Winter 2024/2025 January Thread

[Wurbus]

Let's just lock this look in for the next week.

[Carvers Gap]

My guess (FWIW) is this will get stronger over time and jog northwest.  Modeling is just now potentially figuring this out.  If it consolidates during future runs, it would likely be stronger.  That is where we want it at this range IMHO.

[Carvers Gap]

Looks to me like some warm air slides up the valley ahead of the storm, and then switches to snow as the storm slides by.  That used to be pretty common at TRI.  I doubt higher elevations would see mix with that.   Seems like in 94 or 96(I was in Knoxville at the time....) that we had some glaze which was followed by snow, and then cold.  It was a mess.  I was cleaning of my car, and the glaze shattered.   I thought I had broken the rear window!!!   LOL.  That glaze also backed up the water from draining on my roof....came right into the apartment on Lonas.  

[AMZ8990]

[AMZ8990]

[Carvers Gap]

The 12z CMC missed almost exactly like the 6z GFS did.  Looks like it will phase the let behind energy with the next system.

[Carvers Gap]

All I want to see is the northern and southern streams interacting at this range.  The GFS and CMC are loaded up in that regard.  

[Carvers Gap]

The 12z CMC does indeed grab that energy with the next pass....left us at 240 with a slp sitting in the eastern Panhandle which is traditionally a good spot.  Looked like it had plenty of room to gain latitude.  Again, for now, looks like pay me now or pay me later with that energy in the southwest.  We just want it consolidated and not sheered into two system - I don't "think."

[Carvers Gap]

Either situation w/ the 12z GFS or CMC works.  If the first system misses, it leaves "money in the bank" over the southwest, and the next system picks it up.  I know a folks don't like JB...but I learned that setup from listening to him over the years.  Generally, that is a true statement if the energy is real.  Add 8-9 days out, really that is about all that we can ask for.

[Carvers Gap]

12z UKMET is south for system 1 and has system 2 on deck ready to rock.

[Carvers Gap]

Kicks and giggles.

[John1122]

Then comes the Euro......

[Carvers Gap]

 

[Carvers Gap]

As for the system two...the point of inflection (go, no go) looks like if the northern stream will grab the energy over the southwest.   The 12z ICON and GFS got the phase.  The 12z CMC and Euro did not.  Ensembles will be unlikely to show that phase at this range.  They will wash-out that solution. 

When there is no storm, the 500 maps look nearly identical.  When there is a storm, there is a phase there.  Several days ago the concern was suppression.  I think we have exactly opposite of that problem - for now.  Don't be surprsied if the cold shows back up on modeling either. 

[John1122]

The EURO op is way warmer/wetter than the EPS, which remains in the supression/colder camp.

[Carvers Gap]

Regarding the 10th....

Roughly 6/30 GEFS members have the storm - about 20%.  

Roughly 8/30 GEPS members have the storm - about half.

Interestingly, almost all of the ones that miss....follow-up with that energy a couple of days later.  Mostly snow and pretty good storms at that.

EPS is pretty similar to the GEFS but a little less enthused.

Short story...There are two camps for the 10th on modeling. One is an phase on the 10th, and the other is a couple of days later.

I tend to lean towards a phase with the northern stream for a storm on the 10th.  I could be wrong.  However, the GFS has modeled the southwest(against my earlier suspicions for the system on the third) correctly when other models did not.  For now, it gets the nod for scoring a big time coup on Jan 6.  It also caught that trend before any other deterministic or ensemble member, even its own ensemble.

[John1122]

JKL posted a winter storm watch for their border counties. Modeling is showing warning criteria ice here.

[Carvers Gap]

With the exception of a couple of western border counties, all bordering counties in Kentucky(w/ Tenn) have been placed under winter storm watches.  

edit: Sorry, John....Just saw your post about the same.  

[Carvers Gap]

1 minute ago, John1122 said:

JKL posted a winter storm watch for their border counties. Modeling is showing warning criteria ice here.

