NYC/PHL Jan 11-14 Threat Potential

[am19psu]

so are you thinking that an ots solution is greatest concern now, cause i know earlier you said you were thinking the primary is going to go to far north to help phl out.

I don't know what I'm thinking. That really flat, broad trough across the Eastern 2/3s of the country isn't the most common solution, so if that's wrong, like eduggs said, the s/w will head northward toward OH. But if that flat, broad trough is right, then I have a hard time seeing the storm turning the corner and RDU gets jackpotted. I guess if I had a gun to my head, I still like the GEM the best, but the consensus of the meteorologists on the board that are better than me at winter forecasting is that OTS is the worrisome solution. :shrug:

[tombo82685]

I don't know what I'm thinking. That really flat, broad trough across the Eastern 2/3s of the country isn't the most common solution, so if that's wrong, like eduggs said, the s/w will head northward toward OH. But if that flat, broad trough is right, then I have a hard time seeing the storm turning the corner and RDU gets jackpotted. I guess if I had a gun to my head, I still like the GEM the best, but the consensus of the meteorologists on the board that are better than me at winter forecasting is that OTS is the worrisome solution. :shrug:

lol hahaha seriously i would hate to have your guys job this year esp, i give all the props to mets.

[Ralph Wiggum]

so are you thinking that an ots solution is greatest concern now? Cause i know earlier you said you were thinking the primary is going to go to far north to help phl out.

Tom, seems like we have about a 50/50 split of mets who are caught between an Appalachian redevelopment (primary into lower OV and redveloping 'around' the mountains off the VA Capes) and a too far suppressed track.

I don't see how a surface low would be able to gain too much latitude to our West with a piece of the PV and/or the block still in place and a NW flow at H5 over the MA. I guess there is an argument that this could miss our neck of the woods by scooting out to our South BUT with successive runs, I am seeing more and more ridging tring to develop out ahead of the main upper low. Will it be enough to take the SLP North in time?

I'm with the "concern for an OTS solution" camp right now, which isn't a bad place to be. Better than cheering for an Apps runner to shift East I suppose.

[tombo82685]

Tom, seems like we have about a 50/50 split of mets who are caught between an Appalachian redevelopment (primary into lower OV and redveloping 'around' the mountains off the VA Capes) and a too far suppressed track.

I don't see how a surface low would be able to gain too much latitude to our West with a piece of the PV and/or the block still in place and a NW flow at H5 over the MA. I guess there is an argument that this could miss our neck of the woods by scooting out to our South BUT with successive runs, I am seeing more and more ridging tring to develop out ahead of the main upper low. Will it be enough to take the SLP North in time?

I'm with the "concern for an OTS solution" camp right now, which isn't a bad place to be. Better than cheering for an Apps runner to shift East I suppose.

yea i was earlier in the cut it west of the apps and redevelop it like adam was. Earlier a lot of the models were really amplifying the trof out west causing the se ridge to go on roids. As we progress closer that idea is losing its ground, as its now replaced with a broad trof, and we are depending on the back side energy in the plains to dig over or east of the miss river to pump the hgts along the coast to get this to come further north...Again this is all going to come down to fridays event and how strong that 50/50 low is and where its progged to be and the state of the block.

[am19psu]

yea i was earlier in the cut it west of the apps and redevelop it like adam was. Earlier a lot of the models were really amplifying the trof out west causing the se ridge to go on roids. As we progress closer that idea is losing its ground, as its now replaced with a broad trof, and we are depending on the back side energy in the plains to dig over or east of the miss river to pump the hgts along the coast to get this to come further north...Again this is all going to come down to fridays event and how strong that 50/50 low is and where its progged to be and the state of the block.

Yeah, and that's why I said a KU isn't out of the question, because it could evolve that way, it just won't be anything like you would read about in a textbook.

[tombo82685]

Yeah, and that's why I said a KU isn't out of the question, because it could evolve that way, it just won't be anything like you would read about in a textbook.

what also can happen, if we miss the coastal we could still get some snow with the ULL coming across the region to spawn something. Something else to keep in mind.

[Manny]

Very informative discussion, and I agree that the features are highly complex at this moment, and likelihood for various solutions remains viable, whether it be a OTS, KU storm, mid-atlantic storm, or inland, it just shows that there are certain negatives like the broad trough, or some of the positives that are creating an array of outcomes.

