Re: Long Range Thread 29.0

[Irish]

rb, how much snow are we getting today? just having some fun, appreciate the work you put in here.

[heehaw453]

I am pretty confident of the cold air supply as we get towards the 20th. You can see this very well in troposphere on 12/17.

Couple that with the PNA pump via the jet streak and TPV lobe parked on the Hudson Bay. It may not snow a flake the rest of December but December temps will be at least -3 BN when all is said and done. Normally that type of deviation in December renders snow right to the coast.

hudson bay tpv



trop 850's



jet streak

[heehaw453]

This has the makings of a snow storm on 12/20. The proverbial Rockies ridge and a TPV in Hudson Bay. Before I buy into anything sig would need to see some Atlantic trough show up. Considering the TPV that is very possible at least some weak trough will compress heights enough for coastal plain and slow things down. Even w/out the trough the coastal plain could still be cold enough with a fresh injection of n/s energy compliments of the TPV. There are multiple paths to the white gold and that I like in the event one fails.

Need to watch this over the next 3 days or so...

[billg315]

We shall see. Snow the weekend before Christmas would be perfect timing. Rather have it then and have it still on the ground at Christmas than have it early and washed away by then.

[amugs]

Morning data runs 12-20 to 12-25 aka leading up to #Christmas.

Everything is colder east.

With that said the ECMWF-AI is quite a bit colder and we think that is because it understands that the TPV is not moving while the other data fails to see the connection. pic.twitter.com/YOCmVbDyrF

— BAM Weather (BAMWX) (@bamwxcom) December 11, 2024

AI has been doing well with the patterns especially seeing the cold in the 7 -8 day timeframe

[CPcantmeasuresnow]

We shall see. Snow the weekend before Christmas would be perfect timing. Rather have it then and have it still on the ground at Christmas than have it early and washed away by then.

For those that remeber and haven't blanked it out of your mind like a bad nightmare, four years ago we had over a foot of snow through much of the region on December 16-17, 2020, even down to the coast. 10.5 inches in NYC to be exact. 13 inches where I am.

There was still almost 10 inches on the ground Christmas Eve morning and then the mother of all Great Lake cutters hit late in the day with torrential rain, high winds and temperatures that jumped into the upper 50's. By Christmas morning that beautiful white mantle was only a memory. I still have nightmares.

[heehaw453]

Storm still possible on 12/20 ish

Both GEFS and EPS show good ridge axes over Id, MT. Now w/out the trough I'd be  concerned coastal plain has poor shot at snow, but the n/s TPV feeding energy into the trough gives me some optimism that this storm could generate a lot its own cold air.  Also the surface analysis you see the PNA provide a slide for the AO domain cold air from the north pole downward and the TPV presses on it southward. This is one way lacking of 50/50 trough can still work for the coast. I would expect colder solutions to win out unless the ridge axis gets pushed out of ideal spot.

Also say that 850 temp profile is classic sig for coastal plain getting it done...

This could fail 8 ways to Sunday and very well may, but it's a legit threat for now IMO.

[heehaw453]

We shall see. Snow the weekend before Christmas would be perfect timing. Rather have it then and have it still on the ground at Christmas than have it early and washed away by then.

For those that remeber and haven't blanked it out of your mind like a bad nightmare, four years ago we had over a foot of snow through much of the region on December 16-17, 2020, even down to the coast. 10.5 inches in NYC to be exact. 13 inches where I am.

There was still almost 10 inches on the ground Christmas Eve morning and then the mother of all Great Lake cutters hit late in the day with torrential rain, high winds and temperatures that jumped into the upper 50's. By Christmas morning that beautiful white mantle was only a memory. I still have nightmares.

CP he hears and he watches of that I'm sure.

[sroc4]

Storm still possible on 12/20 ish

Both GEFS and EPS show good ridge axes over Id, MT. Now w/out the trough I'd be  concerned coastal plain has poor shot at snow, but the n/s TPV feeding energy into the trough gives me some optimism that this storm could generate a lot its own cold air.  Also the surface analysis you see the PNA provide a slide for the AO domain cold air from the north pole downward and the TPV presses on it southward. This is one way lacking of 50/50 trough can still work for the coast. I would expect colder solutions to win out unless the ridge axis gets pushed out of ideal spot.

