Cold Shot: Part Duex - January 18-20th Arctic Blast and Freezing Rain/Snow Event

[John1122]

We may get the sequel to the current event Thursday and Friday through the weekend. The ICON came more on board with the GFS tonight. The Canadian is trying a bit itself. We aren't likely to get nearly as much snow as we did with this system, but some of us may get more. 

People rarely like the sequel better, after all. But maybe for our mix/rain victims, this one will be better. The original is going to be hard to beat for most of us. 

 

 

 

[John1122]

My current forecast from MRX is 80 percent snow Thursday night with moderate accumulations possible. That's usually wording for 2-4 inches. 

It's gonna be bitter cold behind it with some 10 to 20 below wind chills. So we're getting the Arctic Blast regardless of snow or not. 

[John1122]

The Canadian. It's crept south with the snow line as well. 

 

[MattPetrulli]

Once again Euro vs GFS.

GFS is kind of the outlier here, only model in its camp is the ICON. The rest are just a slushy mix for most of the valley.

 

[weathertree4u2]

OHX Morning Discussion...

000
FXUS64 KOHX 161218
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
618 AM CST Tue Jan 16 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday)
Issued at 231 AM CST Tue Jan 16 2024

The mid state now has a legitimate snow pack and this will need to
be taken into account in terms of dealing with our upcoming temp
fcst. Looks like 4-8 inches of snow depth is rather common place
area wide. For now though its a very cold morning with current temps
holding in the 10-15 degree range.

Clouds are still in place but we will get some clearing by afternoon
from nw to se. It`s not going to warm up much however as we have two
things working against it. For one, the snowpack will of course act
to reflect much of the afternoon solar radiation that we finally
start to get. Secondly, strong thermal troughing will be building
our way with those 850 mb temps dropping toward -15C by this
afternoon. So, will undercut the NBS numbers by a few degrees. Looks
like highs today will reach just the 14F to 19F range.

Looks like a bone chilling cold night ahead. By Wednesday morning
the sfc high will reach MS with ridging extending northeastward.
Clear skies and the snow pack will help send our temperatures down
to close to zero for many locations. Following this, the
Wed afternoon temperatures will finally warm back up into the 20s.

For the wind chill advisory, latest apparent t grids suggest that
the advisory shall continue. It will therefore remain in effect
until 9am Wednesday morning. Though winds will be on the lighter
side, the temperatures themselves will be cold enough to produce
some negative wind chill values. This is due to the 8-10 mph winds
that are expected at times.

Moving on, another storm system will take shape near the Arklatex
region late Wednesday night. The sfc low will stay to our south and
there is some n-s inversion with the system. Hence, there will be
some waa trying to kick in on Wednesday and into Wednesday night.
However, when taking into account the expected wet bulbs at a
variety of levels, the recovery looks a touch overdone by the
models. That said, for now, it appears that this next system will be
mostly snow north and rain and snow south. We could also experience
some IP activity across the south as well but for now will avoid the
inclusion. The system right now does not appear to be all that
strong but some light snow accumulations cannot be ruled out.
Perhaps an inch or so of snow will be possible Thursday into
Thursday night, mainly north and Plateau.

&&

.LONG TERM...
(Thursday Night through next Tuesday) Issued at 231 AM CST Tue
Jan 16 2024

In the extended forecast, another arctic front will be on the heels
of the Thursday system. Lows by Friday morning will be back down to
near 20 for many areas with just a small warmup during the day.
Adding to the chill will be some light snowfall that could continue
into the day. The rest of the extended looks dry but very cold. Look
for single digits for lows into the weekend with moderating temps
and highs near 40F by Monday.

&&

.AVIATION...
(12Z TAFS)
Issued at 618 AM CST Tue Jan 16 2024

Light snow showers should end SRB/CSV by 16/14Z-16/15z. Initial
IFR/MVFR ceilings SRB/CSV will become exclusive MVFR after thru
17/00Z. Initial VFR ceilings will continue to prevail CKV/BNA/MQY
with gradual ceiling degradation CKV to MQY 16/23Z-17/01Z.
Errosion of ceilings at all terminals should occur no later than
17/03Z as high pressure influences surface and aloft strengthen
across our area. Initial sfc sustained NW winds around 10kts
should slowly back to S as 17/12Z approaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      18   2  28  15 /   0   0   0   0
Clarksville    16   4  28  15 /   0   0   0   0
Crossville     15  -2  25  12 /   0   0   0   0
Columbia       18  -1  27  13 /   0   0   0   0
Cookeville     15  -2  24  13 /   0   0   0   0
Jamestown      15  -2  25  12 /   0   0   0   0
Lawrenceburg   17  -1  26  13 /   0   0   0   0
Murfreesboro   17  -2  27  12 /   0   0   0   0
Waverly        17   2  28  15 /   0   0   0   0

