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Feb Long Range Discussion (Day 3 and beyond) - MERGED


WinterWxLuvr
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@stormtracker you are right to be skeptical.  I’m wrong plenty of times. But let me lay out why I think our opportunities increase the further into this pattern we get. And I feel confident not because the guidance shows this because this was the progression I started laying out days ago before it was as apparent as it is on todays EPS. I’m confident because the guidance is going towards what makes sense wrt how the pattern should progress. 
 

Let’s start with why that first wave around day 8 is going to have trouble staying snow despite the block. It’s about what happens before it. 
The genesis is day 4. 
ciARHbR.jpg

The pac ridge (1) is going up and retrograding. It don’t look like much yet but the energy in western Canada and AK is digging into the west (2) in response. As that trough digs downstream once that trough in the east moves out there is nothing to stop a ridge from popping (3).  The NAO block (4) is not yet in a spot to be helpful. Actually it’s really still just an extension of the WAR there. 
 

So let’s go out a few more days...

ff0dWhS.jpg
Now the blocking is getting going. But even there is still centered just east of Greenland and it can’t go back in time and erase that ridge already in the east!  It’s not that the block isn’t good but it’s too little too late. But keep in mind the location of key features there. Block just east of Greenland and 50/50 just NW of NF.  Could that force a secondary south of us...yea but that ridge is a bit much and more problematic look at the airmass in front of that wave coming...

xxDbFst.png
Just being honest...all that ridging with a block just getting into ideal position and no cold in front...isn’t likely to end well. Not impossible but I’m not getting my hopes up. 
 

But now that the block is up and there is cold getting into N America as the pac flow finally relaxes look at the progression. With each wave more cold will bleed east under the block. So lets try this again a couple days later...

SuP4k8K.jpg
At first glance it might seem that’s the same. But the ridge is flatter. And look at the key features. The blocking is now centered just WEST of Greenland. And the 50/50 is over NF. But most importantly look at the temps in front of the next wave...

cIu8RQJ.png
ok...that’s not Arctic but that’s much more workable.  And look at the MSLP anomalies. They hint at exactly what I was looking for...

jv8GeJi.jpg
LLmwc37.jpg

15Qw3na.jpg

And imo the wave AFTER that day 11 threat has an even better chance.  Fast forward to 300 hours and we try again but...

ytup0ea.jpg
look how flat the ridge is that time...look at the location of the block and 50/50. And look at the temps in front this time...

MFJMDGO.png
Now we’re cooking...the mslp is washed out by that range but the mean precip during that period hints at what is going on. 
CyOLz4f.png

so yes this all relies on certain things happening that may not happen. But it fits the pattern progression. I’m showing this because the EPS went to how the pattern should progress imo. If it does the wave around day 11 will have a better chance then day 8 and the wave around day 14 will have an even better chance. 
 

sorry for the war and peace post. 

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@psuhoffman Great post.  Have a question though.  I was digging through some of my older posts and have noticed a similarity with extended NAO looks.  Below is 300+ hr forecast for the EPS gor Jan 13 showing a very nice west based block and fast forward to today and it is more centered as an east based NAO.  It’s been the pattern it seems all winter.  I’m curious to what too look for to make sure we get the retro west that has been seen in the past but failed so far through January.

EAC0E2AD-30DF-4B8E-AA9B-72DEB0BBCA58.png

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6 minutes ago, LP08 said:

@psuhoffman Great post.  Have a question though.  I was digging through some of my older posts and have noticed a similarity with extended NAO looks.  Below is 300+ hr forecast for the EPS gor Jan 13 showing a very nice west based block and fast forward to today and it is more centered as an east based NAO.  It’s been the pattern it seems all winter.  I’m curious to what too look for to make sure we get the retro west that has been seen in the past but failed so far through January.

EAC0E2AD-30DF-4B8E-AA9B-72DEB0BBCA58.png

Well one is getting it inside 300 hours.

The genesis of the pattern is only 5/6 days out 

4C7A0B6F-9202-4F63-BC45-9CFA41FB8204.thumb.png.a7aa1565f81bea935f47da342b9d12a8.png

from there you can extrapolate...

But also other factors. One being the pacific flow backing off which won’t destructively interfere as much. Another is more cold injected into the pattern. We did have pretty good (not as good) look up top the last 10 days but with no cold we wasted it.  3rd guidance often is too fast with a pattern progression both setting in and breaking down. Lastly the effects of the SSW are just starting to couple with the troposphere so increased blocking is supported. It could still fail. But those are reasons I have optimism. 

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11 minutes ago, StormchaserChuck! said:

Maybe if you moved to the West coast it would be different? Greenlandblocks are not what they used to be. 

Isn’t it just the fact that Canada was flooded with PAC air prior to the block?  Yeah I know the PAC itself is crap but north of the border has been an inferno.  Bad luck yes but is it fair to say that same pattern now but frigid source region would result in a colder outcome?  Just random musings 

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Mount Holly-

Another storm system likely approaches the area late next week with potential ptype concerns...however the trending negative PNA and the (related) hints of a building SE ridge, make this setup sub-optimal for snow lovers.

WOMP

C'mon man, don't be so boilerplate. The potential!

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26 minutes ago, Cobalt said:

Usually you'd expect the weeklies to do its best to revert back to a nina pattern and to pump the SE ridge, but even going a month out the blocking looks decently stout, SE ridge squashed too. Workable look especially when considering Weeklies bias 2 weeks out. 

ecmwf-weeklies-avg-namer-z500_anom-3088000.thumb.png.020be5248ecb83b784d7cf1ddad274fa.png

 

They have tried to kill the -AO/NAO state all cold season just as guidance tried to weaken the +AO in previous winters. Part of that is reversion to mean at range. Part is guidance misidentifying a key driver. 2 years ago it was a nino that never coupled. This year is a Nina that’s being countermanded by other influences. 

