Winter 2024/2025 January Thread

[John1122]

It's moving much slower this run vs it's 12z cutter. 

[John1122]

The ICON took a big shift south initially that run vs 12z, but rather than moving west to east like 12z, it runs almost due northeast and still crosses over Nashville like it did at 12z, then moves due east, transfers to the coast and dies.

Incredible warmth ahead of it. Mid-70s in Alabama. Doesn't seem believable to pump that much warmth up. 

[Wurbus]

Wild that we have 20 pages on the Jan thread before it even begins!

[John1122]

Basically a Miller B on the ICON. 

[Carvers Gap]

The further south this makes landfall on the West Coast, the better the chances it exits. at a similar latitude.  Opens the door for an inland runner down the line.  However, for now, looks very similar to the ICON.  I wonder if it meanders as much as it did?

[Wurbus]

Looked like it was amped and cut through TN. A little ice in East TN, but it warms up into the 40s as it cuts. I'll take that over the inch of ice.

[Daniel Boone]

1 hour ago, John1122 said:

The ICON took a big shift south initially that run vs 12z, but rather than moving west to east like 12z, it runs almost due northeast and still crosses over Nashville like it did at 12z, then moves due east, transfers to the coast and dies.

Incredible warmth ahead of it. Mid-70s in Alabama. Doesn't seem believable to pump that much warmth up. 

Yeah. Seems it's slower solution is causing it to estimate a bit of a SER pump up and pull up that extreme warmth. 

[John1122]

Just gonna hope for a few northern stream pulses after this likely cutter exits. Looks like the 2018 analog has a good shot at verifying. 

[Daniel Boone]

1 minute ago, John1122 said:

Just gonna hope for a few northern stream pulses after this likely cutter exits. Looks like the 2018 analog has a good shot at verifying. 

Sure hope not but would be our luck. I'd rather no big system having come out of the SW and have 1-3 or 2-4" Clippers than have it come along and piss on us and dump North and NW of us while shoving everything way South after passing.

 Hopefully we get in a Pattern that produces at least 2-3 Clippers from the NS after this debacle and the next way deep south Storm.  If not, cold and dry until the pattern breaks. 

   There's still hope with this one. We need Canadian HP to drop down faster or the 50-50 to create more confluence and force the LP from coming all the way up to Tennessee but to slide East across Alabama and Georgia. 

   

[Daniel Boone]

That GFS run was just terrible if you like snow in the Great Valley. More along the Gulf Coast . Kind of laughable in that it has St Louis getting about 4 Feet ! Knoxville getting hammered with a dusting. 

[matt9697]

The GFS is still moving around. Look at the last 24 hour of output. The cold seemed stable; however, the latest run brings the coldest air in at the end of the run instead of around the 10th

[AMZ8990]

Just now, matt9697 said:

The GFS is still moving around. Look at the last 24 hour of output. The cold seemed stable; however, the latest run brings the coldest air in at the end of the run instead of around the 10th

Most definitely, the strength of this cold shot is creating lots of volatility on the models from run to run.  6z GFS still wanting to take the low right through the midsouth.  Big run for the Missouri/Indiana crew though.  GFS is still trying to bring a 2nd system in on the 10th though, lots of potential there but HP kept it suppressed to the Deep South as it moved east.  

[matt9697]

15 minutes ago, AMZ8990 said:

Most definitely, the strength of this cold shot is creating lots of volatility on the models from run to run.  6z GFS still wanting to take the low right through the midsouth.  Big run for the Missouri/Indiana crew though.  GFS is still trying to bring a 2nd system in on the 10th though, lots of potential there but HP kept it suppressed to the Deep South as it moved east.  

Yes, however, looks to me like that second system moved north a bit from the previous run. Places north of here can have the ice! 

