January Medium/Long Range Discussion

[CAPE]

Just now, nj2va said:

I’ll take a +PNA over a -NAO. 

-AO is king. -NAO typically occurs concurrently. Tough to beat for cold/snow in these parts. We can do fine with a -PNA, and some of our best storms have occurred with the PNA negative, but not severely so, like we can tend to see in a Nina. I would guess the -AO/NAO and -PNA combo mostly produces in a Nino winter for the DC area, but psu is the man to confirm or debunk that.

[IronTy]

19 minutes ago, CAPE said:

He hammered it. Beat the living eff out the dead horse. He was right. That said, a persistent -PNA is highly correlated to a Nina. One simple post would have done the trick. Didn't really need 100+.

Idk, I'll give him more credit for really hammering it home and commiting to it 100 percent.  One post woulda been meh.  100 posts and you have to wonder...what is his secret sauce?

[WEATHER53]

2 hours ago, Scraff said:

Tomorrow will bring something different and entirely new. I’ll just close my blinds until the morning. 

Cover all the bases to claim accuracy no matter which way it turns out.  That’s why beyond 5 days is useless 

[StormchaserChuck!]

21 minutes ago, CAPE said:

-AO is king. -NAO typically occurs concurrently. Tough to beat for cold/snow in these parts. We can do fine with a -PNA, and some of our best storms have occurred with the PNA negative, but not severely so, like we can tend to see in a Nina. I would guess the -AO/NAO and -PNA combo mostly produces in a Nino winter for the DC area, but psu is the man to confirm or debunk that.

I think EPO is king, because cold air sits over land. -EPO/+NAO Winter's were pretty impressively cold, 

01-02 was kind of -NAO/+EPO

97-98 was -NAO too lol

 

 

[CAPE]

5 minutes ago, StormchaserChuck! said:

I think EPO is king, because cold air sits over land. -EPO/+NAO Winter's were pretty impressively cold, 

01-02 was kind of -NAO/+EPO

A -EPO can deliver some big cold yes, but also can be dry. In conjunction with a +AO/+NAO, amped storms have the tendency to cut NW.

-AO has the strongest correlation to significant snow for the DC area.

[StormchaserChuck!]

-AO correlates to +PNA.

(AO minus NAO)

[psuhoffman]

2 hours ago, CAPE said:

-AO is king. -NAO typically occurs concurrently. Tough to beat for cold/snow in these parts. We can do fine with a -PNA, and some of our best storms have occurred with the PNA negative, but not severely so, like we can tend to see in a Nina. I would guess the -AO/NAO and -PNA combo mostly produces in a Nino winter for the DC area, but psu is the man to confirm or debunk that.

Skip to the bold paragraph if you just want the simple simple simple abridged answer…

I think we’re falling prey to both recency bias and some attempts to over simplify with the “it’s the Nina” stuff I’m seeing.  Let me again post the mean Dec-Feb h5  for all Nina’s the last 30 years to use as a frame of reference. 

Actually a crazy -pna isn’t a common problem in a Nina. At least no more so than it can be for a time in any enso phase.  You can see the tendency for lower heights in western Canada but notice on the means heights are avg in the east and the pac ridge extends into the southwest.  Also our temps avg near normal in Nina’s which is actually colder than if you take all other winters but exclude the 3 modoki ninos we’ve had during that time.  The 2 major correlations with a Nina are the central pac ridge and weaker STJ. 
 

You’re seeing the smoothing of 2 different Nina patterns there though.  In a Nina when there is a flatter pac ridge and no HL help we see the pac jet blast N America. 
 

But Typically in a Nina pattern when there is a more poleward pac ridge and or some HL blocking we see the cold spread out across N America centered in western Canada but extending into the northeast.  Neither typically features what we’re seeing now though!

 

And the current pna is bordering on possibly setting the December record. Last I saw it was just behind as the lowest pna but with what’s forecast the rest of the month I would bet it ends as the most neg pna December ever. Just that fact alone shows we’re dealing with something anomalous that we can’t just attribute to “typical Nina”. This hasn’t happened in any other Nina lol. 

