January 15th-17th 2024 Arctic Blast/Snow Event

[PowellVolz]

No they don’t and that has me a little disconcerted I am right on the line in West Knox and that gives me maybe 2 in.

I actually think west Knoxville is in a great location


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[PowellVolz]

Bring it


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[John1122]

21z RAP

 

[Jesse from KY]

Thoughts on WFO Jackson's discussion this afternoon? It appears they aren't too excited about the potential for Eastern Kentucky? I hope their thinking changes. I soo want a good snow for SE KY

Key Messages:

* An arctic airmass will be in place at the start the work week, 
  with daily highs from Monday through Wednesday expected to 
  remain at or below freezing. Tuesday morning will drop close to 
  zero, or possibly below zero depending on our snow cover. 
  Temperatures will moderate above freezing on Thursday before a 
  second, reinforcing round of arctic air arrives at the end of 
  the period.

* There is a chance for accumulating snow Monday through Tuesday
  and possibly again later in the week. At this time confidence
  remains low on exact amounts. Areas generally south of the
  Mountain Parkway and Highway 80 appear to have the best
  opportunity of seeing accumulating snow. However, overall 
  trends have taken snowfall accumulations further south and 
  towards lower amounts. 

Analysis and Discussion: 

Our pattern remains active and highly amplified, with a Hudson 
Bay low drifting slowly southward to the Great Lakes Region by the
end of the extended portion of the forecast. This will keep a 
mean trough and unseasonably cold air in place across the eastern 
CONUS. Relatively weak mid/upper level disturbances will round the
base of the mean trough with eastern Kentucky just within the 
corridor of influence of these series of disturbances. 

The first of these features within the extended period will 
transit the Commonwealth Monday through Tuesday. Precipitation 
will develop across the area as a result of weak isentropic lift. 
Surface features with this first disturbance are not even 
recognizable, providing insight into just how weak this system 
will be. At this time there appears to be enough energy to 
generate a swath of light snow with eastern Kentucky on the 
northern fringes of this systems influence. Trends in run to run 
solutions have taken snowfall accumulations further south and 
towards lower amounts overall. At present, ensemble probabilistic 
snowfall amounts suggest a high probability (> 70%) of an inch or 
more along and southeast of a Monticello-Jackson- Paintsville line
with the first system. Probabilities drop rapidly for higher 
amounts, with average probabilities of 3 inches or more generally 
below 50%, with highest probabilities in along the KY/VA state 
line. 

The second system basically impacts eastern Kentucky Thursday
night through Friday night. This second system is quite similar to
the first, but appears a little stronger with some weak surface
features appearing in the solutions. As is typical, the only sure
bet is that things will change with time, and it remains to be
seen exactly how much winter precipitation is produced with the
second disturbance, if any. 

These are weak systems, which make it a bigger challenge when
trying to forecast detailed sensible weather. However, we can 
take some confidence that in general, we are in a pattern that
favors the opportunity of wintry weather, with our forecast area 
in the northern, colder sections of these transient disturbances. 
Thus odds should be in our favor that a system will eventually 
produce a decent round of wintry weather. 

[Icy Hot]

1 minute ago, John1122 said:

21z RAP

 

I’ll take that 5.2 in Colonial Heights thank you very much. What’s the latest you think models will continue to change? Sunday PM?

[John1122]

3 minutes ago, Icy Hot said:

I’ll take that 5.2 in Colonial Heights thank you very much. What’s the latest you think models will continue to change? Sunday PM?

It was actually still snowing over East Tennessee at the end of the run. 

[TellicoWx]

HRRR looking more like the Icon vs NAM so far at 700..see where she goes

[John1122]

8 minutes ago, Jesse from KY said:

Thoughts on WFO Jackson's discussion this afternoon? It appears they aren't too excited about the potential for Eastern Kentucky? I hope their thinking changes. I soo want a good snow for SE KY

Key Messages:

* An arctic airmass will be in place at the start the work week, 
  with daily highs from Monday through Wednesday expected to 
  remain at or below freezing. Tuesday morning will drop close to 
  zero, or possibly below zero depending on our snow cover. 
  Temperatures will moderate above freezing on Thursday before a 
  second, reinforcing round of arctic air arrives at the end of 
  the period.

* There is a chance for accumulating snow Monday through Tuesday
  and possibly again later in the week. At this time confidence
  remains low on exact amounts. Areas generally south of the
  Mountain Parkway and Highway 80 appear to have the best
  opportunity of seeing accumulating snow. However, overall 
  trends have taken snowfall accumulations further south and 
  towards lower amounts. 

Analysis and Discussion: 

Our pattern remains active and highly amplified, with a Hudson 
Bay low drifting slowly southward to the Great Lakes Region by the
end of the extended portion of the forecast. This will keep a 
mean trough and unseasonably cold air in place across the eastern 
CONUS. Relatively weak mid/upper level disturbances will round the
base of the mean trough with eastern Kentucky just within the 
corridor of influence of these series of disturbances. 

The first of these features within the extended period will 
transit the Commonwealth Monday through Tuesday. Precipitation 
will develop across the area as a result of weak isentropic lift. 
Surface features with this first disturbance are not even 
recognizable, providing insight into just how weak this system 
will be. At this time there appears to be enough energy to 
generate a swath of light snow with eastern Kentucky on the 
northern fringes of this systems influence. Trends in run to run 
solutions have taken snowfall accumulations further south and 
towards lower amounts overall. At present, ensemble probabilistic 
snowfall amounts suggest a high probability (> 70%) of an inch or 
more along and southeast of a Monticello-Jackson- Paintsville line
with the first system. Probabilities drop rapidly for higher 
amounts, with average probabilities of 3 inches or more generally 
below 50%, with highest probabilities in along the KY/VA state 
line. 