Also say that 850 temp profile is classic sig for coastal plain getting it done...

This could fail 8 ways to Sunday and very well may, but it's a legit threat for now IMO.

Def not a knock on this analysis Heehaw as I agree pretty much with everything you say except.  Except I think pointing out anything between the surface through 850 is a waste of time.  I know you pointed out there are many ways it may not work out and that the colder soln should win as long as the ridge axis is in the right spot, but I want to make sure folks understand what looking at an ensemble image really means at these lead times.  Everything is smoothed out into an avg forecast such that what you see now is almost guaranteed to not be what will be depending on which collection of ensembles ends up being the correct depiction of the 500mb pattern.  This is esp true at the surface.  For the EPS there are 50 members each with their own forecast that then is blended into an average forecast which is what we are looking at here.

For me a big question mark lookin at the two 500mb maps, in addition to the Atlantic domain where there is no trough marked, is looking at all that vorticity just off the WC of NA in the Pac domain.  One of our main party crashers for the past few years has been energy crashing the west coast knocking down the Ridging that once looked so promising. Last night was also an example of this.  We had a full lat WC ridge that set up the Full lat EC trough and cross polar flow, but energy crashing the wc seemed to knock down the northern fringe as the trough headed east not allowing it to dig deep enough.  The result was a trough that tilted neg and pivoted too far west and lifted out too far instead of digging a little bit further S&E before that happened.  At least thats how I see it.  

The Atlantic domain was also a reason for this as well.  So again without the Atlantic domain as pointed out as a real possibility we have to watch how all that vorticity plays out and its affect on both ridge axis position but also ridge amplitude as well as the timing of all of it.  One final note which is positive, is that the deeper into the cold season we get, the stronger and harder the cold air can push with these +PNA and -EPO teleconnections, so the odds of overcoming "less than ideal" factors gets easier.  I will remain cautiously optimistic for now.

[heehaw453]

Storm still possible on 12/20 ish

Both GEFS and EPS show good ridge axes over Id, MT. Now w/out the trough I'd be  concerned coastal plain has poor shot at snow, but the n/s TPV feeding energy into the trough gives me some optimism that this storm could generate a lot its own cold air.  Also the surface analysis you see the PNA provide a slide for the AO domain cold air from the north pole downward and the TPV presses on it southward. This is one way lacking of 50/50 trough can still work for the coast. I would expect colder solutions to win out unless the ridge axis gets pushed out of ideal spot.

Also say that 850 temp profile is classic sig for coastal plain getting it done...

This could fail 8 ways to Sunday and very well may, but it's a legit threat for now IMO.

Def not a knock on this analysis Heehaw as I agree pretty much with everything you say except.  Except I think pointing out anything between the surface through 850 is a waste of time.  I know you pointed out there are many ways it may not work out and that the colder soln should win as long as the ridge axis is in the right spot, but I want to make sure folks understand what looking at an ensemble image really means at these lead times.  Everything is smoothed out into an avg forecast such that what you see now is almost guaranteed to not be what will be depending on which collection of ensembles ends up being the correct depiction of the 500mb pattern.  This is esp true at the surface.  For the EPS there are 50 members each with their own forecast that then is blended into an average forecast which is what we are looking at here.

For me a big question mark lookin at the two 500mb maps, in addition to the Atlantic domain where there is no trough marked, is looking at all that vorticity just off the WC of NA in the Pac domain.  One of our main party crashers for the past few years has been energy crashing the west coast knocking down the Ridging that once looked so promising. Last night was also an example of this.  We had a full lat WC ridge that set up the Full lat EC trough and cross polar flow, but energy crashing the wc seemed to knock down the northern fringe as the trough headed east not allowing it to dig deep enough.  The result was a trough that tilted neg and pivoted too far west and lifted out too far instead of digging a little bit further S&E before that happened.  At least thats how I see it.  

