December 2025 OBS and Discussion

[SACRUS]

 

2015 high temps in the 70s 10 years ago and 15 years ago models started to show signs of a blizzard on the 26th.

[bluewave]

This season is going to be an interesting case study for snowy La Niña Decembers across the NYC Metro region and the rest of the season. With the storm coming in next few days, December 2025 will rank in our snowier La Niña December list of years. Most of the time these seasons got to 25”+ from Newark out to Islip.

But the way we are getting this snowy December is different from the past La Niña cases. Unusually early stratospheric disruption with the record low sea ice in the Kara and Barents. The forecast is calling for a reversal of this pattern in the stratosphere after the first week of January. 

So it will be interesting to see if we follow up later in the season with more snow getting us over the 25” mark from Newark out to Islip. My guess is that we would probably need at least one NESIS KU event with a rapidly deepening low near the benchmark to pull this off. Since we haven’t reached 25”+ without at least one KU NESIS storm in the last 30 years.

But this storm track has been inactive since January 2022 with all our snow this December coming with an unusually snowy clipper snowfall pattern that we haven’t seen in many years. 

The overall 500 mb pattern leading to this is quite unique for December. It doesn’t match previous Decembers. So with all the unusual influences this month, it’s difficult to say for sure we will repeat the past winter snowfall outcomes following snowy La Niña Decembers. 

But we can say for sure that December 2025 will go into the books as one of the our coldest and snowiest in a long time regardless of what happens after the first week of January.

 
 

 

[steve392]

42 and howling winds... Again.  Really sick of these winds. 

[Stormlover74]

5 minutes ago, steve392 said:

42 and howling winds... Again.  Really sick of these winds. 

Our whole neighborhood is doing luminaries this year. Going to be a pain if this wind keeps up

[IrishRob17]

49 minutes ago, Stormlover74 said:

Our whole neighborhood is doing luminaries this year. Going to be a pain if this wind keeps up

I've made ice luminaries in years past. They are awesome when the weather cooperates.  

[wthrmn654]

How's Europe doing so far? They seeing snow or cold? 

 

They been brutally hot past few summers i know curious how there winters have been. 

If anyone knows

[Stormlover74]

3 minutes ago, IrishRob17 said:

I've made ice luminaries in years past. They are awesome when the weather cooperates.  

We did 8000+ this year as a community. I have like 200 in my garage that neighbors are supposed to help distribute and light. 

[wthrmn654]

[MANDA]

1 hour ago, Stormlover74 said:

Our whole neighborhood is doing luminaries this year. Going to be a pain if this wind keeps up

Post some pictures if you can.  Should be really nice.

Sand in the bags really helps against the wind.

[Stormlover74]

4 minutes ago, MANDA said:

Post some pictures if you can.  Should be really nice.

Sand in the bags really helps against the wind.

Yeah we have plenty of sand 

[Krs4Lfe]

Steve D from NYNJPA weather says to watch 12/31-1/1 for a potential storm around that time 

[donsutherland1]

1 hour ago, wthrmn654 said:

How's Europe doing so far? They seeing snow or cold? 

 

They been brutally hot past few summers i know curious how there winters have been. 

If anyone knows

So far, it's been a warm winter, but a colder pattern is forecast to develop.

[SnowGoose69]

3 hours ago, EastonSN+ said:

The SE Ridge linking to the -NAO has always occured, however a MET previously stated that we will still snow if we have a 50/50 low present. Likely what happened a lot 1970 through 1989.

It does seem the SER is worse now and the 50/50 region trofing is not there as much.  Here are 2 setups from the 80s which nowadays I would bet result in much more massive SERs than they did back then.  Notice in both cases the low heights in the NW ATL, now it seems that feature is there less.

 

https://www.meteo.psu.edu/ewall/NARR/1989/us0205.php

 

 

https://www.meteo.psu.edu/ewall/NARR/1985/us0204.php

[EastonSN+]

6 minutes ago, SnowGoose69 said:

It does seem the SER is worse now and the 50/50 region trofing is not there as much.  Here are 2 setups from the 80s which nowadays I would bet result in much more massive SERs than they did back then.  Notice in both cases the low heights in the NW ATL, now it seems that feature is there less.

 

https://www.meteo.psu.edu/ewall/NARR/1989/us0205.php

 

 

https://www.meteo.psu.edu/ewall/NARR/1985/us0204.php

Would be interesting if we do have solid evidence, however wouldn't the catalyst be deeper west coast troughing?

[nycwinter]

it is so windy i was pushed back by the wind i felt like a little kid again..

[Stormlover74]

2 hours ago, MANDA said:

Post some pictures if you can.  Should be really nice.

Sand in the bags really helps against the wind.

Unfortunately the guy who filed with a drone last year isn't around but will have video and pics

[SACRUS]

 

Just made it to 50, not quite the 75 in 2015 (ten years ago) but warm today and liekly not this warm again till after Jan 4th

[wthrmn654]

6 minutes ago, SACRUS said:

 

Just made it to 50, not quite the 75 in 2015 (ten years ago) but warm today and liekly not this warm again till after Jan 4th

77 at my sister's in Tennessee 

[SACRUS]

3 minutes ago, wthrmn654 said:

77 at my sister's in Tennessee 

The US Temperature map will be interesting this weekend with the tremendous warmth into the center of the nation / and the south and the dramatic drop off to the northeast

[psv88]

47 and sunny today. 

