December 2024

[bluewave]

  On 12/1/2024 at 2:51 PM, SACRUS said:

Outside of the first of Dec - this looks forecast similar to 2010 through the 10th or so temp-wise.

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The main difference was that 2010 stayed cold the whole month with no moderation.

[snowman19]

  On 12/1/2024 at 3:19 PM, bluewave said:

The main difference was that 2010 stayed cold the whole month with no moderation.

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Exactly and I see absolutely no comparison whatsoever to December, 2010. That was driven by severe AO/NAO blocking and a poleward Aleutian ridge. We are going to see a big moderation mid-month

 

 

 

 

[MJO812]

  On 12/1/2024 at 3:27 PM, snowman19 said:

Exactly and I see absolutely no comparison whatsoever to December, 2010. That was driven by severe AO/NAO blocking and a poleward Aleutian ridge. We are going to see a big moderation mid-month

 

 

 

 

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Big warmup? Looks like a brief milder pattern before right back into winter.

[qg_omega]

the mid month warmth could be historic unlike this current below normal air which is not even close.  Evidence of a very strong polar vortex forming and CONUS blowtorch

[bluewave]

  On 12/1/2024 at 3:27 PM, snowman19 said:

Exactly and I see absolutely no comparison whatsoever to December, 2010. That was driven by severe AO/NAO blocking and a poleward Aleutian ridge. We are going to see a big moderation mid-month

 

 

 

 

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My guess is that the first week to 10 days of December may have the coldest departures we see this month. The extended EPS is already backing off the cold it was showing for the 9th through 16th. This has been typical December local climatology with the usual warm up as we approach the solstice and Christmas. 
 

New run closer to average December 9th through 16th

 

Old run was colder

 

Longer term December temperature trends cooler to start and warming up as we approach the solstice and holidays

[brooklynwx99]

  On 12/1/2024 at 3:42 PM, qg_omega said:

the mid month warmth could be historic unlike this current below normal air which is not even close.  Evidence of a very strong polar vortex forming and CONUS blowtorch

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show evidence

[NEG NAO]

  On 12/1/2024 at 3:19 PM, bluewave said:

The main difference was that 2010 stayed cold the whole month with no moderation.

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December 1995 December 2000 and December 2010 - all below 33 avg temp and all three seasons La Nina's of various strengths and all 3 had over 50 inches seasonal snowfall in NYC.....

[bluewave]

  On 12/1/2024 at 4:17 PM, NEG NAO said:

December 1995 December 2000 and December 2010 - all below 33 avg temp and all three seasons La Nina's of various strengths and all 3 had over 50 inches seasonal snowfall in NYC.....

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Yeah, we don’t get Decembers that cold anymore regardless of La Niña, neutral, or El Niño.

[NEG NAO]

  On 12/1/2024 at 4:20 PM, bluewave said:

Yeah, we don’t get Decembers that cold anymore regardless of La Niña, neutral, or El Niño.

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give it time IMO........looking at the averages since the beginning they are all over the place in December and impossible to determine any specific trends there have been stretches of above normal in the past then returns to below normal monthlyannualtemp.pdf

[bluewave]

  On 12/1/2024 at 4:23 PM, NEG NAO said:

give it time IMO........looking at the averages since the beginning they are all over the place in December and impossible to determine any specific trends there have been stretches of above normal in the past then returns to below normal monthlyannualtemp.pdf

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Very unlikely that we see a December this year anywhere near 32° in NYC given the record warmth across North America and the globe this fall.

[eduggs]

12z GFS is pretty interesting around the 10th. That would probably work. But it's a long way off and too much run-to-run variability to have any confidence. The threat for the 8th keeps decreasing in likelihood.

[Snowshack]

  On 12/1/2024 at 4:23 PM, NEG NAO said:

give it time IMO........looking at the averages since the beginning they are all over the place in December and impossible to determine any specific trends there have been stretches of above normal in the past then returns to below normal monthlyannualtemp.pdf

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The warming trend is pretty clear on that chart though.  

[eduggs]

Sign me up for the 12z GFS. Some snow to long duration frozen mix. Nice trof axis and pretty cold surface. But unlikely outcome.

[Allsnow]

  On 12/1/2024 at 4:36 PM, eduggs said:

Sign me up for the 12z GFS. Some snow to long duration frozen mix. Nice trof axis and pretty cold surface. But unlikely outcome.

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We hope It has a clue because the eps wants nothing to do with it 

[psv88]

23. 

