March 13 - 15 Major Winter Storm Potential

[Paragon]

9 minutes ago, JetsPens87 said:

Yes they would have taken into account the rising NAO. However, to put it in better terms, they were at that point forecasting the NAO further out than they are now. So at shorter lead times we should have a more accurate reflection of the impact of the NAO. It appeared days ago that all the energy would have consolidated sooner and had a slower moving system. As the lead time shortens we are getting a more accurate reflection of the pieces of energy in play and how the rest of the global system reflects that.

The rising NAO should theoretically have been helping us because it would have been an Archembault event going from - to +, similar to how PD2 was positive when the actual storm was occurring, but during the set up phase was actually in the process of going from - to +.

If the NAO is this + it actually makes me somewhat concerned for the next system also, which is progged for Saturday.

 

[JetsPens87]

2 minutes ago, JerseyWx said:

Here's a question:  What are you actually looking at with the 500mb maps?  What do they represent in other words?

Also, Ulster mentioned the NHC.  What sort of data does the NHC collect for these storms?

Great questions,

Let me start off with the NHC, the NHC utilizes dropsondes to sample actual live data from the atmosphere in the path of projected storms. This data can then be ingested into the models' algorithms to more accurately represent the atmosphere. The more live data that can be input into the system the more theoretically accurate the model can be. Think of it this way, the more accurate the initial representation of the atmosphere that a model can represent, theoretically the less error propagation over time as RU said.

As to your next question, 500mb is extremely important. I look at both the 500mb heights and vort maps. The 500mb height maps can identify greater spikes in PNA ridging (or less for that matter, but hopefully not), higher heights off the east coast, and any possible hints of pseudo blocking.

The 500mb vort map identifies were specific pieces of upper atmosphere energy lie. Here I am looking for hints of earlier phasing, cleaner phasing and just how much energy (vorticity) there is at that level with certain different streams (polar, arctic, and southern).

[Paragon]

7 minutes ago, Violentweatherfan said:

Thanks, now I see why you are leaning towards the latter in your previous post.

I think  there is another check box to add to the KU list, is the blocking/-NAO continuous throughout the storm timeframe.

I'm not sure that's necessarily true however, because a lot of our really big storms have been in the process of changing from - to +  When the actual storm happened the NAO was + but during the set up phase it was transitioning from - to +.  Also a lot of our really big winters are near neutral to slightly +.  You don't want the NAO to be too - or you'll have suppression.

[JerseyWx]

2 minutes ago, JetsPens87 said:

Great questions,

Let me start off with the NHC, the NHC utilizes dropsondes to sample actual live data from the atmosphere in the path of projected storms. This data can then be ingested into the models' algorithms to more accurately represent the atmosphere. The more live data that can be input into the system the more theoretically accurate the model can be. Think of it this way, the more accurate the initial representation of the atmosphere that a model can represent, theoretically the less error propagation over time as RU said.

As to your next question, 500mb is extremely important. I look at both the 500mb heights and vort maps. The 500mb height maps can identify greater spikes in PNA ridging (or less for that matter, but hopefully not), higher heights off the east coast, and any possible hints of pseudo blocking.

The 500mb vort map identifies were specific pieces of upper atmosphere energy lie. Here I am looking for hints of earlier phasing, cleaner phasing and just how much energy (vorticity) there is at that level with certain different streams (polar, arctic, and southern).

Awesome, thank you for taking the time to respond.

[nzucker]

26 minutes ago, nyblizz44 said:

That NAO was the bugaboo I feared, I know Kocin storms are rare beasts. Lets us see what 0 Z has in store for us, we should have a better idea in 4.5 hours. If the Euro trends east again I think many of us will prepare mentally for a reduction in expectations. Thanks a lot for clarifying and GO PNA+++

There's a little bit of ridging left over near Hudson Bay/Davis Strait from the previous NAO block. There is not a complete lack of blocking to the north.

[Violentweatherfan]

Just now, Paragon said:

I'm not sure that's necessarily true however, because a lot of our really big storms have been in the process of changing from - to +  When the actual storm happened the NAO was + but during the set up phase it was transitioning from - to +.  Also a lot of our really big winters are near neutral to slightly +.  You don't want the NAO to be too - or you'll have suppression.

I have always thought it's best at 0 or -/+1, Jets said its approaching +2.  My original question was when we where seeing 18+ totals region wide did the models factor the NAO at close to +2 or was it nuetral or +1.

[Paragon]

7 minutes ago, ILoveWinter said:

I thought we had a 50/50 helping to slow things down? Is that no longer a factor?

I believe Wave 2 was supposed to be our 50/50 if you remember when the wave was coming up the coast, Wave 3 (Tuesday's storm) was a nonfactor.  But when Wave 2 got suppressed, it gave room for Wave 3 to be the one to amplify.