The Atlantic domain was also a reason for this as well.  So again without the Atlantic domain as pointed out as a real possibility we have to watch how all that vorticity plays out and its affect on both ridge axis position but also ridge amplitude as well as the timing of all of it.  One final note which is positive, is that the deeper into the cold season we get, the stronger and harder the cold air can push with these +PNA and -EPO teleconnections, so the odds of overcoming "less than ideal" factors gets easier.  I will remain cautiously optimistic for now.

Well said.

Let me add that in the 6-10 day range (medium term) ensembles are what I use for most part for discrete threats. Outside of 10 days it's not reliable enough to pay much detailed attention to for discrete threats. Inside 5 days rely more on the op model which is a member of the ensemble suite. Smoothing out the results tends to provide much better insight in that medium term.

I disagree on the surface to the 850's being a waste of time in medium term. The synoptic setup is important here as it always is. For example, there's got to be a mechanism to deliver cold air which the banana H is alluding to. If I don't see that I question the cold air transport. Also the signature of the 850's tell me west ridge placement is good and potential storm would be BM or inside BM. If I see the 850's 0 line touching or inside the SNE coast that's a red flag to me that my ridge might be too far west or I have an anomalous ridge in the 50/50 which then predisposes the antecedent air mass to warmth or allows for higher height rises too early. Also I want to see where the source cold is coming from and how deep it is. How much of that could get fed into the storm with a wave break kind of thing. So 100% be guarded, but also remember that as long as it stays cold the odds will go up for a flush hit at some point right to coast. I'm much more confident in December finishing at least -3 BN than a sig snowstorm to the coastal plane.

[frank 638]

[dkodgis]

I hear the screams in the distance…

[SENJsnowman]

I've always said that the CFS model seems to be the most reliable!

[bloc1357]

I've always said that the CFS model seems to be the most reliable!

CFS = Crazy For Snow?

[heehaw453]

For grins this GFS 12Z h5 would probably evolve into what Frank calls a Godzilla.

Obviously take this with grain of salt but there is potential when you have the a TPV that can drop n/s energy into a deep and digging trough.

[MattyICE]

Might even be a digital, ever elusive FRANK-zilla, verbatim. CMC wasn’t crazy far off either.

[sroc4]

Well said.

Let me add that in the 6-10 day range (medium term) ensembles are what I use for most part for discrete threats. Outside of 10 days it's not reliable enough to pay much detailed attention to for discrete threats. Inside 5 days rely more on the op model which is a member of the ensemble suite. Smoothing out the results tends to provide much better insight in that medium term.

I disagree on the surface to the 850's being a waste of time in medium term. The synoptic setup is important here as it always is. For example, there's got to be a mechanism to deliver cold air which the banana H is alluding to. If I don't see that I question the cold air transport. Also the signature of the 850's tell me west ridge placement is good and potential storm would be BM or inside BM. If I see the 850's 0 line touching or inside the SNE coast that's a red flag to me that my ridge might be too far west or I have an anomalous ridge in the 50/50 which then predisposes the antecedent air mass to warmth or allows for higher height rises too early. Also I want to see where the source cold is coming from and how deep it is. How much of that could get fed into the storm with a wave break kind of thing. So 100% be guarded, but also remember that as long as it stays cold the odds will go up for a flush hit at some point right to coast. I'm much more confident in December finishing at least -3 BN than a sig snowstorm to the coastal plane.

Without question there needs to be a mechanism for cold air delivery.  As you pointed out that +PNA and to degree -EPO couplet should do just that.  But the devil is in the details.  Banana highs and where the 850 0*c line is 200hrs out doesnt help with the details.  Below is a copy and pasted convo between you Ray(rb) and myself back on the morning of Nov 28th regarding the cold air and snow chances that was coming compliments of the same teleconnections: Sorry its long:

HOLY SCHNIKEES…….I have to take a deeper look, but I still like the period from about December 5th-7th for another wintry event, but I think a big dog is brewing for about the 9th-12th. I’ll have more to say on this in due course, but I’d suggest that we get our sleep, because the opening of December could be pretty awesome.

Coincidence?




