December warm NOT White

[Stormlover74]

This is when you kinda have to say the climate really is changing. If we finish over +12 that's a one in a couple hundred year events (during a normal steady state climate)

The past decade has seen an unprecedented amount of records fall both in the rain and snowfall departments as well as extreme temperature, mostly in the warm department. It really is crazy how many times we've seen warmest month, wettest month, top 10 snowiest month records falling.

[LongBeachSurfFreak]

Gotta love those post cold-front 60+ temps in MID DECEMBER.

I was just thinking that walking to the train in a light sweatshirt. Strong west winds this time of the year should at least have some bite.

[IsentropicLift]

The Euro has a plume of nearly +20C 925mb temps along the coast on Christmas Eve. 2M temps in the low to mid 70's and dew points near 60 leading to around 750-1000 J/KG of SBCAPE as the warm front reaches all the way to Toronto.

 

The 12z GEFS mean is on board.

 

[bluewave]

This is when you kinda have to say the climate really is changing. If we finish over +12 that's a one in a couple hundred year events (during a normal steady state climate)

 

The 2000's redefined the meaning of extreme weather. Just look how many records for warmth and precipitation

have been set. Hurricane Sandy takes the prize for most extreme widespread singular storm event.

[IsentropicLift]

The 2000's redefined the meaning of extreme weather. Just look how many records for warmth and precipitation

have been set. Hurricane Sandy takes the prize for most extreme widespread singular storm event.

The biggest question IMO is if we're still rebounding from the extreme stretch that we saw from 09-12 or if we're setting ourselves up for another extreme run back in the other direction. 

[JC-CT]

December Warm or White ?

 

Warm.

[IrishRob17]

December Warm or White ?

 

Warm.

 

That's a bold call.

[JC-CT]

That's a bold call.

 

I hope I'm not too late to the party.

[Rittenhouse]

December Warm or White ?

 

Warm.

 

 

Nah, more like green.

[IsentropicLift]

I ran out last night in a t-shirt and shorts and was perfectly comfortable on December 14th. That says it all.

[Rittenhouse]

 

up up up and away!

[SnoSki14]

I ran out last night in a t-shirt and shorts and was perfectly comfortable on December 14th. That says it all.

Well it was similar to something you'd see in July minus the bugs of course.

[bluewave]

 

 

up up up and away!

 

Would love to know what caused the flip after the record breaking March 2013 -AO of -3.185.

It's been wall to wall positive since then with some scattered negative months thrown in.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

[Brian5671]

 

up up up and away!

4 to 5 STD positive=megatorch

[Brian5671]

Gotta love those post cold-front 60+ temps in MID DECEMBER.

I was just thinking that, post front and we're still 55-62

[Brian5671]

Would love to know what caused the flip after the record breaking March 2013 -AO of -3.185.

It's been wall to wall positive since then with some scattered negative months thrown in.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

That's one part of the Jan-March piece I am wary of (the calls for a flip to a -AO and -NAO)  Both have been very hard to come by in the winter since March 2013

[donsutherland1]

If the MEX MOS is correct through 12/22, the remainder of December could average 3.0° below normal, and December 2015 would still wind up as the warmest December on record. For the 10 warmest Decembers on record, NYC had median January-April snowfall of 15.1" and mean January-April snowfall of 15.5". Three winters saw more than 20" January-April snowfall from that subset:

 

1923-24: 26.0"

1891-92: 25.4"

1982-83: 24.2"

 

Two featured less than 10" January-April snowfall:

 

2001-02: 3.5"

2011-12: 4.5"

[Rittenhouse]

If the 12z GFS is correct, dew points on Christmas Eve will be in the mid to upper 60's. It will feel like summer again.

[Damage In Tolland]

If the MEX MOS is correct through 12/22, the remainder of December could average 3.0° below normal, and December 2015 would still wind up as the warmest December on record. For the 10 warmest Decembers on record, NYC had median January-April snowfall of 15.1" and mean January-April snowfall of 15.5". Three winters saw more than 20" January-April snowfall from that subset:

 

1923-24: 26.0"

1891-92: 25.4"

1982-83: 24.2"

 

Two featured less than 10" January-April snowfall:

 

2001-02: 3.5"

2011-12: 4.5"

Considering how this season is mirroring 11-12 so far with some folks expecting a big flip and it not happening..that is worrisome

[donsutherland1]

Would love to know what caused the flip after the record breaking March 2013 -AO of -3.185.

It's been wall to wall positive since then with some scattered negative months thrown in.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

It's possible that a longer-term cycle may be involved.

 

screen shot on pc

 

FWIW, the trendline is slightly positive for the annual, 5-year moving average, and 10-year moving average. The coefficient of determination increases for the longer periods: annual average: 0.0682; 5-year moving average: 0.225; and, 10-year moving average: 0.4559. Nevertheless, there is tremendous year-to-year variability.

[Brian5671]

If the 12z GFS is correct, dew points on Christmas Eve will be in the mid to upper 60's. It will feel like summer again.

damp and foggy I assume?

