December Low Temperature Not Impressive For NYC

[bluewave]

You would think from looking at the monthly temperature departure in NYC which is running at -5.2 below normal that

the low for the month which is currently at 19 degrees would be lower.I guess it's just a combination of the -PNA/-AO/-NAO

and the best departures and record low temperatures occurring more towards the SE US.I know several of us have posted

in the past about the greater difficulty in getting record low temperatures here over the 2000's so far.

I put together a list of Decembers from the past few years and also years when the average temperature came in below 33 degrees for comparison.You can see more single digits and lower from the 80's back to 1960 when global average temperatures were lower.

YEAR / DEC AVG /LOWEST DAILY

2010..32.4....19

2009..35.9....16

2008..38.1....13

2007..37.0....20

2006..43.6....18

2005..35.3....14

2000..31.1....14

1995..32.4....15

1989..25.9....6

1980..32.5...-1

1976..29.9...9

1963..31.2...11

1962..31.5...4

1960...30.9..8

[nzucker]

I don't think it has too much to do with global average temperatures compared to the fact the month was relatively cloudy and windy. Most of Central Park's negative anomalies this month come from CAA days where strong NW winds and occasional cloud cover kept daytime highs in the lower 30s. 850s did drop near -20C after the mid-December lakes cutter but conditions stayed very windy and Central Park only made it down to 19F. The lack of snowpack also hurt radiating conditions, as the storm track was very poor for Central Park until the December 26th event; I bet most of the months with very cold readings that you posted had snow on the ground.

[donsutherland1]

The coldest air remained on the other side of the globe. Hence, the blocking that led to the persistent cold could not bring extreme air masses into the eastern U.S. Instead, the same blocking regime led to a severely cold December in, among other places, Western Europe.

[SnowGoose69]

The coldest air remained on the other side of the globe. Hence, the blocking that led to the persistent cold could not bring extreme air masses into the eastern U.S. Instead, the same blocking regime led to a severely cold December in, among other places, Western Europe.

That has generally been the case the last 20 years or so it seems that the coldest air seems to have generally remained over in Europe or Asia when these blocking events occur.

[bluewave]

I don't think it has too much to do with global average temperatures compared to the fact the month was relatively cloudy and windy. Most of Central Park's negative anomalies this month come from CAA days where strong NW winds and occasional cloud cover kept daytime highs in the lower 30s. 850s did drop near -20C after the mid-December lakes cutter but conditions stayed very windy and Central Park only made it down to 19F. The lack of snowpack also hurt radiating conditions, as the storm track was very poor for Central Park until the December 26th event; I bet most of the months with very cold readings that you posted had snow on the ground.

That's more toward the overall trend we have been seeing over the long term.Outside of January 2004,we have not really seen too many more extreme cold shots here.If January 2004 would have occurred in earlier decades, NYC would have probably seen below 0 temps.

[bluewave]

The coldest air remained on the other side of the globe. Hence, the blocking that led to the persistent cold could not bring extreme air masses into the eastern U.S. Instead, the same blocking regime led to a severely cold December in, among other places, Western Europe.

Right,Europe and Asia bore the brunt of the cold but the SE US was right up there also.

[uncle W]

the average temperature and lowest monthly minimum are rising for now...

Here is some stats from my winter temperature posts...

December 1869-2010 Central Park...

there is a noticeable lack of single digit temperatures since the 1980's...

decade..ave.temp..high..low...ave.max/min..max..min...precipitation...snowfall

1870's......32.7......37.4......24.9....'.....................64......-2...2.88"...6.7"

1880's......33.6......40.0......26.5......57.3.....7.9....67......-6...3.28"...7.1"

1890's......35.9......42.3......29.9......58.8...12.0....66.......8...2.97"...4.3"

1900's......34.8......38.9......30.3......57.1...13.6....64.......4...3.95"...6.2"

1910's......34.1......39.4......25.0......59.4...10.8....64....-13...3.80"...7.5"

1920's......35.5......42.0......28.9......59.0...13.2....68.......7...3.49"...4.2"

1930's......35.9......41.0......30.0......61.2...11.7....68......-6...2.86"...4.3"

1940's......35.4......39.4......31.0......59.5...11.7....70......-4...3.39"...9.1"

1950's......36.8......41.3......29.4......59.7...12.0....67.......5...3.49"...4.7"

