WHY the +AO = WARM WINTER argument is in deep Doo

[DTWXRISK]

 this map says it all 


 

[DTWXRISK]

 pretty  much self  explanatory

[Amped]

Thanks DT, hope the snow pans out.

[WEATHER53]

I agree that many who have called for warmth in November, and December, and Jan have been wrong for Nov.and will continue to be wrong.

[HM]

If you take the 20 most negative WP Decembers, you get 13 with a -AO, 5 with a +AO and 2 with a neutral AO. So, overall from this small sample, the combination of a very anomalous -WP with an overall +AO is the rarer combination. The 20 most positive WP Decembers, on the other hand, have about 10 with +AO and 8 with -AO. That group, too, had about 2 with a neutral AO.

 

 

The -WPO/neutral AO years were 1956 and 1980. Both directed the pipeline of cold into Canada but the less negative AO either forced it well north of the CONUS (1956) or only into the eastern third of CONUS (1980). The PDO state likely played a role there. 1956 was, more or less, a blowtorch December. 1980 was exceptionally warm for the western 2/3s of the CONUS.

 

The +AO Decembers with an anomalous -WPO (in the 20 most negative only) looked more like a hybrid El Nino-like pattern. The cold anomalies were more focused in south, even if you take away the very cold 1983 year, and the northern-tier was above normal. This rare combination consists only of 5 years out of the 20 -WPO set: 1954, 1974, 1975, 1999 and 1983.

[HM]

Below are the temperatures anomalies for the +AO/-WP years. I have 1 with 1983 and one without. The winter was definitely the oddball with exceptional CONUS cold. The rest looked like an El Niño. Funny thing is: none of them are an El Niño! They are all La Niña Decembers.

 

[HM]

I agree that many who have called for warmth in November, and December, and Jan have been wrong for Nov.and will continue to be wrong.

 

This is simply an unfair observation and I wouldn't say, "I told you so" until Feb. The same reasons that have led to the cold this month would actually lead to WARMTH in DJF. Should the cold continue this winter, it won't be because of what is happening in November.

[NJwinter23]

This is simply an unfair observation and I wouldn't say, "I told you so" until Feb. The same reasons that have led to the cold this month would actually lead to WARMTH in DJF. Should the cold continue this winter, it won't be because of what is happening in November.

 

Thank you! 

[WEATHER53]

This is simply an unfair observation and I wouldn't say, "I told you so" until Feb. The same reasons that have led to the cold this month would actually lead to WARMTH in DJF. Should the cold continue this winter, it won't be because of what is happening in November.

I am sorry but the statement that what is "making  it cold now will make it warm later" is nonsensical and open ended enough that it could neither be confirmed nor denied later on.

[donsutherland1]

I am sorry but the statement that what is "making  it cold now will make it warm later" is nonsensical and open ended enough that it could neither be confirmed nor denied later on.

 

Assuming all other variables are held equal, the change in wavelengths between the seasons can lead to differing outcomes for a given teleconnection. For example, there is a direct relationship between the NAO and temperatures across much of the U.S. in January (NAO+ = warmth; NAO- = cold). Yet, in July, for much of the south/southeast, there is an indirect relationship (NAO+ = cool; NAO- = warm).

 

Of course, all other variables, and factors beyond the teleconnections also have an impact. Consequently, one can wind up getting all the teleconnections correct, but additional variables not captured by the teleconnections can lead to differing outcomes.

[HM]

I am sorry but the statement that what is "making  it cold now will make it warm later" is nonsensical and open ended enough that it could neither be confirmed nor denied later on.

 

lol

 

It's not about forecasting something and being ambiguous. It is about, you know, actual research and what we understand about our climate. So which point do you care to elaborate on first?

 

1. Record breaking positive AO that we've seen this November wouldn't be warm in DJF?

2. Tropical forcing over Indonesia / lower AAM state wouldn't be warm in DJF?

3. Cold stratosphere and weaker waves wouldn't be warm in DJF?

 

Let's just start there first.

[michsnowfreak]

I agree that many who have called for warmth in November, and December, and Jan have been wrong for Nov.and will continue to be wrong.

