Low Sea Ice Warm Fall USA?

[blizzard1024]

I ran the surface temperature anomalies (which uses the warmer 1981-2010 means)

for Sept-Nov 2007-2011 for the USA which are low sea ice years. One wonders

if this loads the dice for a warm fall in the northern and central U.S/Canada outside

of the subtropics.

[Jonger]

Remove 2007 and just run the last 4 years and here is Oct.

Here Sept-Nov for the past 4 years.

[Jonger]

2007 was a warm fall.

[blizzard1024]

Good point...but I still wonder if the die is loaded some toward a milder than normal fall in the north. Does not

mean it will happen...but there is a greater likelihood....like 60-40 toward warmer than normal.

[The_Global_Warmer]

November is the one really really being effected the last decade.

[Jonger]

November is the one really really being effected the last decade.

Yup, November has been the biggest anomaly of the year for the past decade. You would think October would be subjected to the same temps, but its been one of the coldest months.

[tacoman25]

Yup, November has been the biggest anomaly of the year for the past decade. You would think October would be subjected to the same temps, but its been one of the coldest months.

Also interestingly, despite how warm Novembers have been, the early winter weather has been cold overall.

I would have to guess that November's recent anomalies are probably mostly due to chance, not the sea ice.

[Jonger]

Also interestingly, despite how warm Novembers have been, the early winter weather has been cold overall.

I would have to guess that November's recent anomalies are probably mostly due to chance, not the sea ice.

Look at the last 5 February's! The entire lower 48 is below mostly... And significantly.

Sent from my ADR6425LVW 2

[The_Global_Warmer]

Pending the time period and other factors like solar altitude the arctic cold pool will have more or less of an effect on our weather.

Thinking any month is the same and then using that to decide the arctic's influence is nothing and it's about chance seems short sided.

I doubt the arctic has much influence in July vs January.

But I bet it has more influence in April vs July.

Which means it would have more influence in December than November but far more influence in November vs October.

The next question you ask is how the arctic is doing and how much cold is it generating during certain periods?

November is when the arctic is still very warm from the summer ice crippling and it's influence on our Weather goes up dramatically from October while solar insolation drops off a rock.

[ORH_wxman]

Pending the time period and other factors like solar altitude the arctic cold pool will have more or less of an effect on our weather.

Thinking any month is the same and then using that to decide the arctic's influence is nothing and it's about chance seems short sided.

I doubt the arctic has much influence in July vs January.

But I bet it has more influence in April vs July.

Which means it would have more influence in December than November but far more influence in November vs October.

The next question you ask is how the arctic is doing and how much cold is it generating during certain periods?

November is when the arctic is still very warm from the summer ice crippling and it's influence on our Weather goes up dramatically from October while solar insolation drops off a rock.

Why would this be?

This is not supported by the CONUS temp correlation with the AO.

[blizzard1024]

Look at the projected 7-10 day means 500 mb geopotential height fields for Euro and GFS models.

Warm, warm and more warm in the sub Arctic regions. Normal near the polar regions which generally

means stormy, not necessarily cold. In my mind, warm falls are becoming the norm. This could all

be wrong, but the die is weighted. I have been watching these projections for years and years

and this is about as warm as it gets. see below

.

[CoastalWx]

Pending the time period and other factors like solar altitude the arctic cold pool will have more or less of an effect on our weather.

Thinking any month is the same and then using that to decide the arctic's influence is nothing and it's about chance seems short sided.

I doubt the arctic has much influence in July vs January.

But I bet it has more influence in April vs July.

Which means it would have more influence in December than November but far more influence in November vs October.

The next question you ask is how the arctic is doing and how much cold is it generating during certain periods?

November is when the arctic is still very warm from the summer ice crippling and it's influence on our Weather goes up dramatically from October while solar insolation drops off a rock.

I don't quite follow you here, what is your reasoning behind it?

[Entropy]

Look at the projected 7-10 day means 500 mb geopotential height fields for Euro and GFS models.

Warm, warm and more warm in the sub Arctic regions. Normal near the polar regions which generally

means stormy, not necessarily cold. In my mind, warm falls are becoming the norm. This could all

be wrong, but the die is weighted. I have been watching these projections for years and years

and this is about as warm as it gets. see below

.

It's possible, I suppose. September and October don't really show any enhanced warming over the yearly mean, though. November, however, has been one of the faster warming months based on the data I've compiled.

