February Medium/Long Range Thread

[Superstorm]

That looks is fantastic!


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[Ralph Wiggum]

1 hour ago, frd said:

 

 

Regarding the - AO 4 SD block. This is how we are failing in my area I would imagine.  Great post by  @bluewave below, which is from the NY forum. 

Goes to show you even a - 4 SD AO block is no gaurantee of a significnat snowfall.  This is the second time in 4 years this is happening with a - 4 SD AO.  You can think what you want but somrthing is not working like it should in the snowfall department.   

 

The Southeast Ridge would link up only sporadically with weaker to moderate -AO events from the 1950s through the 1990s .The best known stronger event from that era was 1-9-98.

It could be related to the stronger Pacific Jet and the record warm Atlantic SSTs. So it’s the frequency and intensity which has been something new during the 2020s. The coming event this week will be the 2nd -4 link up in just a little over 2 years. 

The south based block in December 2020 allowed BGM to get the 40” jackpot instead of closer to NYC. It lead to the first snowfall shut out for us back in December 2022 with similar past La Niña and -AO levels. Then the March 2023 pattern followed a similar script. Now we are getting mixed precipitation events with this present  south based -AO block. The 11-12th event may be one of the few events without mixing issues in NYC. Interior spots that build up a big enough snowpack could become susceptible to flooding if one or more of the coming storms rides too far north.

2nd -4 -AO in only a little over 2 years this week linking up with the Southeast Ridge

 

-4 -AO December 2022 linking up Southeast Ridge 

2022 12 18 -4.151
2022 12 19 -3.671
2022 12 20 -3.326

Earlier era linkage during 97-98 super El Niño 

1998  1  9 -3.987
1998  1 10 -4.269

 

 

 

@psuhoffmanI really hope we don't have to, but have been getting a sickening feeling for 3 days now....you're gonna need to dig that log book out my friend.

[Ralph Wiggum]

30 minutes ago, mitchnick said:

We'll call it the "Psu Lucky Guess" storm. Lol

I wonder with the block rotting at that time and the nao trending neutral/positive if this trends North? @Stormchaserchuck1 what say you? 

[aldie 22]

2 minutes ago, Ralph Wiggum said:

I wonder with the block rotting at that time and the nao trending neutral/positive if this trends North? @Stormchaserchuck1 what say you? 

Hey Ralph don't turn around your shadow is following you...BOO !

[Stormchaserchuck1]

17 minutes ago, Ralph Wiggum said:

I wonder with the block rotting at that time and the nao trending neutral/positive if this trends North? @Stormchaserchuck1 what say you? 

I actually like that timeframe because there is a -EPO. It's a nice Polar connection of ridging from AO to EPO, and maybe even +PNA. If 500mb doesn't change, it should trend more wintry for the Mid Atlantic. But it's still 11 days away, but I really do especially like that -EPO modeled right now. 

That Day 7 storm though, is really +NAO. That low just south of Greenland gets up to -500dm. That's strong positive! It's a rare case of super -AO and super +NAO at the same time! 

Edit: I just saw for the Day 11 storm, models keep holding onto the south-based +NAO throughout their run. Just know that -EPO/+NAO is more ice, but +PNA/-EPO/+NAO is more snow. 

[frd]

10 minutes ago, Ralph Wiggum said:

I wonder with the block rotting at that time and the nao trending neutral/positive if this trends North? @Stormchaserchuck1 what say you? 

If I may, please note that the AO link to the SER will be broken once we get to the end of next week, after that the typical block evolution should increase SECS potential. 

For example, you can that today on the 264 hour ECM ensemble forecast......... WOOF !  

[Stormchaserchuck1]

7 minutes ago, frd said:

If I may, please note that the AO link to the SER will be broken once we get to the end of next week, after that the typical block evolution should increase SECS potential. 

For example, you can that today on the 264 hour ECM ensemble forecast......... WOOF !  