Now let me simplify our snow chances as I see them based on major phases.  It’s the STJ. Both Nina’s and ninos can have variable longwave features and both favorable and negative features and in the last 30 years there isn’t much difference in mean temps in a Nina v Nino. Both can feature cold and warm periods. But a Nino favors more stj and we need that!  That stacks the deck that if/when we do get some cold we get a big snow. Look at 1983 and 2016!  And if we get lucky and get a good longwave pattern and blocking in a Nino then we get 1987/2003/2010!  But that’s not all ninos either. But if you remove all the big stj driven snows from ninos the snow climo wouldn’t look any better than Nina’s!  The problem in a Nina is often when we do get long cold stretches without the STJ it’s just dry. We’re too far south to get a lot of snow from pure NS storms. 
 

Last thought:  we’ve all noticed the pac base state of the last 6 years. And even the Nino of 2019 couldn’t disrupt it much. Maybe this is what happens when you add a second year Niña in top of that base state and so maybe this is the new “typical Nina” if the pac is going to remain in this phase.  But we didn’t have this amount of issue with the pna last year once blocking set in. But this is a second year Niña so…

[psuhoffman]

36 minutes ago, CAPE said:

-AO is king. -NAO typically occurs concurrently. Tough to beat for cold/snow in these parts. We can do fine with a -PNA, and some of our best storms have occurred with the PNA negative, but not severely so, like we can tend to see in a Nina. I would guess the -AO/NAO and -PNA combo mostly produces in a Nino winter for the DC area, but psu is the man to confirm or debunk that.

Follow up on the pna. It’s about degrees. Everything is a trade off. See saw wave game!  We can do well in a -pna if the equation is balanced by the AO/NAO. That’s not possible when the pna is 5 std dev lol. 

[CAPE]

26 minutes ago, psuhoffman said:

Skip to the bold paragraph if you just want the simple simple simple abridged answer…

I think we’re falling prey to both recency bias and some attempts to over simplify with the “it’s the Nina” stuff I’m seeing.  Let me again post the mean Dec-Feb h5  for all Nina’s the last 30 years to use as a frame of reference. 

Actually a crazy -pna isn’t a common problem in a Nina. At least no more so than it can be for a time in any enso phase.  You can see the tendency for lower heights in western Canada but notice on the means heights are avg in the east and the pac ridge extends into the southwest.  Also our temps avg near normal in Nina’s which is actually colder than if you take all other winters but exclude the 3 modoki ninos we’ve had during that time.  The 2 major correlations with a Nina are the central pac ridge and weaker STJ. 
 

You’re seeing the smoothing of 2 different Nina patterns there though.  In a Nina when there is a flatter pac ridge and no HL help we see the pac jet blast N America. 
 

But Typically in a Nina pattern when there is a more poleward pac ridge and or some HL blocking we see the cold spread out across N America centered in western Canada but extending into the northeast.  Neither typically features what we’re seeing now though!

 

And the current pna is bordering on possibly setting the December record. Last I saw it was just behind as the lowest pna but with what’s forecast the rest of the month I would bet it ends as the most neg pna December ever. Just that fact alone shows we’re dealing with something anomalous that we can’t just attribute to “typical Nina”. This hasn’t happened in any other Nina lol. 

Now let me simplify our snow chances as I see them based on major phases.  It’s the STJ. Both Nina’s and ninos can have variable longwave features and both favorable and negative features and in the last 30 years there isn’t much difference in mean temps in a Nina v Nino. Both can feature cold and warm periods. But a Nina favors more stj and we need that!  That stacks the deck that if/when we do get some cold we get a big snow. Look at 1983 and 2016!  And if we get lucky and get a good longwave pattern and blocking in a Nino then we get 1987/2003/2010!  But that’s not all ninos either. But if you remove all the big stj driven snows from ninos the snow climo wouldn’t look any better than Nina’s!  The problem in a Nina is often when we do get long cold stretches without the STJ it’s just dry. We’re too far south to get a lot of snow from pure NS storms. 
 

Last thought:  we’ve all noticed the pac base state of the last 6 years. And even the Nino of 2019 couldn’t disrupt it much. Maybe this is what happens when you add a second year Niña in top of that base state and so maybe this is the new “typical Nina” if the pac is going to remain in this phase.  But we didn’t have this amount of issue with the pna last year once blocking set in. But this is a second year Niña so…

Thanks, good post. In the bolded, you meant Nino favors stj, not Nina.

And yes that is a major factor at our latitude to get bigger storms, and that's the big difference- in a Nino with an active stj we can score a big event or 2, and the winter as a whole is not necessarily even very cold. Combined with a -AO/NAO, we get the opportunity for a much more favorable storm track to maximize chances. 2009-10 was just cold enough with the -AO/NAO plus the active southern jet.