Bill Deedler, a local climate historian & retired met from DTX, issued his annual winter outlook, and he has a decent track record. He has been issuing outlooks for 17 years, and said its one of the strongest colder than normal signals he had seen in 17 years of doing outlooks. He did acknowledge of course, that nothing is ever a slam dunk (In one of the strongest below normal signals I've seen in the 17 years of Outlooks; you'd think it'd be a slam dunk but not always. Granted most of the time when a temperature trend was even close to this strong, it turned out to be in the right direction. I can recall a few winters however, where that backfired and the minority ruled)

 

The outlook caters to SE MI but obviously the discussion can be expanded to other areas of the country

 

http://weatherhistorian.blogspot.com/2013/11/second-neutral-winter-leaves-southeast.html

[donsutherland1]

Bill Deedler, a local climate historian & retired met from DTX, issued his annual winter outlook, and he has a decent track record. He has been issuing outlooks for 17 years, and said its one of the strongest colder than normal signals he had seen in 17 years of doing outlooks. He did acknowledge of course, that nothing is ever a slam dunk (In one of the strongest below normal signals I've seen in the 17 years of Outlooks; you'd think it'd be a slam dunk but not always. Granted most of the time when a temperature trend was even close to this strong, it turned out to be in the right direction. I can recall a few winters however, where that backfired and the minority ruled)

 

The outlook caters to SE MI but obviously the discussion can be expanded to other areas of the country

 

http://weatherhistorian.blogspot.com/2013/11/second-neutral-winter-leaves-southeast.html

Josh,

 

It's an interesting outlook. One thing confused me, though. Deedler wrote:

 

Best below normal chances would be at Detroit but that's only because of the inflated heat island norms.

 

The norms are from the 1981-2010 base period. They are the product of all temperatures that occurred during that timeframe, all of which were recorded in the heat island environment. If that's the case, then why wouldn't the 2013-14 temperatures also be affected by the same heat island effect?

 

Was the station at which Detroit's temperatures are presently recorded moved from where they were recorded during the 1981-2010 base period?

 

[tacoman25]

Below are the temperatures anomalies for the +AO/-WP years. I have 1 with 1983 and one without. The winter was definitely the oddball with exceptional CONUS cold. The rest looked like an El Niño. Funny thing is: none of them are an El Niño! They are all La Niña Decembers.

 

decnegwpoposao.JPG

 

Yes but how about -WP and -EPO?

 

Plus 3 of those years were major -ENSO years (and all were -ENSO actually) as you noted...

[tacoman25]

This is simply an unfair observation and I wouldn't say, "I told you so" until Feb. The same reasons that have led to the cold this month would actually lead to WARMTH in DJF. Should the cold continue this winter, it won't be because of what is happening in November.

 

So you discount the EPO Nov to DJF correlation?

[michsnowfreak]

Josh,

 

It's an interesting outlook. One thing confused me, though. Deedler wrote:

 

Best below normal chances would be at Detroit but that's only because of the inflated heat island norms.

 

The norms are from the 1981-2010 base period. They are the product of all temperatures that occurred during that timeframe, all of which were recorded in the heat island environment. If that's the case, then why wouldn't the 2013-14 temperatures also be affected by the same heat island effect?

 

Was the station at which Detroit's temperatures are presently recorded moved from where they were recorded during the 1981-2010 base period?

 

Detroit temps have been at present-day location (DTW) since 1966. From 1874-March 1966 they were at various locations in Detroit (first downtown then City Airport, DET) then from April 1966 to present they have been at Detroit Metro Airport (DTW) in suburban Romulus (approx 20 miles SW of downtown Detroit and 25 miles SW of City Airport). From the 1960s to at least the early 1980s, the place was a radiating magnet, often one of the lowest low temps in the area. While its still a somewhat rural area, the concrete/runways and general buildup of the area has caused definite UHI at the airport so that nowadays, on a great radiating night DTW is on the higher end of low temps in the area, often the highest, a complete reversal from the 1960s-70s. Obviously, this has been reflected in the most recent 1981-2010 norms.

