December 2025 OBS and Discussion

[CPcantmeasuresnow]

5 minutes ago, MJO812 said:

Suppression?

F the Mid-Atlantic

[Brasiluvsnow]

What is this that we are looking at for Monday = looks like rain yuck

[SACRUS]

Interesting Satellite visible loop with the clouds / snow / showers-flurries east, clearing west into EPA/NW NJ and clouds beyond further west

 

[EasternLI]

January looks quite promising actually. Look at the direction of travel on the EPS. We're starting out the month with what looks increasingly likely to be strong blocking. So it's a time to keep eyes open simply due to that.

Then, beyond that, the big Pacific block was taken out. There's a trough now in the Aleutian Islands forcing a +PNA. With what very well could be a decaying west based NAO block by then... There's some really good potential in all of that as we head into peak climo. 

[MJO812]

12 minutes ago, Brasiluvsnow said:

What is this that we are looking at for Monday = looks like rain yuck

Yep 50 and rain

[MANDA]

6 minutes ago, EasternLI said:

January looks quite promising actually. Look at the direction of travel on the EPS. We're starting out the month with what looks increasingly likely to be strong blocking. So it's a time to keep eyes open simply due to that.

Then, beyond that, the big Pacific block was taken out. There's a trough now in the Aleutian Islands forcing a +PNA. With what very well could be a decaying west based NAO block by then... There's some really good potential in all of that as we head into peak climo. 

I guess we're all always in search of the elusive KU / NESDIS Cat. 5 snowstorm !  

Gotta believe.

[bluewave]

This has to be one of the most unusual December patterns that we have ever seen. The record low Arctic sea ice near the Kara and Barents seas has been linked to stratospheric warming events. 2025 marks one of the earliest SSWs on record.

It’s also possible that this is our first December with two distinct 4-8” clipper snow events. Plus I am not even sure when the last time was that there were two 4-8” clipper events only two weeks apart during December to March.

So I am not really sure yet what if anything this December will say about the rest of the winter. Since we have never had a December pattern like this before. Also note how each of the clipper events is being followed by a strong Great Lakes cutter with rain and a quick warm up. 
 

 

[psv88]

Just now, bluewave said:

This has to be one of the most unusual December patterns that we have ever seen. The record low Arctic sea ice near the Kara and Barents seas has been linked to stratospheric warming events. 2025 marks one of the earliest SSWs on record.

It’s also possible that this is our first December with two distinct 4-8” clipper snow events. Plus I am not even sure when the last time was that there were two 4-8” clipper events only two weeks apart during December to March.

So I am not really sure yet what if anything this December will say about the rest of the winter. Since we have never had a December pattern like this before. Also note how each of the clipper events is being followed by a strong Great Lakes cutter with rain and a quick warm up. 
 

 

Eh. The last storm had the snow stick around for 3-4 days. That’s not so much a quick warm up

[bluewave]

4 minutes ago, psv88 said:

Eh. The last storm had the snow stick around for 3-4 days. That’s not so much a quick warm up

I am comparing it to the old days when we would more extended snowcover with not so many warm ups with rain in between.

[psv88]

15 minutes ago, bluewave said:

I am comparing it to the old days when we would more extended snowcover with not so many warm ups with rain in between.

That rarely happened in mid December. If ever. 

[bluewave]

5 minutes ago, psv88 said:

That rarely happened in mid December. If ever. 

50°+ warm ups with or without rain have become much more common prior to and following snow events here than they used to be. 

[psv88]

7 minutes ago, bluewave said:

50°+ warm ups with or without rain have become much more common prior to and following snow events here than they used to be. 

It’s December. The last event was mid December. There’s never a long lasting snowpack for all of december  

[TheClimateChanger]

38 minutes ago, bluewave said:

This has to be one of the most unusual December patterns that we have ever seen. The record low Arctic sea ice near the Kara and Barents seas has been linked to stratospheric warming events. 2025 marks one of the earliest SSWs on record.

It’s also possible that this is our first December with two distinct 4-8” clipper snow events. Plus I am not even sure when the last time was that there were two 4-8” clipper events only two weeks apart during December to March.

So I am not really sure yet what if anything this December will say about the rest of the winter. Since we have never had a December pattern like this before. Also note how each of the clipper events is being followed by a strong Great Lakes cutter with rain and a quick warm up. 
 

 

Updated PRISM here (through Christmas day). We've been tacking on 0.5F+/day during this Torchmas pattern. Probably around ~+3.2F once updated through yesterday.

[TheClimateChanger]

2 minutes ago, TheClimateChanger said:

Updated PRISM here (through Christmas day). We've been tacking on 0.5F+/day during this Torchmas pattern. Probably around ~+3.2F once updated through yesterday.

Not too shabby. I think this might wind up warmer than any December prior to 2015.

 

[GaWx]

1 hour ago, TheClimateChanger said:

Not too shabby. I think this might wind up warmer than any December prior to 2015.

