December 2025 OBS and Discussion

[jm1220]

52 minutes ago, psv88 said:

27/3 now. Arctic airmass. 
 

good for the utility companies and ski resorts up north. Otherwise useless 

And for stores that sell ChapStick. 

[WeatherGeek2025]

any word from the EPS?

[Dan76]

For Ant

Today

Snow. The snow could be heavy at times. Widespread dense freezing fog before 2pm, then areas of dense freezing fog after 3pm. High near 22. Wind chill values between -2 and 3. Windy, with a west southwest wind 36 to 40 mph, with gusts as high as 55 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 41 to 47 inches possible.

Tonight

Snow, mainly before 3am. The snow could be heavy at times. Low around 12. Wind chill values between -2 and -7. Windy, with a west southwest wind 44 to 49 mph decreasing to 36 to 41 mph after midnight. Winds could gust as high as 70 mph. Chance of precipitation is 100%. New snow accumulation of 41 to 47 inches possible.

Tuesday

Snow. The snow could be heavy at times. High near 23. Wind chill values between -7 and 3. West southwest wind around 16 mph, with gusts as high as 26 mph. Chance of precipitation is 100%. New snow accumulation of 16 to 22 inches possible.

Tuesday Night

Snow. The snow could be heavy at times. Low around 17. Wind chill values between 1 and 6. Windy, with a west southwest wind 32 to 37 mph increasing to 41 to 46 mph after midnight. Winds could gust as high as 65 mph. Chance of precipitation is 100%. New snow accumulation of 26 to 32 inches possible.

Wednesday

Snow. The snow could be heavy at times. High near 22. Windy, with a west southwest wind 31 to 41 mph, with gusts as high as 60 mph. Chance of precipitation is 100%. New snow accumulation of 23 to 29 inches possible.

[North and West]

although some can survive anything-the spotted lanternfly egg nests can survive down to -20.

Unfortunately true


.

[NEG NAO]

12Z GFS and 12Z Euro Very Close

[WeatherGeek2025]

11 minutes ago, NEG NAO said:

12Z GFS and 12Z Euro Very Close

we need a really wound up system to get a tone of snow it's cold so i don't think we'll worry about mid unless we are overhead 

[NEG NAO]

11 minutes ago, WeatherGeek2025 said:

we need a really wound up system to get a tone of snow it's cold so i don't think we'll worry about mid unless we are overhead 

what is a "tone" of snow "- ??? i don't think we'll worry about mid unless we are overhead " -- what are you talking about ????

[NEG NAO]

1 hour ago, WeatherGeek2025 said:

any word from the EPS?

[NorthShoreWx]

51 minutes ago, Dan76 said:

For Ant

Today

Snow. The snow could be heavy at times. Widespread dense freezing fog before 2pm, then areas of dense freezing fog after 3pm. High near 22. Wind chill values between -2 and 3. Windy, with a west southwest wind 36 to 40 mph, with gusts as high as 55 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 41 to 47 inches possible.

Tonight

Snow, mainly before 3am. The snow could be heavy at times. Low around 12. Wind chill values between -2 and -7. Windy, with a west southwest wind 44 to 49 mph decreasing to 36 to 41 mph after midnight. Winds could gust as high as 70 mph. Chance of precipitation is 100%. New snow accumulation of 41 to 47 inches possible.

Tuesday

Snow. The snow could be heavy at times. High near 23. Wind chill values between -7 and 3. West southwest wind around 16 mph, with gusts as high as 26 mph. Chance of precipitation is 100%. New snow accumulation of 16 to 22 inches possible.

Tuesday Night

Snow. The snow could be heavy at times. Low around 17. Wind chill values between 1 and 6. Windy, with a west southwest wind 32 to 37 mph increasing to 41 to 46 mph after midnight. Winds could gust as high as 65 mph. Chance of precipitation is 100%. New snow accumulation of 26 to 32 inches possible.