[RDM]

24 minutes ago, psuhoffman said:

Skip to the bold paragraph if you just want the simple simple simple abridged answer…

I think we’re falling prey to both recency bias and some attempts to over simplify with the “it’s the Nina” stuff I’m seeing.  Let me again post the mean Dec-Feb h5  for all Nina’s the last 30 years to use as a frame of reference. 

Actually a crazy -pna isn’t a common problem in a Nina. At least no more so than it can be for a time in any enso phase.  You can see the tendency for lower heights in western Canada but notice on the means heights are avg in the east and the pac ridge extends into the southwest.  Also our temps avg near normal in Nina’s which is actually colder than if you take all other winters but exclude the 3 modoki ninos we’ve had during that time.  The 2 major correlations with a Nina are the central pac ridge and weaker STJ. 
 

You’re seeing the smoothing of 2 different Nina patterns there though.  In a Nina when there is a flatter pac ridge and no HL help we see the pac jet blast N America. 
 

But Typically in a Nina pattern when there is a more poleward pac ridge and or some HL blocking we see the cold spread out across N America centered in western Canada but extending into the northeast.  Neither typically features what we’re seeing now though!

 

And the current pna is bordering on possibly setting the December record. Last I saw it was just behind as the lowest pna but with what’s forecast the rest of the month I would bet it ends as the most neg pna December ever. Just that fact alone shows we’re dealing with something anomalous that we can’t just attribute to “typical Nina”. This hasn’t happened in any other Nina lol. 

Now let me simplify our snow chances as I see them based on major phases.  It’s the STJ. Both Nina’s and ninos can have variable longwave features and both favorable and negative features and in the last 30 years there isn’t much difference in mean temps in a Nina v Nino. Both can feature cold and warm periods. But a Nina favors more stj and we need that!  That stacks the deck that if/when we do get some cold we get a big snow. Look at 1983 and 2016!  And if we get lucky and get a good longwave pattern and blocking in a Nino then we get 1987/2003/2010!  But that’s not all ninos either. But if you remove all the big stj driven snows from ninos the snow climo wouldn’t look any better than Nina’s!  The problem in a Nina is often when we do get long cold stretches without the STJ it’s just dry. We’re too far south to get a lot of snow from pure NS storms. 
 

Last thought:  we’ve all noticed the pac base state of the last 6 years. And even the Nino of 2019 couldn’t disrupt it much. Maybe this is what happens when you add a second year Niña in top of that base state and so maybe this is the new “typical Nina” if the pac is going to remain in this phase.  But we didn’t have this amount of issue with the pna last year once blocking set in. But this is a second year Niña so…

PSU,

    The part in bold echos with an interview I had with a pro Met back in Ohio in 80 when I was trying to decide whether to go to Case Western and transfer to PSU for Met School.  (I didn't).  Remember vividly him saying without a STJ in the game to provide the moisture tap into the GOM and/or an ingredient for a phase, it is difficult to get a major snow in the eastern third of the nation from Ohio S and Eastward.   Realize Ohio isn't the Mid Atlantic, but where we lived ivo Dayton we were just far enough south for the 40N "natural boundary" to be a major player in our weather.  Same for the M-D for most of us around here.  

[CAPE]

 

[StormchaserChuck!]

09-10 sucked, we had 30% of what the records show because everything melted so fast. 

[clskinsfan]

sorry wrong thread

[cbmclean]

23 minutes ago, CAPE said:

 

What is "P2" and "LC2"?

[BristowWx]

6 minutes ago, StormchaserChuck! said:

09-10 sucked, we had 30% of what the records show because everything melted so fast. 

When we tally the final score for this winter I have a sneaky suspicion we will be quite surprised how it sucked way more than what we initially thought it would

[anotherman]

09-10 sucked, we had 30% of what the records show because everything melted so fast. 

Hahahaha it most certainly did not suck. Maybe not wall to wall winter, but there were three storms of 20 inches or more.

[CAPE]

1 minute ago, cbmclean said:

What is "P2" and "LC2"?

LC2 = cyclonic wave breaking equatorward

P2 = anticyclonic wave breaking poleward

[RIC_WX]

1 hour ago, nj2va said:

I’ll take a +PNA over a -NAO. 

The Garrett crowd concurs here for sure.  :-)

[Solution Man]

11 minutes ago, BristowWx said:

When we tally the final score for this winter I have a sneaky suspicion we will be quite surprised how it sucked way more than what we initially thought it would

Not shaping up well, is it?

