Excessive November Warmth

[donsutherland1]

In my opinion, Winter 2011-12 will likely feature much less blocking than last winter and, with another La Niña, there will be no rescue by the Arctic Oscillation. Hence, a milder than normal winter appears likely for the NYC area and throughout much of the East.

The excessive warmth that has prevailed in November further reinforces that message. Through 11/28, the mean temperature for NYC has been 51.8°. The month will likely finish at that level or a little warmer. Since 1869, there have been 6 years with a mean temperature of 51.8° or above in November: 1931, 1948, 1975, 1994, 2001, and 2006. Such November warmth has been abnormal for La Niña winters, so that's a possible caveat. The other caveat is the small sample size.

The December and winter (December-February) data for such winters is quite ugly:

• Mean December temperature: 40.9°

• 5/6 (83%) cases had a warmer than normal December

• 4/6 (67%) cases had a December with a mean temperature at or above 40°

• Coldest December: 35.9°, 1975

• Warmest December: 44.1°, 2001

• Mean winter (December-February) temperature: 38.0°

• 5/6 (83%) cases had a warmer than normal winter

• 4/6 (67%) cases had a winter that was 2° or more above normal

• 2/6 (33%) cases had a winter mean temperature at or above 40°

• Coldest winter: 34.4°, 1975-76

• Warmest winter: 41.5°, 2001-02

• Mean seasonal snowfall (October-May): 16.2" (skewed by 1948-49)

• Median seasonal snowfall (October-May): 12.1"

• 5/6 (83%) cases had seasonal snowfall < 20"

• 4/6 (67%) cases had seasonal snowfall < 15"

• 2/6 (33%) cases had seasonal snowfall < 10"

• Lowest seasonal snowfall: 3.5", 2001-02

• Highest seasonal snowfall: 46.6", 1948-49

[Brian5671]

Tend to agree in my humble opinion...another thing that has been discussed is the lack of storminess and rainfall playing into the picture--warm/dry November equals crappy winter...

[uncle W]

In my opinion, Winter 2011-12 will likely feature much less blocking than last winter and, with another La Niña, there will be no rescue by the Arctic Oscillation. Hence, a milder than normal winter appears likely for the NYC area and throughout much of the East.

The excessive warmth that has prevailed in November further reinforces that message. Through 11/28, the mean temperature for NYC has been 51.8°. The month will likely finish at that level or a little warmer. Since 1869, there have been 6 years with a mean temperature of 51.8° or above in November: 1931, 1948, 1975, 1994, 2001, and 2006. Such November warmth has been abnormal for La Niña winters, so that's a possible caveat. The other caveat is the small sample size.

The December and winter (December-February) data for such winters is quite ugly:

• Mean December temperature: 40.9°

• 5/6 (83%) cases had a warmer than normal December

• 4/6 (67%) cases had a December with a mean temperature at or above 40°

• Coldest December: 35.9°, 1975

• Warmest December: 44.1°, 2001

• Mean winter (December-February) temperature: 38.0°

• 5/6 (83%) cases had a warmer than normal winter

• 4/6 (67%) cases had a winter that was 2° or more above normal

• 2/6 (33%) cases had a winter mean temperature at or above 40°

• Coldest winter: 34.4°, 1975-76

• Warmest winter: 41.5°, 2001-02

• Mean seasonal snowfall (October-May): 16.2" (skewed by 1948-49)

• Median seasonal snowfall (October-May): 12.1"

• 5/6 (83%) cases had seasonal snowfall < 20"

• 4/6 (67%) cases had seasonal snowfall < 15"

• 2/6 (33%) cases had seasonal snowfall < 10"

• Lowest seasonal snowfall: 3.5", 2001-02

• Highest seasonal snowfall: 46.6", 1948-49

Good post Don...It looks like a mild December coming up...I think we will get more than 12" of snow this year...We already have 2.9"...I'm hoping we get some blocking in February...I think we see another storm like we saw in October with colder temperatures...

[donsutherland1]

Thanks to what will be a negative to strongly negative EPO during the first 1-2 weeks of December, there might be some opportunities for cold shots and maybe some snow, despite the AO+. Timing will be critical. Had the EPO also been positive, we'd probably be looking at a continuation of the excessive warmth through a good chunk of that period.

[Stormlover74]

While December might not be looking too promising I wouldn't throw in the towel for the rest of the winter just yet. Most of the forecasts were for winter to be somewhat front loaded like last year easing up in February and March. Hopefully we'll see the reverse!. And you always have the opportunity for a Feb 83 type storm that comes out of nowhere in an otherwise benign winter.

