2013-14 MA Winter Disco - 'cause it's never too early.

[mappy]

According to Wes's graph, we seem to have a higher # of 4"+ events when in both a +AO/NAO as opposed to a -NAO and +AO

 

gotcha, thanks!

[mattie g]

which in stupid people terms, means what?

 

First time someone has lumped me in the not-stupid crowd in a while!

 

Basically if we are going to have a +AO all winter it is better that the NAO be + as well

 

Exactly.  I see things fairly simplistically because I don't know anything about SSW and tropopause folding and sting jets and solar and all that other jazz.  And I don't really know the reasons why the atmosphere does what it does.  But I understand graphs, and I'm pulling for a +NAO until someone tells me otherwise!

[H2O]

First time someone has lumped me in the not-stupid crowd in a while!

 

 

Exactly.  I see things fairly simplistically because I don't know anything about SSW and tropopause folding and sting jets and solar and all that other jazz.  And I don't really know the reasons why the atmosphere does what it does.  But I understand graphs, and I'm pulling for a +NAO until someone tells me otherwise!

 

But key in that is if the PNA(pacific) will be in a state to help.  Without it a +AO/NAO will mean mowing in january

[WxUSAF]

According to Wes's graph, we seem to have a higher # of 4"+ events when in both a +AO/NAO as opposed to a -NAO and +AO

 

 

Basically if we are going to have a +AO all winter it is better that the NAO be + as well

 

 

gotcha, thanks!

 

I'd still caveat about the statistics of small numbers.  There's also the fact that the AO and NAO have a high (but not perfect) correlation.  So, basically, they often have the same sign because the weather patterns that makes one have a particular sign also makes the other have the same sign.  That's not always true, but it's true more often than not.  I bet someone could post a chart of that to make sure I'm not talking out my rear end.  

 

The point is, I think one reason there's a low amount of snow events with a +AO/-NAO is because that doesn't happen often and doesn't last very long when it does happen.  +AO/+NAO happens WAY more often.  So, I'm still going to root for a -NAO and -AO in all situations.    

[mappy]

too many signs for me to understand

[usedtobe]

I'd still caveat about the statistics of small numbers.  There's also the fact that the AO and NAO have a high (but not perfect) correlation.  So, basically, they often have the same sign because the weather patterns that makes one have a particular sign also makes the other have the same sign.  That's not always true, but it's true more often than not.  I bet someone could post a chart of that to make sure I'm not talking out my rear end.  

 

The point is, I think one reason there's a low amount of snow events with a +AO/-NAO is because that doesn't happen often and doesn't last very long when it does happen.  +AO/+NAO happens WAY more often.  So, I'm still going to root for a -NAO and -AO in all situations.    

I think that is totally true about the +AO and -nao since the AO is calculated using more area it is tough to get a negative nao with a positive AO.  I'm still little surprised by how many negative AO and positive NAO 4 inch events that should also be kind of rare using the same logic.  The bottom line is having a negative AO is the thing I'll root for most and hope it also results in a negative NAO but won't worry too much if it doesn't. 

[H2O]

too many signs for me to understand

 

Like this?

 

[Bob Chill]

I think that is totally true about the +AO and -nao since the AO is calculated using more area it is tough to get a negative nao with a positive AO.  I'm still little surprised by how many negative AO and positive NAO 4 inch events that should also be kind of rare using the same logic.  The bottom line is having a negative AO is the thing I'll root for most and hope it also results in a negative NAO but won't worry too much if it doesn't. 

 

Wes, I think it's also worthy of pointing out the fluid state of the AO/NAO leading up to events. Taking a snapshot on the day of the event tells a good bit of the story but not all of it. I'm not at all suggesting that you should do anything to the data because it is spot on as is. Just another consideration. I think the NAO would be more significant irt the days preceding an event because it's much more volitile and has a more direct impact on the sensible outcome of a specific event. 

 

I did a quick data scan this AM with Nov AO monthly readings and what happens in Dec. Strong +AOs Nov have pretty high correlation bleeding into December. Pretty much along the same lines of thinking when we looked at Dec AO's and it makes sense. When anomalous, the AO is a slow mover. I would have to graph the dailies to get a better idea of the behavior over the 2 month span. Monthlies can be misleading at times. 

 

Here's a breakdown of all Novembers since 1950 when the AO averaged +.5 or more:

 

 

78 and 01 are the only 2 real "flip years". There is definitely a bias towards a +AO Dec overall. 