[tacoman25]

Look at the projected 7-10 day means 500 mb geopotential height fields for Euro and GFS models.

Warm, warm and more warm in the sub Arctic regions. Normal near the polar regions which generally

means stormy, not necessarily cold. In my mind, warm falls are becoming the norm. This could all

be wrong, but the die is weighted. I have been watching these projections for years and years

and this is about as warm as it gets. see below

For the U.S., November is the only month that seems to support that assertion. If that were true, don't you think it strange that Decembers have been so cold? It's the month right after November and if November has been warm because an albedo effect from the ice melt, why wouldn't that carry over into December?

[Jonger]

Sept-November 2000-2010.

Heres 2000-2010 full year.

[blizzard1024]

Also interestingly, despite how warm Novembers have been, the early winter weather has been cold overall.

I would have to guess that November's recent anomalies are probably mostly due to chance, not the sea ice.

This pattern looks like the cold PDO signature. For us northeasterner's our ski season will depend

on the phase of the NAO. I hope low sea ice= negative NAO as some research suggests. The physics

of it seems to make sense as I have read a couple papers....but I am

skeptical and someone made a good comment that we have a small sample size on this. I started

downhilling again last year with my boys and only got 5 runs in...almost all man-made snow

and lots of ICE!!! I have lived in upstate NY and northern PA almost my whole life and have

never seen such a horrible winter last year. 2005-06 and 2001-02 were bad, 1997-98 second worst behind last year, 1998-99 bad

1994-95 bad, late 80s/early 90s bad...but at least we could count on some prolonged cold for snow making.

2011-12 we could not hold onto a period of cold for anything...all the polar/arctic air continually was swept into

the North Atlantic across Canada. Positive NAOs really suck!

[blizzard1024]

This pattern looks like the cold PDO signature. For us northeasterner's our ski season will depend

on the phase of the NAO. I hope low sea ice= negative NAO as some research suggests. The physics

of it seems to make sense as I have read a couple papers....but I am

skeptical and someone made a good comment that we have a small sample size on this. I started

downhilling again last year with my boys and only got 5 runs in...almost all man-made snow

and lots of ICE!!! I have lived in upstate NY and northern PA almost my whole life and have

never seen such a horrible winter last year. 2005-06 and 2001-02 were bad, 1997-98 second worst behind last year, 1998-99 bad

1994-95 bad, late 80s/early 90s bad...but at least we could count on some prolonged cold for snow making.

2011-12 we could not hold onto a period of cold for anything...all the polar/arctic air continually was swept into

the North Atlantic across Canada. Positive NAOs really suck!

EXCEPT FOR 1993-94!!!!!!!!!!!!!!!!

[Jonger]

This pattern looks like the cold PDO signature. For us northeasterner's our ski season will depend

on the phase of the NAO. I hope low sea ice= negative NAO as some research suggests. The physics

of it seems to make sense as I have read a couple papers....but I am

skeptical and someone made a good comment that we have a small sample size on this. I started

downhilling again last year with my boys and only got 5 runs in...almost all man-made snow

and lots of ICE!!! I have lived in upstate NY and northern PA almost my whole life and have

never seen such a horrible winter last year. 2005-06 and 2001-02 were bad, 1997-98 second worst behind last year, 1998-99 bad

1994-95 bad, late 80s/early 90s bad...but at least we could count on some prolonged cold for snow making.

2011-12 we could not hold onto a period of cold for anything...all the polar/arctic air continually was swept into

the North Atlantic across Canada. Positive NAOs really suck!

I wouldn't use 2011-2012 winter as a basis for ANYTHING in the lower 48. It was such an anomaly in a otherwise "normal" global winter.

[tacoman25]

Look at the projected 7-10 day means 500 mb geopotential height fields for Euro and GFS models.

Warm, warm and more warm in the sub Arctic regions. Normal near the polar regions which generally

means stormy, not necessarily cold. In my mind, warm falls are becoming the norm. This could all

be wrong, but the die is weighted. I have been watching these projections for years and years

and this is about as warm as it gets. see below

Doesn't look terribly warm though, at least on this side of the globe in the midterm. Not that we could necessarily correlate any of this to the question posed in this thread.

[Jonger]

Doesn't look terribly warm though, at least on this side of the globe in the midterm. Not that we could necessarily correlate any of this to the question posed in this thread.

That cold anomaly over Alaska scares the crap out of me the closer we get to winter.