Yeah, if they get it...odds are that you are as well.

[Grothar of Herndon]

Pulled this from Mid Atlantic forum. Euro latest run

[*Flash*]

2 minutes ago, Grothar of Herndon said:

Pulled this from Mid Atlantic forum from Euro latest run

DT WxRisk will certainly take it. 

[Grothar of Herndon]

Yeah he was the person who posted. He is definitely hugging it!

[Carvers Gap]

18z NAM jogs north.  SW VA under WSW.

[Daniel Boone]

1 hour ago, Grothar of Herndon said:

Yeah he was the person who posted. He is definitely hugging it!

Yeah, Dt is a Character. 

[John1122]

I got no forecast product but my forecast now says snow changing to freezing rain with a high of 32 Sunday, freezing rain Sunday evening with the temp falling to 28 before beginning to rise later.

MRX said the global models were too fast in scouring out the sub-freezing air across the area. That the couldn't quite handle low level cold well enough to see how it sticks in valleys.

[matt9697]

At least no one is under ice storm warnings; I feel for these guys in southern Missouri, .75 of ice is bad

[matt9697]

7 minutes ago, John1122 said:

I got no forecast product but my forecast now says snow changing to freezing rain with a high of 32 Sunday, freezing rain Sunday evening with the temp falling to 28 before beginning to rise later.

MRX said the global models were too fast in scouring out the sub-freezing air across the area. That the couldn't quite handle low level cold well enough to see how it sticks in valleys.

So, wonder what they will put you under as far as advisory? Wondering the same for Nashville....

[ladyjmayo]

29 minutes ago, matt9697 said:

So, wonder what they will put you under as far as advisory? Wondering the same for Nashville....

I think MRX is going to hold off until morning so they have a better idea of what areas will be impacted.

[Carvers Gap]

MRX afternoon disco excerpt....

An impactful winter storm is possible on Sunday across the region
with impacts expected across portions of our forecast area,
especially the northern half. A cold, dry airmass will be located
across the region on Saturday night with southwesterly flow aloft
and isentropic lift increasing ahead of a low pressure system across
the Southern Great Plains.

This isentropic ascent will produce light precipitation, mainly west
of Interstate 75, early Sunday morning with precipitation gradually
beginning to increase eastward throughout the day. Very cold, dry
air will be in place at the surface. RAP forecast soundings now
extend out through 18z Sunday, and these soundings show wet bulb
temperatures in the mid 20s. Precipitation will have a difficult
time making it to the surface at first with evaporative cooling
keeping temperatures colder into the afternoon. This is one of these
situations where cold air will already be across the region, and
models often do not resolve the shallow cold air very well. This
causes many global models with coarser resolution to quickly bring
WAA into the area faster than observed. The higher-res mesoscale
model guidance is showing this more realistically with temperatures
across the northern half of the forecast area struggling to get
above freezing until late Sunday afternoon. The RAP soundings are
showing this with temperatures across the central valley remaining
near 31-32 even at 18z Sunday. Overall QPF totals are not very high,
but even light amounts around 0.1 inch would result in hazardous,
icy travel. With the southerly flow, downslope and warming
conditions across the western mountain foothills will result in a
warm nose west of the mountain chain across the foothills. This
means that the highest probabilities of freezing rain ice
accumulation greater than 0.1 inch will be north of Interstate 40
and northwest of Interstate 81. The highest ice accumulation is
expected near the Kentucky line and into southwest Virgina where 0.1
to 0.25 inch of ice accumulation is currently forecast, with locally
higher amounts.

[Carvers Gap]

These snow squalls this afternoon in NE TN and SW VA have meant business.  Interestingly, there will now be snow on the ground in some places(that weren't expecting it) well before the next system arrives Sunday.  There are places in Johnson Co and in SW VA with 1-3" of snow on the ground now.  Roads are a mess.  Very much overperformed.  This cold front has been strong.