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until 10 AM CST Wednesday for Bedford-Cannon-
Cheatham-Clay-Coffee-Cumberland-Davidson-De Kalb-Dickson-
Fentress-Giles-Grundy-Hickman-Houston-Humphreys-Jackson-Lawrence-
Lewis-Macon-Marshall-Maury-Montgomery-Overton-Perry-Pickett-
Putnam-Robertson-Rutherford-Smith-Stewart-Sumner-Trousdale-Van
Buren-Warren-Wayne-White-Williamson-Wilson.

&&

$$

SHORT TERM...21
LONG TERM....21
AVIATION.....JB Wright

[Save the itchy algae!]

OHX Morning Discussion...

000FXUS64 KOHX 161218AFDOHXArea Forecast DiscussionNational Weather Service Nashville TN618 AM CST Tue Jan 16 2024...New AVIATION....SHORT TERM...(Today through Thursday)Issued at 231 AM CST Tue Jan 16 2024The mid state now has a legitimate snow pack and this will need tobe taken into account in terms of dealing with our upcoming tempfcst. Looks like 4-8 inches of snow depth is rather common placearea wide. For now though its a very cold morning with current tempsholding in the 10-15 degree range.Clouds are still in place but we will get some clearing by afternoonfrom nw to se. It`s not going to warm up much however as we have twothings working against it. For one, the snowpack will of course actto reflect much of the afternoon solar radiation that we finallystart to get. Secondly, strong thermal troughing will be buildingour way with those 850 mb temps dropping toward -15C by thisafternoon. So, will undercut the NBS numbers by a few degrees. Lookslike highs today will reach just the 14F to 19F range.Looks like a bone chilling cold night ahead. By Wednesday morningthe sfc high will reach MS with ridging extending northeastward.Clear skies and the snow pack will help send our temperatures downto close to zero for many locations. Following this, theWed afternoon temperatures will finally warm back up into the 20s.For the wind chill advisory, latest apparent t grids suggest thatthe advisory shall continue. It will therefore remain in effectuntil 9am Wednesday morning. Though winds will be on the lighterside, the temperatures themselves will be cold enough to producesome negative wind chill values. This is due to the 8-10 mph windsthat are expected at times.Moving on, another storm system will take shape near the Arklatexregion late Wednesday night. The sfc low will stay to our south andthere is some n-s inversion with the system. Hence, there will besome waa trying to kick in on Wednesday and into Wednesday night.However, when taking into account the expected wet bulbs at avariety of levels, the recovery looks a touch overdone by themodels. That said, for now, it appears that this next system will bemostly snow north and rain and snow south. We could also experiencesome IP activity across the south as well but for now will avoid theinclusion. The system right now does not appear to be all thatstrong but some light snow accumulations cannot be ruled out.Perhaps an inch or so of snow will be possible Thursday intoThursday night, mainly north and Plateau.&&.LONG TERM...(Thursday Night through next Tuesday) Issued at 231 AM CST TueJan 16 2024In the extended forecast, another arctic front will be on the heelsof the Thursday system. Lows by Friday morning will be back down tonear 20 for many areas with just a small warmup during the day.Adding to the chill will be some light snowfall that could continueinto the day. The rest of the extended looks dry but very cold. Lookfor single digits for lows into the weekend with moderating tempsand highs near 40F by Monday.&&.AVIATION...(12Z TAFS)Issued at 618 AM CST Tue Jan 16 2024Light snow showers should end SRB/CSV by 16/14Z-16/15z. InitialIFR/MVFR ceilings SRB/CSV will become exclusive MVFR after thru17/00Z. Initial VFR ceilings will continue to prevail CKV/BNA/MQYwith gradual ceiling degradation CKV to MQY 16/23Z-17/01Z.Errosion of ceilings at all terminals should occur no later than17/03Z as high pressure influences surface and aloft strengthenacross our area. Initial sfc sustained NW winds around 10ktsshould slowly back to S as 17/12Z approaches.&&.PRELIMINARY POINT TEMPS/POPS...Nashville      18   2  28  15 /   0   0   0   0Clarksville    16   4  28  15 /   0   0   0   0Crossville     15  -2  25  12 /   0   0   0   0Columbia       18  -1  27  13 /   0   0   0   0Cookeville     15  -2  24  13 /   0   0   0   0Jamestown      15  -2  25  12 /   0   0   0   0Lawrenceburg   17  -1  26  13 /   0   0   0   0Murfreesboro   17  -2  27  12 /   0   0   0   0Waverly        17   2  28  15 /   0   0   0   0&&.OHX WATCHES/WARNINGS/ADVISORIES...Wind Chill Advisory until 10 AM CST Wednesday for Bedford-Cannon-Cheatham-Clay-Coffee-Cumberland-Davidson-De Kalb-Dickson-Fentress-Giles-Grundy-Hickman-Houston-Humphreys-Jackson-Lawrence-Lewis-Macon-Marshall-Maury-Montgomery-Overton-Perry-Pickett-Putnam-Robertson-Rutherford-Smith-Stewart-Sumner-Trousdale-VanBuren-Warren-Wayne-White-Williamson-Wilson.&&$$SHORT TERM...21LONG TERM....21AVIATION.....JB Wright