ETA: point is I doubt it just flips. If we fail this winter we can’t blame the high latitudes. That might make a fail even more painful 

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1 hour ago, psuhoffman said:

@stormtracker you are right to be skeptical.  I’m wrong plenty of times. But let me lay out why I think our opportunities increase the further into this pattern we get. And I feel confident not because the guidance shows this because this was the progression I started laying out days ago before it was as apparent as it is on todays EPS. I’m confident because the guidance is going towards what makes sense wrt how the pattern should progress. 
 

Let’s start with why that first wave around day 8 is going to have trouble staying snow despite the block. It’s about what happens before it. 
The genesis is day 4. 
ciARHbR.jpg

The pac ridge (1) is going up and retrograding. It don’t look like much yet but the energy in western Canada and AK is digging into the west (2) in response. As that trough digs downstream once that trough in the east moves out there is nothing to stop a ridge from popping (3).  The NAO block (4) is not yet in a spot to be helpful. Actually it’s really still just an extension of the WAR there. 
 

So let’s go out a few more days...

ff0dWhS.jpg
Now the blocking is getting going. But even there is still centered just east of Greenland and it can’t go back in time and erase that ridge already in the east!  It’s not that the block isn’t good but it’s too little too late. But keep in mind the location of key features there. Block just east of Greenland and 50/50 just NW of NF.  Could that force a secondary south of us...yea but that ridge is a bit much and more problematic look at the airmass in front of that wave coming...

xxDbFst.png
Just being honest...all that ridging with a block just getting into ideal position and no cold in front...isn’t likely to end well. Not impossible but I’m not getting my hopes up. 
 

But now that the block is up and there is cold getting into N America as the pac flow finally relaxes look at the progression. With each wave more cold will bleed east under the block. So lets try this again a couple days later...

SuP4k8K.jpg
At first glance it might seem that’s the same. But the ridge is flatter. And look at the key features. The blocking is now centered just WEST of Greenland. And the 50/50 is over NF. But most importantly look at the temps in front of the next wave...

cIu8RQJ.png
ok...that’s not Arctic but that’s much more workable.  And look at the MSLP anomalies. They hint at exactly what I was looking for...

jv8GeJi.jpg
LLmwc37.jpg

15Qw3na.jpg

And imo the wave AFTER that day 11 threat has an even better chance.  Fast forward to 300 hours and we try again but...

ytup0ea.jpg
look how flat the ridge is that time...look at the location of the block and 50/50. And look at the temps in front this time...

MFJMDGO.png
Now we’re cooking...the mslp is washed out by that range but the mean precip during that period hints at what is going on. 
CyOLz4f.png

so yes this all relies on certain things happening that may not happen. But it fits the pattern progression. I’m showing this because the EPS went to how the pattern should progress imo. If it does the wave around day 11 will have a better chance then day 8 and the wave around day 14 will have an even better chance. 
 

sorry for the war and peace post. 

I’m sorry, but do you have cliff notes available? :lol:

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5 minutes ago, psuhoffman said:

They have tried to kill the -AO/NAO state all cold season just as guidance tried to weaken the +AO in previous winters. Part of that is reversion to mean at range. Part is guidance misidentifying a key driver. 2 years ago it was a nino that never coupled. This year is a Nina that’s being countermanded by other influences. 

It still does trend towards more of a typical Nina look, but much less so than recent runs. Good sign maybe.

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3 minutes ago, CAPE said:

Cobalt kind of :ph34r:'ed me, but he went out beyond the timeframe where the tool has some decent skill, so not really :P 

 

8 minutes ago, psuhoffman said:

They have tried to kill the -AO/NAO state all cold season just as guidance tried to weaken the +AO in previous winters. Part of that is reversion to mean at range. Part is guidance misidentifying a key driver. 2 years ago it was a nino that never coupled. This year is a Nina that’s being countermanded by other influences. 

 

I know that the accuracy tends to drop off significantly out there, and that's also why I prefaced my post with saying that outside of 3 weeks the weeklies really go out of their way to go towards typical ENSO patterns. Although with that being said, my takeaway from that week 4 h5 map was that it was surprisingly not doing what it did the past few runs at that range, and instead tried to get us back into a favorable progression despite it's biases. Not worth much this far out, but will certainly be super fascinating to follow in about a week or two. 

yeah basically what CAPE just said 

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Just now, Cobalt said:

 

I know that the accuracy tends to drop off significantly out there, and that's also why I prefaced my post with saying that outside of 3 weeks the weeklies really go out of their way to go towards typical ENSO patterns. Although with that being said, my takeaway from that week 4 h5 map was that it was surprisingly not doing what it did the past few runs at that range, and instead tried to get us back into a favorable progression despite it's biases. Not worth much this far out, but will certainly be super fascinating to follow in about a week or two. 

I agree.

You are becoming a solid poster btw. You have done it right- read a lot, and post sparingly. Make your posts count. Good job.

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3 minutes ago, nj2va said:

Anyone see any data recently on SST/Nina strength?  DT posted something about a month ago showing some models predicting a mod Nina vs strong...hard to predict the outcomes of that but could help us in late winter.  I can't remember where he pulled that from or else I'd go try to find it.

Just updated today. 

Quote

A majority of the models in the IRI/CPC plume predict La Niña to continue through the Northern Hemisphere spring [Fig. 6]. The forecaster consensus is in line with the models and suggests a transition to ENSO-neutral in the late spring 2021. 

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

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