[earthlight]

I don't know what I'm thinking. That really flat, broad trough across the Eastern 2/3s of the country isn't the most common solution, so if that's wrong, like eduggs said, the s/w will head northward toward OH. But if that flat, broad trough is right, then I have a hard time seeing the storm turning the corner and RDU gets jackpotted. I guess if I had a gun to my head, I still like the GEM the best, but the consensus of the meteorologists on the board that are better than me at winter forecasting is that OTS is the worrisome solution. :shrug:

I'm almost certain that the chances of this cutting inland are very slim at this point. The longwave pattern would have to change dramatically as close in as +60 hours out for this to have any chance of doing that. When I say "this" I mean the big southern stream shortwave..which is an old piece of a Pacific vortex. Because there could be confusion if this vort gets suppressed and then the second piece of Pac energy ejects afterwards. Who knows what might happen then. But when it comes to the first storm, you can see even at 60 hours that this storm is either going to come up towards the 40/70 or go out to sea--it's chance of going inland seem very slim to me.

Also..by inland...I mean a track that would bring liquid precipitation problems to Philly and north. South of there might have a westward track even if the shortwave is stronger than progged and has stronger ridging ahead of it. But with the confluence forecast by every model and the positioning of that vortex..the chances of such a feature redeveloping are extremely high and I don't think we will have to worry in that regard.

The chances of this going off the coast are much higher than anything like that, though, if you ask me..given the ensemble mean height pattern and superensemble upper air pattern analogs.

[mattinpa]

Very informative discussion, and I agree that the features are highly complex at this moment, and likelihood for various solutions remains viable, whether it be a OTS, KU storm, mid-atlantic storm, or inland, it just shows that there are certain negatives like the broad trough, or some of the positives that are creating an array of outcomes.

Sums it up very well.

[eduggs]

Once the features shake out in a few days and we have a low in the SE with moisture building, this should be much more straight forward to track. I look forward to this sort of situation where changes are easier to anticipate and to accept. For those of us between PHL and BOS it's nice to have a wild card event that could whiten the ground and distract our attention in the meantime!

[atownwxwatcher]

I think there is a big red flag to this whole system when you have the 18 Z GFS and the 18 Z Nogaps almost in the exact same spot at 144 hrs when you factor in that the NOGAPS has the most notorious progressive bias and SE bias..

GFS 144

The Nogaps may be a slight tick NW actually but it pretty much shows that I do not think the 18 Z GFS is anywhere in the correct camp.

The solutions have been changing every 6 hrs and for anyone to give up hope...pronounce a big storm...pronounce a non event is only hugging the models and what they show every 6 hrs.

Again, i think it is more wise and prudent to look at the pattern at this point and range then specific solutions...

6 Z

00z

12 Z

As you can see the model has been changing every 6 hours. Essentially what you are seeing is possible solutions until we get down closer in time range and can get this figured out....

[bluehens]

I would kill for 2/6/10 again.....27" in my backyard

Geez, you guys are acting like it's 90/10 we're going to get a KU storm, when in actuality, it's about 10/90. Look where the ridge is out west, look how much ridging there is out in front, look when and where the H5 low cuts off. This has a TON of work to do before you can start throwing around 12/16/09 and 2/6/10.

[am19psu]

I'm almost certain that the chances of this cutting inland are very slim at this point. The longwave pattern would have to change dramatically as close in as +60 hours out for this to have any chance of doing that. When I say "this" I mean the big southern stream shortwave..which is an old piece of a Pacific vortex. Because there could be confusion if this vort gets suppressed and then the second piece of Pac energy ejects afterwards. Who knows what might happen then. But when it comes to the first storm, you can see even at 60 hours that this storm is either going to come up towards the 40/70 or go out to sea--it's chance of going inland seem very slim to me.

Also..by inland...I mean a track that would bring liquid precipitation problems to Philly and north. South of there might have a westward track even if the shortwave is stronger than progged and has stronger ridging ahead of it. But with the confluence forecast by every model and the positioning of that vortex..the chances of such a feature redeveloping are extremely high and I don't think we will have to worry in that regard.

The chances of this going off the coast are much higher than anything like that, though, if you ask me..given the ensemble mean height pattern and superensemble upper air pattern analogs.

1. Yeah, and that's where my head is with the OH Valley/redevelopment solution. Those situations have seen the initial s/w that's off CA right now getting sheared out by the suppressive flow. I agree with your doesn't-get-sheared-out scenario.

2. In the sheared out scenario, it really depends when and where the low would transition, but in Philly, I'd be worried. Not in NYC, though.

3. Yeah, the 12z ensemble package is what made me really start questioning the synoptic scenario that I had been laying out all week. Far fewer Miller Bs in this afternoon's ensemble guidance.

[A-L-E-X]

Like Will said, we need to get this first storm out of the way first before we can have a good idea what the next one will do.

[TheTrials]

I think there is a big red flag to this whole system when you have the 18 Z GFS and the 18 Z Nogaps almost in the exact same spot at 144 hrs when you factor in that the NOGAPS has the most notorious progressive bias and SE bias..

GFS 144

The Nogaps may be a slight tick NW actually but it pretty much shows that I do not think the 18 Z GFS is anywhere in the correct camp.