 

[JetsPens87]

7 minutes ago, ILoveWinter said:

I thought we had a 50/50 helping to slow things down? Is that no longer a factor?

Another good question,

The 50/50 Low is helping to serve to keep the cold air source locked in. Often times we find the high to the north "escape" east and cause an Easterly return flow, however with a 50/50 low it helps to keep the HP in place longer and prevent that return flow. It doesn't necessarily serve to slow down the flow however, that would be the function of a -NAO to do so.

[Paragon]

1 minute ago, Violentweatherfan said:

I have always thought it's best at 0 or -/+1, Jets said its approaching +2.  My original question was when we where seeing 18+ totals region wide did the models factor the NAO at close to +2 or was it nuetral or +1.

yes near neutral or slightly positive is good, actually anywhere from -1 to +1, as the switching of phases is really whats important.  

But in terms of the set up prior to the storm (which could be days in advance) it's best to have a -AO/-NAO combo. A ridge on the west coast is also important (+PNA) but usually less so in March with the shorter wavelengths.  It's become more important now because we lost the NAO blocking.

[nzucker]

1 minute ago, JetsPens87 said:

Another good question,

The 50/50 Low is helping to serve to keep the cold air source locked in. Often times we find the high to the north "escape" east and cause an Easterly return flow, however with a 50/50 low it helps to keep the HP in place longer and prevent that return flow. It doesn't necessarily serve to slow down the flow however, that would be the function of a -NAO to do so.

The NAO and 50/50 are related however. Having high heights over Greenland promotes low heights over the Canadian Maritimes, and vice versa.

One of the reasons we have the 50/50 and associated cold air is because of the antecedent -NAO block.

[JetsPens87]

3 minutes ago, Violentweatherfan said:

I have always thought it's best at 0 or -/+1, Jets said its approaching +2.  My original question was when we where seeing 18+ totals region wide did the models factor the NAO at close to +2 or was it nuetral or +1.

I think I may have been mistaken about the +2, forgive me for that. I thought I had read earlier in this thread that is what we were approaching.

 

[Paragon]

6 minutes ago, nzucker said:

There's a little bit of ridging left over near Hudson Bay/Davis Strait from the previous NAO block. There is not a complete lack of blocking to the north.

Yeah this is what you need, just enough of a block to slow things down a bit but not too much or else there will be suppression.  The earlier runs from a few days ago had suppression.

[UlsterCountySnowZ]

Higher res Nams delayed due to data ingestion 

[Paragon]

2 minutes ago, JetsPens87 said:

I think I may have been mistaken about the +2, forgive me for that. I thought I had read earlier in this thread that is what we were approaching.

 

well according to that the NAO has been positive the entire time.

[Paragon]

1 minute ago, UlsterCountySnowZ said:

Higher res Nams delayed due to data ingestion 

hey let it eat all the data it wants, we can wait, as long as it doesn't get indigestion

[nyblizz44]

1 minute ago, UlsterCountySnowZ said:

Higher res Nams delayed due to data ingestion 

How ironic! LOL. Exactly what we need for more accuracy and that delays what we are all anticipating! 

[Violentweatherfan]

2 minutes ago, Paragon said:

yes near neutral or slightly positive is good, actually anywhere from -1 to +1, as the switching of phases is really whats important.  

But in terms of the set up prior to the storm (which could be days in advance) it's best to have a -AO/-NAO combo. A ridge on the west coast is also important (+PNA) but usually less so in March with the shorter wavelengths.  It's become more important now because we lost the NAO blocking.

I was curious if during the runs where we were getting huge totals were they due to the data ingested/used during those runs was the NAO at an optimum?  And now during today's run did the catch on to the rising NAO

[ILoveWinter]

8 minutes ago, JetsPens87 said:

Another good question,

The 50/50 Low is helping to serve to keep the cold air source locked in. Often times we find the high to the north "escape" east and cause an Easterly return flow, however with a 50/50 low it helps to keep the HP in place longer and prevent that return flow. It doesn't necessarily serve to slow down the flow however, that would be the function of a -NAO to do so.

 

6 minutes ago, nzucker said:

The NAO and 50/50 are related however. Having high heights over Greenland promotes low heights over the Canadian Maritimes, and vice versa.

One of the reasons we have the 50/50 and associated cold air is because of the antecedent -NAO block.

Thanks for the info! 

