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Jan Medium/Long Range Disco: Winter is coming


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A couple points to clarify my earlier post.
 

I should have explained in my post the reason a -nao is worse in a -pna TNH pattern is the SER links with the nao as a full lat WAR.  I’m not talking about a Nino split flow -pna but a full latitude Nina like western trough.  
 

A -nao block works to suppress storms if systems are forced under and through the 50/50 space. But with a full latitude trough in the west systems cut west of the nao and pump the SE ridge. The nao acts like a WAR even if it extends into the nao domain. There is no suppressive mechanism in the flow. 
 

A positive nao can be better if the tpv gets displaced south a bit. Then it can act as a suppressive agent. It doesn’t work often. Typically we’re pretty screwed with a western trough but a positive nao with a tpv displaced into Canada to our north is one way that has rarely worked out. RARELY being the key. 
 

Second, with a -AO that look isn’t a total shutout look like 2020 and 2023. A -pna TNH +AO is the trifecta that causes most of our total shutout (or close to it say below 5”) seasons.  A -PNA TNH -AO pattern won’t be a complete shutout. We likely would luck into a progressive wave or two. Some secondary development. Or a weaker wave timed up behind a cutter. But it won’t lead to a snowy winter on the whole. It’s not as bad as 2020 or last year but it would be a hell of a way to spoil a -AO Nino and turn what would normally be our best shot at a big snowfall season into a below avg one!  

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55 minutes ago, psuhoffman said:

I wanted to illustrate what I am talking about regarding what we want and more importantly DONT WANT regarding the longwave patter for snow.  Instead of cluttering up the thread with a bunch of replies I thought I would lay this out in one thread with evidence to support what I am saying.  

This is the mean H5 for every 25" snowfall winter at BWI since 1958.  From 1958 to 2016 there were 19 of those, a mean of 1 every 3 years!  So I did not only select our EPIC winters...these are basically all the good and great winters.  I did not want to be super selective. These winters used to happen pretty regularly.  This is the "what we want" pattern for the winter 

all25inchsnows.png.b50f2e72aa735a9e5a32d2c3cd4fc419.png

Try to ignore the overall heights because they are skewed colder by the years prior to 1980 when heights in general were much lower on average.  But try to look at where the lower and higher heights are centered and angled...what the longwave pattern looks like.  To make it even easier I pulled out the years prior to 1980 below...still the same pattern though just with higher heights in general so closer to what it would look like today on guidance now.  

Since1980.png.77a3dc796d8868ca5b40f81501f52909.png

The major take away...we want the lower heights centerer SOUTH OF US...not to our northwest.  We do NOT under any circumstances want lower heights centered in wester canada, that's where we want a ridge.  All this canada is warm talk is annoying because Canada is warm in almost all of our snowy winters.  We are way to far southeast and close to the Atlantic and with Gulf influence for a pattern with a mean trough position to our northwest to work for us.  

Look at the current day 16 GEFS

b52d1832e95ce132241f84820b2abd57.thumb.jpg.d9d1d55dd479cca7f37718406b5965a2.jpg

It's the antilog to our snowy years...everything is opposite where we want it in terms of the trough/ridge axis in the long wave pattern.  

Frankly that is even further NW than Detroit wants...this is the analog for Detroits snowiest winters...

Detroit1.png.86925063ab443981ac8ca0981eae18e9.png

Even they want the trough axis and the ridge in the pac centered significantly further east than the guidance is showing.  That is probably a great look for Chicago and Green bay on the GEFS.  Also...some of those years for Detroit are ok here...we did ok, not great we got scraps compared to places to our NW but ok...but notice the NAO is positive!  If we were going to try to make a long wave pattern with a trough to our west work we want the NAO positive!  Our best chance is to have a TPV over us and once in a while it gets displaced a bit south and can act to suppress the waves.  That's how 2014 worked!  It's still super rare and isn't likely to lead to a good year...but at least an OK one, but a western trough with a negative NAO is actually EVEN WORSE!  

Lastly...2014 is an example of the very very rare case a trough to our NW worked out but notice the differences here

2014snow.png.0112c26049ed39e42519a76b7fbe2f27.png

Look at the NAO domain...again a negative displaced south to suppress the flow...we have a big positive there now, not going to work.  And look at where the pacific ridge is and the downstream trough over N AMerica.  There is a central pacific trough not ridge its just displaced southwest of where it typically is in our best years.  This year was an anomaly.  It's the ONLY season in the analog set where BWI got 25" of snow with a trough centered to the NW of us.  THE ONLY ONE.  And it had those very specific and odd features to go with it.  A full latitude EPO/PNA ridge and a displaced TPV in eastern Canada.  

