October/November Mid/Long Range Disco

[Typhoon Tip]

1 hour ago, showmethesnow said:

I understand what you are saying but you lost me with the 582dm heights. The farthest north I see that come is southern Texas through central Florida. What am I missing?

'bounce back latitude' .... 

It just means that the rest state of the atmosphere is not very conducive to getting those trough depths into sufficiently lower latitudes.  ... The difference between the depth of any long wavy trough over top compared to that of the ambient 582+ domain to the south, creates too much wind.  The 582 may look like it is in central Florida, but that's illusory if one doesn't know that if the flow stops pressing the trough down from the top, the rest state is actually aligning at a higher latitude.  

Thing is .. we do need gradient.  Gradient is what drives everything.  When there's gradient, the atmosphere does what it can to neutralize ... it's what generates weather.   However, too much gradient and that produces too much wind speed. 

But it's hard to describe this stuff without using a lot of pricey words ...  The problem from that point on is that any S/W (short wave) is thus no longer "differentiating" against the ambient fast sped up flow. 

Cyclogenesis mechanics weaken midway thru too much gradient.  The reason why gets a little techy talky....  

Short waves contain an average of about 75 to 140 kts ...weak to strong, in the middle troposphere.   As the wave space propagates through the flow.. this nested wind max is concomitant...  

Now, imagine a short wave say ...110 kts ...about in the middle of that range.  It's wind max is situated within the wave space of the total short wave trough.  Now ...imagine this wave is sitting in a gradient rich environment where the wind is already moving along at 70 kts.   The trough's mechanic power is reduced to 40 kts ...   

Contrasting, if you place that same short wave in a less compacted, looser geopotential medium the surrounding winds may only be 30 kts.  Now you have a 90 kts of mechanical power.  

40

90

which one usually has the bigger storm?   ...

But, be careful - these are not absolutes.  It's really about balancing take-aways and add ins.  There can be a 'shear' type of high velocity set up, but other parameters can be very large to offset the detriment and then there may be a fast moving bomb.  Or, the other parameters may be weak, but ...the mechanic aspects are very powerful, and the storm ends up moderate with decent impact. There's a symphony of idiosyncrasies in the white noise of the wind.  

In a general sense ... if you see 500 mb heights > 582 over MIA, and winds over southern GA are over 50 kts prior to a S/W crossing the border up near the Dakotas .. that's a larger --> shorter scaled interference pattern. 

[psuhoffman]

26 minutes ago, Maestrobjwa said:

Oh PLEASE let that be true!! (where did you see said stat? Link?)

There was a discussion on twitter a while ago, started by reputable sources (pro mets) and there was data to back up the correlation.  

[showmethesnow]

3 minutes ago, Typhoon Tip said:

'bounce back latitude' .... 

It just means that the rest state of the atmosphere is not very conducive to getting those trough depths into sufficiently lower latitudes.  ... The difference between the depth of any long wavy trough over top compared to that of the ambient 582+ domain to the south, creates too much wind.  The 582 may look like it is in central Florida, but that's illusory if one doesn't know that if the flow stops pressing the trough down from the top, the rest state is actually aligning at a higher latitude.  

Thing is .. we do need gradient.  Gradient is what drives everything.  When there's gradient, the atmosphere does what it can to neutralize ... it's what generates weather.   However, too much gradient and that produces too much wind speed. 

But it's hard to describe this stuff without using a lot of pricey words ...  The problem from that point on is that any S/W (short wave) is thus no longer "differentiating" against the ambient fast sped up flow. 

Cyclogenesis mechanics weaken mid too much gradient.  The reason why gets a little techy talky....  

Short waves contain an average of about 75 to 140 kts ...weak to strong, in the middle troposphere.   As the wave space propagates through the flow.. this nest wind max is concomitant...  

Now, imagine a short wave say ...110 kts ...about in the middle of that range.  It's wind max is situated within the wave space of the total short wave trough.  Now ...imagine this wave is sitting in a gradient rich environment where the wind is already moving along at 70 kts.   The trough's mechanic power is reduced to 40 kts ...   

Contrasting, if you place that same short wave in a less compacted, looser geopotential medium the surrounding winds may only be 30 kts.  Now you have a 90 kts of mechanical power.  

40

90

which one usually has the bigger storm?   ...

But, be careful - these are not absolutes.  It's really about balancing take-aways and add ins.  There can be a 'shear' type of high velocity set up, but other parameters can be very large to offset the detriment and then there may be a fast moving bomb.  Or, the other parameters may be weak, but ...the mechanic are very powerful, and the storm ends up moderate with decent impact. There's a symphony of idiosyncrasies in the white noise of the wind.  

In a general sense ... if you see 500 mb heights > 582 over MIA, and winds over southern GA are over 50 kts prior to a S/W crossing the border up near the Dakotas .. that's a larger --> shorter scaled interference pattern. 

I really appreciate the time you took for the reply. You did a great job of explaining the mechanics behind the interaction of a short wave within a gradient field. Thanks again.