[Paragon]

9 minutes ago, Violentweatherfan said:

I have always thought it's best at 0 or -/+1, Jets said its approaching +2.  My original question was when we where seeing 18+ totals region wide did the models factor the NAO at close to +2 or was it nuetral or +1.

based on the graphs just posted the nao has been between neutral and +1 the entire time it never went below neutral and it never went higher than +1, that is strange since I strongly recall a few days ago people being extremely excited about the nao going negative, hmmmm

[Violentweatherfan]

1 minute ago, Paragon said:

based on the graphs just posted the nao has been between neutral and +1 the entire time it never went below neutral and it never went higher than +1, that is strange since I strongly recall a few days ago people being extremely excited about the nao going negative, hmmmm

I mis quoted jetspenns my bad

[JetsPens87]

1 minute ago, Paragon said:

well according to that the NAO has been positive the entire time.

Assuming because as someone said what was supposed to become our eventual 50/50 low actually wound up dampened out.

[nyblizz44]

3 minutes ago, JetsPens87 said:

Assuming because as someone said what was supposed to become our eventual 50/50 low actually wound up dampened out.

I made the same assumption before an altogether different reason. The earlier runs with European showing a 30-hour storm led me to, mistakenly, believe the evolution was being slowed by the 50/50 low upstream

[Paragon]

2 minutes ago, Violentweatherfan said:

I was curious if during the runs where we were getting huge totals were they due to the data ingested/used during those runs was the NAO at an optimum?  And now during today's run did the catch on to the rising NAO

I guess it's possible.  Look at the nao graph just posted, it looks like when people thought the nao was going to go negative it was in a steep decline but it never actually went negative, it touched 0 and went right back up.  It's possible that when the models forecasted a negative nao to develop is when the big storm forecasts first came out and then when the nao ended up never going below 0 and bounced right back up, things became more progressive.

The original forecast was for us to have a nice NAO/AO block from the middle of the first week to close to the end of the second week of March and the possibility of a big storm near the middle of March when the block would be breaking down and the NAO going back positive.  But it looks like it never actually went negative in the first place.

From that graph it looks like our base state for the NAO this season is actually +0.5  In other words, the NAO behaves as if +0.5 is neutral and stays positive even when it's supposed to be negative.....

[Violentweatherfan]

3 minutes ago, JetsPens87 said:

Assuming because as someone said what was supposed to become our eventual 50/50 low actually wound up dampened out.

Hey I'm sorry if I'm causing you any grief by quoting you 

[Paragon]

4 minutes ago, JetsPens87 said:

Assuming because as someone said what was supposed to become our eventual 50/50 low actually wound up dampened out.

Yes  that was Wave 2

[JetsPens87]

Just now, nyblizz44 said:

I need the same assumption before an altogether different reason. The earlier runs with European showing a 30-hour storm led me to, mistakenly, believe the evolution was being slowed by the 50/50 low upstream

Though in a way you would have been correct since there is a correlation between the 50/50 and NAO, as someone pointed out a 50/50 low would pump heights in the NAO region which that system in turn would slow down everything.

[JetsPens87]

2 minutes ago, Paragon said:

I guess it's possible.  Look at the nao graph just posted, it looks like when people thought the nao was going to go negative it was in a steep decline but it never actually went negative, it touched 0 and went right back up.  It's possible that when the models forecasted a negative nao to develop is when the big storm forecasts first came out and then when the nao ended up never going below 0 and bounced right back up, things became more progressive.

The original forecast was for us to have a nice NAO/AO block from the middle of the first week to close to the end of the second week of March and the possibility of a big storm near the middle of March when the block would be breaking down and the NAO going back positive.  But it looks like it never actually went negative in the first place.

From that graph it looks like our base state for the NAO this season is actually +0.5  In other words, the NAO behaves as if +0.5 is neutral and stays positive even when it's supposed to be negative.....

Yes I think that is a reasonable thought. Once we got past the eventual "wave 2" I think they realized the NAO wasn't in fact going to go negative.

[JetsPens87]

5 minutes ago, weatherpruf said:

It sounds to me like we are beginning to conduct the autopsy already.....

I'd say it's more of an investigative biopsy heh, nothing "dead" about this system at all.

[LongBeachSurfFreak]

1 minute ago, JetsPens87 said:

I'd say it's more of an investigative biopsy heh, nothing "dead" about this system at all.

Anyone saying this ones dead is just as ridiculous as those saying this monster total runs last night were a lock

00z is huuuuuuge. We can start talking in more certainty after those runs 

[JetsPens87]

1 minute ago, LongBeachSurfFreak said:

Anyone saying this ones dead is just as ridiculous as those saying this monster total runs last night were a lock

00z is huuuuuuge. We can start talking in more certainty after those runs 

Not sure what is going on with 00z runs. My friend just sent me a tweet that almost made it sound like we weren't going to be getting the new extra dropsonde data into the 00z suite. But I am not sure if we are delayed because we are waiting for that data or delayed for other reasons and not getting that data.