So we do NOT want a trough centered to our west under any circumstances.  Only one time in 70 years has it lead to a snowy year and that season we had two other very specific features that we do NOT have this year.  We want the trough to be centered south of us with higher heights in western canada!  The complete opposite of that look some are saying is ok.  

This is an absolutely top shelf meteorological education with regards to snow in the Mid Atl. Thanks! It is going on my board and also up into Drive. It is priceless!

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This pattern might not be exactly what we wanted/expected heading into mid Jan, but there is a mechanism for cold air delivery which is NUMBER ONE if you want snow. Because we are in a Nino, we have an active southward displaced Jetstream, bring disturbances eastward along the flow within it. There is cold enough air at the surface as advertised, and the thermal boundary is in the vicinity and will surely be southward enough periodically for well timed waves to give us chances. The -NAO would help facilitate that despite the less than ideal Pacific. That's what I see anyway.

1705104000-iYjFb5WIB0s.png

1705104000-eQiNvejn1Fc.png

1705104000-L345ZVm0kt0.png

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44 minutes ago, CAPE said:

Maybe those 'saying its ok' fully realize the advertised look is not what we ideally want to see, but also recognize that if that that's hand we are dealt we have a couple choices- find something else to do, or continue to look for chances within that pattern. We have managed to snow in non-ideal longwave patterns you don't approve of in recent winters, and many here are happy with any snow at all, and don't have your high standards of 40"+ per season and KUs in every Nino. In this area we suck at snow in general, and its likely not getting any better going forward. Maybe you need to adjust a bit.

I think his point, and one I share, is that when we finally get a Nino where things look like they should be lined up for a big season, you have to get that big season. We are coming out of an awful period for snow. I know where I live, I don't expect 96/03/09-10/14 every year. I get it. Those years are few and far between. But especially when our snow in general seems to be really decreasing in the crappy seasons, we have to hit big on the good seasons. To nickel and dime my way to 12-15 inches this year would be dreadful.

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1 minute ago, osfan24 said:

I think his point, and one I share, is that when we finally get a Nino where things look like they should be lined up for a big season, you have to get that big season. We are coming out of an awful period for snow. I know where I live, I don't expect 96/03/09-10/14 every year. I get it. Those years are few and far between. But especially when our snow in general seems to be really decreasing in the crappy seasons, we have to hit big on the good seasons. To nickel and dime my way to 12-15 inches this year would be dreadful.

Expectations play a big role in this for sure. Mine are modest. Only takes 20" here for above avg, and I hit that back in Jan 2022.

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1 minute ago, CAPE said:

Expectations play a big role in this for sure. Mine are modest. Only takes 20" here for above avg, and I hit that back in Jan 2022.

I don't know about anybody else, but for me it's not even about just expecting something: It's what you want to happen. Low expectations don't cure disappointment--because you're looking for something better than you've had. Just one snowfall of 6 inches, something with a little bit more of something. When what you desire doesn't happen, there's disappointment regardless of whether you had low expectations or not.

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Just now, Maestrobjwa said:

I don't know about anybody else, but for me it's not even about just expecting something: It's what you want to happen. Low expectations don't cure disappointment--because you're looking for something better than you've had. Just one snowfall of 6 inches, something with a little bit more of something. When what you desire doesn't happen, there's disappointment regardless of whether you had low expectations or not.

How about realistic expectations? Try that.

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23 minutes ago, psuhoffman said:

A couple points to clarify my earlier post.
 

I should have explained in my post the reason a -nao is worse in a -pna TNH pattern is the SER links with the nao as a full lat WAR.  I’m not talking about a Nino split flow -pna but a full latitude Nina like western trough.  
 

A -nao block works to suppress storms if systems are forced under and through the 50/50 space. But with a full latitude trough in the west systems cut west of the nao and pump the SE ridge. The nao acts like a WAR even if it extends into the nao domain. There is no suppressive mechanism in the flow. 
 

A positive nao can be better if the tpv gets displaced south a bit. Then it can act as a suppressive agent. It doesn’t work often. Typically we’re pretty screwed with a western trough but a positive nao with a tpv displaced into Canada to our north is one way that has rarely worked out. RARELY being the key. 
 