1960's......34.8......40.5......30.9......61.6...12.9....68.......4...3.70"...7.4"

1970's......37.4......41.1......29.9......61.6...17.6....67.......9...4.63"...1.7"

1980's......36.6......43.8......25.9......61.0...11.8....72......-1...3.14"...2.1"

1990's......39.5......43.2......32.4......64.0...16.5....75.....10...4.04"...2.9"

2000's......37.7......44.1......31.1......62.9...16.6....71.....11...4.45"...7.8"

LT ave......35.6......41.0......29.0......60.2...12.9....68.......2...3.58"...5.4"

30 yrs.......37.9......43.7......29.8......62.6...15.0....73.......7...3.88"...4.3"

other winter stats here...

[bluewave]

Thanks for the great stats Uncle.

Those single digits are getting harder to come by.

[uncle W]

You would think from looking at the monthly temperature departure in NYC which is running at -5.2 below normal that

the low for the month which is currently at 19 degrees would be lower.I guess it's just a combination of the -PNA/-AO/-NAO

and the best departures and record low temperatures occurring more towards the SE US.I know several of us have posted

in the past about the greater difficulty in getting record low temperatures here over the 2000's so far.

I put together a list of Decembers from the past few years and also years when the average temperature came in below 33 degrees for comparison.You can see more single digits and lower from the 80's back to 1960 when global average temperatures were lower.

YEAR / DEC AVG /LOWEST DAILY

2010..32.4....19

2009..35.9....16

2008..38.1....13

2007..37.0....20

2006..43.6....18

2005..35.3....14

2000..31.1....14

1995..32.4....15

1989..25.9....6

1980..32.5...-1

1976..29.9...9

1963..31.2...11

1962..31.5...4

1960...30.9..8

since 1970 the average minimum for December is 15.6 with the 1970's having the warmest average at 17.6...

[uncle W]

Thanks for the great stats Uncle.

Those single digits are getting harder to come by.

it's not only December...I think the last 10 years had five without single digits...

[bluewave]

it's not only December...I think the last 10 years had five without single digits...

Sure, and the lack of daily record low temperatures in general.

[A-L-E-X]

That's more toward the overall trend we have been seeing over the long term.Outside of January 2004,we have not really seen too many more extreme cold shots here.If January 2004 would have occurred in earlier decades, NYC would have probably seen below 0 temps.

Id rather have somewhat cold + lots of snow, rather than very cold + average snowfall lol. Jan 2004 was a rare beast that had both. But I wouldnt be too enthused about a 1976-77 kind of winter. 1977-78 didnt get extremely cold either, but had tons of snow-- that's more like it

[Stormlover74]

I know. It does seem like after almost every big storm we get at least a moderate warmup/rainstorm. It's been a while since we had snowpack for a good 3-4 weeks with several storms on top of each other. 2003 had that streak of below freezing days in a row but had no snow on the ground

Id rather have somewhat cold + lots of snow, rather than very cold + average snowfall lol. Jan 2004 was a rare beast that had both. But I wouldnt be too enthused about a 1976-77 kind of winter. 1977-78 didnt get extremely cold either, but had tons of snow-- that's more like it

[bluewave]

Id rather have somewhat cold + lots of snow, rather than very cold + average snowfall lol. Jan 2004 was a rare beast that had both. But I wouldnt be too enthused about a 1976-77 kind of winter. 1977-78 didnt get extremely cold either, but had tons of snow-- that's more like it

January 1977 was like the Arctic tundra around here.I can remember leaving to go to school when I was 10 years old

in close to zero degree readings.The amount of ice on the back bays around here was an amazing sight to see.You

would have liked that super cold front that blasted through later in the month.Also the sledding was great at Bethpage

State Park during FEB 78 and79.

[A-L-E-X]

January 1977 was like the Arctic tundra around here.I can remember leaving to go to school when I was 10 years old

in close to zero degree readings.The amount of ice on the back bays around here was an amazing sight to see.You

would have liked that super cold front that blasted through later in the month.Also the sledding was great at Bethpage

State Park during FEB 78 and79.

The last time I remember that kind of super arctic outbreak was back in 1993-94... it was fun watching those ice flows come down the hudson river from work lol.