[donsutherland1]

Good post Don...It looks like a mild December coming up...I think we will get more than 12" of snow this year...We already have 2.9"...I'm hoping we get some blocking in February...I think we see another storm like we saw in October with colder temperatures...

Thanks Uncle W. I do hope that we will have some blocking and later winter might offer the best prospects. Maybe March will have more snowfall than during the last two winters? Half of the cases had 4" or more in March.

[psv88]

Thanks Uncle W. I do hope that we will have some blocking and later winter might offer the best prospects. Maybe March will have more snowfall than during the last two winters? Half of the cases had 4" or more in March.

March snow sucks. By then most people are ready for spring, the bulbs are sprouting and the snow will melt in a few days. Waste if u ask me...

[MJO812]

Great writeup. Everyone has been forecasting a cold and snowy winter. This is probably the first warm winter forecast that I have read for our area.

[easternsnowman]

Statistics are overrated especially for today's climate. One thing to remember how much november has warmed over the lat 10 years, I don't consider it a good indication of the winter any longer.

[Stormlover74]

Let's also remember last year everyone was saying a KU storm was impossible in a strong nina. Mostly because it never happened before.

So yes the safe bet is we are in for a warmer than normal winter, or at least December, but I wouldn't say its a lock. And even if it is warm we could still a few decent snowstorms, or it could turn cold and dry and we get nothing.

By the way one month ago today it was about 30 degrees colder and snowing :-)

Statistics are overrated especially for today's climate. One thing to remember how much november has warmed over the lat 10 years, I don't consider it a good indication of the winter any longer.

[uncle W]

Since 1931 there have been 16 Novembers averaging 50.0 or higher...here are the winters average and the coldest 30 day period...Blue is La Nina years and red El nino years...Only two La Nina years and both had a very cold 30 day period...Snowfall was on the light side...

season.....Nov.....Winter.....coldest 30 day period...

1931..........51.9..........40.1..........35.8

1941..........50.0..........32.9..........29.0

1946..........50.5..........34.8..........29.3

1948..........52.4..........38.5..........36.3

1963..........50.4..........33.3..........31.1

1975..........52.3..........34.4..........27.1

1979..........52.5..........35.4..........30.9

1982..........50.4..........37.9..........32.9

1985..........50.0..........33.4..........31.0

1990..........50.4..........39.2..........34.5

1994..........52.0..........37.1..........31.5

1999..........50.6..........36.2..........26.2

2001..........52.7..........41.5..........35.4

2003..........50.0..........32.4..........22.5

2006..........51.9..........36.5..........25.8

2009..........51.2..........33.8..........31.6

average......51.2..........36.1..........30.7

LT. average 46.2..........33.4..........28.0 est...

[KEITH L.I]

Very broad brush topic here..yes December might be mild,but that doesn't mean you can't have snowfalls..Very mild Decembers have lead to some snow..1948 was very mild but we got lucky..1984..one of the mildest,but a snowfall after Xmas..1990 ect..1998 blowtorch December but it snowed on Dec 24th..to throw away the winter on a warm November is quite a reach

[Stormlover74]

Its funny because if you go back 10 years, the expectations for December were so much lower. In reality the only snowy December we had was in 1995 with many decembers mild, rainy, or just boring in general. Even getting a 4" snowfall would essentially be normal or above the long term average.

Very broad brush topic here..yes December might be mild,but that doesn't mean you can't have snowfalls..Very mild Decembers have lead to some snow..1948 was very mild but we got lucky..1984..one of the mildest,but a snowfall after Xmas..1990 ect..1998 blowtorch December but it snowed on Dec 24th..to throw away the winter on a warm November is quite a reach

[Isotherm]

I think the thread title is a bit misleading honestly. Posted this awhile ago, but it's not as easy as warm Nov=bad winter.

Below is the temp composite of Novembers preceding all 40"+ winters since 1960 in NYC. Granted, only two of them were Ninas, 1995 and 2010, but the point is, excessive November warmth in itself holds little weight wrt the ensuing winter, at least IMO.

However, if you take it a step further, including October's temp profile, plus the ENSO state, we may get a more reliable result. Tony (rainshadow) in the PHL forum did this, and based on a warm Oct, warm Nov couplet in a Nina year, the ensuing winter avg was warmer than normal and less snow than normal.

So I definitely see where you're coming from with this Don, but I just think the thread title on its own can be deceiving, as we've had plenty of excellent winters following warm novs.

