December 2022 Medium/Long Range Pattern Discussion Thread

[1234snow]

The 12Z CMC came in wayyyyyyy different and dumps the trough in the west with no PNA ridge……. Then it cuts the low to Wisconsin and floods us with warm air/rain.

The run before it it held the 500 low not digging much at all.

[PowellVolz]

It's liable to be way off but it did this in March this year when the Euro was reluctant to get on board at this range.

That’s where I was going. This is like 5 runs in a row now. Lol


.

[John1122]

It's odd to watch these models cutting storms straight towards the heart of a big H over Eastern Canada then they get caught in Northern Michigan and sit and spin because they can't go any further.

[1234snow]

12z ICON with a similar wild shift. It also dumps the trough in the west and gets a low to Wisconsin. Wasn’t close to this solution on this run before.

Not being a Debby downer just relaying what I see that all 3 of the models so far (GFS, CMC ICON) have dug our TPV energy more into the western states. On the GFS it is perfect, on the other 2 it is cutter City.

I suspect the Euro will have a change as well to a deeper trough.

[Wurbus]

I created a thread for the cold and potential snow for this event. Hopefully it will all pan out and we all get clobbered, but the cold looks legit across all models regardless if the snow comes or not.

[Vol4Life]

1 minute ago, Wurbus said:

I created a thread for the cold and potential snow for this event. Hopefully it will all pan out and we all get clobbered, but the cold looks legit across all models regardless if the snow comes or not.

Hopefully, you don’t have any jinx powers…lol!

[Carvers Gap]

Looks to me like the 12z Euro is super similar to the 12z CMC.  The 12z GFS may be on to something, but it has absolutely zero support right now at 12z.  It can sniff out storms, but it might be sniffing something as well....has been since the upgrade.  Both camps are plausible.

[Carvers Gap]

Basically we have a cutter on the Euro/CMC vs the wildly erratic GFS(and slightly progressive).  I hope the GFS is right, but it is gonna have to have some support.  

[Carvers Gap]

Would not surprise me either w/ the Euro having issues w/ digging a tad too much out west which is cutting the slp directly into the block - and that doesn't make sense.

[Carvers Gap]

The 12z Euro is a more extreme cutter than the CMC in my opinion.  The CMC is kind of in the middle of the GFS and Euro in terms of track.  Not a step in the right direction for the Euro.  That said, if it is hanging on to that energy too long in the northern plains(and it easily could be doing that), the GFS could be right...but no way in heck I am sharing a foxhole w/ the GFS after the past 3-4 weeks of performance.  Again, the big thing right now is there is going to be some variation as this is still seven days out.  I lean cutter for now...but barely.

[Carvers Gap]

We need the PNA ridge in the LR to get a bit taller.  If it doesn't, we are going to see a continent-wide chinook to end December.  I think we cool off again as modeling has trended towards a favorable January...but it is worth noting that early January could be seasonal to AN.  The 12z GFS was a great lead off....rest of the modeling suite left it on base w/ the side getting struck out in order.    What does interest me is a storm which will follow this cold blast which is firmly on all modeling.  Again, at this range everything is on the table.  Christmas is still nine days out.

[TellicoWx]

Treat the Ops as 1 more ensemble member..GEFS and CMC ensemble took steeps in the right direction as far as the mean...all solutions still on the table when you look at their 10/90 depth spreads.

[Carvers Gap]

In the LR, looks this cold shot will break fast as a continent wide chinook looks to develop later this month and into early January(500 pattern doesn't change a ton, but enough to allow maritime air into the pattern).  The BN heights in Alaska are at odds with the trough in the SE.  Something is going to give there.  As is, the BN heights in Alaska flood the top of the PNA ridge w/ maritime air.  Most modeling has had this, but maybe not the the extreme seen on the 12z suite.  We still keep the trough - no cold in early January to dump into it (poor source regions).  That said, this original cold pattern looked to lack a good source region and that changed.  I agree w/ Tellico above, the operationals (at 7 days out) are just another ensemble.  

[Carvers Gap]

Does anyone have the most updated verification scores for modeling inside of days 10, 7, and 5?

[Carvers Gap]

The GFS has been absolutely terrible since the upgrade.  Last winter, it definitely led the way on multiple occasions.  I would like to get some recent verification scores for the GFS (short, medium, and long range).  Seems like it has done better during the past week or so.  That said, the GFS was abysmal in the medium and long range when predicting this cold outbreak.  If I remember correctly, it kept sticking the upcoming trough in the west and missed the timing on the cold outbreak almost completely - looked like it misread the MJO.  At one point the upgrade was scoring worse than its predecessor.  

OTH, the bias of the Euro(amping things up) could certainly be in play.  However, that is usually not the game of the CMC.  Sometimes the Euro holds energy back in error, and sometimes it is right...but it pretty much does this for almost every system in the d7 range during winter.  

The only support the GFS has is the JMA.  The JMA used to be fairly accurate when hunting big storms.  Now, it just throws darts w/ a blindfold on.....

