December 2025 OBS and Discussion

[wdrag]

I've appended the week 3-4 CPC Outlook issued 11/21 and the monthly outlook issued 11/20. Click for clarity.

There has been discussion of the stratwarm impact on North America In December.  I hope I'm very wrong thinking "is that all there is around the NYS subforum?"

For now unless the 5H cold core recenters - penetrates significantly further south into Hud Bay (below 60N) or we develop a 'general' +PNA, -NAO  in December,  its impact here in the northeast may be minimal. I just don't know.  Others hereon are more informed. 

Entire month open to discussion...bring on the snow and lets get off to a good start in CP etc.  

[NEG NAO]

At least the storm track will not be too far south according to their Precip Outlook and  the Polar Vortex is not going to plunge too far south  when it is stretched by the Strat Warming Event according to their Monthly Temp Outlook. Heard that the Vortex will be stretching rather than a full displacement............

[wdrag]

31 minutes ago, NEG NAO said:

At least the storm track will not be too far south according to their Precip Outlook and  the Polar Vortex is not going to plunge too far south  when it is stretched by the Strat Warming Event according to their Monthly Temp Outlook. Heard that the Vortex will be stretching rather than a full displacement............

Yes, I hear its not full blown.  I guess we cannot count on a stratwarm in late winter since they're rare.  if we end up below normal snowfall in Dec, the best of winters long nights and snow potential may be gone for the season.  

Hoping this comes together for us.

[gravitylover]

I was thinking similarly. Considering the warmer background state it seems that as the early cold degrades winter may struggle to stay.

[donsutherland1]

 

 

[NEG NAO]

Looks like the main storm track will stay west of us at least through the Ohio Valley up into Canada through December 5th with quick shots of colder air - progressive pattern with no established cold air YET....Southeast ridge in control as we migrate from MJO phase 6 into 7 and then 8 2nd week of DEC

[SnoSki14]

You won't see MJO 8, it's already curling back to COD

[NEG NAO]

16 minutes ago, SnoSki14 said:

You won't see MJO 8, it's already curling back to COD

wanna make a bet ?

[MJO812]

1 hour ago, SnoSki14 said:

You won't see MJO 8, it's already curling back to COD

No its not

Stop posting nonsense 

[MJO812]

[eduggs]

If there's any way the 12z ICON is on the right track at the end of its run, that would play out a lot better for early December than 0z/6z GFS/CMC/ECM...

We'll see if the ICON is far off on its own or a harbinger of a 12z trend.

[eduggs]

The 12z CMC is trying to snow to the CA beaches again. That won't work out well for us. When we stop seeing strong ULLs over southern CA we will have a shot of wintry.

[IrishRob17]

37 minutes ago, eduggs said:

The 12z CMC is trying to snow to the CA beaches again. That won't work out well for us. When we stop seeing strong ULLs over southern CA we will have a shot of wintry.

You better hope Anthony doesn’t read that, facts as there are. 

[MJO812]

32 minutes ago, IrishRob17 said:

You better hope Anthony doesn’t read that, facts as there are. 

Its not facts at all.  We are going into a favorable pattern .

[IrishRob17]

6 minutes ago, MJO812 said:

Its not facts at all.  We are going into a favorable pattern .

Agree that what the models show are not facts. Hopefully this year breaks favorably for us but I learned years ago not to count on the chickens too soon. 

[Stormlover74]

4 minutes ago, IrishRob17 said:

Agree that what the models show are not facts. Hopefully this year breaks favorably for us but I learned years ago not to count on the chickens too soon. 

and even a great pattern doesn't always produce. Look at last February. 

[IrishRob17]

1 minute ago, Stormlover74 said:

and even a great pattern doesn't always produce. Look at last February. 

There was another one a few years ago in December I believe, great pattern, didn’t produce. Not being a Debbie Downer, just looking at the facts. 

[snowman19]

15 minutes ago, IrishRob17 said:

There was another one a few years ago in December I believe, great pattern, didn’t produce. Not being a Debbie Downer, just looking at the facts. 