Yeah I think it's a pretty legit shot at something good. Hopefully storm systems keep being as strong as modeled. If that Pacific pattern that is currently modeled holds, watch out... 

It's a good observation too that a 90N block correlates with cold at 45N, but further south at 40N there could be a tropical ridge tendency as the 3rd wave down. Today it has evolved to look like that because of south-based +NAO though. 

[Maestrobjwa]

24 minutes ago, Ralph Wiggum said:

@psuhoffmanI really hope we don't have to, but have been getting a sickening feeling for 3 days now....you're gonna need to dig that log book out my friend.

Maaan I don't wanna talk about PSU's logbook unless the fail scenario was perfect track rain or a -nao-+SER linkup or something. If some other random junk gets in the way ala 2018, that would be another story.

[Stormchaserchuck1]

25 minutes ago, Ralph Wiggum said:

@psuhoffmanI really hope we don't have to, but have been getting a sickening feeling for 3 days now....you're gonna need to dig that log book out my friend.

I think for future reference, it's a good research to do where the block is. A lot of AO data overlaps with NAO, and a lot of times it's a Greenland block that is -AO.. but this time it's over the North Pole, so that's actually a little different.  This is why I like to look at raw 500mb maps vs the actual index numbers, although you could probably look at AO vs NAO and get a good analog system from that. 

[psuhoffman]

16 minutes ago, Stormchaserchuck1 said:

I actually like that timeframe because there is a -EPO. It's a nice Polar connection of ridging from NAO to AO to EPO, and maybe even +PNA. If 500mb doesn't change, it should trend more wintry for the Mid Atlantic. But it's still 11 days away, but I really do especially like that -EPO modeled right now. 

That Day 7 storm though, is really +NAO. That low just south of Greenland gets up to -500dm. That's strong positive! It's a rare case of super -AO and super +NAO at the same time! 

We’re on the same team finally 

[Stormchaserchuck1]

8 minutes ago, psuhoffman said:

We’re on the same team finally 

Before we get 1" of new snow! 

I would have actually favored more of a Weak Nina late season look, because I've correlated the ENSO subsurface with Pacific PNA pattern, and it actually came back with high forecasting predictability.  But this season is different.. a good case study!  A week ago, I wasn't thinking it would be as favorable as this.... I'm still real curious though to see if we can get solid cold in the 2nd half of Winter.. I do think that as the average temperature starts to increase, there is tendency of late to keep us warm. 

[Ralph Wiggum]

21 minutes ago, frd said:

If I may, please note that the AO link to the SER will be broken once we get to the end of next week, after that the typical block evolution should increase SECS potential. 

For example, you can that today on the 264 hour ECM ensemble forecast......... WOOF !  

We are pinning out hopes on that linkage breaking just correctly and at the right time. Seems complicated. Maybe for a change we can do complicated successfully.

[Ralph Wiggum]

13 minutes ago, psuhoffman said:

We’re on the same team finally 

Please wear Kelly green, that's my only request.

[Stormchaserchuck1]

1 minute ago, Ralph Wiggum said:

We are pinning out hopes on that linkage breaking just correctly and at the right time. Seems complicated. Maybe for a change we can do complicated successfully.

It's probably more about the Pacific pattern being good vs neutral/not. 

[psuhoffman]

@Ralph Wiggum before you start a panic can we wait and see.  I’m on the record sharing your concern. But if it’s true that strong high latitude blocks will continue to link to a SER the whole time we might as well just give up and stop tracking because that’s how we get 90% of both our HECS storms and BIG snow seasons. So what are we even doing here if you think it won’t work anymore?   Let’s see how it plays out. 

[Stormchaserchuck1]

6 minutes ago, psuhoffman said:

@Ralph Wiggum before you start a panic can we wait and see.  I’m on the record sharing your concern. But if it’s true that strong high latitude blocks will continue to link to a SER the whole time we might as well just give up and stop tracking because that’s how we get 90% of both our HECS storms and BIG snow seasons. So what are we even doing here if you think it won’t work anymore?   Let’s see how it plays out. 