[WinterWxLuvr]

1 hour ago, nj2va said:

I’ll take a +PNA over a -NAO. 

Me too. Hallelujah somebody said it.

The Pacific drives the bus. The Atlantic may cause an emergency stop that allows for a big snow, but the Pacific is large and in charge.

[BristowWx]

3 minutes ago, Solution Man said:

Not shaping up well, is it?

I can’t help but think delayed is denied.  Hunting is fun but so is eating…you gotta eat eventually or you starve.  

[Stormfly]

38 minutes ago, StormchaserChuck! said:

09-10 sucked, we had 30% of what the records show because everything melted so fast. 

It sucked for those that only had a shovel and a bad back!

[clskinsfan]

3 hours ago, EastCoast NPZ said:

Just checking in today and see the models have brought tidings of great joy.  Just great.  Perfect.

Nothing better than Speedo's on Christmas morning friend. 

[IronTy]

26 minutes ago, anotherman said:

Hahahaha it most certainly did not suck. Maybe not wall to wall winter, but there were three storms of 20 inches or more.

Yeah, 100% suckage all winter long. 

[psuhoffman]

2 hours ago, WEATHER53 said:

Cover all the bases to claim accuracy no matter which way it turns out.  That’s why beyond 5 days is useless 

Trying to ask this as respectfully as possible. So if you think there is no value to long range forecasting why do you come into the long range thread?  

[Eskimo Joe]

42 minutes ago, anotherman said:

Hahahaha it most certainly did not suck. Maybe not wall to wall winter, but there were three storms of 20 inches or more.

That was the best winter of my life. The only thing that would've made it better is if the December snow lasted for Christmas.

[psuhoffman]

1 hour ago, StormchaserChuck! said:

09-10 sucked, we had 30% of what the records show because everything melted so fast. 

Dude 

[psuhoffman]

Wrt these “what single factor is most important” arguments it depends on the degree and what combinations were talking about. For instance a mildly positive pna with a +epo/AO/NAO wont to us any good. 
 

What I can say is this, historically the -AO/NAO is the single factor that shows up the most in our warning level snows. Again I think we’re falling victim to recency bias because we’ve had a few -NAOs ruined by flat out awful atrocious pacific patterns recently.  That’s not necessarily how it would always work. But the pac base state has been so bad lately…yea we need that to relax. But it won’t necessarily do any good if the AO goes to crap. Truth is we need more than just any one thing to be somewhat favorable to get snow.  

[nj2va]

20 minutes ago, psuhoffman said:

Wrt these “what single factor is most important” arguments it depends on the degree and what combinations were talking about. For instance a mildly positive pna with a +epo/AO/NAO wont to us any good. 
 

What I can say is this, historically the -AO/NAO is the single factor that shows up the most in our warning level snows. Again I think we’re falling victim to recency bias because we’ve had a few -NAOs ruined by flat out awful atrocious pacific patterns recently.  That’s not necessarily how it would always work. But the pac base state has been so bad lately…yea we need that to relax. But it won’t necessarily do any good if the AO goes to crap. Truth is we need more than just any one thing to be somewhat favorable to get snow.  

I feel like the look in early January (from yesterday/two days ago) would work for us…high heights in the AO/NAO and the pacific ridge shifted east just enough to mute the SE ridge. If we can just get a bit of help from the Pacific with the current look in the Atlantic we’d be in the game. 
 

and overall I’d rather a favorable Pacific IMO. 

[WinterWxLuvr]

20 minutes ago, psuhoffman said:

Wrt these “what single factor is most important” arguments it depends on the degree and what combinations were talking about. For instance a mildly positive pna with a +epo/AO/NAO wont to us any good. 
 

What I can say is this, historically the -AO/NAO is the single factor that shows up the most in our warning level snows. Again I think we’re falling victim to recency bias because we’ve had a few -NAOs ruined by flat out awful atrocious pacific patterns recently.  That’s not necessarily how it would always work. But the pac base state has been so bad lately…yea we need that to relax. But it won’t necessarily do any good if the AO goes to crap. Truth is we need more than just any one thing to be somewhat favorable to get snow.  

We also had great winters in 2013-2014, and 2014-2015 with no help in the Atlantic. 2012-2013 was decent (location dependent) and 2018-2019 was good. I don’t think those were friendly Atlantic’s either.
 

We have seen this discussion crop up year after year and everyone has their opinion, but for me, I like nickel and dime winters that are frequent and consistent. Not much for the big event and let’s call it a winter type winters.