December 2025 Short/Medium Range Forecast Thread

[Daniel Boone]

9 minutes ago, Carvers Gap said:

It is back to 6" for portions of Sullivan Co on the 12z today.  The AIFS has 1-3".  I still think it is over done, but the GFS can sometimes score a weird coup from time to time.  For now it is an extreme outlier.  I wouldn't be surprised for NW facing slopes to see 1-2" out of that system tomorrow night.

The GFS may score here as the same thing as far as mosisture is concerned may do as last System. It kinda looks like an anafrontal wave deal or Lee Low Snow Print.

[Carvers Gap]

12 minutes ago, Daniel Boone said:

I guess I still go by 1980 to 2010 Averages more. The Avgerages have really jumped over the year's and the thing is that's not always caught is the last sevral Year's that jump is added on in the NWS Station Avgs. The Avg high for Pennington gap this Date was 47 Hi 27 low in 2010 I think. So, average is running below that for the balance but not extreme( however, I think that has gone up some now). KTRI  now says the Average high there is like 51 or so Low 31 I think. That's several degrees milder than used to be for there.  

So, with "Today's" Averages we're running a good bit below. the point basically being the difference in comparison to our west and East. There is a Spike through here of not of below as the aforementioned. I think John actually hit it with the western Ridge Height as far as the point being addressed. 

    I see your reasoning though as the cold we have got has been constant. Of which is a rarity, especially this early.

      

Models haven't missed by much with the exception of the 4-5 day SER/feedback hiccup.  They really haven't amplified the pattern with just a few exceptions.  Mid-month may well change that.  I think the wavelengths are just flatter, and that may help us later on as this will be tough to dislodge as climo gets increasingly colder.  This has been a pretty cold start IMBY.  I do think there is a window for a piece of the TPV to drop into NA to lower latitudes than the GL.  Also, you noted that the Pac NW has been pretty active.  That Pac flow also might be modifying the colder temps at the base of the trough, and that was shown on modeling.  Interestingly, the Sierra Nevadas in California and the Colorado Rockies have been stuck under that ridge, and are way, way BN on snowfall.   Lastly, the pattern doesn't really amplify in phase 7 of the MJO, but it can w/ phase 8.  I think modeling erroneously tried to loop the MJO, and that made a mess.  Now, it is forecast to stall by some models in phase 8.  It may just keep on making the circuit, but...it did make a turn(per the EMON) today which could signal a stall.  We will know more in a few days.  Overall though, this has been a very cold start IMBY.

[Carvers Gap]

5 minutes ago, Daniel Boone said:

The GFS may score here as the same thing as far as mosisture is concerned may do as last System. It kinda looks like an anafrontal wave deal or Lee Low Snow Print.

If we see that really cold shot between Dec 14-16, I would say we have a 50/50 shot(or better) at a strong anafront.  As for Sunday night, I have no idea...it is interesting to see the GFS hang onto that.  Overall, we need that ridge to backup just a bit.  I see where several folks on other forums have been talking about -PNA.  I don't know if that is a true -PNA.  That looks like a +PNA on modeling, and it is centered a bit too far to the east.

[Carvers Gap]

Congratulations, everyone.  The HOT donuts sign is on for this thread.  Haha!  Now, I am gonna go watch some football. 

[Carvers Gap]

There is a noticeable and significant uptick in juice w/ the 18z short range models w/ regards to Sunday night.  The GFS continues w/ its outlier look in NE TN, but the 12z NAM has the same deformation band.   Almost all short range models now have increased backing over Virginia and/or North Carolina.  Can it get west of the Apps???  I don't know about that.