 

You pose a good question, and my GUESS would be that Deedler was implying that UHI is less defined in a true arctic airmass. For instance, DTW got down to -15F in Jan 2009, and -20F in Jan 1994....when an arctic airmass packs that much punch, UHI is more of a nonfactor. In your more "typical" winter coldblast, the outlying areas may come up in the -5F to 0F range while DTW will be, say, 2F to 5F. So if indeed its a very cold winter, UHI wont be as much of a factor. Detroits present 30-yr average temp is 27.9F, but the 100-yr average is 26.7F, the difference almost entirely made up of low temps rather than high temps.

[WEATHER53]

Assuming all other variables are held equal, the change in wavelengths between the seasons can lead to differing outcomes for a given teleconnection. For example, there is a direct relationship between the NAO and temperatures across much of the U.S. in January (NAO+ = warmth; NAO- = cold). Yet, in July, for much of the south/southeast, there is an indirect relationship (NAO+ = cool; NAO- = warm)

 

Of course, all other variables, and factors beyond the teleconnections also have an impact. Consequently, one can wind up getting all the teleconnections correct, but additional variables not captured by the teleconnections can lead to differing outcomes.

So you are agreeing with "what makes/made November cold makes/will make Dec and Jan. warm" ??

[donsutherland1]

Detroit temps have been at present-day location (DTW) since 1966. From 1874-March 1966 they were at various locations in Detroit (first downtown then City Airport, DET) then from April 1966 to present they have been at Detroit Metro Airport (DTW) in suburban Romulus (approx 20 miles SW of downtown Detroit and 25 miles SW of City Airport). From the 1960s to at least the early 1980s, the place was a radiating magnet, often one of the lowest low temps in the area. While its still a somewhat rural area, the concrete/runways and general buildup of the area has caused definite UHI at the airport so that nowadays, on a great radiating night DTW is on the higher end of low temps in the area, often the highest, a complete reversal from the 1960s-70s. Obviously, this has been reflected in the most recent 1981-2010 norms.

 

You pose a good question, and my GUESS would be that Deedler was implying that UHI is less defined in a true arctic airmass. For instance, DTW got down to -15F in Jan 2009, and -20F in Jan 1994....when an arctic airmass packs that much punch, UHI is more of a nonfactor. In your more "typical" winter coldblast, the outlying areas may come up in the -5F to 0F range while DTW will be, say, 2F to 5F. So if indeed its a very cold winter, UHI wont be as much of a factor. Detroits present 30-yr average temp is 27.9F, but the 100-yr average is 26.7F, the difference almost entirely made up of low temps rather than high temps.

Thanks Josh, both for the stations' history and possible explanation.

[donsutherland1]

So you are agreeing with "what makes/made November cold makes/will make Dec and Jan. warm" ??

 

There are many variables at play. My point is that at least one or more variables might well have a different impact as the wavelengths change.

[tacoman25]

So you are agreeing with "what makes/made November cold makes/will make Dec and Jan. warm" ??

 

I don't understand this argument (not saying you are making it). The primary reason November has been cold has been the -EPO. Why would that make Dec/Jan warm?

[N. OF PIKE]

Josh,

 

It's an interesting outlook. One thing confused me, though. Deedler wrote:

 

Best below normal chances would be at Detroit but that's only because of the inflated heat island norms.

 

The norms are from the 1981-2010 base period. They are the product of all temperatures that occurred during that timeframe, all of which were recorded in the heat island environment. If that's the case, then why wouldn't the 2013-14 temperatures also be affected by the same heat island effect?

 

Was the station at which Detroit's temperatures are presently recorded moved from where they were recorded during the 1981-2010 base period?

 

One thing that has me confused on his outlook is that he thinks the AO/NAO dominant state will be negative. Seems he is unaware of the LR tools and their correlation % or just not a believer in them.

[tacoman25]

The cold being delivered to the CONUS right now is pretty impressive, regardless of climate eras.

[HM]

Yes but how about -WP and -EPO?

 

Plus 3 of those years were major -ENSO years (and all were -ENSO actually) as you noted...

 

The point of this thread is about the WP and AO relationship. Of course a -EPO would change everything. The years are not meant to be analogs to this winter, so I'm not sure why you are saying anything about their ENSO state. The point is that a -WPO December isn't that cold when the AO is positive, and it even manages to reverse the La Nina spatial anomaly positioning! Pretty cool.

