Jump to content

  • Member Statistics

    17,507
    Total Members
    7,904
    Most Online
    SnowHabit
    Newest Member
    SnowHabit
    Joined

The early speculation on winter 2013-14

weathafella

By weathafella,
in New England

Recommended Posts

NJwinter23

NJwinter23

Posted
Posted

Warm fall? we are below normal for the month

 

Sorry, I was speaking more from a broader national standpoint with regards to using this as an analog year...though it has been somewhat of a sneaky cool month in the northeast (in my opinion) thanks to some chilly morning lows, the country as a whole is having a top 10 warm Sept.

Link to comment
Share on other sites
  • Replies 1.5k
  • Created
  • Last Reply
Ginx snewx

Ginx snewx

Posted
Posted

Sorry, I was speaking more from a broader national standpoint with regards to using this as an analog year...though it has been somewhat of a sneaky cool month in the northeast (in my opinion) thanks to some chilly morning lows, the country as a whole is having a top 10 warm Sept.

we are the center of our universe lol, But seriously NE is influenced much more by N/AO than anything other index
Link to comment
Share on other sites
NJwinter23

NJwinter23

Posted
Posted

we are the center of our universe lol, But seriously NE is influenced much more by N/AO than anything other index

 

 

I think EPO might actually trump that..esp in terms of temps.

 

 

It's tough, we know the AO flat out is not a very reliable indication as sometimes the cold air just doesnt dump into NA (see late Jan 2012 and Dec 2012). But even when you regionalize it into the NAO or EPO, the correlations to temps are not too strong in New England versus elsewhere (though they obviously lean in the direction you'd expect). I think I'm with Scott on the EPO trumping things solely because that is pretty much a lock to dump arctic air into the country. I almost think of the -EPO as more feast or famine (often brings brutal cold but can possibly end up with nothing if it tucks into the West/se ridge is strong) and the -NAO as more even-keeled (not as likely to turn brutally cold in new england but also not as likely to end up warm)..Then theres the whole east-based versus west-based discussion..

Link to comment
Share on other sites
CoastalWx

CoastalWx

Posted
Posted

It's tough, we know the AO flat out is not a very reliable indication as sometimes the cold air just doesnt dump into NA (see late Jan 2012 and Dec 2012). But even when you regionalize it into the NAO or EPO, the correlations to temps are not too strong in New England versus elsewhere (though they obviously lean in the direction you'd expect). I think I'm with Scott on the EPO trumping things solely because that is pretty much a lock to dump arctic air into the country. I almost think of the -EPO as more feast or famine (often brings brutal cold but can possibly end up with nothing if it tucks into the West/se ridge is strong) and the -NAO as more even-keeled (not as likely to turn brutally cold in new england but also not as likely to end up warm)..Then theres the whole east-based versus west-based discussion..

 

I think EP/EPO (whatever you want to call it these days) definitely has a higher correlation with cold here. IIRC, usually a true -EPO will at least subdue the intensity of the SE ridge and keep it cold here...although it's not the same case perhaps south of PHL. My only problem with the -AO/NAO is that it tends to recycle garbage air if the Pacific doesn't allow for more cross polar flow. 

Link to comment
Share on other sites
ORH_wxman

ORH_wxman

Posted
Posted

I think EP/EPO (whatever you want to call it these days) definitely has a higher correlation with cold here. IIRC, usually a true -EPO will at least subdue the intensity of the SE ridge and keep it cold here...although it's not the same case perhaps south of PHL. My only problem with the -AO/NAO is that it tends to recycle garbage air if the Pacific doesn't allow for more cross polar flow. 

 

 

The EPO has the highest correlation to temperatures here out of the main indices...NAO is probably second. EPO is abotu a 0.50 correlation here in Jan/Feb (Dec gives an error on the esrl dataset)...NAO about 0.3 (to 0.4 in CT/RI)

Link to comment
Share on other sites
CoastalWx

CoastalWx

Posted
Posted

The EPO has the highest correlation to temperatures here out of the main indices...NAO is probably second. EPO is abotu a 0.50 correlation here in Jan/Feb (Dec gives an error on the esrl dataset)...NAO about 0.3 (to 0.4 in CT/RI)

 

Yeah I remember you posting about this last winter. Thanks Ginxy for the images. Pretty much a lock to rock with a -EPO.

Link to comment
Share on other sites
ORH_wxman

ORH_wxman

Posted
Posted

Does anyone know why the EPO is not calculated in Dec?

 

 

No, some of us have tried writing to them with no response a few years ago. Its been that way for years now (as far back as I can remember on eastern in the mid-2000s)...they have a bunch of "9999" values in their dataset for December. No clue why.

Link to comment
Share on other sites
radarman

radarman

Posted
Posted

No, some of us have tried writing to them with no response a few years ago. Its been that way for years now (as far back as I can remember on eastern in the mid-2000s)...they have a bunch of "9999" values in their dataset for December. No clue why.

 

I saw that... It says:

"Values are set to -99.90 for calendar months when the pattern is not normally a leading mode of variability"

 

Not sure if this means they actually do calculate it but claim no correlations with anything, therefore don't bother publishing?  How can they say it's not a leading mode if it's not been calculated?  Strange.  Anyway thanks for the response.

