Medium Range-Long Range thread

[HM]

Yep. And can it time right with the PNA > 0?

 

Exactly. I think an early Feb PNA spike is a possibility still after an up-and-down rollercoast to end Jan. This could time nicely with the "-AO building" to lead to the window (2/5-10).

 

Sigh... 

[BxEngine]

Question...(since this longer range thread is much more readable than some others, lol)...even if the pna goes -, dont we seem to still have a better shot at some minor stuff (or at least not completely torching) because of better cold in Canada then we've seemed to have the last 2 winters?

Or can/will it overwhelm the pattern? Im trying to learn the mjo and pna responses, am i completely off base here?

[HM]

Question...(since this longer range thread is much more readable than some others, lol)...even if the pna goes -, dont we seem to still have a better shot at some minor stuff (or at least not completely torching) because of better cold in Canada then we've seemed to have the last 2 winters?

Or can/will it overwhelm the pattern? Im trying to learn the mjo and pna responses, am i completely off base here?

 

Without a solid -NAO, the cold can easily be removed with a poor CONUS-PAC pattern. However, the extent of the cold will make it more difficult than what we have been dealing with so far this winter, which can lead to mixed events/changeovers etc. So I don't think we are in a full blown torch given the cold air source/-AO.

[HM]

Another factor: strong poleward propagation of westerly AAM is on the way to close out Jan. This, too, will cause an "acceleration" of the jet but will also possibly make things favorable the following week as compensating torques/earth exchange alter the flow again (birthing lee-rockies lows will give way again to another PNA-styled high).

[HM]

Also, think of the pattern in these terms...we will be in a "progressive anomaly pattern" through 1/25-1/30 (large anomalies shifting east with time) and then we will begin to shift west again thereafter for a retrograding anomaly pattern from that point into the first half of Feb. We currently are in the middle of the progressive shift.

 

Periods that go from progressive to retrogressive are always of interest to me for several reasons. A lot of magical things can happen to the flow!

[SnowGoose69]

Well, I think we are equally worried since last week I've basically stated those concerns. And just like that, a warm shot is being modeled on the euro with no big storm Jan 25. This is exactly the PNA related issues I was worried about. Also, the PV doesn't shift east with the clipper bomb which ruins any KU setup either.

 

The big question is: how long does it take for the stratospheric anomaly / -AO to build down into the NAO domain?

 

Yeah that event on the 25th has some potential for maybe some front end snows due to the strong cold airmass  in place but this particular Euro run shows it more like just a cold frontal passage, last night's more had a look of a possible cutting system into the Adirondacks.

[am19psu]

Another factor: strong poleward propagation of westerly AAM is on the way to close out Jan. This, too, will cause an "acceleration" of the jet but will also possibly make things favorable the following week as compensating torques/earth exchange alter the flow again (birthing lee-rockies lows will give way again to another PNA-styled high).

The +AAM anomalies propagating northward has me a little interested. I noticed it this morning on the ESRL images (though I'm not sure how well the last 2-3 days are capped due to the averaging method). Certainly bodes well for a possible favorable southern stream.

[tombo82685]

Question, First off what is a kelvin wave? How do you track them? How do they influence patterns. I remember HM back in december was saying that mjo pulse that showed phases 8-2 was kelvin wave driven.

[Harbourton]

Three vortexes out in the western PAC that have to climb over the PNA ridge. Hopefully one will hit the sweet spot in the developing east coast trough.

 

[famartin]

Question, First off what is a kelvin wave? How do you track them? How do they influence patterns. I remember HM back in december was saying that mjo pulse that showed phases 8-2 was kelvin wave driven.

Always trust Wikipedia to lead you to the answer   (well, not really, but I think this is essentially correct)

http://en.wikipedia.org/wiki/Kelvin_wave

[tombo82685]

Always trust Wikipedia to lead you to the answer   (well, not really, but I think this is essentially correct)

http://en.wikipedia.org/wiki/Kelvin_wave

Thanks Ray, but  how does a kelvin wave affect the weather?   

[Mike.Ventrice]

Question, First off what is a kelvin wave? How do you track them? How do they influence patterns. I remember HM back in december was saying that mjo pulse that showed phases 8-2 was kelvin wave driven.

