Countdown to Winter 2017-2018 Thread

[RUNNAWAYICEBERG]

1 hour ago, Henry's Weather said:

Does anybody know where you can find EPO monthly values?

https://www.esrl.noaa.gov/psd/data/correlation/epo.data

[weathafella]

2 hours ago, RUNNAWAYICEBERG said:

https://www.esrl.noaa.gov/psd/data/correlation/epo.data

Those values for the epic 2014-15 winter are surprisingly positive.

[Ginx snewx]

26 minutes ago, weathafella said:

Those values for the epic 2014-15 winter are surprisingly positive.

Been ranting about people using monthly values for ever. 

[weathafella]

3 minutes ago, Ginx snewx said:

Been ranting about people using monthly values for ever. 

Yeah it gives an inaccurate impression often.  Another thing to look at is the trend line.  December EPO value was high and that month was an inferno.   Values dropped steeply thereafter and February was the coldest in 81 years.

[Ginx snewx]

2 minutes ago, weathafella said:

Yeah it gives an inaccurate impression often.  Another thing to look at is the trend line.  December EPO value was high that month was an inferno.   Values dropped steeply thereafter and February was the coldest in 81 years.

Yes trends! Wish someone would post monthly using dailies in graph form plotted against temp anomalies 

[OSUmetstud]

The loading pattern of the positive EPO uses positive height anomalies west of California in its calculation. That probably messed up its utility during that winter since the ridge during February was very stout in Alaska down through the west coast.  You can argue the positive pna index captured the cold pattern better. 

 

[uncle W]

daily ao/nao/pna numbers...

ftp://ftp.cpc.ncep.noaa.gov/cwlinks/

[Isotherm]

Those values must be reversed to yield the correct EPO numbers. The following link shows the true values:

http://www.wxmidwest.com/epo/newepo.txt

Strongly negative for 13-15 winters.

[Ginx snewx]

19 minutes ago, Isotherm said:

Those values must be reversed to yield the correct EPO numbers. The following link shows the true values:

http://www.wxmidwest.com/epo/newepo.txt

Strongly negative for 13-15 winters.

Why does it end mid 16?

[Ginx snewx]

Negative EPO =get us the cold it will snow

[OSUmetstud]

35 minutes ago, Isotherm said:

Those values must be reversed to yield the correct EPO numbers. The following link shows the true values:

http://www.wxmidwest.com/epo/newepo.txt

Strongly negative for 13-15 winters.

That doesnt make sense.  The loading pattern of the +EPO has troughing over AK.  Why would you have to reverse the number to get the proper result?  

[nzucker]

9 hours ago, OSUmetstud said:

That doesnt make sense.  The loading pattern of the +EPO has troughing over AK.  Why would you have to reverse the number to get the proper result?  

I don't see a trough over AK in the Feb 2015 mean...that's a very strong ridge. Is the EPO just positive because the index "sees" the high heights off the West Coast and assumes they teleconnect to a -PNA/GoA low? 

When the ridge is really broad and powerful, it would seem the EPO would perhaps be incorrect in terms of the effect on the sensible weather.

[OSUmetstud]

5 hours ago, nzucker said:

I don't see a trough over AK in the Feb 2015 mean...that's a very strong ridge. Is the EPO just positive because the index "sees" the high heights off the West Coast and assumes they teleconnect to a -PNA/GoA low? 

When the ridge is really broad and powerful, it would seem the EPO would perhaps be incorrect in terms of the effect on the sensible weather.

Yeah that's what I was getting at in my first response.  The ridging off California contaminated the number.   There should be no need to reverse the sign to get the right value.  

[OSUmetstud]

Lastest CPC Nino 3.4 weekly is down to -0.8c.  

[Isotherm]

17 hours ago, OSUmetstud said:

That doesnt make sense.  The loading pattern of the +EPO has troughing over AK.  Why would you have to reverse the number to get the proper result?  

 

Because the calculation is actually for the EP-NP index, which has its positive phase indicated by positive height anomalies over AK/Western Canada and negative height anomalies from the Western NP to the central NP. Therefore, the modality of the EPO index is actually opposite that of the EP-NP index.

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

"The positive phase of this pattern features positive height anomalies located over Alaska/ Western Canada, and negative anomalies over the central North Pacific and eastern North America. Strong positive phases of the EP-NP pattern are associated with a southward shift and intensification of the Pacific jet stream from eastern Asia to the eastern North Pacific, followed downstream by an enhanced anticyclonic circulation over western North America, and by an enhanced cyclonic circulation over the eastern United States. Strong negative phases of the pattern are associated with circulation anomalies of opposite sign in these regions."

 

 

[Isotherm]

18 hours ago, Ginx snewx said:

Why does it end mid 16?

 

Don't know; you can ask Al Marino (guess he stopped updating it).

[RUNNAWAYICEBERG]

18 minutes ago, Isotherm said:

 

Because the calculation is actually for the EP-NP index, which has its positive phase indicated by positive height anomalies over AK/Western Canada and negative height anomalies from the Western NP to the central NP. Therefore, the modality of the EPO index is actually opposite that of the EP-NP index.

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

"The positive phase of this pattern features positive height anomalies located over Alaska/ Western Canada, and negative anomalies over the central North Pacific and eastern North America. Strong positive phases of the EP-NP pattern are associated with a southward shift and intensification of the Pacific jet stream from eastern Asia to the eastern North Pacific, followed downstream by an enhanced anticyclonic circulation over western North America, and by an enhanced cyclonic circulation over the eastern United States. Strong negative phases of the pattern are associated with circulation anomalies of opposite sign in these regions."