GEM wasn’t far off either.

Get your rest, folks. This signal is legit.

Looking at some of the tea leaves this morning Id say I have to agree.  A legit serious storm seems to be brewing for sure.  A few things that I really like.  

First and foremost cold air should be readily available.  The pattern following todays system moving through looks to be one reinforcing cold shot after another for awhile compliments of a -EPO/WPO, but more importantly the establishment to what seems to be a fairly robust and potentially entrenched +PNA.  Heehaw and I discussed this a little last weekend, but what this means is the development of a "split flow" at 200mb which will translate to 500mb.  Here is Heehaws comments from Sunday:

We'll have to see but damn this early December jet on the EPS is so dramatically different than what we had December 2023. Nice split flow with western ridge helping ooze cold air to ES. If this keeps up have to like December for a snow event right to coast.

 I've said this in prev yeas, but IMHO a +PNA is probably more important that any other teleconnection; esp for the coastal plain.  At least in recent years we have had one transient +PNA after another such that we have needed to rely on the perfect timing and ability of of N/S energy to dig into the S/S energy just right because Pac energy crashes the coast at the most inopportune times which ultimately flattened our PNA ridge.  This consequently moderates cold air sources, prevents/limits interactions between N/S and S/S energy and leads to storms that never materializing into anything noteworthy.  This has been exceptionally true for the coast in the recent past.

Anyway back to this year.  Here is a look at what Im talking about with what we want to see at 500mb.  



This look begins to take shape between hr 72-90 as of last nights 00z runs.  Looking across all three ensemble packages, GEFS, EPS, and GEFS,  this look appears to be firmly set up pretty much throughout the runs which takes us out to mid December.  Now there are some differences at various times between models etc, but there is a shit ton to like about the pattern for the next two weeks.  Now I am one to hesitate and say things like "we have been burned so many times in the past..." but I am going to go out on a limb and say that if we dont see at least some form of accumulating snow out of the next two weeks all the way down to the coast I truly will be shocked.  

Now more specifically about Ray Ray's window of approx. Dec7-9th, I think was his time frame, I also really like how the -NAO is actually forecast to relax towards a more neutral state.  IMHO when you have "favorable" teleconnections in both the western and eastern domains, relative to our little NE region, that are too robust at the same time, you tend to get the cold, but no major storms.  Its when one or the other tend to ease up that it allows the ingredients, ie: n/s an s/s energy, to come together just right along the coast to give us a bigger ticket outcome.  This has been esp true for when the Pac domain cooperates and the -NAO domain is the tele that relaxes.  So while Im certainly not ready to sound any alarms I too think a fairly robust storm signal exists in Rays window for a Godzilla type set up for at least some of us on this board, with the coastal plain certainly in the game given that the cold air seems to be in place for this window.  On top of that I also think there will be more than one opportunity to accumulate down to the coast ove the next 2 weeks should the pattern truly stay set up like it appears is the case.  One threat at a time though.  

I do want to make one comment about the longer term.  I have heard many amateur and professional weather enthusiast claim that a La Nina is no longer a threat.  I personally would say not so fast.  I still think we could potentially reach La Nina status before we are said and done.  The last two weeks the SOI has been in a fairly robust La Nina state.  https://www.longpaddock.qld.gov.au/soi/  The result has seen the Easterlies kicking up across the trop pac and the ENSO regions have begun to cool again over the past 2 weeks as well.  You can see by the image below that even though thre has been some moderation of the developing La Nina since Sept, there is still cold subsurface temps, so if the easterlies cont to blow for awhile it will cause upwelling in the eastern Pac and cooling at the surface from east to west as well.  Now whether or not by the strictest of definitions a mild La Nina actually gets established I still think this exciting pattern I just outlined for the next 2 weeks will unfort collapse at some point, and the dreaded SE Ridge will shifts our storm track back west into the spine of the Apps and GL sometime towards the middle to end of Dec.  How long it lasts I'm not sure, but I think its coming.  I def could be wrong on this point, but we'll see.  



For the next two weeks; however,.....

WE TRACK!!  