[jaxjagman]

.LONG TERM...
(Thursday Night through next Wednesday)
Issued at 145 AM CST Wed Jan 1 2025

By Thursday night, a quick-hitting clipper system will push through
across the Ohio River Valley. As of now, it appears the only
influence we`ll feel from it will be an increase in clouds Thursday
night through Friday and a drop in temperatures. There is a low
possibility that a few snow showers could pass through our
extreme northeastern counties Friday morning, but nothing of any
consequence. Ensembles do not currently favor that outcome, thus
left mention of any precip out of the forecast for now. This
system will usher is the first real Arctic air of our upcoming
series of cold blasts; lows Friday night will dip as low as 14
degrees along the Plateau and 20-25 degrees elsewhere across
Middle TN.

The biggest question mark of this forecast package continues to be
the messy system that moves in during the Sunday afternoon/Monday
morning timeframe. Confidence in exact precip type and amount remains
low, but confidence in precip occuring during this timeframe is
high. After analyzing the wet-bulb temperature profile on a few
soundings, the current window for any freezing precip looks to be
small, at least from looking at the GFS and GEFS ensemble members.
It`s important to note here that there is a large spread in the
ensembles of what the temperature at the surface will be on
Sunday. Also realize that these outcomes will likely change plenty
more times between now and then, so take whatever you see with a
grain of salt. Whatever precip we do get will stay with us through
the majority of the day Monday, coming to an end from west to
east.

After this system, conditions look to remain dry through at least
Thursday, but temperatures will be bitterly cold through the week
with highs barely near freezing and overnight lows in the teens
to low 20s. The "warmest" day of the week currently looks to be
Monday with highs in the upper 30s to low 40s.

[matt9697]

4 minutes ago, jaxjagman said:

.LONG TERM...
(Thursday Night through next Wednesday)
Issued at 145 AM CST Wed Jan 1 2025

By Thursday night, a quick-hitting clipper system will push through
across the Ohio River Valley. As of now, it appears the only
influence we`ll feel from it will be an increase in clouds Thursday
night through Friday and a drop in temperatures. There is a low
possibility that a few snow showers could pass through our
extreme northeastern counties Friday morning, but nothing of any
consequence. Ensembles do not currently favor that outcome, thus
left mention of any precip out of the forecast for now. This
system will usher is the first real Arctic air of our upcoming
series of cold blasts; lows Friday night will dip as low as 14
degrees along the Plateau and 20-25 degrees elsewhere across
Middle TN.

The biggest question mark of this forecast package continues to be
the messy system that moves in during the Sunday afternoon/Monday
morning timeframe. Confidence in exact precip type and amount remains
low, but confidence in precip occuring during this timeframe is
high. After analyzing the wet-bulb temperature profile on a few
soundings, the current window for any freezing precip looks to be
small, at least from looking at the GFS and GEFS ensemble members.
It`s important to note here that there is a large spread in the
ensembles of what the temperature at the surface will be on
Sunday. Also realize that these outcomes will likely change plenty
more times between now and then, so take whatever you see with a
grain of salt. Whatever precip we do get will stay with us through
the majority of the day Monday, coming to an end from west to
east.

After this system, conditions look to remain dry through at least
Thursday, but temperatures will be bitterly cold through the week
with highs barely near freezing and overnight lows in the teens
to low 20s. The "warmest" day of the week currently looks to be
Monday with highs in the upper 30s to low 40s.

NWS in Nashville is, in my opinion, notoriously stubborn to include any mention of snow in their forecasts, they tend to wait almost to the point that it is actually snowing before they include it in a forecast. Perhaps by tomorrow afternoon models will be putting out a the same solution? 

[jaxjagman]

1 minute ago, matt9697 said:

NWS in Nashville is, in my opinion, notoriously stubborn to include any mention of snow in their forecasts, they tend to wait almost to the point that it is actually snowing before they include it in a forecast. Perhaps by tomorrow afternoon models will be putting out a the same solution? 