Second, with a -AO that look isn’t a total shutout look like 2020 and 2023. A -pna TNH +AO is the trifecta that causes most of our total shutout (or close to it say below 5”) seasons.  A -PNA TNH -AO pattern won’t be a complete shutout. We likely would luck into a progressive wave or two. Some secondary development. Or a weaker wave timed up behind a cutter. But it won’t lead to a snowy winter on the whole. It’s not as bad as 2020 or last year but it would be a hell of a  

Absolutely excellent analysis. I like how you explained how a -NAO isn’t always necessarily a rule of thumb for whether or not it will be cold and snowy in the south and East because of how it could fully lat connect with the SER when there’s a -PNA / western trough. Last winter we all learned the lesson that a -NAO doesn’t necessarily mean cold and snow in the mid Atlantic when there’s a hostile pacific driving the trough into SW Canada. Great stuff

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33 minutes ago, snowfan said:

That post was far too long to quote. Why start with the 57-58 season for the analysis of seasons with >= 25” with the statement that these winters used to happen regularly?

The 57-58 season just so happens to be the beginning of arguably our most prolific period of seasonal snowfall on record at BWI. In fact, BWI reported 7 seasons of >= 25” snowfall in the 10 year period starting with 57-58 with an average over 30”. In the decade prior, it didn’t happen once. Why was that 10 year stretch left out of the analysis?

Because the analog set limits you to 20 seasons and only goes back to 1950.  I would have gone back further if I could.  If we use Baltimores full period of record it’s happened 49 times in 140 years for an average of once every 2.9 years. That’s even more frequent than the number I quoted. I promise I was not trying to skew the data. I just can’t do an analog set for the whole period of record but it wouldn’t change the point.  If anything it would make it more pronounced. 

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We should take all the comments regarding our feelings towards the pattern to banter or my “will it ever snow” thread. I didn’t mean to start this bickering. I was trying to point out what our snowy patterns look like and what does and doesn’t work if we want a 25” plus season. I didn’t mean to start a debate about how we feel about that or what is or isn’t realistic expectations. I’m interested in that debate too but it doesn’t belong here. 

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46 minutes ago, CAPE said:

This pattern might not be exactly what we wanted/expected heading into mid Jan, but there is a mechanism for cold air delivery which is NUMBER ONE if you want snow. Because we are in a Nino, we have an active southward displaced Jetstream, bring disturbances eastward along the flow within it. There is cold enough air at the surface as advertised, and the thermal boundary is in the vicinity and will surely be southward enough periodically for well timed waves to give us chances. The -NAO would help facilitate that despite the less than ideal Pacific. That's what I see anyway.

1705104000-iYjFb5WIB0s.png

1705104000-eQiNvejn1Fc.png

1705104000-L345ZVm0kt0.png

It's subtle but the EPS look is way more workable than the GEFS.  Subtle longwave changes make all the difference for a specific location.  I would still argue that look isn't great if we want a big season, but its certainly workable if we just want to get some snow.  The GEFS look is pretty bad.  

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Geese... I live in far NW Cecil County and for the last week or so I have seen literally thousands and thousands of Geese flying South.  I have been here for over 25 years and never have witnessed anything like this.  Sure I have seen some flocks flying over before but in the last week it has been non-stop!  There have been so many and so loud I can hear them while inside my house!  What this means I have no idea but I can tell you it has not happened like this in the last 25 years! 

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6 minutes ago, ChillinIt said:

Geese... I live in far NW Cecil County and for the last week or so I have seen literally thousands and thousands of Geese flying South.  I have been here for over 25 years and never have witnessed anything like this.  Sure I have seen some flocks flying over before but in the last week it has been non-stop!  There have been so many and so loud I can hear them while inside my house!  What this means I have no idea but I can tell you it has not happened like this in the last 25 years! 

Ditto that up here in Southeastern PA I saw about 5 flocks of geese heading SSE the other day before the heavy rain set in.  I always calculated and observed this, and it snowed like 2 to 3 weeks later after I saw the flocks, just something to keep an eye on.  Mother Nature always knows first!

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19 minutes ago, ChillinIt said:

Geese... I live in far NW Cecil County and for the last week or so I have seen literally thousands and thousands of Geese flying South.  I have been here for over 25 years and never have witnessed anything like this.  Sure I have seen some flocks flying over before but in the last week it has been non-stop!  There have been so many and so loud I can hear them while inside my house!  What this means I have no idea but I can tell you it has not happened like this in the last 25 years! 

They're all coming to eat our excess acorn crop, unless beaten by the woolly caterpillars  (all black or all brown...can't remember ), and the extra thick corn husks; or onion skins; plus whatever else I missed from you folklore guys.

(This is banter, but started as an obs)

Eta; but I'm glad it's on record now; just in case

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31 minutes ago, psuhoffman said:

We should take all the comments regarding our feelings towards the pattern to banter or my “will it ever snow” thread. I didn’t mean to start this bickering. I was trying to point out what our snowy patterns look like and what does and doesn’t work if we want a 25” plus season. I didn’t mean to start a debate about how we feel about that or what is or isn’t realistic expectations. I’m interested in that debate too but it doesn’t belong here. 