 

 

Thanks Ray, but  how does a kelvin wave affect the weather?   

 

On a very rainy day, when cable goes out and and there's absolutely nothing to do, here's a quick read about CCKWs

http://www.atmos.albany.edu/student/ventrice/documents/publications/Dissertation.pdf

 

Otherwise you can go the other route if you like journal format:

http://www.atmos.albany.edu/student/ventrice/documents/publications/Ventrice%20et%20al.%202012a.pdf

http://www.atmos.albany.edu/student/ventrice/documents/publications/Ventrice%20et%20al.%202012b.pdf

http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-12-00147.1

 

Now when you ask with respect to extratropical flow... you will have to perform the research on your own becuase it does not exist yet

[Mike.Ventrice]

Question, First off what is a kelvin wave? How do you track them? How do they influence patterns. I remember HM back in december was saying that mjo pulse that showed phases 8-2 was kelvin wave driven.

 

The most common way to track CCKWs is by prefiltering data in wavenumber and frequency. I have some real-time CCKW tracking plots here following such methods among others: http://mikeventrice.weebly.com/tropical-waves.html

 

If you want to get into the bolts and nuts, we can discuss offline if you'd like.

[famartin]

Now when you ask with respect to extratropical flow... you will have to perform the research on your own becuase it does not exist yet

You just made me feel less dumb for failing to find anything

[tombo82685]

On a very rainy day, when cable goes out and and there's absolutely nothing to do, here's a quick read about CCKWs

http://www.atmos.albany.edu/student/ventrice/documents/publications/Dissertation.pdf

 

Otherwise you can go the other route if you like journal format:

http://www.atmos.albany.edu/student/ventrice/documents/publications/Ventrice%20et%20al.%202012a.pdf

http://www.atmos.albany.edu/student/ventrice/documents/publications/Ventrice%20et%20al.%202012b.pdf

http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-12-00147.1

 

Now when you ask with respect to extratropical flow... you will have to perform the research on your own becuase it does not exist yet

thanks Mike, much appreciated as usual. I will try to wrap my head around this, though i give it a 5% chance of understanding it 

[tombo82685]

What worries me, with the lack of blocking and the dominate northern stream is that we continuously get storms that track to our north or swfe. When we do get a good pv placement we get the surpression. That is why el nino's are golden around here because its southern stream disturbances.

[Rainshadow]

What worries me, with the lack of blocking and the dominate northern stream is that we continuously get storms that track to our north or swfe. When we do get a good pv placement we get the surpression. That is why el nino's are golden around here because its southern stream disturbances.

 

The Pacific has not been helpful and the negative nao(s) so far have been more -nao east and the one Baffin block came too early.  It has been ninaish, lack of phasing. IDK.  Still its good to have the PV this far south, the lows can only go so far north.

[NaoPos]

What worries me, with the lack of blocking and the dominate northern stream is that we continuously get storms that track to our north or swfe. When we do get a good pv placement we get the surpression. That is why el nino's are golden around here because its southern stream disturbances.

0z GFS demonstrates this very well through 240.

[NaoPos]

for the tuesday system, the 0z euro looks like more northern stream invilvment/digging earlier than the 12z. little quicker on the transfer and redevelopment of the coastal low.

the quicker transfer causes the precip shield to bloom closer to shore. Still offshore, but you can see the difference. just something to keep an eye on.

Also, the GgEm @120

Could be grasping at straws here. But to see the GGEM not as progressive as the other models makes you notice.

[tombo82685]

for the tuesday system, the 0z euro looks like more northern stream invilvment/digging earlier than the 12z. little quicker on the transfer and redevelopment of the coastal low. the quicker transfer causes the precip shield to bloom closer to shore. Still offshore, but you can see the difference. just something to keep an eye on. Also, the GgEm @120 Could be grasping at straws here. But to see the GGEM not as progressive as the other models makes you notice.

 

 

i think the ggem would blow any storm up that is on the east coast. 