But they've been wrong many times and the public dont understand in winter time strorms.Its hard to forecast the magnitude of  artic air in our parts because the models have notoriously been wrong in past storms.I really dont blame them...jmho

[Holston_River_Rambler]

Since the long range 12z Euro decided it hates us and wants us to die (and at the risk of being accused of throwing spaghetti against a wall) I thought I'd try a bit of a deep dive this AM. 

Upstream tropical first:

I hadn't looked at the convection in a while because we've had much more exciting stuff to look at the past week. But looking at the MC regions, it looks like there is still a lot of convection hung up there:

 

In fact I would say the MJO 4/5/6 regions have the majority of the tropical convection across the globe:

This is, I think, shown in the RMM plots with the data plotted in such a way as to stall it out again, for almost 5 days now:

 

Sometime in the next week models seem to think convection will die out over the MC and we will get more overt he Western Hemisphere and especially Africa:

Those are the BOMM, GEFS, and EPS evaluations of where the MJO is and where it may be going. 

Verification for GEFS at least (all I have access to) has been pretty good the past week, but it tried to kill it off too quickly in the 2 week period. 

(2 week verifictation on top):

 

So I think is probably a good bet that at least so far as were can count on tropical convection, we may finally get to see what a nice clean pass through the more favorable phases looks like, at our climatological peak for winter weather. Does that guarantee anything, no, or course not, but I don't know that we've seen that progression in a while. But I have to think that the models seeing the tropics up stream of us as a little stagnant for now, has some implications for how they handle the downstream pattern. 

As far as any stratosphere stuff goes, I don't see anything that makes me think the SPV will be anything but strong and wound up in teh foreseeable future at the atmospheric levels available to me (10mb, 30mb, and 50mb), but here is a pretty gif:

 

Don't really have time for more right now, but some reasons for optimism IMO even after whatever happens between Jan 6 - 11. 

 

 

 

 

[matt9697]

15 minutes ago, jaxjagman said:

But they've been wrong many times and the public dont understand in winter time strorms.Its hard to forecast the magnitude of  artic air in our parts because the models have notoriously been wrong in past storms.I really dont blame them...jmho

That is truth indeed! Have seen it go the opposite direction on them no matter how they call it too many times to count. Weather is difficult but then when you add in the variables we are talking about, it becomes even more difficult!

[AMZ8990]

1 hour ago, matt9697 said:

Yes, however, looks to me like that second system moved north a bit from the previous run. Places north of here can have the ice! 

It did, no snow in key west that run.  lol.  In all seriousness though a couple more ticks north and that’s a huge storm for a lot of the forum.  I’m with you on the ice too, I want no part of that!

[Carvers Gap]

Pretty rare to see LR, 16 day modeling go end-to-end with cold and chances for storms on globals.  We have that on the GFS, Euro AIFS 6z, and the CMC.  I am not sure global actually can even see the end of the pattern yet.  I think we are good for about three weeks of cold, then IDK.  We might steal one more week of seasonal before a warm-up.  The Euro weeklies control is just one cold shot after another(for 46 days) as is the control for the GEFS ext.  Their ensembles, though, tip the trough back West after Jan 20 and send temporary shots of cold SE.  Either option wouldn't surprise me.  The trough to the Mountain West seems probably...if anything because we will due a break.

Morning thoughts:

1.  Jan 6 looks baked in the cake.  Possible front end ice, and then rain.  Time of day will be crucial to getting precip right, and if the storm moves rapidly enough to trap existing cold in the valleys.

2.  What happens after that?  This is a no holds barred pattern.  I don't think modeling even remotely have details correct after the 6th.  This has the chance to be a prolonged cold shot.  For the Jan 6 system, we have seen runs take cutters to Michigan and slide a low to Tallahassee.  It looks like deterministic models finally have the cone narrowed down.  At range, those wild deterministic runs remind us that (at range) ensembles are the way to go.  Cold looks very likely, and maybe extreme at times.  I liked 2018 as an analog for my winter forecast ideas(one of only two analogs).  I still like it, but I do think we see more snow(maybe much more snow) than that year.  We will see.  Why?  December is just not a great month climo wise IMBY.  Yes, recently it has snowed more in December...but not really a ton prior to 2009 in my lifetime (locations at elevation are a different story).  January can feature a more active pattern than December as December is exiting our driest time of the year.