[Snowlover11]

Wind is brutal today despite being 41F.

[wthrmn654]

44 here today. 

[donsutherland1]

Tomorrow will be a mainly dry day with readings topping out in the lower and middle 40s. A few spots could pick up a sprinkle or shower. Colder air will then press into the region tomorrow night. That will set the stage for a winter storm to end the week.

Friday will see increasing clouds. Snow will arrive during the late afternoon or evening and continue overnight. The snow could fall moderately to even heavily for a time. Sleet or freezing rain could mix in toward the end of the storm in parts of the region. A general 4"-8" snowfall is likely in and around the New York City area.

The RRFS A, which will succeed the NAM, appears to have inherited the NAM's idiosyncratic behavior. It shows a narrow area of 4"-6" snows from southeastern Pennsylvania running southeastward across southern New Jersey. It shows less than 0.5" of snow in New York City and no measurable snow just north of New York City. Just one EPS member has less than 1" of snow in New York City. The RRFS A output is an outlier and is not considered.

The storm will be followed by a chilly weekend. The closing days of December will likely be colder than normal.

December 2025 will very likely finish with a maximum monthly temperature below 60° in New York City. The last time that happened was in 2019 when the monthly high was 58°. If 2025 has a monthly high below 60°, that would be only the fifth such occurrence since 2000 (2003, 2004, 2005, and 2019 are the cases since 2000).

The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.8°C for the week centered around December 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.40°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions will likely continue through at least mid-winter.

The SOI was +6.12 today. 

The preliminary Arctic Oscillation (AO) was +0.578 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a cooler than normal December (1991-2020 normal). December will likely finish with a mean temperature near 33.8° (5.3° below normal). That will make December 2025 the coldest December since 2010 when the monthly mean temperature was 32.8°. It would also make 2025 the third coldest December since 2000.

Supplemental Information: The projected mean would be 3.6° below the 1981-2010 normal monthly value. 

 

[etudiant]

5 hours ago, donsutherland1 said:

Tomorrow will be a mainly dry day with readings topping out in the lower and middle 40s. A few spots could pick up a sprinkle or shower. Colder air will then press into the region tomorrow night. That will set the stage for a winter storm to end the week.

Friday will see increasing clouds. Snow will arrive during the late afternoon or evening and continue overnight. The snow could fall moderately to even heavily for a time. Sleet or freezing rain could mix in toward the end of the storm in parts of the region. A general 4"-8" snowfall is likely in and around the New York City area.

The RRFS A, which will succeed the NAM, appears to have inherited the NAM's idiosyncratic behavior. It shows a narrow area of 4"-6" snows from southeastern Pennsylvania running southeastward across southern New Jersey. It shows less than 0.5" of snow in New York City and no measurable snow just north of New York City. Just one EPS member has less than 1" of snow in New York City. The RRFS A output is an outlier and is not considered.

The storm will be followed by a chilly weekend. The closing days of December will likely be colder than normal.

December 2025 will very likely finish with a maximum monthly temperature below 60° in New York City. The last time that happened was in 2019 when the monthly high was 58°. If 2025 has a monthly high below 60°, that would be only the fifth such occurrence since 2000 (2003, 2004, 2005, and 2019 are the cases since 2000).

The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.8°C for the week centered around December 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.40°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions will likely continue through at least mid-winter.

The SOI was +6.12 today. 

The preliminary Arctic Oscillation (AO) was +0.578 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a cooler than normal December (1991-2020 normal). December will likely finish with a mean temperature near 33.8° (5.3° below normal). That will make December 2025 the coldest December since 2010 when the monthly mean temperature was 32.8°. It would also make 2025 the third coldest December since 2000.

Supplemental Information: The projected mean would be 3.6° below the 1981-2010 normal monthly value. 

 

Don,

More than anyone, you are the voice of reason on this forum.

Thank you for your work.

A very Merry Christmas as well as a Happy New Year to you and all of yours!

[donsutherland1]

7 minutes ago, etudiant said:

Don,

More than anyone, you are the voice of reason on this forum.

Thank you for your work.

A very Merry Christmas as well as a Happy New Year to you and all of yours!

Thank you. Have a wonderful Holiday season, too.

[eduggs]

Flurries possible overnight? Radar, HRRR, FV3 etc say maybe. But only Santa will know.

[NorthShoreWx]

So, is Friday night's storm going to hit Bermuda Saturday night?

[NorthShoreWx]

2 hours ago, eduggs said:

Flurries possible overnight? Radar, HRRR, FV3 etc say maybe. But only Santa will know.

Radar looks really lit now to our west and northwest, but I can't find any evidence of anything reaching the ground in NY or PA.

[bluewave]

Models not quite as cold for the end of December and the start of January as prior runs with the core of the cold now forecast to stay to our north.

[IrishRob17]

Less than 1" at my stake but still plenty of snow to see out there 29/25. Merry Christmas!