Block at 90N has only sustained though for more than a few days maybe 4-7 times since 1948 (I've gone through and looked at the data on daily - came up with 7 main index regions in the N. Hemisphere, and North Pole was not one of them).  It's because of this a super strong low is now projected to form just south of Greenland. It's too bad it's not 5 degrees south, because that would have been an awesome 50/50 low. But the H5 change between projected time and day-of is not big, because the CPC calculates NAO error, and it has like a 90% chance in that graph of verifying positive.  It's because of this slight displacement north of the 50/50 that we will now have a SE ridge! Unfortunate, but I'm saying there is a reason in this case for the -AO to link up with a SE ridge.. it's a little too far north.  Now, 2017-2023, there were a lot of anomalous SE ridge's in that time (especially 22-23). 

[Maestrobjwa]

12 minutes ago, psuhoffman said:

@Ralph Wiggum before you start a panic can we wait and see.  I’m on the record sharing your concern. But if it’s true that strong high latitude blocks will continue to link to a SER the whole time we might as well just give up and stop tracking because that’s how we get 90% of both our HECS storms and BIG snow seasons. So what are we even doing here if you think it won’t work anymore?   Let’s see how it plays out. 

So when do you think we'll know at the end whether that unfortunate feature is gonna pop up again? Later this week, perhaps?

[Ralph Wiggum]

5 minutes ago, Stormchaserchuck1 said:

Block at 90N has only sustained though for more than a few days maybe 4-7 times since 1948 (I've gone through and looked at the data on daily - came up with 7 main index regions in the N. Hemisphere, and North Pole was not one of them).  It's because of this a super strong low is now projected to form just south of Greenland. It's too bad it's not 5 degrees south, because that would have been an awesome 50/50 low. But the H5 change between projected time and day-of is not big, because the CPC calculates NAO error, and it has like a 90% chance in that graph of verifying positive.  It's because of this slight displacement north of the 50/50 that we will now have a SE ridge! Unfortunate, but I'm saying there is a reason in this case for the -AO to link up with a SE ridge.. it's a little too far north.  Now, 2017-2023, there were a lot of anomalous SE ridge's in that time (especially 22-23). 

This North Pole block / -4 SD AO is sort of unchartered territory for us in quite some time. This could end up being the perfect set of ingredients to set off a powder keg or it could end up in the same dumpster fire of super anomalous teleconnections we have seen over the past decade, ie, too much of a good thing.

It's sort of the concern that psu and I are (i think) sharing. If we are consistently failing on what used to be our most common events and then we keep failing with these super duper drool-worthy tellies that used to be our high-end MECS/HECS, then what's left? 

Let's hope this last hurrah next week wrt hemispheric pattern can work it's magic for us. 

[Stormchaserchuck1]

2 minutes ago, Ralph Wiggum said:

This North Pole block / -4 SD AO is sort of unchartered territory for us in quite some time. This could end up being the perfect set of ingredients to set off a powder keg or it could end up in the same dumpster fire of super anomalous teleconnections we have seen over the past decade, ie, too much of a good thing.

It's sort of the concern that psu and I are (i think) sharing. If we are consistently failing on what used to be our most common events and then we keep failing with these super duper drool-worthy tellies that used to be our high-end MECS/HECS, then what's left? 

Let's hope this last hurrah next week wrt hemispheric pattern can work it's magic for us. 

We are failing though because there is +NAO tendency this season. I posted it on the last page, this connection is a little warmer. 

Because we are at 40N, south of 45N, what happens in the mid-latitudes is actually more important for us than what happens at 90N. 