It just seems like you keep coming up with different ways of repeatedly writing the same general thing……big snowfall/aa snowfall seasons are less frequent now than in the past. And I don’t see many people on here arguing that overall sentiment. What value comes from repeating it over and over?

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29 minutes ago, ChillinIt said:

Geese... I live in far NW Cecil County and for the last week or so I have seen literally thousands and thousands of Geese flying South.  I have been here for over 25 years and never have witnessed anything like this.  Sure I have seen some flocks flying over before but in the last week it has been non-stop!  There have been so many and so loud I can hear them while inside my house!  What this means I have no idea but I can tell you it has not happened like this in the last 25 years! 

I live near Richmond and saw several flocks flying south today as well. I looked up at them and thought that was strange for this time of year too.

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1 hour ago, WinterWxLuvr said:

We are talking about two different things. I’m not talking about heights relative to normal. Draw a curve from Montana down to Texas around and up to the Carolina coast. That’s what I mean by a broad trough. These troughs that look like a cucumber from Wisconsin down to Ga and back up to Mass ain’t gonna do it. For one they get booted out easily. They last a day. Broad troughs give you a supply of cold to our nw that can get tapped. It also leaves room for secondary development on the tail end of fronts that do sweep through. Just my take.

I agree a broad bowl shaped trough is better... but we want the main trough axis to be in the east and the lowest height anomalies to be centered to our south not our northwest.  We can do good with a full CONUS trough with some -PNA in a split flow so long as the deeper end of the trough is in the east and centered south of us.  That look people were posting from the long range ensemble guidance is a broad trough but its centered way too far west and would put us on the warm side of almost any amplified wave.  

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I agree a broad bowl shaped trough is better... but we want the main trough axis to be in the east and the lowest height anomalies to be centered to our south not our northwest.  We can do good with a full CONUS trough with some -PNA in a split flow so long as the deeper end of the trough is in the east and centered south of us.  That look people were posting from the long range ensemble guidance is a broad trough but its centered way too far west and would put us on the warm side of almost any amplified wave.  

The fact that all the modeling looks like crap now when we expected the opposite look is pretty discouraging on the 1st day of the pattern change. Proud of you for holding it together. Today reminds me of every day last winter
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32 minutes ago, snowfan said:

It just seems like you keep coming up with different ways of repeatedly writing the same general thing……big snowfall/aa snowfall seasons are less frequent now than in the past. And I don’t see many people on here arguing that overall sentiment. What value comes from repeating it over and over?

this seems to be the exact kind of post I said didn't belong in this thread, but thanks.  You could have told me this in banter or the "will it snow again" thread.  My main post was purely about the pattern... then we get 500 replies about what our expectations should be or whether I am being fair holding us to whatever "good" standard I used to pick my analog pattern.  Then I reply and get told I am derailing the thread.  

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2 minutes ago, Ji said:


The fact that all the modeling looks like crap now when we expected the opposite look is pretty discouraging on the 1st day of the pattern change. Proud of you for holding it together. Today reminds me of every day last winter

It is what it is.  I've seen troubling signs that have started to make me a little nervous regarding my expectations for this winter for a while now.  But I tried to keep it on the down low because I knew what the reaction would be.  Unfortunately I've been on here way too long and everyone knows my tells, and I am not particularly good at hiding my thoughts.  

I am not convinced it's all going sideways yet.  There is time to pull out of this.  Maybe, just maybe, the pacific ridge is temporary and we simply can't see past it yet.  I did think that honestly and still think its a strong possibility.  But the amplitude of that ridge is starting to really go ape on the long range guidance, and the forcing is getting stuck in the MC again like the last few years.  Frankly I am seeing a lot of similarities to what happened in 2019 and it bothers me.  We did "OK" wrt snowfall that year but a lot of that came early in January during a flux in the pattern, once the pacific ridge set in it was pretty crappy the rest of the winter.  

The euro is better but honestly I don't love where its trending either.  I think your weeklies post was legit and I don't know why so many took issue with it.  The weeklies for a long time showed the pattern we wanted setting in by late December.  Then it pushed it to mid January.  And now its punting January but has that look in February.  That pattern disturbs me, its exactly what happened in 2019.  I know the running theory, and I fully bought into it also so I am at fault here too, was that the issue was the nino was too weak.  But what if the issue has nothing to do with enso and we are trying to mitigate something with other things when the only solution is for the root cause to stop which is more rooted in the pattern AROUND enso not enso itself!  

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