My point with quoting this is we had a great pattern set up with cold air in place ahead of the system, but the details still didnt pan out. There was alot of things to be excited about but as we got in tight we realized, while there was a full lat trough involved and a cross polar flow, the alignment wasnt right and storm track still went west. IMHO We likely had the influence from a La Nina like background state that cause WC energy to tamp down our WC Ridging and the SE ridge to press just enough at the worst timing to pivot the trough too far N&W for our coverage area.   The cold air was there ahead of time.  

Now that said I will say it looks to possibly be slight diff this time, but time will tell.  The SOI has/had been for over a month in the mod to strong positive state indicating strong easterlies in the western trop Pac.  This IMO played an important role for why we failed over the past week despite a strong arctic/polar air mass knocking on the door.

The past two days, the first time in a long time the daily SOI values are around 0.00 give or take: https://www.longpaddock.qld.gov.au/soi/  Now two days is not a trend for the SOI to change the overall background state of the pattern.  However if we see it hover here, and/or drop lower, then as JB would say there will be a "cattle prod" to the pattern.  So this next time frame we are discussing, ie: after the 20th, very well could end up different.  In addition the MJO which had looked like it was going into the null phase seems to be forecast to amplify in phase 7 in a week which for the NDJ composite is a cold phase.  So Ill be paying attention to the SOI and MJO over the next week or so before getting my hopes up, but again IMH if the SOI trend is real, which btw I think would lead to the MJO pulse if it is, then the outcome of this next arctic invasion compliments of the +PNA/-EPO could yield or more beneficial result for many.  

Time will tell.

[heehaw453]

Well said.

Let me add that in the 6-10 day range (medium term) ensembles are what I use for most part for discrete threats. Outside of 10 days it's not reliable enough to pay much detailed attention to for discrete threats. Inside 5 days rely more on the op model which is a member of the ensemble suite. Smoothing out the results tends to provide much better insight in that medium term.

I disagree on the surface to the 850's being a waste of time in medium term. The synoptic setup is important here as it always is. For example, there's got to be a mechanism to deliver cold air which the banana H is alluding to. If I don't see that I question the cold air transport. Also the signature of the 850's tell me west ridge placement is good and potential storm would be BM or inside BM. If I see the 850's 0 line touching or inside the SNE coast that's a red flag to me that my ridge might be too far west or I have an anomalous ridge in the 50/50 which then predisposes the antecedent air mass to warmth or allows for higher height rises too early. Also I want to see where the source cold is coming from and how deep it is. How much of that could get fed into the storm with a wave break kind of thing. So 100% be guarded, but also remember that as long as it stays cold the odds will go up for a flush hit at some point right to coast. I'm much more confident in December finishing at least -3 BN than a sig snowstorm to the coastal plane.

Without question there needs to be a mechanism for cold air delivery.  As you pointed out that +PNA and to degree -EPO couplet should do just that.  But the devil is in the details.  Banana highs and where the 850 0*c line is 200hrs out doesnt help with the details.  Below is a copy and pasted convo between you Ray(rb) and myself back on the morning of Nov 28th regarding the cold air and snow chances that was coming compliments of the same teleconnections:  Sorry its long:

HOLY SCHNIKEES…….I have to take a deeper look, but I still like the period from about December 5th-7th for another wintry event, but I think a big dog is brewing for about the 9th-12th. I’ll have more to say on this in due course, but I’d suggest that we get our sleep, because the opening of December could be pretty awesome.

Coincidence?




GEM wasn’t far off either.

Get your rest, folks. This signal is legit.

Looking at some of the tea leaves this morning Id say I have to agree.  A legit serious storm seems to be brewing for sure.  A few things that I really like.  

First and foremost cold air should be readily available.  The pattern following todays system moving through looks to be one reinforcing cold shot after another for awhile compliments of a -EPO/WPO, but more importantly the establishment to what seems to be a fairly robust and potentially entrenched +PNA.  Heehaw and I discussed this a little last weekend, but what this means is the development of a "split flow" at 200mb which will translate to 500mb.  Here is Heehaws comments from Sunday:

We'll have to see but damn this early December jet on the EPS is so dramatically different than what we had December 2023. Nice split flow with western ridge helping ooze cold air to ES. If this keeps up have to like December for a snow event right to coast.