 

 

A +EP/NP is essentially a -EPO.

Why so many accronyms and indexes for the same thing.....

[LurkerBoy]

I have a weirdly good feeling about this winter given the current signs.

[JBinStoughton]

21 minutes ago, LurkerBoy said:

I have a weirdly good feeling about this winter given the current signs.

Yeah that is weird ha. 

[40/70 Benchmark]

1 hour ago, Isotherm said:

 

Because the calculation is actually for the EP-NP index, which has its positive phase indicated by positive height anomalies over AK/Western Canada and negative height anomalies from the Western NP to the central NP. Therefore, the modality of the EPO index is actually opposite that of the EP-NP index.

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

"The positive phase of this pattern features positive height anomalies located over Alaska/ Western Canada, and negative anomalies over the central North Pacific and eastern North America. Strong positive phases of the EP-NP pattern are associated with a southward shift and intensification of the Pacific jet stream from eastern Asia to the eastern North Pacific, followed downstream by an enhanced anticyclonic circulation over western North America, and by an enhanced cyclonic circulation over the eastern United States. Strong negative phases of the pattern are associated with circulation anomalies of opposite sign in these regions."

 

 

Tom, when are you posting thoughts?

You're on my short list, brother.

[40/70 Benchmark]

41 minutes ago, LurkerBoy said:

I have a weirdly good feeling about this winter given the current signs.

Well, that settles it-

[Isotherm]

15 minutes ago, 40/70 Benchmark said:

Tom, when are you posting thoughts?

You're on my short list, brother.

 

Ray - around the same time I believe as you're releasing your outlook - should be second week or so of November. Want to see how the next three weeks evolve, especially for my autumn NAO indicator.

[J Paul Gordon]

Ahh, the quiet before the storm (of what kind we do not yet know)

My bets... a sharp cool down in November to below average by Thanksgiving (maybe some snow, if everything lines up nice) and a colder than normal December. January cold, early; above average, late--maybe a classic January thaw, evaporating deep snow cover. February mixed, slightly to much above normal. March, drops like a rock, coldest month of the winter except for December. Storms can rock this late or break hearts when a cutter follows a numbing period of cold (relative to season).

Oh yeah, the reasons. Heights in the Aleutians, trough central-eastern US (some good shots of seriously cold air right down to the Gulf by Christmas). Flip flop during January (a la 1989, 1990. Bigger chilldown in March, though, which did not happen that winter. Not as extremely cold in December, either.)

[SnowHole413]

1 hour ago, J Paul Gordon said:

Ahh, the quiet before the storm (of what kind we do not yet know)

My bets... a sharp cool down in November to below average by Thanksgiving (maybe some snow, if everything lines up nice) and a colder than normal December. January cold, early; above average, late--maybe a classic January thaw, evaporating deep snow cover. February mixed, slightly to much above normal. March, drops like a rock, coldest month of the winter except for December. Storms can rock this late or break hearts when a cutter follows a numbing period of cold (relative to season).

Oh yeah, the reasons. Heights in the Aleutians, trough central-eastern US (some good shots of seriously cold air right down to the Gulf by Christmas). Flip flop during January (a la 1989, 1990. Bigger chilldown in March, though, which did not happen that winter. Not as extremely cold in December, either.)

Yeah man I am feeling almost completely the same. Basically a 95-96 redux lol.

[OSUmetstud]

Week 3 and 4 looks neae normal on the weeklies.  -epo and pos nao

 

[FlashFreeze]

I remember both November and December being very cold in 89, New Years eve was warm, the rest of the winter was mild in Wethersfield Ct, the winter of 95-96 in Farmington CT was one of the best early winters I remember, cold but not extreme cold with many mid size snow events and the January blizzard     

[tamarack]

13 hours ago, FlashFreeze said:

I remember both November and December being very cold in 89, New Years eve was warm, the rest of the winter was mild in Wethersfield Ct, the winter of 95-96 in Farmington CT was one of the best early winters I remember, cold but not extreme cold with many mid size snow events and the January blizzard     

Nov. 1989 was running about -2 thru the 20th, then came the thunderblizzard and crashing temps - 21st-30th was about 13F BN and was followed by NNE's coldest Dec.  Jan was quite mild but the frequent storms mainly coincided with cold so the month was snowy - kind of polar opposite of Jan. 2014 here. 

[AfewUniversesBelowNormal]

Have you ever seen a bigger subsurface-surface disconnect that wasn't lagged? I think this is a blocking signal. 

[40/70 Benchmark]

48 minutes ago, StormchaserChuck said:

Have you ever seen a bigger subsurface-surface disconnect that wasn't lagged? I think this is a blocking signal. 

Do you have any scientific references to attest to this?

[AfewUniversesBelowNormal]

9 minutes ago, 40/70 Benchmark said:

Do you have any scientific references to attest to this?

I have studied subsurface ENSO temperatures, creating a dataset and comparing in a correlation coefficient with surface ENSO SST. What I found was strong in the direction of subsurface being more important than surface. - individually when there was a disconnect, the subsurface won out pretty much every time (pattern connections, SLP etc).
The theory now is when the subsurface does not win out as much as usual, is it because energy potential is dispersing at the surface?, in which case, does it favor blocking?