[Brian5671]

Considering how this season is mirroring 11-12 so far with some folks expecting a big flip and it not happening..that is worrisome

If it does not happen by 1/15-20 then yes, time to pull the plug.  Even at that, while we did well last year in the snow dept, normally when you give away all of December and half or more of Jan, we don't do well at all as noted above.  Average if we are very lucky.  Last year was like hitting 7-7-7 on a slot machine.

[donsutherland1]

Considering how this season is mirroring 11-12 so far with some folks expecting a big flip and it not happening..that is worrisome

If the polar vortex remains strong or rebuilds each time it is weakened and the Aleutian low does not retrograde, that will be a very disturbing situation. So far, no meaningful stratospheric warming events appear likely through at least the next 10 days.

[bluewave]

It's possible that a longer-term cycle may be involved.

 

screen shot on pc

 

FWIW, the trendline is slightly positive for the annual, 5-year moving average, and 10-year moving average. The coefficient of determination increases for the longer periods: annual average: 0.0682; 5-year moving average: 0.225; and, 10-year moving average: 0.4559. Nevertheless, there is tremendous year-to-year variability.

 

Great chart Don. It's interesting that several climate models were indicating this from late 2012 on. They did it

indirectly through the forecast of colder SST's south of Greenland caused by the stronger NATL vortex since April 2013. 

[PB GFI]

Lol at the 11/12 comparison . The calls for the pattern change were failing in early and mid Jan in 2012 . You are in a warm December pattern , that is all and should shock no one.

There has been zero calls here for a pattern change this December by any serious person on this board , to the contrary a warm December was called for NYC back in July and most expect this NOT to change through early Jan .

Let me say this again there is no pattern change in our immediate future .

So this is becoming a dumber argument every time it is used.

Some of us believe you will start to see this pattern evolve around mid Jan .

So there's your forecast , so please come back in mid Jan with that crap

[donsutherland1]

Lol at the 11/12 comparison . The calls for the pattern change were failing in early and mid Jan in 2012 . You are in a warm December pattern , that is all and should shock no one.

There has been zero calls here for a pattern change this December by any serious person on this board , to the contrary a warm December was called for NYC back in July and most expect this NOT to change through early Jan .

Let me say this again there is no pattern change in our immediate future .

So this is becoming a dumber argument every time it is used.

Some of us believe you will start to see this pattern evolve around mid Jan .

So there's your forecast , so please come back in mid Jan with that crap

I agree that it's too soon to assume that there won't be a turnaround. I suspect that if that scenario will play out, we'll see the signs by mid-January. The pattern could well go the way it did after late December 1965's lack of blocking/warmth. Late January witnessed the arrival of sustained blocking coupled with cold anomalies and snowfall opportunities.

[AvantHiatus]

Would love to know what caused the flip after the record breaking March 2013 -AO of -3.185.

It's been wall to wall positive since then with some scattered negative months thrown in.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

I would wager it's related to the NPAC warming or hadley cell expansion. If the North Atlantic cooling is involved, you can count on this pattern to remain consistent with brief intervals of variability. This is because the NATL vortex is driven by the AMOC slowdown.

[PB GFI]

I agree that it's too soon to assume that there won't be a turnaround. I suspect that if that scenario will play out, we'll see the signs by mid-January. The pattern could well go the way it did after late December 1965's lack of blocking/warmth. Late January witnessed the arrival of sustained blocking coupled with cold anomalies and snowfall opportunities.

 

I like how this has progressed since mid summer .  I found some really early AN calls for Dec way back in that ENSO thread ,

Then we looked at where this would set up going forward . So far the tropical forcing in November  is similar to what we saw in other  NINOs that saw warm finish Decembers only to turn in mid Jan like you said ., 57 65 are in here . 

[bluewave]

I would wager it's related to the NPAC warming or hadley cell expansion. If the North Atlantic cooling is involved, you can count on this pattern to remain consistent with brief intervals of variability. This is because NATL vortex is driven by the AMOC slowdown.

 

There have been more positive intervals in the early 1970's and late 1980's into early 1990's

following extended negative phases. But the key this time was that the climate models saw

it indirectly through cooler SST's caused by a more active NATL vortex. Another climate

model successfully saw that there would be a two year El Nino with the second year stronger 

than the first. But greatly underestimated the magnitude of the second year event. Perhaps

the climatologists could key in on the precursors to these changes  in a scientific paper.

[donsutherland1]

There have been more positive intervals in the early 1970's and late 1980's into early 1990's

following extended negative phases. But the key this time was that the climate models saw

it indirectly through cooler SST's caused by a more active NATL vortex. Another climate

model successfully saw that there would be a two year El Nino with the second year stronger 

than the first. But greatly underestimated the magnitude of the second year event. Perhaps

the climatologists could key in on the precursors to these changes  in a scientific paper.

Great observations. I agree. Such a paper would be informative and might yield some insight that could be valuable for seasonal forecasting.