 

Looking at CPC guidance implies that the first half of Nov will likely average +2.0 or so. Who knows if that will verify and how the second half shakes out. 

 

 

 

It's probably worth revisiting in a couple weeks. We may have some clues to consider for Dec. 

[usedtobe]

Wes, I think it's also worthy of pointing out the fluid state of the AO/NAO leading up to events. Taking a snapshot on the day of the event tells a good bit of the story but not all of it. I'm not at all suggesting that you should do anything to the data because it is spot on as is. Just another consideration. I think the NAO would be more significant irt the days preceding an event because it's much more volitile and has a more direct impact on the sensible outcome of a specific event. 

 

I did a quick data scan this AM with Nov AO monthly readings and what happens in Dec. Strong +AOs Nov have pretty high correlation bleeding into December. Pretty much along the same lines of thinking when we looked at Dec AO's and it makes sense. When anomalous, the AO is a slow mover. I would have to graph the dailies to get a better idea of the behavior over the 2 month span. Monthlies can be misleading at times. 

 

Here's a breakdown of all Novembers since 1950 when the AO averaged +.5 or more:

 

AO NOV.JPG

 

78 and 01 are the only 2 real "flip years". There is definitely a bias towards a +AO Dec overall. 

 

Looking at CPC guidance implies that the first half of Nov will likely average +2.0 or so. Who knows if that will verify and how the second half shakes out. 

 

Current AO.JPG

 

 

It's probably worth revisiting in a couple weeks. We may have some clues to consider for Dec. 

Mike Ventice says the current AO forecasts might be misleading as the real strong negative height anomalies don't fit the loading pattern.  However, I'm guessing that the calculations are the same as found in the CPS record.   Hopefully,  the month will not average as high as it looks.  Thanks for the stats.  I've been leaning towards a positive AO dec for the last couple of weeks. 

[snow.]

Mike Ventice says the current AO forecasts might be misleading as the real strong negative height anomalies don't fit the loading pattern.  However, I'm guessing that the calculations are the same as found in the CPS record.   Hopefully,  the month will not average as high as it looks.  Thanks for the stats.  I've been leaning towards a positive AO dec for the last couple of weeks.

 

I am so confused about December

[WinterWxLuvr]

I am so confused about December

Wait 8 weeks.  It'll be more clear then.

[snow.]

Wait 8 weeks.  It'll be more clear then.

 

I have to do an outlook in the next week

[WinterWxLuvr]

I have to do an outlook in the next week

 

I don't envy you that one.

 

Go for near normal temps and below normal snow.  If you're right, nobody is caught unaware.  If you're wrong, most people are happy with a snowy Dec. (before the wusses start yapping about spring).

[Bob Chill]

I have to do an outlook in the next week

 

Yea, I'm a little rattled too. Having a +AO Dec isn't a death knell but it stacks the odds against a cold month overall. Most Decembers with an AO of +1 or greater on the month are either warm coast to coast or cold only in the west. However, there are some ways to get cold here and it seems to hinge almost exclusively on the EPO being negative. The more the better. I picked out a couple years that managed to be cold in Dec for the east. 

 

Dec of 88 was good. The month as a whole looks similar to the composite below but the first 15 days really show what I'm talking about:

 

 

 

2004 was another year that went chilly in the east in the face of a +AO:

 

 

 

I've been thinking that we start cold this year for months and I'm not going to back down yet. I do find all the +AO talk a little disconcerting but I'm not ready to buy anything. If this month features a pretty strong +AO it could easily be on the wane during December. Especially during the second half. 

 

I don't envy you having to make an outlook. 

[EastCoast NPZ]

I have to do an outlook in the next week

 

Above normal temps and below normal precip is usually a safe call.

[snow.]

I don't envy you that one.

 

Go for near normal temps and below normal snow.  If you're right, nobody is caught unaware.  If you're wrong, most people are happy with a snowy Dec. (before the wusses start yapping about spring).

 

I want to get the months right..snow is pretty easy

[snow.]

Yea, I'm a little rattled too. Having a +AO Dec isn't a death knell but it stacks the odds against a cold month overall. Most Decembers with an AO of +1 or greater on the month are either warm coast to coast or cold only in the west. However, there are some ways to get cold here and it seems to hinge almost exclusively on the EPO being negative. The more the better. I picked out a couple years that managed to be cold in Dec for the east. 