3.  Best snow mechanisms in order of likelihood seen on modeling the past few days....embedded northern stream energy (clippers for lack of a better word), anafront, and sliders.  Could we see a Miller A?  Possibly, but the 500 pattern makes it tough right now.  As the trough backs into the west between the 15th and 25th...that might be our best shot or an inland runner.  I do think we see an anafront snow before this is all said and done.  I also think a mid-south slider is probable given the pattern, the deep cold, and history.  Could is snow in Florida?  Maybe.  However, I suspect models are overcooking the cold in most(not all cases).  That means the pattern probably adjusts northward some.  If the pattern flattens out some, then multi-day overrunning is possible.

4.  1985 and 1977.  Those have been kicked around a lot.  Honestly, they were probably best left on the shelf with their numbers retired.  However, there are elements of those years found in upcoming modeling.  I find that pretty remarkable.  Both of those years featured wild weather.  And it is good to remember that really cold air can take minimal precip and cause systems to over-perform.  So even the slightest precip on a map could yield decent results.

I hope when this is all said and done that we are looking at a new, modern benchmark month for winter.

Happy New Year!!!

[AMZ8990]

1 hour ago, Holston_River_Rambler said:

Since the long range 12z Euro decided it hates us and wants us to die (and at the risk of being accused of throwing spaghetti against a wall) I thought I'd try a bit of a deep dive this AM. 

Upstream tropical first:

I hadn't looked at the convection in a while because we've had much more exciting stuff to look at the past week. But looking at the MC regions, it looks like there is still a lot of convection hung up there:

 

In fact I would say the MJO 4/5/6 regions have the majority of the tropical convection across the globe:

This is, I think, shown in the RMM plots with the data plotted in such a way as to stall it out again, for almost 5 days now:

 

Sometime in the next week models seem to think convection will die out over the MC and we will get more overt he Western Hemisphere and especially Africa:

Those are the BOMM, GEFS, and EPS evaluations of where the MJO is and where it may be going. 

Verification for GEFS at least (all I have access to) has been pretty good the past week, but it tried to kill it off too quickly in the 2 week period. 

(2 week verifictation on top):

 

So I think is probably a good bet that at least so far as were can count on tropical convection, we may finally get to see what a nice clean pass through the more favorable phases looks like, at our climatological peak for winter weather. Does that guarantee anything, no, or course not, but I don't know that we've seen that progression in a while. But I have to think that the models seeing the tropics up stream of us as a little stagnant for now, has some implications for how they handle the downstream pattern. 

As far as any stratosphere stuff goes, I don't see anything that makes me think the SPV will be anything but strong and wound up in teh foreseeable future at the atmospheric levels available to me (10mb, 30mb, and 50mb), but here is a pretty gif:

 

Don't really have time for more right now, but some reasons for optimism IMO even after whatever happens between Jan 6 - 11. 

 

 

 

 

Great stuff, Holston.  Thanks for sharing 

[Silas Lang]

33 minutes ago, Carvers Gap said:

Pretty rare to see LR, 16 day modeling go end-to-end with cold and chances for storms on globals.  We have that on the GFS, Euro AIFS 6z, and the CMC.  I am not sure global actually can even see the end of the pattern yet.  I think we are good for about three weeks of cold, then IDK.  We might steal one more week of seasonal before a warm-up.  The Euro weeklies control is just one cold shot after another(for 46 days) as is the control for the GEFS ext.  Their ensembles, though, tip the trough back West after Jan 20 and send temporary shots of cold SE.  Either option wouldn't surprise me.  The trough to the Mountain West seems probably...if anything because we will due a break.