[nzucker]

That cold anomaly over Alaska scares the crap out of me the closer we get to winter.

Need to get rid of that +EPO in the next few months.

We've seen some warming of the GoA but wondering if that will translate into the atmospheric pattern by winter time.

[tacoman25]

This pattern looks like the cold PDO signature. For us northeasterner's our ski season will depend

on the phase of the NAO. I hope low sea ice= negative NAO as some research suggests. The physics

of it seems to make sense as I have read a couple papers....but I am

skeptical and someone made a good comment that we have a small sample size on this. I started

downhilling again last year with my boys and only got 5 runs in...almost all man-made snow

and lots of ICE!!! I have lived in upstate NY and northern PA almost my whole life and have

never seen such a horrible winter last year. 2005-06 and 2001-02 were bad, 1997-98 second worst behind last year, 1998-99 bad

1994-95 bad, late 80s/early 90s bad...but at least we could count on some prolonged cold for snow making.

2011-12 we could not hold onto a period of cold for anything...all the polar/arctic air continually was swept into

the North Atlantic across Canada. Positive NAOs really suck!

Yeah, there is no doubt the lack of a good -NAO really hurt much of the country last winter. There actually was a significant -AO during parts of Jan/Feb, but all the cold air went into Asia and Europe (a large area of the NH land was very cold last Jan/Feb). What really killed most folks last winter was the persistent +EPO...no blocking on the Pacific side can be just as meaningful for the CONUS as no -NAO.

We lucked out here in the Denver area...had a nice December and February with some big storms. But the mountains did terribly.

[The_Global_Warmer]

I don't quite follow you here, what is your reasoning behind it?

Different times of the year different factors hold more or less weight.

solar insolation in March is the same as early October.

But the arctics muscle is far more powerful in March than October on the mid latitudes.

From Sept-Nov the arctics influenc grows.

The arctic is impaired and regains its prowess throughout the fall.

I believe November it culminates its effects.

[Entropy]

One possible mechanism for enhanced warming could be through intensification of the Aleutian and Icelandic lows, which would favor the positive phase of the North Atlantic Oscillation. Some have posited that the anomalous low pressure system north of Alaska may have been intensified by the latent heat released from the unusually open waters of the Arctic Ocean. This same mechanism (i.e. less ice cover and warmer SSTs in northern oceans) could serve to deepen these predominant areas of low pressure. A deeper Aleutian and Icelandic low would result in an enhanced pressure gradient between the subtropical high pressure cells (e.g. the Azores high), which would intensify the westerlies during the Northern Hemisphere winter. This enhanced westerly flow would aid the transport of heat and moisture to the mid- and high-latitudes.

[Jonger]

Different times of the year different factors hold more or less weight.

solar insolation in March is the same as early October.

But the arctics muscle is far more powerful in March than October on the mid latitudes.

From Sept-Nov the arctics influenc grows.

The arctic is impaired and regains its prowess throughout the fall.

I believe November it culminates its effects.

This is all hind sight forecasting. Sept-Oct normal to below....November above... December below... There is no pattern.

Sent from my ADR6425LVW 2

[CoastalWx]

Pending the time period and other factors like solar altitude the arctic cold pool will have more or less of an effect on our weather.

Thinking any month is the same and then using that to decide the arctic's influence is nothing and it's about chance seems short sided.

I doubt the arctic has much influence in July vs January.

But I bet it has more influence in April vs July.

Which means it would have more influence in December than November but far more influence in November vs October.

The next question you ask is how the arctic is doing and how much cold is it generating during certain periods?

November is when the arctic is still very warm from the summer ice crippling and it's influence on our Weather goes up dramatically from October while solar insolation drops off a rock.

With the arctic virtually dark in November and the sun angle reaching it's lowest point in a month, I don't see how the influence in the month of November goes up. It also goes against some correlations anyways, but that's another story. Snow and ice pack build up very quickly in October and November...even after it has been melted. Sure it may not be multi year ice, but it should matter very little.

[ORH_wxman]

With the arctic virtually dark in November and the sun angle reaching it's lowest point in a month, I don't see how the influence in the month of November goes up. It also goes against some correlations anyways, but that's another story. Snow and ice pack build up very quickly in October and November...even after it has been melted. Sure it may not be multi year ice, but it should matter very little.

I have no idea what he was trying to explain there. Didn't give any reasoning other than "I think its impact is greater in November".