 

Dec of 88 was good. The month as a whole looks similar to the composite below but the first 15 days really show what I'm talking about:

 

dec1-15 1988.JPG

 

 

2004 was another year that went chilly in the east in the face of a +AO:

 

dec 2004.JPG

 

 

I've been thinking that we start cold this year for months and I'm not going to back down yet. I do find all the +AO talk a little disconcerting but I'm not ready to buy anything. If this month features a pretty strong +AO it could easily be on the wane during December. Especially during the second half. 

 

I don't envy you having to make an outlook. 

 

2004 ended up being pretty normal here....I think a +<1

 

I am leaning toward cold as well, but I am worried that ENSO is too neutral...If I knew 3.4 would cool again, I would go cold...I like the idea of a decent PAC and a undetermined Atlantic...so I don't know...Maybe I should cop out and just go normal

[Bob Chill]

2004 ended up being pretty normal here....I think a +<1

 

I am leaning toward cold as well, but I am worried that ENSO is too neutral...If I knew 3.4 would cool again, I would go cold...I like the idea of a decent PAC and a undetermined Atlantic...so I don't know...Maybe I should cop out and just go normal

 

It could be normal overall but with 2 opposite extreme periods....

[usedtobe]

I am so confused about December

 

Heck, I'm confused about the entire winter as there seem to be conflicting signals.  I've put together scatter diagrams for 8 inch or greater events as well as the 4 inch or greater. I'm not going to post them yet as I want to use them in a CWG article.    Almost all the 8 inch or greater events have a positive PNA and a negative AO and NAO.    There are no events with the  AO and NAO both being positive.   Also,  1979 is kind of misleading as the NAO was strongly negative right up to the day of the event and it then collapsed as the pattern broke.   

[snow.]

Heck, I'm confused about the entire winter as there seem to be conflicting signals.  I've put together scatter diagrams for 8 inch or greater events as well as the 4 inch or greater. I'm not going to post them yet as I want to use them in a CWG article.    Almost all the 8 inch or greater events have a positive PNA and a negative AO and NAO.    There are no events with the  AO and NAO both being positive.   Also,  1979 is kind of misleading as the NAO was strongly negative right up to the day of the event and it then collapsed as the pattern broke.   

 

 

yes...though I am less confused about snow, as I don't think there is any reason to think there will be a robust southern stream...

[Bob Chill]

Wes, my general thoughts have been that there will be no prolonged favorable or unfavorable patterns like we've seen lately. We've have a little run of a tale of 2 winters but I have my doubts that will continue this year. 

 

My best WAG is an overall normal winter irt temps but windows of opportunity presenting themselves every 2-3 weeks. Less than climo snow of course unless we do thread/phase something. 

[usedtobe]

yes...though I am less confused about snow, as I don't think there is any reason to think there will be a robust southern stream...

The MJO could work with the GWO to give us a period with a southern stream but in general I agree with you. 

[snow.]

It could be normal overall but with 2 opposite extreme periods....

 

We have seen that Nina or faux Nina, particularly if weak has a -AO in December...doesn't necessarily mean cold...1996 was a torch even with the strong -AO, as there was a huge -PNA and a ridge to our northeast...

 

Not sure how Nina-esque this winter will be....But I can't wait until November 20th to see if there is some intransigent vortex locked up over the EPO region, so I can go warm...in past winters we have know the deal by end of November that December would be a disaster

[WxUSAF]

Yea, I'm a little rattled too. Having a +AO Dec isn't a death knell but it stacks the odds against a cold month overall. Most Decembers with an AO of +1 or greater on the month are either warm coast to coast or cold only in the west. However, there are some ways to get cold here and it seems to hinge almost exclusively on the EPO being negative. The more the better. I picked out a couple years that managed to be cold in Dec for the east. 

 

Dec of 88 was good. The month as a whole looks similar to the composite below but the first 15 days really show what I'm talking about:

 

dec1-15 1988.JPG

 

 

2004 was another year that went chilly in the east in the face of a +AO:

 

dec 2004.JPG

 

 

I've been thinking that we start cold this year for months and I'm not going to back down yet. I do find all the +AO talk a little disconcerting but I'm not ready to buy anything. If this month features a pretty strong +AO it could easily be on the wane during December. Especially during the second half. 

 

I don't envy you having to make an outlook. 

