December 2025 Short/Medium Range Forecast Thread

[jaxjagman]

4 hours ago, Carvers Gap said:

Someone remind me…the SOI tanking means a potential bigger winter storm, right?  Strong amplification incoming and stormy.

Be a good case study upcoming in general cause around the 23rd of Nov the SOI dropped,and took out the Nina base state but rose shortly afterwards back towards NINA,so you'd have BN temps towards the middle of Dec but this would be transient because afterwards a few days the SOI would rise again.But the large fall the last few days would tell you it could get rather cold right before X-Mas unlike some of what the models seemingly show,but other teleconnections still play apart

[jaxjagman]

Ill use what the EPS shows,as heights rise into East China/Koreas this should be a warming in the east,BUT during this time the blocking along the Aluetians get shifted into Siberia,this would cause height falls into East Asia,i really think we will have a cold X-Mas,plus the MJO into which seems TO to be maybe in Africa right now maybe or at least western IO

 

[jaxjagman]

But you should see a definite warm up past the Mid of Dec,probably not brutal but AN

[Holston_River_Rambler]

Interesting to see the trend for more return flow moisture for the Sunday night into Monday system on the GFS

 

If anything the Euro is getting dryer 

 

It still has a little slug of moisture over S Alabama and eastern Georgia, but it doesn't really make it north. 

To be honest my choice to use 700mb is arbitrary, but is the place I see the biggest difference between the GFS and Euro on relative humidity panels:

 

 

the 500 mb vort seems slightly more amped on the GFS, but not by much. 

 

 

NAMs and RRFS (thanks John for the heads up about ol Rufus) emphasize a second shortwave connected to the above, dropping in and enhancing upslope without much fanfare for the first shortwave the GFS likes.  Here is Rufus and teh second shortwave in all Rufus's pixilated glory. 

 

 I suspect the GFS is wrong about the first shortwave, since even the NAM in NAMing range isn't too interested, but could be nice for elevation areas in NE TN, SW VA, and especially Western NC if not. 

I think Carvers pointed out a run of the GFS yesterday that had like 6" in portions of that area. 

[Holston_River_Rambler]

Some ensemble interest on the GEFS for Sunday night into Monday morning:

 

As expected, Euro, not so much:

 

[*Flash*]

20 hours ago, Carvers Gap said:

Someone remind me…the SOI tanking means a potential bigger winter storm, right?  Strong amplification incoming and stormy.

Yeah, that SOI sauce be crazy. As some have mentioned, the devil is in the latency of effect, but to what gives us stronger amp, we should generally root for. On an unrelated note, what are our thoughts on the second half of winter? I got one more bag Fry set to arrive on 12/17/25 so I'll be grounded from chasin' for 6 weeks (wife can't drive post c-section). Come Groundhog's Day, I'll be able to get back on the road and potentially bring my 10-year-old with me. 

[Matthew70]

2 hours ago, *Flash* said:

Yeah, that SOI sauce be crazy. As some have mentioned, the devil is in the latency of effect, but to what gives us stronger amp, we should generally root for. On an unrelated note, where are our thoughts on the second half of winter? I got one more Bag Fry set to arrive on 12/17/25 so I'll be grounded from chasin' for 6 weeks (wife can't drive post c-section). Come Groundhog's Day, I'll be able to get back on the road and potentially bring my 10-year-old with me. 

Congratulations to the you & your wife on the next little one! 

[jaxjagman]

2 hours ago, *Flash* said:

Yeah, that SOI sauce be crazy. As some have mentioned, the devil is in the latency of effect, but to what gives us stronger amp, we should generally root for. On an unrelated note, where are our thoughts on the second half of winter? I got one more Bag Fry set to arrive on 12/17/25 so I'll be grounded from chasin' for 6 weeks (wife can't drive post c-section). Come Groundhog's Day, I'll be able to get back on the road and potentially bring my 10-year-old with me. 

Congrats bro !!

[Daniel Boone]

Congratulations !

[jaxjagman]

Ensembles are going Zonal in the long range,not a warm look but its not cold either,very little QPFS,probably the only hope would be a bowling ball if it could manifest any cold with it

I'm starting to wonder if the CFS is more right with the RMM'S,its been showing it going into WP the last several days,now its showing another Kelvin,Rossby into the WP towards the end of the year and crapping out there,we'll see if it keeps showing this.

[John1122]

The GFS is just ridiculously cold and dry as a bone. Shades of December '83 all over again.

[Matthew70]

Definitely some cold air for next weekend.  If we could just get an Alberta clipper to swing thru. Below average December looks to continue for the next 2 weeks

[Matthew70]

Just now, John1122 said:

The GFS is just ridiculously cold and dry as a bone. Shades of December '83 all over again.

Hopefully some clippers get into the flow. 

[jaxjagman]

Sure looks like the MJO is getting into the IO/Maritime

10 minutes ago, John1122 said:

The GFS is just ridiculously cold and dry as a bone. Shades of December '83 all over again.

No doubt about that,,big Artic High moving down from the Upper Plains