The AO has the largest influence in the winter months to our winter temps...but October and November are the same, which doesn't support his notion that we see big impact in November but not in October...and certainly doesn't explain the cold recent Decembers.

Recent cold Octobers/Decembers with warm Novembers in between is likely due to chance more than anything directly to sea ice.

[The_Global_Warmer]

With the arctic virtually dark in November and the sun angle reaching it's lowest point in a month, I don't see how the influence in the month of November goes up. It also goes against some correlations anyways, but that's another story. Snow and ice pack build up very quickly in October and November...even after it has been melted. Sure it may not be multi year ice, but it should matter very little.

Solar insolation in October is to strong this far South for the arctic to have much of an impact here. Perfect patterns for cold still won't yield the same results as those perfect patterns a month later or two months later. It doesn't matter what oscillation is taking place. The Oceans are to warm still and the Sun Angle is to high for the arctic to impact us to the same extent in February. Snow Cover is also not established.

November is a huge transitional month. The arctic's reach on November 1st is very small vs November 30th. Snow field have to erected, Ice cover/snow cover cooling the atmosphere must be restored. All of this stuff happening in the arctic will have major impacts on the folks down South in terms of the kind of cold they can receive. Solar insolation in November is weak enough for the arctic to overpower it and bring freezing temps, wintry weather while overpowering the solar insolation. The ocean are still warm compared to similar insolation conditions in later winter months.

'

1950-1995 November mean surface temps vs 2003-2011. The entire Northern Hemisphere is warmer. The largest anomaly's are in the arctic it self. I doubt the AO can be blamed for this large scale energy imbalance. How can anyone say this is chance or the AO?

Until that dark purple is as extensive as it was back then, the dice are very loaded for the subsequent regions that are directly effected by it to not be as cold as they were before.

[ORH_wxman]

Solar insolation in October is to strong this far South for the arctic to have much of an impact here. Perfect patterns for cold still won't yield the same results as those perfect patterns a month later or two months later. It doesn't matter what oscillation is taking place. The Oceans are to warm still and the Sun Angle is to high for the arctic to impact us to the same extent in February. Snow Cover is also not established.

November is a huge transitional month. The arctic's reach on November 1st is very small vs November 30th. Snow field have to erected, Ice cover/snow cover cooling the atmosphere must be restored. All of this stuff happening in the arctic will have major impacts on the folks down South in terms of the kind of cold they can receive. Solar insolation in November is weak enough for the arctic to overpower it and bring freezing temps, wintry weather while overpowering the solar insolation. The ocean are still warm compared to similar insolation conditions in later winter months.

'

1950-1995 November mean surface temps vs 2003-2011. The entire Northern Hemisphere is warmer. The largest anomaly's are in the arctic it self. I doubt the AO can be blamed for this large scale energy imbalance. How can anyone say this is chance or the AO?

Until that dark purple is as extensive as it was back then, the dice are very loaded for the subsequent regions that are directly effected by it to not be as cold as they were before.

All you have shown in this post is that the arctic is a lot warmer in the 2003-2011 time frame versus 1950-1995....we already know that. What this post does not answer is the question we asked regarding why would it make November much warmer in the CONUS recently while October has been colder and December has been colder. The same possible mechanisms that would make November warmer should also apply in December or October to enough of an extent to see a trend, but we do not see any matching trend.

The AO is a good crude way to mention how much or how little of an arctic source we are receiving...using the correlation to temperatures tells us how much it matters to us. The correlation is very small in the summer since the PJ is further north and weaker in the summer, but in the winter it has much higher influence with a further south PJ and stronger. The AO correlation is roughly the same in October and November and stronger in December.

I haven't seen any convincing evidence that the arctic is only influencing the warming in November but doesn't matter in the two months surrounding it.

[Isotherm]

I don't buy into the low sea ice --> -NAO argument; there seems to be very little in the way of correlation there. Looking back at arctic sea ice anomalies since 1980, there were many years w/ high sea ice and -NAO, low sea ice and +NAO.

Note the following graph; I quickly drew in the NAO modality for DJF for each winter season. -NAO years with high sea ice in the mid 80s, mid/late 90s, and quite a few +NAO years in the sea ice minima, like 2007-08, 2011-12, etc.

Also agree w/ those who say the warm November has been mostly a product of chance in recent years. If there was a specific forcing like low sea ice causing its occurence, the effects wouldn't be confined to that 30 day period alone.