Winter 2024/2025 January Thread

[*Flash*]

32 minutes ago, John1122 said:

18z Euro continued the N trend. 

I like it. Middle TN north of 40 is outside looking in at this point but positive trends are my friends. That said, if I have to throw in the towel, I want E Ten peeps to be in the trowal. 

[ShawnEastTN]

Just now, *Flash* said:

I like it. Middle TN north of 40 is outside looking in at this point but positive trends are my friends. That said, if I have to throw in the trowel, I want E Ten peeps to be in the trowal. 

It's not game over for your area yet.

[John1122]

Just now, *Flash* said:

I like it. Middle TN north of 40 is outside looking in at this point but positive trends are my friends. That said, if I have to throw in the trowel, I want E Ten peeps to be in the trowal. 

We're still a good ways out and the biggest NW trends usually fall inside the final 48 hours. I wouldn't give up yet. I'm still somewhat worried about a cutter or runner. 

[John1122]

18z EPS also creeps further NW. 

 

[jaxjagman]

It took it long enough to make some noise potentially.Should take more hits with the MJO going into the IO,Maritime

[Daniel Boone]

2 hours ago, PowellVolz said:

Is there much of a downsloping issue with an overrunning event? 

No. Usually very little wind with them.

[John1122]

ICON significantly north vs 12z when it was way down there. 

[Jed33]

0z RGEM has the low on Sunday developing in central AL and crusing east to the lee side of the apps. Looks a little like the 12z GEM earlier today

[John1122]

The ICON stepped into the GFS camp, held back energy and the second wave was getting up into our area at the end of the run. 

[John1122]

4 minutes ago, Jed33 said:

0z RGEM has the low on Sunday developing in central AL and crusing east to the lee side of the apps. Looks a little like the 12z GEM earlier today

I hope it's correct. It'd been slaughtering the American models in the short range this winter. 

[jaxjagman]

GFS is trying to put this year into the record books in Nashville

[John1122]

GFS coming in with nearly a cutter with a front end thump. 

[John1122]

GFS with one of the craziest runs I've seen it spit out. Random spots of I assume, dynamically driven heavy snow in the middle of heavy rain. 

[John1122]

Canadian went south. The GFS very north. Gonna be a long ride into next week. Hopefully the Canadian is correct about Sunday. 

[jaxjagman]

Lots of moving parts leading up to the end of next week,throwing one piece off the others will follow

[TellicoWx]

Gfs and CMC on 2 different planets with the evolution at 500. GFS opened 500 door wide open for a cutter...if it evolved that way, may get a quick front end (believe if anything would be quick change to some ice then rain). Would be rooting for the beginning of the week (CMC), than taking any chance with the end of the week.

[John1122]

We've somehow went from snow and teens to rain and cutting. Really hoping the RGEM scores a Sunday coup. 

[John1122]

If we are -10 on January 31st and only had the one decent snow event, that's gonna be tough. The Euro was frigid at the end again, just after another rain event. 

[vortexse93]

10 hours ago, nrgjeff said:

The PWAT charts above do not kill Tennessee snow chances. Remember snow, especially dry snow, carries very little liquid compared to rain. I hope central Mississippi can score. It's even more magical in the Deep South.

Then I want to get TROWAL'ed over here in East Tenn. TROWAL me! Talk dirty to me.

That is true, but I also know that drier snow equals to lower snow ratios as well. If that Low can shift just right, could very well see snow in Central MS, but I am not just not completely sold on it. I should have added the QPF totals as it was showing the cut off of the precip right at Central MS.
 

I am still watching the system but not getting excited by what I have seen. Might also have to watch for temps in the 925 to 700 mb range in case warm area over runs the front and then it some of the precip could be sleet/freezing rain event. I think there is a lot of uncertainty for Central MS at the moment in what will happen but it looks like the other areas I have mentioned are going to be the main focus for this event. 
 

Will have to see what happens. 

[Carvers Gap]

6z GFS is back to a winter storm for the forum area....snow and ice.  Modeling just doesn't have this dialed in at this point. 

[Carvers Gap]

Ensembles this morning still have a Deep South slider.  I would be really surprised if this cut.  I think we are in the window where modeling kind of loses storms and gets them back.  Plus, there is a general rule in my mind that modeling doesn't handle severe cold well....that causes wild swings.