It’s not just this post, but the AFD’s with all this coding or whatever is just unreadable. But it’s weird, when I quote it the text then becomes readable in my quote only.

[Greyhound]

It’s not just this post, but the AFD’s with all this coding or whatever is just unreadable. But it’s weird, when I quote it the text then becomes readable in my quote only.

I’ve noticed the same thing, but I primarily use Tapatalk on my phone. Never really paid attention to it when I’m on a computer


.

[John1122]

MRX, in their disco mentioned that neither the GFS nor Euro really have much of a warm nose.  The OHX disco above noted models were over warming highs considering the snowcover. 

[ShawnEastTN]

Just going to throw this out there. It's not very common to have deep snowpack over most of Tennessee with an approaching storm. I think many models are really over doing warming ahead the storm and if they aren't over doing warm nose aloft then I really fear a potential ice storm over much of the snow pack area. If we get .25 QPF of freezing rain it will be very bad in normal situations, let alone on trees that have snow on them that is already enveloped in light ice from the switch to freezing rain at the end in my neck of the woods.

[John1122]

The 12z GFS sticks to it's guns and gives a nice snow event for all but the Ga/Alabama border counties basically from Nashville eastward.

[Carvers Gap]

Looks the Friday event could be a mixed bag for valley locations.  GFS looks too progressive to me.  The CMC is a "slightly off the coast" Miller A.  The ICON is a cutter through middle TN Miller B.  The GFS is a slider(best scenario) and OTS.  My bet is this turns the corner.  With the current storm out of the way, this should come into focus very quickly.

[Wurbus]

11 minutes ago, ShawnEastTN said:

Just going to throw this out there. It's not very common to have deep snowpack over most of Tennessee with an approaching storm. I think many models are really over doing warming ahead the storm and if they aren't over doing warm nose aloft then I really fear a potential ice storm over much of the snow pack area. If we get .25 QPF of freezing rain it will be very bad in normal situations, let alone on trees that have snow on them that is already enveloped in light ice from the switch to freezing rain at the end in my neck of the woods.

GFS could be overdoing the cold, but I noticed it starts with an 12" snow depth in Knoxville while the other models start with 4-6" so I think that could be a major difference in the temp profiles.

[weathertree4u2]

8 minutes ago, Carvers Gap said:

Looks the Friday event could be a mixed bag for valley locations.  GFS looks too progressive to me.  The CMC is a "slightly off the coast" Miller A.  The ICON is a cutter through middle TN Miller B.  The GFS is a slider(best scenario) and OTS.  My bet is this turns the corner.  With the current storm out of the way, this should come into focus very quickly.

So we are still counting on a "half-time" next week right? I need a minute to try to find some more firewood, which should be fun! 

[Silas Lang]

Not really sure what to think of this one. Models showing rain, but with a thick snowpack and frigid air and more coming behind this system, one has to think we have shot a frozen precipitation regardless of what the models spit out. I just don't know how the cold can retreat so easily. 