[KEITH L.I]

Its funny because if you go back 10 years, the expectations for December were so much lower. In reality the only snowy December we had was in 1995 with many decembers mild, rainy, or just boring in general. Even getting a 4" snowfall would essentially be normal or above the long term average.

Yep totally agree,,Decembers in the 70's 80's and 90's were horiffic..to get a 2 3 incher was quite a feat..I guess many people are spoiled by the last ten years..I guess we'll take what we can get this December

[uncle W]

Yep totally agree,,Decembers in the 70's 80's and 90's were horiffic..to get a 2 3 incher was quite a feat..I guess many people are spoiled by the last ten years..I guess we'll take what we can get this December

we already have more snowfall than those years before January...I don't think it will be a total dud winter but nothing like the last two years...

[SnowGoose69]

I had said earlier in the month, there is an extremely fine line when looking at Novembers and knowing when a mild November is a good sign for the coming winter and when its really bad. You cannot simply look at the monthly departures, one year thats 5th warmest for NYC/PHL/BOS may be different than a year thats 4th warmest in those same 3 places. This year to me is neutral, because there were some positives in the overall pattern across the NHEM and there was some cold air over the CONUS, even if it was not necessarily here.

[donsutherland1]

I think the thread title is a bit misleading honestly. Posted this awhile ago, but it's not as easy as warm Nov=bad winter.

Below is the temp composite of Novembers preceding all 40"+ winters since 1960 in NYC. Granted, only two of them were Ninas, 1995 and 2010, but the point is, excessive November warmth in itself holds little weight wrt the ensuing winter, at least IMO...

I'm was referring to the small subset of extremely warm Novembers. Only 6 cases since 1869 had a mean temperature at or above 51.8°F (we could finish around 52°F). For the following winters, 5/6 (83%) had an above normal December-February mean temperature (and that's using the 1981-2010 norms) and 14/18 (78%) of the winter months had above normal readings. The sample size and lack of La Niña cases all hold caution.

My guess for a warmer winter is premised largely on the La Niña, lack of blocking (much less than the last two winters), and SSTAs. IMO, the excessive warmth that one has witnessed this month is largely a product of those factors. It's just one indicator that so far things remain on track. December snowfall will likely offer another clue.

Needless to say, I hope I'm wrong. A lack of snowfall and persistent warmth is not the kind of winter I prefer.

[easternsnowman]

The farmers almanac (both editions) have called for above normal temps for the east but more stormy including more snow. That still gives most locales above the M/D line a chance for above normal snow in a stormy pattern. I don't care if it's a few degrees above or below normal, the snow is what counts.

[nycsnow]

The farmers almanac (both editions) have called for above normal temps for the east but more stormy including more snow. That still gives most locales above the M/D line a chance for above normal snow in a stormy pattern. I don't care if it's a few degrees above or below normal, the snow is what counts.

Awesome post man

[Stormlover74]

It all depends on the timing and degree of warmth. We've had plenty of snowy months that were 1 to 2 degrees above normal. It would be very difficult however to be +3 to +5 and end up on the plus side in the snowfall department. However one brief cold snap followed by a big storm could yield that type of result.

I was looking at 2004-05 and it was a winter that featured quite a bit of extremes. December got quite cold around Christmas but warmed up heading into the first half of January. Then we had a complete flip to cold followed by the big storm on the 22nd. I had forgotten how much we warmed for the first half of February before returning to a snowy pattern to end the month and start march. It really was not a very cold winter but we ended with quite a bit above normal snowfall.

The farmers almanac (both editions) have called for above normal temps for the east but more stormy including more snow. That still gives most locales above the M/D line a chance for above normal snow in a stormy pattern. I don't care if it's a few degrees above or below normal, the snow is what counts.

[SnowGoose69]

It all depends on the timing and degree of warmth. We've had plenty of snowy months that were 1 to 2 degrees above normal. It would be very difficult however to be +3 to +5 and end up on the plus side in the snowfall department. However one brief cold snap followed by a big storm could yield that type of result.

I was looking at 2004-05 and it was a winter that featured quite a bit of extremes. December got quite cold around Christmas but warmed up heading into the first half of January. Then we had a complete flip to cold followed by the big storm on the 22nd. I had forgotten how much we warmed for the first half of February before returning to a snowy pattern to end the month and start march. It really was not a very cold winter but we ended with quite a bit above normal snowfall.

