December 2025 OBS and Discussion

[MJO812]

27 minutes ago, Roger Smith said:

I would bet when it warms up slightly for Christmas Eve into the 25th, it will get very foggy until the warm sector is suppressed south. Foggy and 48-52 F temps, Santa will not find every house. Oh right, I'm supposed to pretend Santa doesn't exist. Forgot about that. 

You mean upper 30s to low 40s.

[nycwinter]

sun angle is increasing looked kinda brighter today..

[uofmiami]

40 minutes ago, nycwinter said:

sun angle is increasing looked kinda brighter today..

Blowtorch effect

[Brian5671]

Sunset times are already increasing went from 4:24 here  around dec 10th to 4:28 today

[cleetussnow]

41 minutes ago, Brian5671 said:

Sunset times are already increasing went from 4:24 here  around dec 10th to 4:28 today

At this rate the sun will never set! 

[MJO812]

The Weather Channel already has it lol

 

[MANDA]

Anyone check out the cold over NW Canada?  Currently -40's to -50's F over Yukon and NWT.  Even a few spots at -60F currently.

Mid to LR forecasts continue to build the cold over the next week.

Where it goes beyond that is the question.  Does it stay bottled up in Canada and slide more east than south or does in make a run south into the U.S. either is pieces or a large Arctic plunge?  I think all options are on the table but something worth following.

 

[NorthShoreWx]

2 hours ago, psv88 said:

I would rather have your latitude and sound proximity during big storms than fake cold 

That's when it giveth...although it isn't always a slam dunk.  We had about the same SWE as everybody else on 12/26/2010, but only 12" of quite dense accumulation. The screaming winds above the deck pulverized the snowflakes before they reached the ground.

[TheClimateChanger]

 

[MANDA]

14 minutes ago, TheClimateChanger said:

 

Been a while since the coldest air in the hemisphere has been on our side of the pole.  We’ll see how things play out as we move through early January.  

[donsutherland1]

A weak system will bring some light snow possibly mixing with or ending as some light rain or drizzle in some areas tomorrow.  New York City will likely see a coating to 1". A 1"-3" snowfall is possible in the northern and western suburbs where it will be somewhat colder.

The temperature will likely remain above freezing throughout the day on Tuesday in New York City. In New York City, only 25.6% of storms have seen measurable snowfall with a daily low of 33° or above with just 9.2% seeing 1" or more snowfall. Almost three-quarters (74.4%) of such events have seen only a trace of snowfall.

Another system could bring precipitation on Friday into Saturday. This system could have more moisture to work with than tomorrow's. 

No exceptionally cold or warm weather appears likely for the first week of astronomical winter. The closing days of December will likely be colder than normal.

December 2025 will 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 +10.59 today. 

The preliminary Arctic Oscillation (AO) was +1.620 today. The PNA was -1.766. That's the lowest winter value since December 24, 2021 when the PNA was -2.084.

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 34.3° (4.8° below normal). 

Supplemental Information: The projected mean would be 3.1° below the 1981-2010 normal monthly value. 

 

[bluewave]

1 hour ago, TheClimateChanger said:

 

Extreme temperature gradients in Asia and North America with multiple 4 to 5 sd jet streaks.

Overall, the Northern Hemisphere is very warm for this time of year due to the warmth covering more real estate.

So it will be hard to trust individual model storm details beyond 72-96 hrs. Since a tiny shift in the gradient between the strong 500 mb mid and high latitude blocking ridges can cause a big swing in local sensible weather. 

It’s looking like a very active pattern with the details to be worked out in the short term.

 

[Roger Smith]

4 hours ago, MJO812 said:

You mean upper 30s to low 40s.

Probably the way models are trending, it's becoming a question of whether the milder air ever makes it past central NJ but I think temps will spike at around 45F for a few hours late Christmas Day, then slide down into high 20s setting up a solid wall of icy resistance when the Friday wave drops southeast, could lead to a much heavier snowfall than forecasts are currently saying (can't say record because it's 78 years after 12-26-1947). A few days ago it was looking like a very mild two days 24th-25th and now it's looking more like a couple of hours of slight warming. Encouraging when the models bust on the warm side. 

[PhiEaglesfan712]

51 minutes ago, Roger Smith said:

Probably the way models are trending, it's becoming a question of whether the milder air ever makes it past central NJ but I think temps will spike at around 45F for a few hours late Christmas Day, then slide down into high 20s setting up a solid wall of icy resistance when the Friday wave drops southeast, could lead to a much heavier snowfall than forecasts are currently saying (can't say record because it's 78 years after 12-26-1947). A few days ago it was looking like a very mild two days 24th-25th and now it's looking more like a couple of hours of slight warming. Encouraging when the models bust on the warm side. 

What about the 12/26/2010 snowstorm?

[qg_omega]

4 hours ago, bluewave said:

Extreme temperature gradients in Asia and North America with multiple 4 to 5 sd jet streaks.

Overall, the Northern Hemisphere is very warm for this time of year due to the warmth covering more real estate.

So it will be hard to trust individual model storm details beyond 72-96 hrs. Since a tiny shift in the gradient between the strong 500 mb mid and high latitude blocking ridges can cause a big swing in local sensible weather. 

It’s looking like a very active pattern with the details to be worked out in the short term.

 

Historic 1,000 year cold building

https://x.com/ryanmaue/status/2003182403121287452?s=46&t=m4Eqkekadb-JCXTm7k-Txg

[Roger Smith]

3 hours ago, PhiEaglesfan712 said:

What about the 12/26/2010 snowstorm?

1947 was 26.4" (26.1" on 26th) and 2010 was 20.0" (12.2" 26th + 7.8" 27th). That 7.8" portion is the daily record for the 27th. The 12.2" on 26th would have been a daily record on every day of December except the 15th (12.7" fell in 1916), the 20th (15.5" fell in 1948), but even without 1947, not  the 26th .... 18 inches fell in 1872 on Dec 26th during a very cold spell. Boxing Day seems good for snow, I think Don showed it was the most likely date in December to see measurable snow, and other significant falls include 7.0" in 1890, and 11.2" in 1933. In 1969 there was 6.3" over the 25th and 26th. 

The three largest December totals for two days all include the 26th. 

[Krs4Lfe]

Fortunately, it seems that the big warmup coming around Christmas and through new years was overestimated by the models. It looks like most of the northeast and mid Atlantic will remain with near normal temperatures and New England will remain a bit colder than normal. That being said the warmth during Christmas week across the country is literally like the inverse of the Arctic air outbreak during Christmas 2022. But either way, this is almost just as impressive with temperatures in the 80s all the way up to Nebraska today. Spring to  summer like weather this week for much of the heartland and the south. Fortunately, it doesn’t appear that will be reaching us during this last week of December. Hopefully all the record cold air bottled up in Canada in Alaska can spill down next month across the country and bring some renewed snowfall chances. Because aside from our snowfall chances here in the northeast, much of the country will remain warm and dry for the foreseeable future.

[wthrmn654]

My sister in Tennessee has been having wild temperatures lately,  65 during day lower 20s at night.  Or 10 at night and 58 next day. 

[MJO812]

Lets see if we can get Sunday's storm to shift south and colder

 

[MJO812]

Cmc would have showed a huge snowstorm past 240.

Models are really cold going forward. The warm pattern is gone.