[A-L-E-X]

I know. It does seem like after almost every big storm we get at least a moderate warmup/rainstorm. It's been a while since we had snowpack for a good 3-4 weeks with several storms on top of each other. 2003 had that streak of below freezing days in a row but had no snow on the ground

its funny, 2008-09 had more snowcover days than 2009-10 with half the snow! We had like a 1-2 inch snowcover during most of January that year and that was our entire snowfall for the month, too! Cold Januarys have become much rarer than they were back in the 80s as per whatever new cycle we've entered lol.

[pazzo83]

The last time I remember that kind of super arctic outbreak was back in 1993-94... it was fun watching those ice flows come down the hudson river from work lol.

That outbreak was freaking insane. In the Shenandoah valley of VA we got down to -20 to -25 F one night. I remember the high the following day being about -5 F.

[nzucker]

The coldest air remained on the other side of the globe. Hence, the blocking that led to the persistent cold could not bring extreme air masses into the eastern U.S. Instead, the same blocking regime led to a severely cold December in, among other places, Western Europe.

Yes, exactly, Don: the blocking was mostly over Northern/Eastern Canada. This keeps the East colder than average by maintaining northerly flow over the region and not allowing the SE ridge to build in, but it does not promote arctic temperatures since the polar vortex sits over Siberia and the Atlantic Arctic near Europe. Having the GoA low basically ensures that Canada remains too warm to allow for an arctic outbreak. I would consider mid-December an "arctic shot" here, though, as we only got up to the low 20s in Westchester when average highs are still around 43F.

[SnoSki14]

As long as its below normal enough and favorable enough to get snow, then I'm happy

I don't think there's any doubt that the globe has warmed, it's certainly not like it was even 20 years ago. The biggest warmth has occurred with the minimum lows and that has more to do with these micro climates that have been created. It's pretty insane that the highs have to be in the 30s for LGA to get to freezing at night.

But maybe it's a cycle and the cold will get on our side of the globe eventually, I don't think it can stay over Asia and Europe forever. However it would probably take a massive PNA and a huge -EPO for that to happen. Having a severe -AO/NAO doesn't really help give us the extremely cold air masses as we saw last winter. Sure it sets us up for snow but not arctic air.

[uncle W]

Id rather have somewhat cold + lots of snow, rather than very cold + average snowfall lol. Jan 2004 was a rare beast that had both. But I wouldnt be too enthused about a 1976-77 kind of winter. 1977-78 didnt get extremely cold either, but had tons of snow-- that's more like it

the lowest temperature for the 1977-78 winter was 10...Other snowy winters with no extreme cold was...

2009-10...

2005-06...

2000-01...

1982-83...

1977-78

1968-69

1963-64

1959-60

1948-49

some snowy and extreme cold winters...

2004-05

2003-04

2002-03

1995-96

1993-94

1978-79

1966-67

1960-61

1957-58

1955-56

1947-48

[JBG]

I don't think it has too much to do with global average temperatures compared to the fact the month was relatively cloudy and windy. Most of Central Park's negative anomalies this month come from CAA days where strong NW winds and occasional cloud cover kept daytime highs in the lower 30s. 850s did drop near -20C after the mid-December lakes cutter but conditions stayed very windy and Central Park only made it down to 19F. The lack of snowpack also hurt radiating conditions, as the storm track was very poor for Central Park until the December 26th event; I bet most of the months with very cold readings that you posted had snow on the ground.

Also I'm suspicious of early measurements. A summer example illustrating my suspicious are the three consecutive summers in a row where NYC topped 100; 1952. 1953 and 1954, followed by the scorching though not 100+ 1955. I suspect the instrument placement may be different in very modern times.

[nzucker]

Thanks for the great stats Uncle.

Those single digits are getting harder to come by.

The thing that makes me suspicious of the global warming argument for increased nighttime lows in Central Park is that Atlanta got down to 14F on December 14th while NYC, around 800 miles to the north, had a monthly minimum of 19F. I know Atlanta has some elevation, but it's in central Georgia for goodness sakes. The fact that Atlanta can get so much colder just shows how ridiculous the urban heat island has become both in the city and around the outlying suburbs, where drastic warming has taken place at night in the last few decades. NYC only managed to get down to 19F with 850mb temperatures of -19C, and in January 2009 only got down to 6F with 850s around -25C. These airmasses are plenty cold for brutal readings in normal locations, but Central Park just fails to radiate 100% of the time. You literally need perfect conditions with heavy snowpack, a light north wind (not NW), and low 850s to get a cold night. For example, they're still at 31F tonight at 1am whereas most of the suburbs are in the teens and low 20s (17F at Essex County Airport, 22F at Islip, 25F at White Plains)...I've noticed driving around that there's about a 20-mile radius around the city that doesn't radiate at all; once you get beyond that, temperatures drop dramatically.