 

So you discount the EPO Nov to DJF correlation?

 

Again, this isn't about the EPO or my forecast or anything. Howard was the one who said everyone going warm would be wrong (he forecasts for the DC / Mid Atlantic area, mind you) and I thought it was an arrogant, unfounded statement.

[NJwinter23]

I don't understand this argument (not saying you are making it). The primary reason November has been cold has been the -EPO. Why would that make Dec/Jan warm?

 

The argument is the underlying forcing across the Tropical Pacific, which I believe has helped enforce a -EPO and the colder leaning pattern in Novy, was in regions that do not support such a pattern and actually a warmer East in the DJF period. Indonesia/phase 4-5 territory.. Team that up with the +AO we saw and you know what happens.

 

[HM]

So you are agreeing with "what makes/made November cold makes/will make Dec and Jan. warm" ??

 

This is a remarkably terrible misrepresentation of what was said and the context. You were the one who made an arrogant statement about people who went warm will be wrong this winter. So, I'm telling you that your statement is baseless and unfounded, considering that the players on the field that control circulation NOW would not mean the same thing come Jan/Feb. Therefore, it is up to you to provide the evidence that the players will continue to alter to favor cold this winter. 

 

There are many variables at play. My point is that at least one or more variables might well have a different impact as the wavelengths change.

 

Good luck trying to convey this concept....sheesh!

[HM]

I don't understand this argument (not saying you are making it). The primary reason November has been cold has been the -EPO. Why would that make Dec/Jan warm?

 

Are you suggesting the EPO is its own entity and not a product of background state-feedback processes, tropical forcing, stratospheric players and ocean-air feedback? It simply is the cause--thee end?

[NJwinter23]

And so nobody even tries to come back to this after say Dec is over, and claim "my forecast was wrong", please get it through your head now, there has been NO FORECAST of mine thrown out in this thread via any arguments laid out here. I'm not saying Dec wont be cold or have a

-EPO...Simply chiming in on how the forcing tends to affect the patterns here as the fall-->winter transition unfolds... And i can speak for HM there as well. This all in response of challenging a baseless claim made by a couple in this thread

[tacoman25]

Are you suggesting the EPO is its own entity and not a product of background state-feedback processes, tropical forcing, stratospheric players and ocean-air feedback? It simply is the cause--thee end?

 

No, I'm not suggesting that any more than those who are looking at the effects and correlations related to the AO are suggesting the AO is "its own entity". 

 

Just as there are correlations associated with the AO and what happens in the fall, there are also correlations with the EPO. It's all blocking and location/magnitude of blocking, and there are forcings that play into that.

[tacoman25]

The point of this thread is about the WP and AO relationship. Of course a -EPO would change everything. The years are not meant to be analogs to this winter, so I'm not sure why you are saying anything about their ENSO state. The point is that a -WPO December isn't that cold when the AO is positive, and it even manages to reverse the La Nina spatial anomaly positioning! Pretty cool.

 

Sure, I see what you are saying about the WPO. I just think it's worth considering what the EPO is doing in regards to the WPO/AO as well. This year is somewhat unusual in that a persistent -WP/-EP regime has been pretty dominant. Regardless of what the AO looks like, above normal heights keep popping up in the NE Pacific, Alaska, and NW Canada.

[tacoman25]

The argument is the underlying forcing across the Tropical Pacific, which I believe has helped enforce a -EPO and the colder leaning pattern in Novy, was in regions that do not support such a pattern and actually a warmer East in the DJF period. Indonesia/phase 4-5 territory.. Team that up with the +AO we saw and you know what happens.

 

 

 

 

That may be correct, but then why has the EPO/WPO been so predominantly negative for so long, regardless of tropical forcing (which I believe was pretty dormant for awhile)? I mean, I understand that tropical forcing becomes more important as we move deeper into fall, but I also know that especially in ENSO neutral years, it tends to cycle through different phases quite a bit. So I guess I'm just trying to understand the emphasis on "well, if we have this same tropical forcing in DJF, the result will be opposite".

 

The November to DJF EPO correlations exist, and there must be a reason for that as well right?