 

 I see ~no chance for Dec ‘25 to come in warmer than Dec ‘39’s 37.7. Through the 27th (last widespread US warm day), MTD could rise to ~38.2. But 12/28-31 are progged to avg ~31. That would bring the full Dec back down to ~37.2.

[donsutherland1]

December 2025 will finish with a mean temperature below 35.0°C (coldest since 2010) and more than 6" of monthly snowfall. Below is how January fared in terms of snowfall following cold and snowy Decembers.

[TheClimateChanger]

13 minutes ago, GaWx said:

 I see ~no chance for Dec ‘25 to come in warmer than Dec ‘39’s 37.7. Through the 27th (last widespread US warm day), MTD could rise to ~38.2. But 12/28-31 are progged to avg ~31. That would bring the full Dec back down to ~37.2.

The progged temps aren’t factoring in the incredibly warm midnight highs that are likely in this regime, so probably way too low.

[TheClimateChanger]

Just now, TheClimateChanger said:

The progged temps aren’t factoring in the incredibly warm midnight highs that are likely in this regime, so probably way too low.

Like in Pittsburgh, Monday afternoon may be in the upper 20s but the high is likely to be near 60 degrees!

[MJO812]

A few inches away from my snow totals for the whole season from last year and the year before.  I had 13 both season.

[GaWx]

17 minutes ago, TheClimateChanger said:

Like in Pittsburgh, Monday afternoon may be in the upper 20s but the high is likely to be near 60 degrees!

Thanks. However, when I did my estimates, I took into account that the 12/29 highs would be at midnight from there through OH/IN, ATL, to BRO, etc. I did the same for 12/28 highs in the Plains/upper MW and the 12/30 highs in the NE. If anything my 31 est. for 12/28-31 is slightly high. I est. 33, 26, 29, 33 for 12/28-31.

 For similar reasons, there were 11:59PM lows to take into account, which I did.

[donsutherland1]

With preliminary PNA values of -1.000 or below both yesterday and today, the snowstorm that just brought 4.3" to Central Park could become New York City's largest December snowfall with PNA values of -1.000 or below for all days during which the snow fell.

[Stormlover74]

Looks like another windy period Monday night and Tuesday. Gusts to 40+

[brooklynwx99]

3 hours ago, EasternLI said:

January looks quite promising actually. Look at the direction of travel on the EPS. We're starting out the month with what looks increasingly likely to be strong blocking. So it's a time to keep eyes open simply due to that.

Then, beyond that, the big Pacific block was taken out. There's a trough now in the Aleutian Islands forcing a +PNA. With what very well could be a decaying west based NAO block by then... There's some really good potential in all of that as we head into peak climo. 

yeah, legitimately exciting... that -NAO is uptrending, too. the 5-7th is our first legit shot at a larger region-wide storm. pattern becomes even more favorable after that, too

[GaWx]

38 minutes ago, donsutherland1 said:

December 2025 will finish with a mean temperature below 35.0°C (coldest since 2010) and more than 6" of monthly snowfall. Below is how January fared in terms of snowfall following cold and snowy Decembers.

 Just looking at the 8 cases that were during -ENSO (16, 22, 26, 33, 42, 44, 95, 10), the Jan SN mean/median rises to 12.8”/9.9”.

[Nibor]

47 minutes ago, donsutherland1 said:

December 2025 will finish with a mean temperature below 35.0°C (coldest since 2010) and more than 6" of monthly snowfall. Below is how January fared in terms of snowfall following cold and snowy Decembers.

Thanks for posting data like this. 25 mean temp in 1876 is wild. 

[donsutherland1]

32 minutes ago, GaWx said:

 Just looking at the 8 cases that were during -ENSO (16, 22, 26, 33, 42, 44, 95, 10), the Jan SN mean/median rises to 12.8”/9.9”.

Yes, the La Niña cases were snowier.

[PhiEaglesfan712]

21 minutes ago, Nibor said:

Thanks for posting data like this. 25 mean temp in 1876 is wild. 

We also had 25 mean temp in Dec 1989, but then we had 40-41 mean temps in Jan and Feb (1990), and 46 mean temp in March. 

[donsutherland1]

42 minutes ago, Nibor said:

Thanks for posting data like this. 25 mean temp in 1876 is wild. 

1917 also had a mean temperature of 25.0° for December 

 

48 minutes ago, GaWx said:

 Just looking at the 8 cases that were during -ENSO (16, 22, 26, 33, 42, 44, 95, 10), the Jan SN mean/median rises to 12.8”/9.9”.

Corrected Table:

Note: The initial table was constructed from summing daily snowfall amounts. Not all daily amounts are in the NYC climate record. Thus, doing so understates the monthly figures. Here's the correct table using the monthly figures.

[MANDA]

17 minutes ago, donsutherland1 said:

1917 also had a mean temperature of 25.0° for December 

 

Corrected Table:

Note: The initial table was constructed from summing daily snowfall amounts. Not all daily amounts are in the NYC climate record. Thus, doing so understates the monthly figures. Here's the correct table using the monthly figures.

Can you imagine what a heating bill would look like these days with a mean monthly temp of 25?   Have to believe it would cause hardship for many.