[psuhoffman]

30 minutes ago, Stormchaserchuck1 said:

Block at 90N has only sustained though for more than a few days maybe 4-7 times since 1948 (I've gone through and looked at the data on daily - came up with 7 main index regions in the N. Hemisphere, and North Pole was not one of them).  It's because of this a super strong low is now projected to form just south of Greenland. It's too bad it's not 5 degrees south, because that would have been an awesome 50/50 low. But the H5 change between projected time and day-of is not big, because the CPC calculates NAO error, and it has like a 90% chance in that graph of verifying positive.  It's because of this slight displacement north of the 50/50 that we will now have a SE ridge! Unfortunate, but I'm saying there is a reason in this case for the -AO to link up with a SE ridge.. it's a little too far north.  Now, 2017-2023, there were a lot of anomalous SE ridge's in that time (especially 22-23). 

We’ve had a decent number of snowstorms from a block where this one ends up. It’s a bit odd how it starts so far north but it retrogrades to Baffin Island which is where a block that starts centered over Greenland typically ends up. So in the end the effect should be the same but it starts out less than ideal which is why I’m not more optimistic for the wave next weekend. I think around the 20th and after we will have legit threats. 
 

Also we can get a AO driven snow but we need some help from either the PNA or EPO and we have that nice to around the 20th. 

[87storms]

11 minutes ago, Stormchaserchuck1 said:

We are failing though because there is +NAO tendency this season. I posted it on the last page, this connection is a little warmer. 

Because we are at 40N, south of 45N, what happens in the mid-latitudes is actually more important for us than what happens at 90N. 

Yep, might be a close call next weekend and beyond.  The cold air seems available, but whether we have the blocking or not might determine whether we're dealing with cutters and cold chasing precip or a coastal low with a beautiful, entrenched high pressure to the north.

[NorthArlington101]

Pretty clear window on the EPS... kinda guessing anything next Sunday/Monday is a tease. PSU storm or bust.

[psuhoffman]

That wave 3 weeks ago and the waves this week are a perfect example why we need blocking to work. It’s so freaking hard to get a flush hit from these progressive boundary waves. There is nothing to lock them into a track. They can go to our south or north based on insignificant changes in amplitude. They have a relatively narrow area of heavy snow west to east that will only give a small portion of the east coast a win. 
 

But with a block and 50/50 if there is enough cold in the pattern you just need any strong wave to come along and crash into the confluence. The win zone is huge. It can try to cut and it will be turned east and we get a ton of snow to ice. It can take an imperfect track and will be forced under us. The precip coverage will be huge compared to these petty boundary waves because the wave is trying to gain latitude and throwing moisture up over the cold air locked in instead of these frustrating west to east waves where we’re at the mercy of a ton of variables any one of which can screw us over.

 
sure we might get lucky this week.  But over the long run this is a hard way to try to get a lot of snow. Throw a juiced up amplifying wave into cold with a blocked flow is simple with a huge margin for error where a minor amplitude shift won’t screw us out of snow!  

[DDweatherman]

1 minute ago, psuhoffman said:

That wave 3 weeks ago and the waves this week are a perfect example why we need blocking to work. It’s so freaking hard to get a flush hit from these progressive boundary waves. There is nothing to lock them into a track. They can go to our south or north based on insignificant changes in amplitude. They have a relatively narrow area of heavy snow west to east that will only give a small portion of the east coast a win. 
 

But with a block and 50/50 if there is enough cold in the pattern you just need any strong wave to come along and crash into the confluence. The win zone is huge. It can try to cut and it will be turned east and we get a ton of snow to ice. It can take an imperfect track and will be forced under us. The precip coverage will be huge compared to these petty boundary waves because the wave is trying to gain latitude and throwing moisture up over the cold air locked in instead of these frustrating west to east waves where we’re at the mercy of a ton of variables any one of which can screw us over.

 
sure we might get lucky this week.  But over the long run this is a hard way to try to get a lot of snow. Throw a juiced up amplifying wave into cold with a blocked flow is simple with a huge margin for error where a minor amplitude shift won’t screw us out of snow!  

Couldn't agree more in the ways to win department. I love a huge win swath with those features in place vs timing a boundary wave where tiny variables have such noticeable impacts on ground truth. Here's to getting a few with our blocking scheme moving in. 