 I've said this in prev yeas, but IMHO a +PNA is probably more important that any other teleconnection; esp for the coastal plain.  At least in recent years we have had one transient +PNA after another such that we have needed to rely on the perfect timing and ability of of N/S energy to dig into the S/S energy just right because Pac energy crashes the coast at the most inopportune times which ultimately flattened our PNA ridge.  This consequently moderates cold air sources, prevents/limits interactions between N/S and S/S energy and leads to storms that never materializing into anything noteworthy.  This has been exceptionally true for the coast in the recent past.

Anyway back to this year.  Here is a look at what Im talking about with what we want to see at 500mb.  



This look begins to take shape between hr 72-90 as of last nights 00z runs.  Looking across all three ensemble packages, GEFS, EPS, and GEFS,  this look appears to be firmly set up pretty much throughout the runs which takes us out to mid December.  Now there are some differences at various times between models etc, but there is a shit ton to like about the pattern for the next two weeks.  Now I am one to hesitate and say things like "we have been burned so many times in the past..." but I am going to go out on a limb and say that if we dont see at least some form of accumulating snow out of the next two weeks all the way down to the coast I truly will be shocked.  

Now more specifically about Ray Ray's window of approx. Dec7-9th, I think was his time frame, I also really like how the -NAO is actually forecast to relax towards a more neutral state.  IMHO when you have "favorable" teleconnections in both the western and eastern domains, relative to our little NE region, that are too robust at the same time, you tend to get the cold, but no major storms.  Its when one or the other tend to ease up that it allows the ingredients, ie: n/s an s/s energy, to come together just right along the coast to give us a bigger ticket outcome.  This has been esp true for when the Pac domain cooperates and the -NAO domain is the tele that relaxes.  So while Im certainly not ready to sound any alarms I too think a fairly robust storm signal exists in Rays window for a Godzilla type set up for at least some of us on this board, with the coastal plain certainly in the game given that the cold air seems to be in place for this window.  On top of that I also think there will be more than one opportunity to accumulate down to the coast ove the next 2 weeks should the pattern truly stay set up like it appears is the case.  One threat at a time though.  

I do want to make one comment about the longer term.  I have heard many amateur and professional weather enthusiast claim that a La Nina is no longer a threat.  I personally would say not so fast.  I still think we could potentially reach La Nina status before we are said and done.  The last two weeks the SOI has been in a fairly robust La Nina state.  https://www.longpaddock.qld.gov.au/soi/  The result has seen the Easterlies kicking up across the trop pac and the ENSO regions have begun to cool again over the past 2 weeks as well.  You can see by the image below that even though thre has been some moderation of the developing La Nina since Sept, there is still cold subsurface temps, so if the easterlies cont to blow for awhile it will cause upwelling in the eastern Pac and cooling at the surface from east to west as well.  Now whether or not by the strictest of definitions a mild La Nina actually gets established I still think this exciting pattern I just outlined for the next 2 weeks will unfort collapse at some point, and the dreaded SE Ridge will shifts our storm track back west into the spine of the Apps and GL sometime towards the middle to end of Dec.  How long it lasts I'm not sure, but I think its coming.  I def could be wrong on this point, but we'll see.  



For the next two weeks; however,.....

WE TRACK!!  

My point with quoting this is we had a great pattern set up with cold air in place ahead of the system, but the details still didnt pan out.  There was alot of things to be excited about but as we got in tight we realized, while there was a full lat trough involved and a cross polar flow, the alignment wasnt right and storm track still went west.  IMHO We likely had the influence from a La Nina like background state that cause WC energy to tamp down our WC Ridging and the SE ridge to press just enough at the worst timing to pivot the trough too far N&W for our coverage area.   The cold air was there ahead of time.  

Now that said I will say it looks to possibly be slight diff this time, but time will tell.  The SOI has/had been for over a month in the mod to strong positive state indicating strong easterlies in the western trop Pac.  This IMO played an important role for why we failed over the past week despite a strong arctic/polar air mass knocking on the door.