December 2002 and 03 were both faily mild for long stretches yet we snuck in 2 snow events in each, and you can include 1993 as well, all 3 of those averaged 1-2 degrees above normal but we got 6 snowstorms total between those 3 years. So long as NYC averages less than 37.5 or so for Dec snow can happen, and 37.5 is about 2 degrees above normal.

[Isotherm]

I'm was referring to the small subset of extremely warm Novembers. Only 6 cases since 1869 had a mean temperature at or above 51.8°F (we could finish around 52°F). For the following winters, 5/6 (83%) had an above normal December-February mean temperature (and that's using the 1981-2010 norms) and 14/18 (78%) of the winter months had above normal readings. The sample size and lack of La Niña cases all hold caution.

My guess for a warmer winter is premised largely on the La Niña, lack of blocking (much less than the last two winters), and SSTAs. IMO, the excessive warmth that one has witnessed this month is largely a product of those factors. It's just one indicator that so far things remain on track. December snowfall will likely offer another clue.

Needless to say, I hope I'm wrong. A lack of snowfall and persistent warmth is not the kind of winter I prefer.

Well, good luck. Respectfully disagree, but should be interesting to see how it turns out. I think blocking will show up in a big way for at least a 3-4 week period this winter.

[jm1220]

I think it's going to be hard to set up a snowy pattern here without significant blocking over Greenland or over the Davis Strait. Last year at around this time we showed signs of the blocking pop up already. We really lucked out last winter a few times thanks to this pattern (12/26 being one of them, due to the related N Stream energy being forced to dive south and phase into a trough that blew up the storm). Without that block, it would have been a generally progressive themed winter even if cold from time to time. The big coastals came as a direct result of this block (1/26 was luck-the pattern really wasn't that supportive for a big storm and without that massive upper low and back end, it would have been a 6-8 incher maybe). It doesn't mean we can't luck out with SW flow events from time to time, but IMO it will be hard to get another major, 12"+ type storm without blockiness over NE Canada or Greenland to force the pattern to slow down, dive south, and phase into a big storm, plus slow that storm down.

FWIW, I think it's about an average winter here snow and tempwise.

[uncle W]

If December averages 40.0 or above there is very little snow fall on average...19 times this happened and only one year had good snows...1957-58...1982-83 had a major storm in February but that was also a El Nino year also...blue= La Nina years...Only one year had above the long term average...No snowstorms over 8"...

10/19 had 20" or more...

10/19 had 0.1" or less in December...

Only 1957-58 had temperatures below the long term average but barely...4/19 are below the 30 year average...

season.....Dec....Jan....Feb....Ave...snowfall...

1889-90...40.0...37.6...37.9...38.5.....24.3"...6.0" in December...6" big snow

1891-92...42.3...31.5...33.4...35.7.....25.4"...0.0" in December...

1923-24...42.0...32.7...33.4...34.6.....27.5"...1.5" in December...

1931-32...41.0...43.2...36.1...40.1.......5.3"...0.1" in december...2" November...

1953-54...41.3...30.8...40.1...37.4.....15.8"...trace in December...2.2" November...

1956-57...40.9...28.5...37.3...35.6.....21.9"...0.9" in December...

1957-58...40.2...31.9...27.4...33.3.....44.7"...8.7" in December...8" big snow

1965-66...40.5...32.2...35.1...35.9.....21.4"...trace in December...

1971-72...40.8...35.1...31.4...35.1.....22.9"...trace in December...

1979-80...41.1...33.7...31.4...35.4.....12.8"...3.5" in December...

1982-83...42.8...34.5...36.4...37.9.....27.2"...3.0" in December...

1984-85...43.8...28.8...36.6...36.4.....24.1"...5.5" in December...4.7" big snow

1990-91...42.6...34.9...40.0...39.2.....24.9"...7.2" in December...7.2" big snow

1994-95...42.2...37.5...31.6...37.1.....11.8"...trace in December...

1996-97...41.3...32.2...40.0...37.8.....10.0"...trace in December...0.1" in November...

1998-99...43.2...33.9...38.9...38.7.....12.7"...2.0" in December...

1999-00...40.0...31.3...37.3...36.2.....16.3"...trace in December...

2001-02...44.1...39.9...40.6...41.5.......3.5"...trace in December...

2006-07...43.6...37.5...28.2...36.5.....12.4"...0.0" in December...

LT AVE.....35.6...31.9...32.7...33.4.....28.3"...5.4"

30 yr ave. 37.9...33.1...35.6...35.5.....25.4"...4.3"