The solutions have been changing every 6 hrs and for anyone to give up hope...pronounce a big storm...pronounce a non event is only hugging the models and what they show every 6 hrs.

Again, i think it is more wise and prudent to look at the pattern at this point and range then specific solutions...

6 Z

00z

12 Z

As you can see the model has been changing every 6 hours. Essentially what you are seeing is possible solutions until we get down closer in time range and can get this figured out....

Here are a few more red flags. Five, even six really solid hits for the nyc/philly area on these ensembles.

Notice how some of them have the storm at 144 and some a little later, but they still get to the same place

http://www.meteo.psu.edu/~gadomski/ENSPRSNE_18z/ensprsloopmref.html

[eduggs]

Also..by inland...I mean a track that would bring liquid precipitation problems to Philly and north. South of there might have a westward track even if the shortwave is stronger than progged and has stronger ridging ahead of it. But with the confluence forecast by every model and the positioning of that vortex..the chances of such a feature redeveloping are extremely high and I don't think we will have to worry in that regard.

The chances of this going off the coast are much higher than anything like that, though, if you ask me..given the ensemble mean height pattern and superensemble upper air pattern analogs.

I agree but would assign a low probability of cutting inland instead of very slim. Ensembles support you with only one 18z member trying to cut inland before redeveloping favorably. A handful show hints of a primary in the Ohio Valley. Actually the ensembles on the whole look very encouraging for a pretty good coastal storm. I still believe this has room to shift significantly NW based on the trof and ridge axes, the southern stream involvement, and the location the mid-level low center drops into the longwave trof. But OTS is the climatological default, so that's almost always the most likely solution.

[bluehens]

If you define pattern as the state of the AO/NAO then yes but this Nina has shown no semblance of a STJ which is very Nina-like.......really its just the blocking that is different

I do not think analogs are good this winter season at all when you factor in that this LA NINA is not behaving like a LA Nina should be behaving. The pattern has trumped the ENSO state....

[atownwxwatcher]

If you define pattern as the state of the AO/NAO then yes but this Nina has shown no semblance of a STJ which is very Nina-like.......really its just the blocking that is different

I would have to completely disagree with that because areas along the East Coast just had a 1-2 foot blizzard from a southern stream system phasing with a northern stream energy essentially...this was NOT suppose to happen in a LA NINA..never mind the fact that it did. Also the SE was 10 + degrees below normal for the month of December.. Another factor that was NOT suppose to happen. I think we get caught up looking at to many climatological barriers when essentially they have been muted and silenced... This is not your normal Moderate La Nina because its being trumped so IMO that makes climatology of a La Nina a little less effective!

[TheTrials]

If you define pattern as the state of the AO/NAO then yes but this Nina has shown no semblance of a STJ which is very Nina-like.......really its just the blocking that is different

Well, the boxing day blizzard water vapor clearly showed the real STJ come alive. It was as close to a real tripple phaser as we have seen in a long time with the STJ going right across the gulf of mexico.

[nzucker]

Well, the boxing day blizzard water vapor clearly showed the real STJ come alive. It was as close to a real tripple phaser as we have seen in a long time with the STJ going right across the gulf of mexico.

That's a piece of the Pacific jet that got split off into the southern stream, not the STJ which remains inactive.

[TheTrials]

That's a piece of the Pacific jet that got split off into the southern stream, not the STJ which remains inactive.

Have to disagree. The WV imagery clearly showed three active branches the polar jet, the split around the vortex in the pacific, and then the real STJ coming from Hawaii over Mexico into the gulf. I am pretty sure HM made a post about it at the time.

[earthlight]

It has some subtropical jet components to it, when you loop the pacific at all levels on the gfs and nam. That being said the main feature comes from an old closed ULL off the west coast which was split from the pacific jet.

[bluehens]

True that the 12/26 Miller A storm is very rare in a Nina but the southern stream involved was really Pacific related and not the true STJ. Like I said I thnk the SE temp departures were really entirely related to the sick -AO/-NAO combo effectively suppressing the SE ridge you'd normally expect in a Nina. I think if the mega blocking goes away then we see the return of normal Nina climo.....not sure it will go away anytime soon though.

I would have to completely disagree with that because areas along the East Coast just had a 1-2 foot blizzard from a southern stream system phasing with a northern stream energy essentially...this was NOT suppose to happen in a LA NINA..never mind the fact that it did. Also the SE was 10 + degrees below normal for the month of December.. Another factor that was NOT suppose to happen. I think we get caught up looking at to many climatological barriers when essentially they have been muted and silenced... This is not your normal Moderate La Nina because its being trumped so IMO that makes climatology of a La Nina a little less effective!

[bluehens]

exactly

That's a piece of the Pacific jet that got split off into the southern stream, not the STJ which remains inactive.