By the way. When I said I thought the pattern had some potential it was more in the sense we might see some snow through that period, not so much it would be a block buster storm. We in the mid-atlantic consider it a win if we see an inch or two, if not a dusting in some of the leaner winters. 

 

[showmethesnow]

12z GEFS says what warm-up? Cold through the whole duration. The possible -NAO in the extended I speculated on yesterday? It is now showing up.

[frd]

12 minutes ago, showmethesnow said:

12z GEFS says what warm-up? Cold through the whole duration. The possible -NAO in the extended I speculated on yesterday? It is now showing up.

Ventrice stated, watch the long range models as I alluded to before for changes, as in colder risks out in time .......seems might be happening ......some winters the cold is like POOF other winters the cold seems to want to stay and when it leaves it returns quickly.  

Maybe this is the other winter , hard to tell yet, but maybe  

 

 

[CAPE]

13 minutes ago, showmethesnow said:

12z GEFS says what warm-up? Cold through the whole duration. The possible -NAO in the extended I speculated on yesterday? It is now showing up.

We will have to monitor that for persistence. Looks like its trying to develop an east based -NAO. Hopefully it sticks on the guidance, and continues to build westward. Would be nice to see a favorable pattern come together for early December. 

[midatlanticweather]

Brrr and coming east --> Taken from Ryan Maue post 

[pasnownut]

Regardless where we end up in the next week, its definitely nice to see blues returning on the precip panels...no matter the verification. 

Gotta start somewhere.  Bonus rounds as we are safely out of October and cant be jinxed by November snows....lol

 

 

[WxUSAF]

Hmmm...yeah, GEFS evolving in a decent direction around Turkey Day.  -WPO transitioning to a -EPO and the Scand Ridge/-ENAO working to split the vortex.  A -WPO/-EPO in isolation can be warm for us if it dumps a trough in the west.  You can see that on the GEFS at long ranges, but the -ENAO keeps things chilly around us.  Actually looks like a cold shot comes through around Thanksgiving +/- 1 day.  Let's see what the EPS show.  GEFS tends to go a bit cold in the long range in general.  

 

Interesting that the Euro has gone to an Apps runner next Tuesday now.  That's a big jump.  In either case, all the guidance suggests that we don't get as quite a cold shot as we though we might after that storm, but conversely, it looks like generally BN temps persist through Thanksgiving week now.  Watch DCA dance around a freeze...

[frd]

This might be better in the Winter thread , but it has to do with November as well. Although I can not pick up on anything ( well of course the preconditioner wave 1 I got that part ) specific for December I believe I posted on this before here , and reading between the lines maybe HM is saying something about the upcoming December NAO , or maybe nothing ;-)

Certainly I feel the warmth up there and the ice free waters, plus the warmth targeted for Finland amongst other things, and that area I guess I would not be surprised to have a -NAO develop in December at some point.   

 

 

 

 

[Typhoon Tip]

1 hour ago, showmethesnow said:

I really appreciate the time you took for the reply. You did a great job of explaining the mechanics behind the interaction of a short wave within a gradient field. Thanks again.

By the way. When I said I thought the pattern had some potential it was more in the sense we might see some snow through that period, not so much it would be a block buster storm. We in the mid-atlantic consider it a win if we see an inch or two, if not a dusting in some of the leaner winters. 

 

thanks!  . ...yeah, I know/knew where you were coming from ..  I was just saying "caveat emptor" (buyer beware...).   Just limits on optimism.. 

I suppose folks are tired of the long summer and the endless murk that's taken up persistent description of these mid autumn days (weeks it seems!), that even snow grains would be an appreciated change of venue at this point ...  

It's been pretty relentlessly uninteresting, huh 

[midatlanticweather]

 

[showmethesnow]

Eps still has a warm up in the extended but... we are now seeing signs of ridging building in from Europe through that period. It may be following the lead of the GEFS with beginning to see signs of a -NAO during that time period and if so we should hopefully see that warmth muted if not reversed as we have seen on the GEFS.

[AfewUniversesBelowNormal]

I think we are going severely -NAO

[frd]

5 minutes ago, AfewUniversesBelowNormal said:

I think we are going severely -NAO

You might be right this time.

However, your post is very general in nature, as is my reply ;-) 

But on a serious note, we could get a decent -NAO event in December despite most saying it can not happen.    

That would be awesome by the way, if we did . I hope you are correct. 

[showmethesnow]

Haven't heard it mentioned but the 12z Euro and roughly half the EPS members seem to feel we see our first flakes in the air overnight Thur into early Fri .

[AfewUniversesBelowNormal]

2 minutes ago, frd said:

You might be right this time.

However, your post is very general in nature, as is my reply ;-) 

But on a serious note, we could get a decent -NAO event in December despite most saying it can not happen.    

That would be awesome by the way, if we did . I hope you are correct. 

There is something to atmospheric balancing that is relevant I think. 

[WxUSAF]

6 minutes ago, showmethesnow said:

Haven't heard it mentioned but the 12z Euro and roughly half the EPS members seem to feel we see our first flakes in the air overnight Thur into early Fri .