The past two days, the first time in a long time the daily SOI values are around 0.00 give or take: https://www.longpaddock.qld.gov.au/soi/  Now two days is not a trend for the SOI to change the overall background state of the pattern.  However if we see it hover here, and/or drop lower, then as JB would say there will be a "cattle prod" to the pattern.  So this next time frame we are discussing, ie: after the 20th, very well could end up different.  In addition the MJO which had looked like it was going into the null phase seems to be forecast to amplify in phase 7 in a week which for the NDJ composite is a cold phase.  So Ill be paying attention to the SOI and MJO over the next week or so before getting my hopes up, but again IMH if the SOI trend is real, which btw I think would lead to the MJO pulse if it is, then the outcome of this next arctic invasion compliments of the +PNA/-EPO could yield or more beneficial result for many.  

Time will tell.

Unfortunately I don't think it's mutually exclusive the way you are presenting it, i.e., teleconnections vs surface maps. Looking at an operational model would be completely non reliable at 200 hours, but not necessarily ENS. If I see the best PNA/EPO combo and no H established over Quebec/NNE on the ENS even at 200 hours I'd raise an eyebrow regardless of what those values are. Especially lacking a 50/50 trough. As it stands now this setup is showing me what I expect to see for snow. Is this all driven by the MJO/SOI I'm not good enough to tell you, but perhaps the stuck TPV is part of the solution to white gold too.

[sroc4]

Unfortunately I don't think it's mutually exclusive the way you are presenting it, i.e., teleconnections vs surface maps. Looking at an operational model would be completely non reliable at 200 hours, but not necessarily ENS. If I see the best PNA/EPO combo and no H established over Quebec/NNE on the ENS even at 200 hours I'd raise an eyebrow regardless of what those values are. Especially lacking a 50/50 trough. As it stands now this setup is showing me what I expect to see for snow. Is this all driven by the MJO/SOI I'm not good enough to tell you, but perhaps the stuck TPV is part of the solution to white gold too.

Maybe im presenting this wrong then.  I am def not trying to say that its teles vs surface maps.  What Im saying is this. Pretend the atmosphere is a car.  Where we end up with the atmosphere is dictated by whos driving the car as well as various inputs from the passengers.  The surface maps are more specific exits that the driver and its passengers may decide to get off at; where as teleconnections, and the MJO, and the strat PV are all individuals that are in the car.  To me this far out looking at a specific exit doesnt give me at least any additional insight into who exactly is driving, or just how much influence one or multiple passengers may have on the final destination.  There is still a chance that the main driver could change and/or the passengers can increase or decrease the influence on where the driver gets off the highway. Ie: an unanticipated change of course due to someone in the car having to pee ie: the SOI begins to make more noise in the outcome becaus eof a huge burst on one direction or another, or perhaps a strong MJO pulse the same thing).  

Bottom line 10days out Im not looking at what the details are off any given exit because we still dont know exactly which exit to get off.  Which one we get off still could shift.  I will 110% concede however that a consistent 500mb ensemble forecast at day ten will certainly limit which exits we will or can be getting off at, esp if multiple ensembles show the same/similar thing, but again for me personally I dont like to try and read the details like where or if HP is present to the N or storm tracks etc simply because minor influences by any one or multiple individuals in the car can drastically change where we end up.  

In the end you and I are def on the same page here regarding this time frame.  I just think our approach to presenting the info to others is slight different.  Personally I appreciate it because it forces me to view it through your eyes, or Rays, or Franks, or Mugs, Matty Ice, whoever, which only helps me in the long run.  Collectively this group here continually treats each other with respect, and in the end despite sometimes differences in approach or ultimate outcomes of a forecast we tend to zero in on it eventually as a group, and we all learn.  This is what I appreciate the most.    

Ok Im done...lol

We Track!  

[jurzdevil]

This is like the few times i buy a lottery ticket, dreaming about winning then having none of the numbers at the drawing. 12Z GFS:


definitely an outlier but maybe indicative there is something brewing?