[Stormlover74]

  On 12/1/2024 at 4:43 PM, Allsnow said:

We hope It has a clue because the eps wants nothing to do with it 

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And cmc is ugly

[nycwinter]

cold breezy and extremely dry got to be the lowest dewpoint we had  since last winter..i was wondering after a few miles walk why i did not sweat one drop..

[NEG NAO]

  On 12/1/2024 at 4:35 PM, Snowshack said:

The warming trend is pretty clear on that chart though.  

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True but aren't all the measurements in Central Park NYC ? I would like to see a chart from outside the "Heat Island" going back to the beginning of recorded measurement time. Also several stations. different directions of NYC

[eduggs]

  On 12/1/2024 at 4:52 PM, Stormlover74 said:

And cmc is ugly

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Most likely outcome IMO. Pray for a snow squall Wed night.

[NEG NAO]

  On 12/1/2024 at 4:36 PM, eduggs said:

Sign me up for the 12z GFS. Some snow to long duration frozen mix. Nice trof axis and pretty cold surface. But unlikely outcome.

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models have been all over the place run to run disagreeing with themselves

[NEG NAO]

  On 12/1/2024 at 4:30 PM, bluewave said:

Very unlikely that we see a December this year anywhere near 32° in NYC given the record warmth across North America and the globe this fall.

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agree and not on the "Heat Island"

[bluewave]

  On 12/1/2024 at 5:01 PM, NEG NAO said:

agree and not on the "Heat Island"

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The heat island doesn’t have anything to do with it since it’s air mass related and not UHI related. The heat island effect has been constant in NYC for a long time. The outlying areas haven’t any any similarly cold Decembers since 2010 either.

[WX-PA]

  On 12/1/2024 at 3:42 PM, qg_omega said:

the mid month warmth could be historic unlike this current below normal air which is not even close.  Evidence of a very strong polar vortex forming and CONUS blowtorch

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Where do you see that?..I see a little bit above normal after the 15th

[donsutherland1]

Back during winter 2022-2023, I posted some information concerning how a warming climate might affect seasonal snowfall in New York City. Based on the experience of cities south of New York City, by the mid-2030s, seasonal snowfall (30-season average) could reach or fall below 20" per season. It is still too soon to be sure whether the two most recent relatively snowless winters are part of the early stages of a transition to a less snowy future. Even in a less snowy future, periodic snowy winters remain likely.

Looking further into the matter, it seems that some locations, including Philadelphia and Washington, DC have seen a temporary increase in seasonal snowfall as the mean winter temperature approached and then exceeded 36.0°. That outcome is probably the result of an increase in moisture exceeding the consequences of a warming climate where bigger snowstorms skew seasonal averages. A larger initial secondary increase in snowfall is likely farther north than Washington, DC or Philadelphia, as New York City (and also Boston) are closer to sources of sufficiently cold air. Eventually, the warmth more than offset the gains resulting from increased moisture.

Below are the current charts for both New York City and Washington, DC:

[Dark Star]

  On 12/1/2024 at 5:23 PM, WX-PA said:

Where do you see that?..I see a little bit above normal after the 15th

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Though persistence is the least scientific forecasting tool, it would be difficult to doubt any extended range outlook for warmer than normal temperatures, given the recent history...

[NorthShoreWx]

  On 12/1/2024 at 3:45 PM, bluewave said:

My guess is that the first week to 10 days of December may have the coldest departures we see this month. The extended EPS is already backing off the cold it was showing for the 9th through 16th. This has been typical December local climatology with the usual warm up as we approach the solstice and Christmas. 
 

New run closer to average December 9th through 16th

 

Old run was colder

 

Longer term December temperature trends cooler to start and warming up as we approach the solstice and holidays

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The general holiday/Christmas warmup has been very noticeable and quite regular, but I'm not aware of any reason why that is more than an unlikely coincidence.  Is there any physical evidence that this should be considered a norm for the second half of December?

[MJO812]

  On 12/1/2024 at 5:23 PM, WX-PA said:

Where do you see that?..I see a little bit above normal after the 15th

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In his brain

[Uniblab]

  On 12/1/2024 at 3:27 PM, snowman19 said:

Exactly and I see absolutely no comparison whatsoever to December, 2010. That was driven by severe AO/NAO blocking and a poleward Aleutian ridge. We are going to see a big moderation mid-month

 

 

 

 

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The usual big Christmas heat wave. 

[NEG NAO]

  On 12/1/2024 at 5:53 PM, Uniblab said:

The usual big Christmas heat wave. 

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not 2 years ago - Teens all day on Christmas

[Stormlover74]

  On 12/1/2024 at 6:02 PM, NEG NAO said:

not 2 years ago - Teens all day on Christmas

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The only cold weather all winter