Morning thoughts:

1.  Jan 6 looks baked in the cake.  Possible front end ice, and then rain.  Time of day will be crucial to getting precip right, and if the storm moves rapidly enough to trap existing cold in the valleys.

2.  What happens after that?  This is a no holds barred pattern.  I don't think modeling even remotely have details correct after the 6th.  This has the chance to be a prolonged cold shot.  For the Jan 6 system, we have seen runs take cutters to Michigan and slide a low to Tallahassee.  It looks like deterministic models finally have the cone narrowed down.  At range, those wild deterministic runs remind us that (at range) ensembles are the way to go.  Cold looks very likely, and maybe extreme at times.  I liked 2018 as an analog for my winter forecast ideas(one of only two analogs).  I still like it, but I do think we see more snow(maybe much more snow) than that year.  We will see.  Why?  December is just not a great month climo wise IMBY.  Yes, recently it has snowed more in December...but not really a ton prior to 2009 in my lifetime (locations at elevation are a different story).  January can feature a more active pattern than December as December is exiting our driest time of the year.

3.  Best snow mechanisms in order of likelihood seen on modeling the past few days....embedded northern stream energy (clippers for lack of a better word), anafront, and sliders.  Could we see a Miller A?  Possibly, but the 500 pattern makes it tough right now.  As the trough backs into the west between the 15th and 25th...that might be our best shot or an inland runner.  I do think we see an anafront snow before this is all said and done.  I also think a mid-south slider is probable given the pattern, the deep cold, and history.  Could is snow in Florida?  Maybe.  However, I suspect models are overcooking the cold in most(not all cases).  That means the pattern probably adjusts northward some.  If the pattern flattens out some, then multi-day overrunning is possible.

4.  1985 and 1977.  Those have been kicked around a lot.  Honestly, they were probably best left on the shelf with their numbers retired.  However, there are elements of those years found in upcoming modeling.  I find that pretty remarkable.  Both of those years featured wild weather.  And it is good to remember that really cold air can take minimal precip and cause systems to over-perform.  So even the slightest precip on a map could yield decent results.

I hope when this is all said and done that we are looking at a new, modern benchmark month for winter.

Happy New Year!!!

Looking at the Jan 6th system and timing, I think east TN should be on lookout. Precip happens at night and early morning on most models.

Also have the possibility of cold air lingering in some valley regions. I forget which year, but I seem to remember am almost mini CAD event with cold air banked up against the plateau and some ridges. Essentially, be prepared and know your microclimates Monday morning. I expect the return to school to be delayed assuming the trends hold.  

[Carvers Gap]

3 minutes ago, Silas Lang said:

Looking at the Jan 6th system and timing, I think east TN should be on lookout. Precip happens at night and early morning on most models.

Also have the possibility of cold air lingering in some valley regions. I forget which year, but I seem to remember am almost mini CAD event with cold air banked up against the plateau and some ridges. Essentially, be prepared and know you micro climates Monday morning. I expect the return to school to be delayed assuming the trends hold.  

I remember that one.  We had downslope on the west slopes of the Apps. It banked the cold up against the Plateau.  E TN, especially points NE of Knoxville and on the Plateau need to keep an eye out for sure.  The 12z ICON posed that risk for sure.  

[Carvers Gap]

The 12z GFS going to try to phase just after 192?

[Carvers Gap]

Looks like a weak phase at 500....

[Carvers Gap]

That is the one if it stays on modeling.  

[Carvers Gap]

The 12z has a phased system between d8-10.  With the way this Jan 6 system has trended north and west....that is right where we want it at this range.  Let's see if that holds on modeling.  Been kind of off-and-on for a few days, but that is a boomer.

[Carvers Gap]

I should clarify...the Jan 6 system trended north, waaaay south, trended north and west, and then locked in.

[Carvers Gap]

The 12z CMC looks like it is also going to phase slightly west(or a lot more west?).

[Carvers Gap]

Last post for a bit....looks like the 12z GFS just wants to phase everything.   Interesting run.