Link to comment
Share on other sites
OKpowdah

OKpowdah

Posted
Posted

I saw that... It says:

"Values are set to -99.90 for calendar months when the pattern is not normally a leading mode of variability"

 

Not sure if this means they actually do calculate it but claim no correlations with anything, therefore don't bother publishing?  How can they say it's not a leading mode if it's not been calculated?  Strange.  Anyway thanks for the response.

 

Right, so they calculate the EOFs of SLP/500mb height climatology for each calendar month. This is the source of the definition of most of our indices we know and love. But if in one particular month, the index does not appear as one of the leading EOFs ("leading mode of variability"), then not only is it considered "insignificant" but the index can't even be appropriately calculated without the EOF to project onto.

Link to comment
Share on other sites
ORH_wxman

ORH_wxman

Posted
Posted

 

I saw that... It says:

"Values are set to -99.90 for calendar months when the pattern is not normally a leading mode of variability"

 

Not sure if this means they actually do calculate it but claim no correlations with anything, therefore don't bother publishing?  How can they say it's not a leading mode if it's not been calculated?  Strange.  Anyway thanks for the response.

 

 

It has to be en error because they bother to calculate it for all other months. The EPO most definitely has a high correlation in December.

 

 

Just going by top 10 coldest and top 10 warmest Decembers in the CONUS since 1950:

 

 

 

Top 10 coldest:

 

 z9_FVw_FBg_FZ.png

Top 10 warmest:

WRcw3_Lisi_Z.png

That's about as solid as a signal you can get for the EPO region.

Link to comment
Share on other sites
ORH_wxman

ORH_wxman

Posted
Posted

 

Related: here's the EP/NP index, which also is referenced as a "spring-summer-fall" pattern, and you'll notice the loading pattern is not included for January either.

 

http://www.cpc.ncep.noaa.gov/data/teledoc/ep.shtml

http://www.cpc.ncep.noaa.gov/data/teledoc/ep_map.shtml

That's pretty silly since there's obviously a huge correlation up in that region during the winter months. But I suppose they can define the EP/NP for whatever season they want to.

Regardless, they should have kept the original EPO numbers for December on the esrl dataset...or put them in to begin with. The old EPO index was always used in winter, so I'm not sure what their excuse was for having the missing December data.

Link to comment
Share on other sites
ORH_wxman

ORH_wxman

Posted
Posted

 

So we know correlations for temp are best with EPO and AO/Nao state, precip has much less correlation with these.  PNA and NINO 1.,2 state have higher precip correlations, so given that. An  -EPO, AO, NAO combined with a + PNA with a Nino warming in 1,2 and its, on like Donkey Kong.

 

Now if only we could forecast the EPO/PNA in advance.

We can get an idea of the AO via October SAI which covers part of the EPO domain, but it doesn't guarantee the signs are the same. Then of course there is that nagging issue of snowfall.

Link to comment
Share on other sites
Ginx snewx

Ginx snewx

Posted
Posted

 

 

Now if only we could forecast the EPO/PNA in advance.

We can get an idea of the AO via October SAI which covers part of the EPO domain, but it doesn't guarantee the signs are the same. Then of course there is that nagging issue of snowfall.

Yea , so its all in futility. MPM is right, thread cancel, no use.

Link to comment
Share on other sites
ORH_wxman

ORH_wxman

Posted
Posted

 

Yea , so its all in futility. MPM is right, thread cancel, no use.

 

I think this just points out our limitations beyond a timerange of 2 months. Speculation leads to new ideas though of which a select few of many thousands eventually have some legs and become reliable indicators.

Snow cover in Siberia was not widely used at all about 12-15 years ago, and even when it started getting used, most didn't pay that much attention to it until recently when more evidence came out with its relationship to the AO...using a modified method of course too...ENSO was barely used 20 years ago.

Link to comment
Share on other sites
Ginx snewx

Ginx snewx

Posted
Posted

 

 

I think this just points out our limitations beyond a timerange of 2 months. Speculation leads to new ideas though of which a select few of many thousands eventually have some legs and become reliable indicators.

 

Exactly why even new ideas that seem sort of off the hook should not be dismissed off hand.  The most reliable indicator who has been spot on for the past 6 years shall remain nameless. I am going to start a company using it/him/she. Going to call it Tipsters..lol

Link to comment
Share on other sites
ORH_wxman

ORH_wxman

Posted
Posted

Exactly why even new ideas that seem sort of off the hook should not be dismissed off hand.  The most reliable indicator who has been spot on for the past 6 years shall remain nameless. I am going to start a company using it/him/she. Going to call it Tipsters..lol

 

Good luck with that. :lol:

Link to comment
Share on other sites
CoastalWx

CoastalWx

Posted
Posted

Exactly why even new ideas that seem sort of off the hook should not be dismissed off hand.  The most reliable indicator who has been spot on for the past 6 years shall remain nameless. I am going to start a company using it/him/she. Going to call it Tipsters..lol

 

What's the correlation and loading pattern of a +TO on Valentine's Day?

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...