December 2025 OBS and Discussion

[MJO812]

East 

[Bxstormwatcher360]

Atleast there's a 80% probability of a storm, I wouldn't be too worried with thermals as of now. Also with a strong enough storm will drag the cold air in,depending on actual high pressure position.

[WeatherGeek2025]

14 minutes ago, MJO812 said:

East 

that looks like white rain south of White Plains, NY.

 

 

We need a colder solution!

[anthonymm]

12z euro quite wintry looking for the metro.

[NEG NAO]

10 minutes ago, WeatherGeek2025 said:

that looks like white rain south of White Plains, NY.

 

 

We need a colder solution!

there is going to be mixing somewhere- these amounts are not accurate yet BUT GFS and Euro moved closer to their mean Ensembles - probably more adjustments to come

[WestBabylonWeather]

A good start. Something to track. Even if it doesn’t pan out for us 

[wdrag]

Am at Thanksgiving family dinner. If All goes well one or two threads will begin 9pm tonight or7am Friday.  If it’s snow it will be for odds on CP first measurable snow sleet    No time to elaborate right now.  Have a wonderful family dinner. Walt

[WeatherGeek2025]

22 minutes ago, wdrag said:

Am at Thanksgiving family dinner. If All goes well one or two threads will begin 9pm tonight or7am Friday.  If it’s snow it will be for odds on CP first measurable snow sleet    No time to elaborate right now.  Have a wonderful family dinner. Walt

happy thanksgiving everybody hope you get to enjoy it with your families!

[donsutherland1]

Tomorrow and Saturday will be unseasonably cold days. Tomorrow will be windy with a possibility of some snow flurries.

There is potential for New York City's Central Park to experience its first freeze of 2025 tomorrow or, more likely, Saturday morning. The 1991-2020 normal first date is November 21. The 1961-1990 baseline was November 11. Last winter's first freeze occurred on November 30.

Saturday and Sunday will see a snowstorm blanket parts of the Great Lakes Region. Chicago and Milwaukee could see 6"-12" of snow. Detroit could pick up 4"-8". Toronto could see 3"-6".

Sunday and Monday will turn somewhat milder. Showers are possible on Monday as a cold front moves across the region. Generally colder than normal conditions could then continue into or through the second week of December. Severe cold appears unlikely through at least the first 10 days of December. 

Moreover, a storm could affect the region on Tuesday into Wednesday, bringing 0.50"-1.50" precipitation to the region. There is a distinct possibility that New York City could see its first measurable snowfall of the season. Interior sections have the highest probability of seeing accumulations of snow.

The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -0.7°C for the week centered around November 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.16°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 +1.97 today. 

The preliminary Arctic Oscillation (AO) was +0.036 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied 96% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 47.1° (0.9° below normal). 

Supplemental Information: The projected mean would be 0.6° below the 1981-2010 normal monthly value. 

 

[North and West]

Am at Thanksgiving family dinner. If All goes well one or two threads will begin 9pm tonight or7am Friday.  If it’s snow it will be for odds on CP first measurable snow sleet    No time to elaborate right now.  Have a wonderful family dinner. Walt

Enjoy the company of the people you love!


.

[mob1]

GFS looks nothing like the Euro and is significantly warmer than its own 12Z run. North and west of the city still make out well. 

 

Pretty good for the ski resorts.

[MJO812]

11 minutes ago, mob1 said:

GFS looks nothing like the Euro and is significantly warmer than its own 12Z run. North and west of the city still make out well. 

 

Pretty good for the ski resorts.

Models are all over

[NEG NAO]

8 minutes ago, MJO812 said:

Models are all over

on to the ensembles - but 0Z will provide newer data.........

[MJO812]

12 minutes ago, NEG NAO said:

on to the ensembles - but 0Z will provide newer data.........

Gefs slightly more amped and warmer 

[NEG NAO]

16 minutes ago, MJO812 said:

Gefs slightly more amped and warmer 

still a long way to go with this - flip flopping at this range is not unusual and 18Z runs are not as reliable as 0Z and 12Z some data could be missing that was included in 12Z who knows ! 

[NEG NAO]

Can't make this stuff up 18Z Euro AI is still off the coast out to sea

[psv88]

2 minutes ago, NEG NAO said:

Can't make this stuff up 18Z Euro AI is still off the coast out to sea

Good

[WeatherGeek2025]

Just now, psv88 said:

Good

maybe in the middle white plains, and north snow south white rain?

[psv88]

22 minutes ago, WeatherGeek2025 said:

maybe in the middle white plains, and north snow south white rain?

What? I live on Long Island, why would I want that

[anthonymm]

31 minutes ago, psv88 said:

Good

nah we want a decent snowpack in our source region. let it destroy the interior i say.

[psv88]

7 minutes ago, anthonymm said:

nah we want a decent snowpack in our source region. let it destroy the interior i say.

That’s not a thing. The Hudson valley of New York is not our source region. Southern Canada is where snow pack may make a difference, not Newburgh

[jm1220]

43 minutes ago, anthonymm said:

nah we want a decent snowpack in our source region. let it destroy the interior i say.

We take what we can get here whenever it happens. There could be 20 feet of snow inland, won’t make any difference if the cutter and SWFE train starts. 

[jm1220]

As for this upcoming event, if we can redevelop the coastal low soon enough and keep winds offshore, we have a shot on LI and the city especially northern. If winds go onshore we’re done. 

[anthonymm]

7 minutes ago, jm1220 said:

We take what we can get here whenever it happens. There could be 20 feet of snow inland, won’t make any difference if the cutter and SWFE train starts. 

I mean if there's a deep anticyclone over Quebec you definitely want as much snowpack in the source region as possible the air that funnels south is cold.

[wdrag]

Holding off 12 hours til 7AFri.  18z ECAI still south but the ECAI Ensemble is not... its similar to the blend EPS-GEFS (melting LI, I95 itself eastward). 

[jm1220]

26 minutes ago, anthonymm said:

I mean if there's a deep anticyclone over Quebec you definitely want as much snowpack in the source region as possible the air that funnels south is cold.

We absolutely want a good source region for surface cold but if the mid levels are torched/ruined by a too late low transfer to the coast, the surface doesn’t matter unless you’re into a lot of sleet or ZR. This setup seems like there’s enough cold air to the north at the surface that we’re more interested in when the low transfers to the coast and surface wind direction. A transfer too late keeps winds onshore and torches our surface, or torches the mid levels by a bad 700/850 low track to our west. You also really want to watch the mid level low evolution in a storm like this and where the 700/850 lows track.