No way.  Freezing levels are 7K feet or higher (mostly much higher).  I ain't buying.  

[showmethesnow]

9 minutes ago, WxUSAF said:

No way.  Freezing levels are 7K feet or higher (mostly much higher).  I ain't buying.  

That was about my reaction when I took a quick glance as well. But who are we to argue with Dr No when he says snow? 

[AfewUniversesBelowNormal]

This is regarding the Day 5 storm, nice chances. It will be an interesting sign for the Winter to see how this trends. 

[frd]

1 hour ago, AfewUniversesBelowNormal said:

There is something to atmospheric balancing that is relevant I think. 

Ah.....I agree as well. Noticing changing SST profiles in the NW Atlantic and off the East Coast. We are losing the incredible warmth that was off the East Coast up until late September, so maybe for every action a reaction ? This is only one small part of the entire ocean-atmospheric puzzle, but will be fun to watch.    

[AfewUniversesBelowNormal]

Swing and a miss on the Day 5 storm, it does set up a 50/50 Low.. 

[Scraff]

3 hours ago, showmethesnow said:

That was about my reaction when I took a quick glance as well. But who are we to argue with Dr No when he says snow? 

Too soon?

[Chris78]

Wow! 

A Neg NAO. I'll  believe it when I see it. But we can dream....

 

[CAPE]

1 hour ago, Chris78 said:

Wow! 

A Neg NAO. I'll  believe it when I see it. But we can dream....

 

Aren't modeled -NAOs just as good?

Lets see if this becomes a persistent feature in future runs, and if the Euro/EPS becomes more enthusiastic about the idea.

[WxUSAF]

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

 and if the Euro/EPS becomes more enthusiastic about the idea.

You can peek at the d11+ EPS, but from what I see out to D10, the EPS is much less enthusiastic. I actually think the GEFS idea is a good one, just probably rushing it by 7-10 days.

[CAPE]

44 minutes ago, WxUSAF said:

You can peek at the d11+ EPS, but from what I see out to D10, the EPS is much less enthusiastic. I actually think the GEFS idea is a good one, just probably rushing it by 7-10 days.

EPS seems to be incrementally moving  in that direction over the past few runs, but probably not in a rush like the GEFS. Better to have the pattern setting up favorably for Dec instead of mid-late November.

[showmethesnow]

Quick run down on some of the major features on the overnight runs.

GEFS is holding strong with the idea of a -NAO in the long range. Starts building roughly day 12 and looks to have some staying power. If we see that break the 10 day and especially the 7 day marker on future runs we can probably start believing it is the real deal. It is also trying hard to flip the +EPO in the longer range as the ridging over the Aleutions is migrating eastward. Also seeing a migration southward of the neg pressure anomalies towards the waters off of central/southern California. Possible cutoff low off the coast in our future? I believe that is a common feature seen during Ninos but correct me if I am wrong. GEFS also is setting up what looks to be somewhat stable low pressure in the Aluetians though at this point it is maybe a little to far north and west for our tastes.

EPS is jumping on the -NAO bandwagon as well. We are seeing an -NAO getting established as ridging begins building into Greenland roughly day 12. Also seeing an attempt to flip the +EPO as we seeing the Aleution ridging moving eastward as well. Also seeing some hints of a possible cutoff off the California coast. And the EPS is pretty much in lock step with the GEFS in regards to low pressure being established in the Aluetian Islands region.

All in all the runs were very favorable with the possible changes they are picking up on in the extended.

[frd]

24 minutes ago, showmethesnow said:

Quick run down on some of the major features on the overnight runs.

GEFS is holding strong with the idea of a -NAO in the long range. Starts building roughly day 12 and looks to have some staying power. If we see that break the 10 day and especially the 7 day marker on future runs we can probably start believing it is the real deal. It is also trying hard to flip the +EPO in the longer range as the ridging over the Aleutions is migrating eastward. Also seeing a migration southward of the neg pressure anomalies towards the waters off of central/southern California. Possible cutoff low off the coast in our future? I believe that is a common feature seen during Ninos but correct me if I am wrong. GEFS also is setting up what looks to be somewhat stable low pressure in the Aluetians though at this point it is maybe a little to far north and west for our tastes.

EPS is jumping on the -NAO bandwagon as well. We are seeing an -NAO getting established as ridging begins building into Greenland roughly day 12. Also seeing an attempt to flip the +EPO as we seeing the Aleution ridging moving eastward as well. Also seeing some hints of a possible cutoff off the California coast. And the EPS is pretty much in lock step with the GEFS in regards to low pressure being established in the Aluetian Islands region.

All in all the runs were very favorable with the possible changes they are picking up on in the extended.

Might get some MJO support for colder risks after December 10 th to the 15 th period 

 

 

[frd]

Although speculation, certainly this goes in the plus column, continued pressure on the PV , this is also centered in the second half of this month, so there are now a few things that could play a hand in December's weather, say after December 10th possibly.