December, 2022. People were all but guaranteeing a December, 2010 redux with textbook KU’s bombing up the coast and the I-95 corridor getting dumped on. It was even called a historic setup by many and we were told to “buckle up, get sleep now, it’s coming”. The hype was off the charts for the better part of 2 weeks….

[NEG NAO]

1 hour ago, MJO812 said:

Its not facts at all.  We are going into a favorable pattern .

Starting when? Favorable for cold outbreaks is a guarantee - Snowstorms are not a guarantee YET IMO ......Need blocking to set up

[MJO812]

Just now, NEG NAO said:

Starting when? Favorable for cold outbreaks is a guarantee - Snowstorms are not a guarantee YET IMO 

Its not guaranteed but the signals are looking good.  Ensembles are still showing a favorable pattern. Op runs will still flip flop 

[NEG NAO]

8 minutes ago, MJO812 said:

Its not guaranteed but the signals are looking good.  Ensembles are still showing a favorable pattern. Op runs will still flip flop 

Need Neg NAO and that all important strong HP in southeast Canada anchored and a weakening of the southeast ridge - storms will cut west of us before this happens........seems like this is repeated here every year over and over - we all know the routine...........

[MJO812]

6 minutes ago, NEG NAO said:

Need Neg NAO and that all important strong HP in southeast Canada anchored and a weakening of the southeast ridge - storms will cut west of us before this happens........

Negative to neutral NAO and PNA to just cooperate.

[NEG NAO]

22 minutes ago, MJO812 said:

Its not guaranteed but the signals are looking good.  Ensembles are still showing a favorable pattern. Op runs will still flip flop 

Which Ensembles ? Just looked at the 12Z GEFS and we have only a couple days of cold outbreaks then when the storm approaches it cuts because of the southeast ridge and no blocking through the 1st week of DEC

[rclab]

4 hours ago, IrishRob17 said:

There was another one a few years ago in December I believe, great pattern, didn’t produce. Not being a Debbie Downer, just looking at the facts. 

 

4 hours ago, snowman19 said:

December, 2022. People were all but guaranteeing a December, 2010 redux with textbook KU’s bombing up the coast and the I-95 corridor getting dumped on. It was even called a historic setup by many and we were told to “buckle up, get sleep now, it’s coming”. The hype was off the charts for the better part of 2 weeks….

Rob you and S19 will never be a D D. Our ocean hugging, UHI blessed five borough coastal plain location ensures Debbie will always be welcome in December. Stay well and hopeful, as always …..

 

 

[eduggs]

For regional weather forecasting, beyond 10 days has low predictive utility, even on the ensemble means. And we don't even have anything favorable within that time period yet. Right now we are looking at mostly a storm track to our west with cold snaps on the wake of storms. That's within seasonal norms. If we get a cold and snowy look inside day 10 on multiple ensembles, it's a plausible outcome. Inside day 7 and it's worth getting a little excited about. But IMO, anything outside of that range is fantasy range territory.

[wdrag]

Unreliable D10-11 EPS signal, but cyclically advertised, possibly biased high by single model output... an ice event  I84 corridor around Dec 3-4? Standard high terrain but even some minor indication valleys just nw of I95. Again D10-11 so chances are?  I am monitoring for myself. 

[NEG NAO]

Let's see how the AI model performs in December -will it show some consistency moving forward ?

 

[wdrag]

32 minutes ago, NEG NAO said:

Let's see how the AI model performs in December -will it show some consistency moving forward ?

 

Just so everyone is aware... this is not AI Ensemble... just a single member.  You'd be astounded if I posted the EC FRAM Freezing rain output from some of the recent EC cycles... ice storm big impact... fortunately ensembles temper enthusiasm and of course we're in the unreliable = beyond 10 day period when this occurs.  I love EC AI but I've Zero experience monitoring beyond a week. Maybe we'll soon have occasion? I attached the most significant ECAI 24 hr 10 to 1 snowfall (not taking into account potential melting pavement). Note that most of this is in the last day or two of the 16 day cycle.  I've no confidence.

However, the ECAI seems a little colder than the traditional globals that we use and it has snow acc for I95 to the coast (including NYC/LI) around Dec 1-2. I need to see more support before it get enthusiastic.