[Scarlet Pimpernel]

14 minutes ago, psuhoffman said:

That wave 3 weeks ago and the waves this week are a perfect example why we need blocking to work. It’s so freaking hard to get a flush hit from these progressive boundary waves. There is nothing to lock them into a track. They can go to our south or north based on insignificant changes in amplitude. They have a relatively narrow area of heavy snow west to east that will only give a small portion of the east coast a win. 
 

But with a block and 50/50 if there is enough cold in the pattern you just need any strong wave to come along and crash into the confluence. The win zone is huge. It can try to cut and it will be turned east and we get a ton of snow to ice. It can take an imperfect track and will be forced under us. The precip coverage will be huge compared to these petty boundary waves because the wave is trying to gain latitude and throwing moisture up over the cold air locked in instead of these frustrating west to east waves where we’re at the mercy of a ton of variables any one of which can screw us over.

 
sure we might get lucky this week.  But over the long run this is a hard way to try to get a lot of snow. Throw a juiced up amplifying wave into cold with a blocked flow is simple with a huge margin for error where a minor amplitude shift won’t screw us out of snow!  

Agree.  I think what we're seeing this upcoming week is pretty much what you stated well before this.  That is, you weren't that big on it, but also said you weren't discounting any snow possibilities which still could happen.  We're now looking at an imperfect and "lucky" event for Tuesday-Wednesday, though obviously we're not going to see those outrageous amounts that models were spitting out late last week.  Still respectable though!  Now right after that, we have to deal with more or less getting washed out, though it shouldn't be a torch per se.  As for next weekend into PD, I'm not overly high on anything there myself either, but I'm paying some attention to the trends that we may have some icy mess perhaps as we get into the blocking regime more (or that's what it looks like, at least for some areas).  Then of course, there's your favored period beginning around the 20th, and I like how the ensembles have remained pretty rock steady so far on that.  It's also good to see a couple of ops runs here and there throw out some nice solutions during that period.  That's what we want to see, though the details remain to be ironed out.

(ETA:  It must help also that we're not coming out of some several week period of Pac puke with absolutely no cold air even in Canada.  So not like we should have to take a long time to "restore" the cold air source as we've had happen in the past).

[Weather Will]

WB latest EPS extended, lot of potential for fun times ahead.

[87storms]

15 minutes ago, psuhoffman said:

That wave 3 weeks ago and the waves this week are a perfect example why we need blocking to work. It’s so freaking hard to get a flush hit from these progressive boundary waves. There is nothing to lock them into a track. They can go to our south or north based on insignificant changes in amplitude. They have a relatively narrow area of heavy snow west to east that will only give a small portion of the east coast a win. 
 

But with a block and 50/50 if there is enough cold in the pattern you just need any strong wave to come along and crash into the confluence. The win zone is huge. It can try to cut and it will be turned east and we get a ton of snow to ice. It can take an imperfect track and will be forced under us. The precip coverage will be huge compared to these petty boundary waves because the wave is trying to gain latitude and throwing moisture up over the cold air locked in instead of these frustrating west to east waves where we’re at the mercy of a ton of variables any one of which can screw us over.

 
sure we might get lucky this week.  But over the long run this is a hard way to try to get a lot of snow. Throw a juiced up amplifying wave into cold with a blocked flow is simple with a huge margin for error where a minor amplitude shift won’t screw us out of snow!  

The possibility still exists that we might end up being exactly who we thought we were.

[psuhoffman]

What a 7 day look 

[Maestrobjwa]

26 minutes ago, psuhoffman said:

What a 7 day look 

Now with that kind of look there there's no SER to even link up to 

[Scarlet Pimpernel]

6 minutes ago, Maestrobjwa said:

Now with that kind of look there there's no SER to even link up to 

Don't jinx it!  I'm thinking of the old "Shaft" song, the "Shut yo' mouth!" part!!  LOL!!!