[Daniel Boone]

18 minutes ago, Carvers Gap said:

I would say I am very confident of a sharp warm-up next week - spring like stuff.  The return of cold continues to get can kicked.  I am much less confident today about February than I have been since June - much less.  I would say that we get a brief, but sharp cold shot from Jan30-Feb3, and then another warmup(not to the degree next week will be).  The duration of that second warm-up will hold the fate of winter for most.  The MJO is forecast to stall in phase 6 which is the warmest phase of the MJO, and there is no running from phase 6 - it is going to warm-up.  Final hurrah of winter should be the final two weeks of February(maybe first week of March) as the MJO should be favorable then, and that is two weeks behind schedule.  The CFSv2 would end winter as its MJO plot rotates and stalls in the warm phases.  

There is a strat split, and we are going to need to roll the dice(I know many don't like that reshuffle) with that reshuffle.  As we have seen this week, sustained cold is the easiest way to winter.  Until we get the MJO to cooperate again, it is thread the needle the rest of the way. So the strat split may be our best option so to speak.  With the strat split, we should its effects 2-3 weeks down the road.  I would encourage everyone to read back through the winter discussion to see the order of regions it tends to focus on.  This current cold snap is probably due to strat warming during mid-late December.  I would look for the NAO to reappear.

Overall, and modeling doesn't show this just yet....I bet the upcoming warm-up is more of a thaw.  This winter just has the feeling that it is going to be back after this week.....I could be wrong.

Agree. I looked over alot of the goings on last night and if right, we're probably looking at maybe 60's as early as next week. If that big SER materializes and we're stuck in the MJO warm phases .. ugh. The SSW is probably needed this go around for sure. Hopefully, guidance is off on the MJO. 

[Daniel Boone]

13 minutes ago, Silas Lang said:

Not really sure what to think of this one. Models showing rain, but with a thick snowpack and frigid air and more coming behind this system, one has to think we have shot a frozen precipitation regardless of what the models spit out. I just don't know how the cold can retreat so easily. 

If they're seeing a strong push of mild air ahead of the System that's why. However, the entrenched lower level cold should spell sleet/freezing rain with still snow northeastern sections (upper valley) as cold from the valley lifts and mixes with the waa ahead of the system. 

[Hurricaneguy]

After my snow dreams were crushed by the warm nose yesterday I’m not betting against the models showing the warm nose again this Friday. Not getting burned twice in one week. Hope we get a nice surprise. 

[PowellVolz]

The main roads like Maynardville Hwy are going to be a disaster later on. It’s clear but soaked. Back roads even like Emory Rd are compacted and traction isn’t the greatest. There’s nothing to grip.

Edit: just realized I’m in the wrong thread. Sorry


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[PowellVolz]

It’s not just this post, but the AFD’s with all this coding or whatever is just unreadable. But it’s weird, when I quote it the text then becomes readable in my quote only.

I take a screenshot of the AFD. Copy and paste from the screenshot and it leaves out all the links.


.

[Holston_River_Rambler]

Here is the 12z Euro:

I think surface temps will verify colder than the models suggest, but I am concerned about 925mb and 850mb temps with this one.  

 

 

 

 

 

 

[Holston_River_Rambler]

I will say I like the vort pass on the 12z Euro better than 0z:

 

 

[John1122]

The Euro did dip south by a bit. The NAM family is amped as usual at this range. I think the threat of frozen is very realistic. 

[Carvers Gap]

14 minutes ago, Holston_River_Rambler said:

Here is the 12z Euro:

I think surface temps will verify colder than the models suggest, but I am concerned about 925mb and 850mb temps with this one.  

 

 

 

 

 

 

This comes in at night, right?  Add in a snowpack, and that is at least a recipe for ice in valley floor locations.

[Carvers Gap]

Time of day being at night is a big advantage.  

[John1122]

The FV3 is more in the GFS camp.

 

[jaxjagman]

Euro shows a 35-45 LLJ,over Mid Tn,lower elevation wont stand a chance here basically up to the Ky line

[Matthew70]

12 minutes ago, jaxjagman said:

Euro shows a 35-45 LLJ,over Mid Tn,lower elevation wont stand a chance here basically up to the Ky line

What does this mean?  Rain? Hopefully not ice.

[John1122]

The NAMs came in more wintery than previous runs, especially the 3k. More ice than snow. 

[Kentucky]

I'm not an expert on this, by any means. But is the NAM not initializing with the snowpack in S/SE TN?

Not sure it will matter in the end as @jaxjagman mentioned but found it interesting. 

 

 

[John1122]

The ICON shifted from a mid-state cutter to an Apps low from 12z to 18z. 

Always heard storms tended to ride below a snow pack but maybe that's an urban legend.