[Holston_River_Rambler]

From just a pure model watching standpoint, it seems like we've had a lot of trouble this winter from models struggling with speed and evolution of shortwaves in the NW flow over western ridges. It happened with the storm last week:

 

The timing, press, number, trajectories, and evolution of these shortwaves is just giving NWP fits, even right up to go time. 

 

 

See above. We have a nice STJ but it just gets squished by those stout shortwaves to the north, more times than not. If one of those can drop down and tap into it it'll have a lot of juice, as some recent model runs have shown, but models just cannot seem to resolve those shortwaves at any sort of range. 

Kind of a weird, twitchy gif here, but just give it a watch:

 

Notice how between 50 and 100 hours the GFS (just chosen for ease of use on TT) does a pretty good job with the longwave features. Big ridges, big troughs are fairly stable. But now look closer at the individual vorts in those ridges and troughs. They are jumping around a lot. Add that weird cutoff mess off the CA coast and you have model problems with finer details. 

We often talk about better obs and data from the RAOB network and yeah, we 100% have much better satellite data than at any time in the past, but even with better data (and I don't know if there are other non-public satellites at play here) some of the sat. imagery just isn't as...continuous? over the polar region:

It's probably hard to have a sat. in geosynchronous orbit there, to be fair, but that can't be helping resolving shortwaves north of the arctic circle, can it? And you can't tell me that is as crisp and clean and detailed as good old GOES 17, 18, 19, or even the Himawari 9:

 

I'm not advocating for a bust or boom next week here, but offering an explanation for some of the model frustration.

 

 

 

[AMZ8990]

The next 2-3 days of models will be very interesting to say the least, Temps next week look brutal.   

[Mrwolf1972]

06 GFS gives valley half inch Ice and 6-8 inches of snow

[Carvers Gap]

For NE TN peeps we are going to have to root for this to move northwest a bunch.  Ensembles have this buried (I mean absolutely buried).  I think the 0z GFS run was a one-off.   I think the 6z GFS is still probably too amped.  The GFS has a little bit of NAM in it at range.  Everything is too amplified.  I would be really surprised if this is a forum wide event.  I think this is going to be a SE TN event, non-event, or E TN event in that order.  It is that suppressed on ensembles.

[matt9697]

11 hours ago, *Flash* said:

I like it. Middle TN north of 40 is outside looking in at this point but positive trends are my friends. That said, if I have to throw in the towel, I want E Ten peeps to be in the trowal. 

All of Middle TN looked good on the last two runs of the GFS

[Carvers Gap]

8 minutes ago, matt9697 said:

All of Middle TN looked good on the last two runs of the GFS

Ensembles barely graze areas north of 40.  There is almost zero support for frozen precip north of 40 right now on ensembles.  It is possible that operationals are leading the way.  I certainly can see that is possible.  But the the ensemble mean is waaaaaay down there.  I would really caution using the GFS right now.  It was woefully wrong with the last system, and is on a total island with this next one.  I hope it is right.  That means I get to see winter one last time before a possible much AN February.

[Carvers Gap]

This is how much the GFS is on an island.  The 0z Euro AIFS doesn't even have the system above Mobile, Alabama.  There are really two impulses.  There is one on the 21st-ish and next on the 24th-ish.  Modeling is probably struggling with which one to amp.   But on the AIFS, neither are there.  Again, looking at ensembles, we are going to need to see those ensembles begin to move today or this one is gonna be tough to reel in.

Overall in the long range, it looks like we take a TBD big-time warm-up after next week.  The GEFS ext MJO ends winter for all but the northern most latitudes of the forum and higher elevations.  The Euro Weeklies race across warm phases and then stall before hitting phase 8 of the MJO.   We want the Euro to be right.  Otherwise, things are going to be blooming by the end of February.  When we start talking about the MJO, usually that means we are about to see extended warmth.  I suspect that seasonal analogs(almost all are warm for Feb) are correct in February being much AN with March cooling back off.  Chance for a little late season magic if analogs are correct for March.  

So far, the 2018 analog has been money.  I had it as one of two analogs for my winter forecast.   2017 was the other.  

The one fly(a good one) in the ointment for February could be the PDO flipping.  If it flips, it will try to trump the MJO and has the ability to do so.  

[PowellVolz]

40 minutes ago, matt9697 said:

All of Middle TN looked good on the last two runs of the GFS

Buddy I wish the GFS was right but it’s on an island and has zero support from its brothers and sisters. 

[Hillbilly]

Curious to see what, if anything, develops on Sunday. Perhaps, a chance for a surprise or two come Monday?