  

The wind may funnel the water even more than it's funneled itself, or how the Penobscot estuary rose 15 feet in 15 minutes and flooded the downtown parking lots in BGR on 2/2/1976

[OSUmetstud]

In all seriousness...I've subjectively noticed that the fv3 gfs doesn't seem to have that severe phasing/suppression/se bias that the op GFS has in the short to medium range. 

[Typhoon Tip]

17 minutes ago, MJOatleast7 said:

This seems like two seasons ago ('16-17) when we had weeks of fast laminar flow south of 40N owing to high heights in the tropics that just wouldn't budge for most of the winter, over a wide swath longitude. I remember many posts from you about how we couldn't get any digging or slowing of the flow. You think we're setting up for a similar thing this go-round?

Ahhh..  not sure. Too early to tell...  the AO tanked a couple weeks to 10 day ago ..or at least, started too.  At least for this side of the hemisphere, the subsequent southward migration of the mean westerlies(core) means "pressing" south and into the tropics, which of course are still loaded with summer hang-over. It could be endemic to the season, or just endemic to this first run in with -AO.  Unknown - 

I'm not sure about 'why' 2016-2017 couldn't shake the Neptune shenanigans.  I recall that happening much of the time last year, too, until late February and the -NAO era began..  Presently the NAO is rising and will spread neutral positive before the weekend's over... and go patently so next week... But, we do have a falling EPO and cold load deeper in the mid range - at a conceptual basis ...rising NAO means rising heights in the Middle Atlantic /NE regions, but with the EPO falling ...  that complicates the picture. 

If the couple decent in heights out west tucks ... in Ebonics, we be f'ed!  ...If the heights and cold spread east... we end up with fast flow because it "compresses" against the opposing +NAO.  

 

[dryslot]

5 minutes ago, OSUmetstud said:

In all seriousness...I've subjectively noticed that the fv3 gfs doesn't seem to have that severe phasing/suppression/se bias that the op GFS has in the short to medium range. 

Hopefully better with the thermal profiles then its predecessor because it blows chunks.

[Typhoon Tip]

7 minutes ago, OSUmetstud said:

I think things are a bit better for the 7th to 9th than the 5th for SNE. 

yup, leaning that way myself. 

There's a subtle index-related mass field correction signal in that 10th of Dec range. It's not hugely obvious - like a massive PNA phase reversal from neggie to posie...but, should the antecedent -EPO lay down the cold across the Canadian sheild, then the flow relax underneath...that is quasi to a similar thing.  

sort of complex to describe. But it is also speculative...  I think if the 5th has legs at all it's going to haulin' arse anyway. 

[OSUmetstud]

Just now, dryslot said:

Hopefully better with the thermal profiles then its predecessor because it blows chunks.

Here we seem to have this thing where it's too warm at the surface but it's too cold at 925/850...not sure if that's true in NE. For example, the 00z GFS last night had several inches of snow for the Avalon Peninsula basically at zero hour which never occurred. 

[dryslot]

Just now, OSUmetstud said:

Here we seem to have this thing where it's too warm at the surface but it's too cold at 925/850...not sure if that's true in NE. For example, the 00z GFS last night had several inches of snow for the Avalon Peninsula basically at zero hour which never occurred. 

And was the opposite here on this last one, And several previous to that one.

[Typhoon Tip]

10 minutes ago, tamarack said:

The wind may funnel the water even more than it's funneled itself, or how the Penobscot estuary rose 15 feet in 15 minutes and flooded the downtown parking lots in BGR on 2/2/1976

well, yeah ... surge, but that's a separate matter to my wise-azzing.   I was ribbing about the air itself. 

[OSUmetstud]

3 minutes ago, dryslot said:

And was the opposite here on this last one, And several previous to that one.

Thats interesting. The surface warm bias is categorically a thing at all lead times. 

[OSUmetstud]

Ah ncep just reversed the bias. So cold and snow for all on the new GFS 

 

[dryslot]

2 minutes ago, OSUmetstud said:

Thats interesting. The surface warm bias is categorically a thing at all lead times. 

I probably should have phrased that differently the i did, It was warm at the surface, But it also has been running warm in the upper levels as well.

[dendrite]

2 minutes ago, OSUmetstud said:

All ncep just reversed the bias. So cold and snow for all on the new GFS 

 

Put the 2 together and you're at 0.

[40/70 Benchmark]

37 minutes ago, TheCloser24 said:

FWIW, FV3-GFS shows major noreaster 12/8-9.

It probably had the PV lobe initiate cyclogenesis itself.