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. 

So we can say it’s looking like a very active pattern with the details to be worked out in the short term.