Wednesday

Snow. The snow could be heavy at times. High near 22. Windy, with a west southwest wind 31 to 41 mph, with gusts as high as 60 mph. Chance of precipitation is 100%. New snow accumulation of 23 to 29 inches possible.

Is this RIC or ORF?

[jm1220]

13 minutes ago, NEG NAO said:

what is a "tone" of snow "- ??? i don't think we'll worry about mid unless we are overhead " -- what are you talking about ????

The tone today is a monotone snow weenie sigh under our thin cirrus deck while SE VA gets their 2nd snowstorm in a week. 

[Cobalt]

2 hours ago, bluewave said:

Miss the 2010-2018 KU benchmark era when we could lock in a 168 hr euro control run showing a near 950 mb low close to  the benchmark and have it be correct. 
 

https://www.weather.gov/okx/Blizzard_Jan42018

This is almost certainly survivorship bias. Few here might remember the string of runs from the Euro and GFS and their ensemble counterparts from the week before that, showing a massive overrunning event that fizzled out at medium range. 

[bluewave]

10 minutes ago, Cobalt said:

This is almost certainly survivorship bias. Few here might remember the string of runs from the Euro and GFS and their ensemble counterparts from the week before that, showing a massive overrunning event that fizzled out at medium range. 

In great winter storm patterns over the years for our area, it wasn’t unusual for at least one of the long range model runs to correctly see the storm potential.

During late January and early February 2021, it was an OP GEM run that had a correct KU forecast from a week out.

With the poor storm track patterns for big snows since February 2022, none of those OP runs showing numerous KUs long range have verified. 

 

[Tatamy]

23 minutes ago, jm1220 said:

The tone today is a monotone snow weenie sigh under our thin cirrus deck while SE VA gets their 2nd snowstorm in a week. 

Current observation at Wakefield is Heavy Snow with 1/4 mile visibility.  They have a WSW with expected totals between 3-6”.  Looks like the corridor between Richmond and Newport News gets the JP.

[psv88]

Time to move south for snowier winters 

[NEG NAO]

Upton is downplaying the late weekend system - maybe some light snow friday night

[MJO812]

[WeatherGeek2025]

2 hours ago, NEG NAO said:

what is a "tone" of snow "- ??? i don't think we'll worry about mid unless we are overhead " -- what are you talking about ????

sorry auto correct made me look like a dumb weenie. What I meant is if the Low pressure is overhead than we should worry about rain or mixing otherwise a strong wound up system that hugs the coast will bring us heavy snow since it's a very fast but fairly cold moving storm. 

[jm1220]

2 hours ago, Tatamy said:

Current observation at Wakefield is Heavy Snow with 1/4 mile visibility.  They have a WSW with expected totals between 3-6”.  Looks like the corridor between Richmond and Newport News gets the JP.

There was a death band S of Richmond to Newport News earlier. Must have been 1-2”/hr under it. 

[SnowGoose69]

I am surprised nobody posted the 18Z GFS at 360

[EastonSN+]

7 hours ago, donsutherland1 said:

Statistical tidbit from 1990-91 through 2024-25:

14/15 (93%) of winters with above normal seasonal snowfall had a least one day with 8" or more snow (72% prior to 1990-91)
17/18 (94%) of winters with below normal seasonal snowfall did not have any 8" or above daily amounts (75% prior to 1990-91)
14/17 (82%) of winters with at least one day with 8" or above snowfall had above normal seasonal snowfall (63% prior to 1990-91)

2014-15 with 50.3" seasonal snowfall was the lone exception for seasons with above normal snowfall with a maximum daily amount of 7.5" since 1990-91.

This data suggests that in the contemporary warmer climate, a big snowstorm has become relatively more important to seasonal snowfall outcomes than in the past. Both subsets are longer than 30 seasons in length suggesting that the difference provides some insight. Moreover, this is what would be expected in a warmer climate with somewhat fewer snowy days.