I am not saying global warming has had no role in changing nighttime winter minimums, but I believe it's overstated when we're discussing Central Park, which is a special case.

[bluewave]

The thing that makes me suspicious of the global warming argument for increased nighttime lows in Central Park is that Atlanta got down to 14F on December 14th while NYC, around 800 miles to the north, had a monthly minimum of 19F. I know Atlanta has some elevation, but it's in central Georgia for goodness sakes. The fact that Atlanta can get so much colder just shows how ridiculous the urban heat island has become both in the city and around the outlying suburbs, where drastic warming has taken place at night in the last few decades. NYC only managed to get down to 19F with 850mb temperatures of -19C, and in January 2009 only got down to 6F with 850s around -25C. These airmasses are plenty cold for brutal readings in normal locations, but Central Park just fails to radiate 100% of the time. You literally need perfect conditions with heavy snowpack, a light north wind (not NW), and low 850s to get a cold night. For example, they're still at 31F tonight at 1am whereas most of the suburbs are in the teens and low 20s (17F at Essex County Airport, 22F at Islip, 25F at White Plains)...I've noticed driving around that there's about a 20-mile radius around the city that doesn't radiate at all; once you get beyond that, temperatures drop dramatically.

I am not saying global warming has had no role in changing nighttime winter minimums, but I believe it's overstated when we're discussing Central Park, which is a special case.

For the lows this month, I mentioned in my original post the orientation of the best anomalies heading for the SE with the way the pattern has set up.

When I speak of an overall warmer climate,I am just looking at the warming cycle coming out of the Little Ice Age where in the 20th century during

+PDO eras the global average temperature has warmed up a bit and during -pdo the temperatures were more or less steady.

I would also add that more recently the arctic intrusions into the US have hit us more indirectly

as opposed to the direct shot that we got back in January 2004 when NYC had a few 1 degree temperatures and -2 in 1994.Since I rely also

on CAA to get single digits here at the shore,my amount of single digits have been tracking pretty close to NYC.Although NYC usually comes in 1-2

degrees warmer during those cold shots than here in Long Beach.

[psv88]

The thing that makes me suspicious of the global warming argument for increased nighttime lows in Central Park is that Atlanta got down to 14F on December 14th while NYC, around 800 miles to the north, had a monthly minimum of 19F. I know Atlanta has some elevation, but it's in central Georgia for goodness sakes. The fact that Atlanta can get so much colder just shows how ridiculous the urban heat island has become both in the city and around the outlying suburbs, where drastic warming has taken place at night in the last few decades. NYC only managed to get down to 19F with 850mb temperatures of -19C, and in January 2009 only got down to 6F with 850s around -25C. These airmasses are plenty cold for brutal readings in normal locations, but Central Park just fails to radiate 100% of the time. You literally need perfect conditions with heavy snowpack, a light north wind (not NW), and low 850s to get a cold night. For example, they're still at 31F tonight at 1am whereas most of the suburbs are in the teens and low 20s (17F at Essex County Airport, 22F at Islip, 25F at White Plains)...I've noticed driving around that there's about a 20-mile radius around the city that doesn't radiate at all; once you get beyond that, temperatures drop dramatically.

I am not saying global warming has had no role in changing nighttime winter minimums, but I believe it's overstated when we're discussing Central Park, which is a special case.

Yes but Atlanta, where i went to college, has an elevation close to 1100 feet...and in the winter has much drier air than ny, with lighter winds since it is inland, so the climate and topography in atlanta helps with the radiational cooling....in the summer it also is cooler than surrounding areas due to its elevation.

[uncle W]

Brooksville Florida was colder than NYC a few mornings this month...I thought February was going to be the coldest/snowiest month before the winter started...If I'm right look out 1995-96 snowfall record...My guess is NYC sees temperatures around 10 in January and below ten in early February...