[TheTrials]

exactly

yes, that was part of it, and then there was the real STJ running across mexico into the gulf. I am gonna find those images so we can all look at it again.

[nzucker]

True that the 12/26 Miller A storm is very rare in a Nina but the southern stream involved was really Pacific related and not the true STJ. Like I said I thnk the SE temp departures were really entirely related to the sick -AO/-NAO combo effectively suppressing the SE ridge you'd normally expect in a Nina. I think if the mega blocking goes away then we see the return of normal Nina climo.....not sure it will go away anytime soon though.

I'm sure the SE ridge would come back if we lost the -AO/-NAO as we're in a -1.6C Niña, and we know what that does with heights in the subtropical regions. However, we're currently benefiting from the wonderful combination of the La Niña cooling off Canada and the globe while the blocking brings the increased cold air, and eventually the PV, into our backyards. We could be setting up for a particularly cold and snowy period starting now and going through around 1/20 including the Norlun Friday, the Miller A threat next week, and then the arctic outbreak as the PV heads into the Plains. I really don't see the high-latitude blocking breaking down soon, fortunately...the 12z GFS ENS showed the return of a monster -NAO block, west-based....You can see that even at Day 12, we have an unreal block over Siberia which is bringing the world's coldest airmass into the Canadian Prairies:

yes, that was part of it, and then there was the real STJ running across mexico into the gulf. I am gonna find those images so we can all look at it again.

I agree that there was a bit of STJ involved but most of it came from a closed low off the California coast which eventually fractured and broke down into distinct shortwaves. Also, the others storms this year that have involved the southern stream, like the mid-December overrunning event in VA, have largely been of this variety, not the STJ that we saw during the 09-10 strong Niño winter. We're unlikely to have much help from the STJ this cold season, but it doesn't seem as if we need it given the fairly active Pacific pattern and blocking downstream.

[bluehens]

wasn't the southern stream involved the same system that slammed into CA and caused all the flooding/massive Sierra snows? i would think that is more Pac jet related. when I think of true STJ I think of the WV images of 2/6 last year when you saw moisture streaming SW-NE across Central America into the Caribbean and then the GOM.

yes, that was part of it, and then there was the real STJ running across mexico into the gulf. I am gonna find those images so we can all look at it again.

[Chris L]

True that the 12/26 Miller A storm is very rare in a Nina but the southern stream involved was really Pacific related and not the true STJ. Like I said I thnk the SE temp departures were really entirely related to the sick -AO/-NAO combo effectively suppressing the SE ridge you'd normally expect in a Nina. I think if the mega blocking goes away then we see the return of normal Nina climo.....not sure it will go away anytime soon though.

Miller As can form in a Nina; (or A/B Hybird)/, for example, Philly's greatest snowstorm, the Blizzard of '96 did not have any STJ involvement and was dominated by the Polar Jet digging so far south.

[TheTrials]

I'm sure the SE ridge would come back if we lost the -AO/-NAO as we're in a -1.6C Niña, and we know what that does with heights in the subtropical regions. However, we're currently benefiting from the wonderful combination of the La Niña cooling off Canada and the globe while the blocking brings the increased cold air, and eventually the PV, into our backyards. We could be setting up for a particularly cold and snowy period starting now and going through around 1/20 including the Norlun Friday, the Miller A threat next week, and then the arctic outbreak as the PV heads into the Plains. I really don't see the high-latitude blocking breaking down soon, fortunately...the 12z GFS ENS showed the return of a monster -NAO block, west-based....You can see that even at Day 12, we have an unreal block over Siberia which is bringing the world's coldest airmass into the Canadian Prairies:

I agree that there was a bit of STJ involved but most of it came from a closed low off the California coast which eventually fractured and broke down into distinct shortwaves. Also, the others storms this year that have involved the southern stream, like the mid-December overrunning event in VA, have largely been of this variety, not the STJ that we saw during the 09-10 strong Niño winter. We're unlikely to have much help from the STJ this cold season, but it doesn't seem as if we need it given the fairly active Pacific pattern and blocking downstream.

Agrred, the split of the pj and the closed low was absolutely the driving force, however, I believe the MJO spiked pretty good into phase 7 and the real STJ came alive. One has to wonder if didnt come alive, would the storm have been as strong? the STJ clearly was interacting with the short wave in the gulf of mexico, it was weak, but it was there.

[TheTrials]

wasn't the southern stream involved the same system that slammed into CA and caused all the flooding/massive Sierra snows? i would think that is more Pac jet related. when I think of true STJ I think of the WV images of 2/6 last year when you saw moisture streaming SW-NE across Central America into the Caribbean and then the GOM.

Last years was the STJ on steroids, the true pineaple express a direct result of the strong nino. The STJ can still be a factor even when not on roids. The water vapor loops showed the hawaii connection all the way to the gulf and off the se coast. It was weak, but it was there.