Thanks for this Don.

It must have been even more common prior to 1970, as I believe 100% of the above average snowfall winters from 1970 to 1999 had at least one 8 inch snowfall.

 

[kat5hurricane]

8 hours ago, bluewave said:

30 years since the mid 90s and over 100 years prior to that period isn’t a small sample size. What you describe as rigid is actually a very comprehensive approach which I have used with great success for long range outlooks.

Since my approach is data driven, I haven’t come to any firm ideas yet on whether we can eventually shift back to at least some occasional benchmark tracks in the future.

But the long term decline in snowfall has been unmistakable. So I leave open the idea of a bounce off these lows in coming years if we can weaken the Pacific Jet a bit. But this is very uncertain since the recent shifts have been so extreme. 

Has the long term decline been unmistakable? It's been a drought over the last 5 years but that was following an 18 year period of one of the snowiest eras ever recorded in the metro area. What's unmistakable is the warming temperatures but I don't think a 5 year period is enough of a sample size to declare that snowfall is now in a long term decline.

[Snowlover11]

22 minutes ago, SnowGoose69 said:

I am surprised nobody posted the 18Z GFS at 360

Because it sucks for our area while central/Northern NY measures in feet. 

[jm1220]

3 minutes ago, Snowlover11 said:

Because it sucks for our area while central/Northern NY measures in feet. 

And next run it will show 60F under a massive ridge, run after that a blizzard, etc. 

[EastonSN+]

Got this off a 2 second search. Can anyone validate?

"

Here are the approximate average seasonal snowfall amounts for Central Park across different periods:

• 1870-1900 average: 33 inches per year.
• 1901-1950 average: 29 inches per year.
• 1951-2000 average: 24 inches per year.
• 1991-2020 average: 25.1 inches per year (the current climate "normal").
• 2001-2023 average: 31 inches per year. "

[NEG NAO]

26 minutes ago, SnowGoose69 said:

I am surprised nobody posted the 18Z GFS at 360

Christmas Eve 2025

[WeatherGeek2025]

anybody know central park high temp today?

[sussexcountyobs]

Currently: Cloudy 17.1°

[lee59]

14 minutes ago, WeatherGeek2025 said:

anybody know central park high temp today?

38 just after midnight

[JonClaw]

14 minutes ago, WeatherGeek2025 said:

anybody know central park high temp today?

37.9 right after midnight

https://forecast.weather.gov/data/obhistory/KNYC.html

[donsutherland1]

Tomorrow will be an unseasonably cold day. The morning low could dip below 20° in Central Park and could rival or even surpass the cold of December 5th at some locations.

The ongoing stretch of below normal temperatures will likely continue into or through the second week of December. December 1-10 will be a solidly colder than normal period. The potential exists for the coldest first 10 days of December since at least 2007 (33.4°, 5th coldest December 1-10 since 2000).

The five coldest December 1-10 periods since 2000 were:

1. 30.6°, 2002
2. 32.2°, 2003
3. 32.4°, 2000
4. 33.1°, 2005
5. 33.4°, 2007

All 5 of these cases had measurable snowfall in Central Park.

The WPO is forecast to become strongly negative beyond December 10th. That would likely contribute to the December 10-20 period also being colder to perhaps much colder than normal overall.

The probability that December 2025 will have a maximum monthly temperature below 60° is increasing. 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 -0.2°C and the Region 3.4 anomaly was -0.5°C for the week centered around December 3. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.27°C and the ENSO Region 3.4 anomaly has averaged -0.65°C. La Niña conditions will likely continue through at least mid-winter.

The SOI was +11.57 today. 

The preliminary Arctic Oscillation (AO) was -1.926 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 88% probability that New York City will have a cooler than normal December (1991-2020 normal). December will likely finish with a mean temperature near 34.3° (4.8° below normal). 

Supplemental Information: The projected mean would be 3.2° below the 1981-2010 normal monthly value.