This is why EPO and WPO are double edged swords for us.  The -EPO ridge like is setting up now is too far to the west, so we get a west coast trough and the SE ridge goes A-Rod or Big Sloppy on us.  But at the same time, it gets Canada (our source region) really really cold, so that doesn't hurt.  

 

-EPO and -WPO help us when they are monstrous and expand to include the PNA region.  This teleconnects to an eastern CONUS trough and then they usually dislodge the PV to the south and we can get some epic cold air blasts.  You can see that sort of in the 2nd chart you posted for 94.  The ridging includes the PNA region, so we're in a bit of a trough.  But the EPO/WPO ridging didn't extend all the way to the pole, so the AO stayed positive and we didn't get really cold as Matt pointed out.  

[ORH_wxman]

This is why EPO and WPO are double edged swords for us.  The -EPO ridge like is setting up now is too far to the west, so we get a west coast trough and the SE ridge goes A-Rod or Big Sloppy on us.  But at the same time, it gets Canada (our source region) really really cold, so that doesn't hurt.  

 

-EPO and -WPO help us when they are monstrous and expand to include the PNA region.  This teleconnects to an eastern CONUS trough and then they usually dislodge the PV to the south and we can get some epic cold air blasts.  You can see that sort of in the 2nd chart you posted for 94.  The ridging includes the PNA region, so we're in a bit of a trough.  But the EPO/WPO ridging didn't extend all the way to the pole, so the AO stayed positive and we didn't get really cold as Matt pointed out.  

 

 

 

We generally want the EPO ridge to setup almost right smack over AK if we are trying to offset a +NAO..or maybe even a little east as you mentioned....December 1983 was probably the best example of this. We had a +NAO/+AO combo, but the one spot where we had mega-high heights was the EPO region over AK and it led to the coldest December on record for the U.S. A result you wouldn't expect if you just looked at the AO and NAO numbers...but makes more sense when looking at the actual maps. If it was just a smidge east, it probably would have been a bit colder in the east.

 

[HM]

 

We have seen that Nina or faux Nina, particularly if weak has a -AO in December...doesn't necessarily mean cold...1996 was a torch even with the strong -AO, as there was a huge -PNA and a ridge to our northeast...

 

Not sure how Nina-esque this winter will be....But I can't wait until November 20th to see if there is some intransigent vortex locked up over the EPO region, so I can go warm...in past winters we have know the deal by end of November that December would be a disaster

 

If you compare ENSO analogs (subtract groups of neutral ENSO--all which have 2013's SST setup over Equator) where just the N PAC SST configuration is different, you tend to see a bias toward cooler (warmer) in December and warmer (cooler) in February during a -PDO/2013-configuration (+PDO). But averaging them separately and altogether basically shows the typical RNA / SE-ridge.

When I make ENSO/PDO type of composites, I try to use the analog in its appropriate climate period. So, for example, if you are using 1961-62, I wouldn't apply the 1981-2010 period to compare configurations. Obviously, 61-62 will be cooler all-around. If you place it in 1950-1980, or something, you'll see that it has a configuration a lot like this year.

[Ji]

merry christmas

 

http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/images/CFSv2.NaT2m.20131101.201312.gif

[snow.]

 

 

If you compare ENSO analogs (subtract groups of neutral ENSO--all which have 2013's SST setup over Equator) where just the N PAC SST configuration is different, you tend to see a bias toward cooler (warmer) in December and warmer (cooler) in February during a -PDO/2013-configuration (+PDO). But averaging them separately and altogether basically shows the typical RNA / SE-ridge.

When I make ENSO/PDO type of composites, I try to use the analog in its appropriate climate period. So, for example, if you are using 1961-62, I wouldn't apply the 1981-2010 period to compare configurations. Obviously, 61-62 will be cooler all-around. If you place it in 1950-1980, or something, you'll see that it has a configuration a lot like this year.

 

 

Thanks...though not sure I totally understand your use of parentheses in your post and how it reads, or your 2nd paragraph and what you mean by that...though I was looking at 61-62 earlier and deciding whether it is on the table...

[usedtobe]

HM,

 

For vortex weakening don't we want a vortex neat the Aleutians (northern Pacific)?   Instead the GEFS ensembles thru 300 hrs are showing above normal heights where we'd like below normal or am I off base?  I remember reading a paper on that with wave 1 and 2 EP flux in it and thought that was what I could take from the paper. 

[donsutherland1]

merry christmas

 

http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/images/CFSv2.NaT2m.20131101.201312.gif

Have a great one, Ji.