[tombo82685]

The Pacific has not been helpful and the negative nao(s) so far have been more -nao east and the one Baffin block came too early.  It has been ninaish, lack of phasing. IDK.  Still its good to have the PV this far south, the lows can only go so far north.

Is their any scientific reasoning as to why in the opast 3 years at least there have been no clippers really? In the past you could at least bank on a couple to help with snow totals. Lately its been all or nothing in terms of storms either coastal bombs or 60 and rain.

[tombo82685]

i would still watch that clipper next tues timeframe. The euro and its ens mean has adjust the track under neath us. I'm not talking about what happens after that. I think its going to be hard in this progressive pattern to get a big miller B. Snows of an inch or two from the clipper could evolve since how cold the airmass will be.

[Rainshadow]

i think the ggem would blow any storm up that is on the east coast. 

 

The ggem was correct in the medium range of bringing the current pcpn threat into our area, even if the threat for most verifies as sub advisory snow.  So I can't post the next time it will be right this winter will be the first time it will be right this winter anymore. Basically if the ggem (or jma) does not have a solution like this, then there is no chance (vs a low chance?) of it occurring.  I know I have a sick mind, but I use reverse logical with the navy nogaps. If that progressive model has "something", then often its game on.

 

Getting back to this winter in general, leading into it I would have thought PHL was good for one six inch or greater event (don't know if that would make the KU cut with what happened elsewhere or not).  This would remain the biggest disappointment of this winter if it didn't occur. Temperatures its just hard to think more than one month in a row can be below average anymore.

[tombo82685]

The ggem was correct in the medium range of bringing the current pcpn threat into our area, even if the threat for most verifies as sub advisory snow.  So I can't post the next time it will be right this winter will be the first time it will be right this winter anymore. Basically if the ggem (or jma) does not have a solution like this, then there is no chance (vs a low chance?) of it occurring.  I know I have a sick mind, but I use reverse logical with the navy nogaps. If that progressive model has "something", then often its game on.

 

Getting back to this winter in general, leading into it I would have thought PHL was good for one six inch or greater event (don't know if that would make the KU cut with what happened elsewhere or not).  This would remain the biggest disappointment of this winter if it didn't occur. Temperatures its just hard to think more than one month in a row can be below average anymore.

 

when was the last back to back below normal months? Had to be 10-11 that winter?

[Rainshadow]

Is their any scientific reasoning as to why in the opast 3 years at least there have been no clippers really? In the past you could at least bank on a couple to help with snow totals. Lately its been all or nothing in terms of storms either coastal bombs or 60 and rain.

 

Well the nao has been in one extreme level or another the previous three winters.  There is no denying though that more extreme events have happened of late. I dont have the number in from of me, but PHL has had more 10" or greater events since 1996 than it did from 1950 through 1995.  I just wonder what one has to do for an old fashioned 4-8" snow? Maybe I have to find my typewriter.

[Rainshadow]

when was the last back to back below normal months? Had to be 10-11 that winter?

 

I believe you are right, Dec '10 and Jan '11.  Nov '10 and Feb '11 were above normal.

[Harbourton]

Well the nao has been in one extreme level or another the previous three winters.  There is no denying though that more extreme events have happened of late. I dont have the number in from of me, but PHL has had more 10" or greater events since 1996 than it did from 1950 through 1995.  I just wonder what one has to do for an old fashioned 4-8" snow? Maybe I have to find my typewriter.

I'd take an ole fashioned 4 +  at this point 

[Rainshadow]

I'd take an ole fashioned 4 +  at this point 

I think the cure is to forward Adam's Phase 6 pic to 10 people and ask them to forward it to 10 additional people...  I just noticed their sneakers match the color of their bikes. 

 

 

[tombo82685]

should mention, though i don't have exact output but the euro gies us precip from the clipper i think its under .1 though.

[Rainshadow]

should mention, though i don't have exact output but the euro gies us precip from the clipper i think its under .1 though.

 

I'm just looking forward to the sun coming out tomorrow and not sinking into six inches of mud next week when walking outside.

 

At the least there should be some nickel and diming next week in part of the area and for the MJO's part once we get toward/into Feb, it shouldn't be a force for warmth. Don't know how the rest is going to play.