[amugs]

We have the Negative EPO and Positive PNA connection.  The Aluetian Vortex keeps deepening. This allows for cold arctic air to pile in and for storms if the PNA holds to take a more coastal track. There is a big cold shot during the 20th -28th time frame and maybe beyond.
The +TNH can NOT be underestimated for what it will for the atmosphere to do.  Quasi 13-14, 14-15 pattern and it was +TNH as well.
Not hyping ,stating facts.

This is a MJO phase 6 pattern.  Cold trough over the EC and a nice West Coast Ridge

[hyde345]

This is like the few times i buy a lottery ticket, dreaming about winning then having none of the numbers at the drawing. 12Z GFS:


definitely an outlier but maybe indicative there is something brewing?

There might be something brewing around the 20th but you have a better chance of winning the lotto than southern Jersey getting 50 inches.

[heehaw453]

06Z Euro Op at D6. Classic setup for snowfall in our region. For illustrative purposes as a plausible outcome for our window of interest.

Gulf moisture coupled with a huge banana H building in. I continue to see what I need to see on the ensembles for snow potential. It's a matter of s/w interactions to see exactly where L pressure sets up and how strong it becomes. I will say with the PNA axis it's less likely to be an Apps runner as 00Z Euro showed.

NOBODY knows that s/w interaction and timing now as your guess is as good as mine and the models will vacillate until that's settled. N/S TPV synergy is a wild card here for good and bad. But if you continue to the H building in like this chances go up for snow. And from what I see guidance has it consistently in one form or another.

I said from the beginning I expect minor/moderate potential as we don't have Atlantic blocking to slow the flow down to allow these waves to meander. Time and accumulations go hand in hand.

Beautiful banana H



Vigorous ULL



GOM moisture fed into the system key ingredient

[sroc4]

Now that we are about a week out we should begin to see how the operationals resolve all the upper level features/energy. I still expect model to model and run to run variation from the ops, but how do they compare to the ensemble mean forecasts? And what subtle shifts in the means of the ensembles do we see which may tip us off as to which op is beginning to hone in on the correct details? I really love the 5-7day time frame of analysis.

[heehaw453]

Very close on the 12Z GFS to 3-6" event for much of the area. If I had to guess just pump that Rockies ridge a bit more and then wham.  Everything else looks good enough IMO.  As I said the TPV wave breaks (see box with X) will be a wild card in this.

Me feel good where things sit ATTM

[sroc4]

Very close on the 12Z GFS to 3-6" event for much of the area. If I had to guess just pump that Rockies ridge a bit more and then wham.  Everything else looks good enough IMO.  As I said the TPV wave breaks (see box with X) will be a wild card in this.

Me feel good where things sit ATTM

Going to need to watch for flys in the ointment.  There are two components to the WC ridging as outlined. Undercutting the northern half of the ridge is a s/w that originates in the Pac that knocks down the Western CONUS half of the WC ridging verbatim which is just SW from the n/s s/w you labeled X. These in opportune Pac s/w's that knock down WC ridges have killed us in the past. CMC looks nothing like this at this same time stamp so obv still long way to go.

[heehaw453]

Very close on the 12Z GFS to 3-6" event for much of the area. If I had to guess just pump that Rockies ridge a bit more and then wham.  Everything else looks good enough IMO.  As I said the TPV wave breaks (see box with X) will be a wild card in this.

Me feel good where things sit ATTM

Going to need to watch for flys in the ointment.  There are two components to the WC ridging as outlined. Undercutting the northern half of the ridge is a s/w that originates in the Pac that knocks down the Western CONUS half of the WC ridging verbatim which is just SW from the n/s s/w you labeled X.  These in opportune Pac s/w's that knock down WC ridges have killed us in the past. CMC looks nothing like this at this same time stamp so obv still long way to go.

For sure and I think there will be follow up s/w's too. so if 12/20 doesn't pan out the western ridge will most likely reload with an opportunity for something else say 12/22ish?, but then the cold air will be much deeper. We need some good juju as it's long overdue for meaningful Dec snowfall.