Seriously, at this range...it is nearly impossible to get a decent read on a system.  For now this is what we probably know....it is going to get really cold.  There is going to be a strong cold front(likely some frozen precip along it).  There is going to be a storm - Plains likely, but not set in stone.

 

[AMZ8990]

19 minutes ago, Carvers Gap said:

Does anyone have the most updated verification scores for modeling inside of days 10, 7, and 5?

 

[Carvers Gap]

Just now, AMZ8990 said:

 

Sorry, I should have been more specific.  Looking for the one which compares the GFS to other global modeling.

[AMZ8990]

2 minutes ago, Carvers Gap said:

Sorry, I should have been more specific.  Looking for the one which compares the GFS to other global modeling.

Trying to find now, there’s a lot of charts to go through. 

[Carvers Gap]

2 minutes ago, AMZ8990 said:

Trying to find now, there’s a lot of charts to go through. 

The one I am thinking of is a line graph w/ time as the x-axis and model verification as the y-axis.  One model is represented w/ triangle points, another squares, and so on.....I am heading out the door or would dig a bit more.

[Daniel Boone]

57 minutes ago, Carvers Gap said:

In the LR, looks this cold shot will break fast as a continent wide chinook looks to develop later this month and into early January(500 pattern doesn't change a ton, but enough to allow maritime air into the pattern).  The BN heights in Alaska are at odds with the trough in the SE.  Something is going to give there.  As is, the BN heights in Alaska flood the top of the PNA ridge w/ maritime air.  Most modeling has had this, but maybe not the the extreme seen on the 12z suite.  We still keep the trough - no cold in early January to dump into it (poor source regions).  That said, this original cold pattern looked to lack a good source region and that changed.  I agree w/ Tellico above, the operationals (at 7 days out) are just another ensemble.  

That's been a concern of mine as I noticed modeling showing LP trying to close in on Alaska. Definitely want any vort to stay outa there. However, strange things have happened even with it there, particularly if enough blocking is in place in the NAO Domain. So, hopefully blocking will reassert and we keep somewhat of a +PNA in conjunction.

[AMZ8990]

Well that was quite a run on the 18z gfs. Massive storm on that go around.  The whole forum gets involved in on the snow.  

[snowmaker]

I would love for the 18z to verify! It would be statewide glory!

[Carvers Gap]

The 18z would be a strikeout for much of the E TN valley.  I would be super happy for you all out west, and that track would fit the last two great winters for middle and west TN.  That run would yield nearly nothing for the E TN valley - model smoothing(high amounts in the mountains) causes the valleys to appear as if they have snow.  A slp moving through E TN is usually a non-starter.  Still, a LONG ways to go before this system is nailed down.  To me, that was a fairly huge step towards the Euro/CMC.  It is a cave in that direction.  Now, I am not sold on things cutting into this block.  Right now, I would set a one from Fayetteville to Nashville w/ backside mood flakes in E TN.

[Carvers Gap]

The 18z GEFS looks awfully similar to the 12z GFS...awfully similar.  

[Carvers Gap]

[Scottie16]

31 minutes ago, Carvers Gap said:

The 18z GEFS looks awfully similar to the 12z GFS...awfully similar.  

Definitely going to stay up late to catch the next GFS. It’ll be interesting to see if it follows its current trend or flips back.

[jaxjagman]

26 minutes ago, Carvers Gap said:

The 18z GEFS looks awfully similar to the 12z GFS...awfully similar.  

 

38 minutes ago, Carvers Gap said:

The 18z would be a strikeout for much of the E TN valley.  I would be super happy for you all out west, and that track would fit the last two great winters for middle and west TN.  That run would yield nearly nothing for the E TN valley - model smoothing(high amounts in the mountains) causes the valleys to appear as if they have snow.  A slp moving through E TN is usually a non-starter.  Still, a LONG ways to go before this system is nailed down.  To me, that was a fairly huge step towards the Euro/CMC.  It is a cave in that direction.  Now, I am not sold on things cutting into this block.  Right now, I would set a one from Fayetteville to Nashville w/ backside mood flakes in E TN.

Yeah,id be concerned tho of losing power.Those would be massive wet flakes when it started to change over then the isobars tighten up

[Daniel Boone]

Really need that TPV to assert under the block to help stave off that thing from cutting. That's the piece of the Puzzle that's missing and hurting the portrait from being a masterpiece.

     Strong LP under that block, whether 50-50 , 60-40, or even 70-30 for that matter should get it done.

    The Blizzard in the Dakota's is an example of a Storm cutting and going toward the block before stalling. A strong enough system will cut without a strong enough mechanism to weaken or shunt it. 

[TellicoWx]

1 hour ago, Carvers Gap said:

The 18z GEFS looks awfully similar to the 12z GFS...awfully similar.  

Another step forward on the means..nice and steady. Have a feeling we are going to see a correction good/bad in the next 24 hrs. 

[Matthew70]

Sad to see after this cold blast it warms up for a chilly rain.  44-50.  TWC says Jan. thaw all month.