The second system basically impacts eastern Kentucky Thursday
night through Friday night. This second system is quite similar to
the first, but appears a little stronger with some weak surface
features appearing in the solutions. As is typical, the only sure
bet is that things will change with time, and it remains to be
seen exactly how much winter precipitation is produced with the
second disturbance, if any. 

These are weak systems, which make it a bigger challenge when
trying to forecast detailed sensible weather. However, we can 
take some confidence that in general, we are in a pattern that
favors the opportunity of wintry weather, with our forecast area 
in the northern, colder sections of these transient disturbances. 
Thus odds should be in our favor that a system will eventually 
produce a decent round of wintry weather. 

According to how far north you live, looks like you're probably good for 1 to 4+ inches. But the story isn't written yet, I don't believe. There's gonna be someone close to an edge north and south that sees snow a few miles away but doesn't get much. 

 

[Jesse from KY]

1 minute ago, John1122 said:

According to how far north you live, looks like you're probably good for 1 to 4+ inches. But the story isn't written yet, I don't believe. There's gonna be someone close to an edge north and south that sees snow a few miles away but doesn't get much. 

 

Thank you. By the way and for what it's worth, I live in Bell County (on the northern tip).

[bearman]

What are the general timeframes for issuing warnings?

[Mrwolf1972]

What are the general timeframes for issuing warnings?

Probably will be in the AM

Sent from my SM-S916U1 using Tapatalk

[ShawnEastTN]

3 minutes ago, bearman said:

What are the general timeframes for issuing warnings?

Usually issued up to 24 hours in advance, not usually before 24 hours but they have some discretion.

[TellicoWx]

15 minutes ago, bearman said:

What are the general timeframes for issuing warnings?

By the looks of that graphic it will be soon..50% of 4+ should meet their criteria 

[TellicoWx]

Next frame should tell which way NAM is headed..already slight improvement at 700 over 18z

[TellicoWx]

Took a half step toward the rest modeling world..see where it goes.

[PowellVolz]

I’m thinking MRX might wait until tomorrow afternoon for the southern valley hazards.


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[fountainguy97]

For those on the Eastern side worried abt  temps... the 00z hrrr and 18z RGEM are very similar as far as precip alignment and placement. But look at that cold push on the hrrr. Much much better. Even keeps my lonesome self below 32. The rgem seems to just be amping hard and eroding that boundary.  But the hrrr is proof there is a solution that delivers even for extreme ETN.

[Stovepipe]

0z NAM looking significantly better for east TN, whew.

[ShawnEastTN]

5 minutes ago, PowellVolz said:

I’m thinking MRX might wait until tomorrow afternoon for the southern valley hazards.


.

Yeah I suspect they might consider pulling Hamilton County out of the WSW, and maybe change it to Advisory and add Bradley, Polk and SW NC counties.  Though there is a strong case to leave Hamilton County in the WSW since portions of the county meet the criteria for WSW.  I think Overnight shift at MRX will likely pull the trigger.  For western areas of the CWA may begin before dawn on Monday.  My point forecast I have 40% change of snow beginning at 1AM Monday morning.

[fountainguy97]

Just now, Stovepipe said:

0z NAM looking significantly better for east TN, whew.

Much better cold push so far!1

[fountainguy97]

Nam cut the distance in half toward the other models. As a result temp profile will be better for most. Still not all the way but a big jump.

[ShawnEastTN]

1 minute ago, fountainguy97 said:

Nam cut the distance in half toward the other models. As a result temp profile will be better for most. Still not all the way but a big jump.

Right, I bet 6Z will complete the cave toward the majority of modeling and no longer blank most of the eastern forum.

[Stovepipe]

The SREF plumes ticked a little better too for TYS.  Still a mess, but moving in the right direction.

[TellicoWx]

Thank you to whoever posted the retired Met twitter post earlier...it unlocked the key. The driver of this system is a 700 jet streak...NAM was up in middle KY, everyone else Middle TN...NAM took a half step that direction. You wanna be on the right side entrance of that jet (basically south side of it)

[PowellVolz]

Yeah I suspect they might consider pulling Hamilton County out of the WSW, and maybe change it to Advisory and add Bradley, Polk and SW NC counties.  Though there is a strong case to leave Hamilton County in the WSW since portions of the county meet the criteria for WSW.  I think Overnight shift at MRX will likely pull the trigger.  For western areas of the CWA may begin before dawn.  My point forecast I have 40% change of snow beginning at 1AM Monday morning.

I should have been more specific and said the border counties. I feel like everything north of a line from Cleveland Tn to the Tn/AL/Ga intersection is in warning criteria IMO.


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[TellicoWx]

Where that streak enters out of AR...whether KY or MS border tells the rest of the run

[Silas Lang]

Looks like the NAM has trended south with it's precipitation. Looks much closer to other guidance now. Should be a huge sigh of relief to those of us in the East. lol 

[Tucker1027]

Yeah I suspect they might consider pulling Hamilton County out of the WSW, and maybe change it to Advisory and add Bradley, Polk and SW NC counties.  Though there is a strong case to leave Hamilton County in the WSW since portions of the county meet the criteria for WSW.  I think Overnight shift at MRX will likely pull the trigger.  For western areas of the CWA may begin before dawn on Monday.  My point forecast I have 40% change of snow beginning at 1AM Monday morning.

Why would they pull Hamilton County out?


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[Tucker1027]

I should have been more specific and said the border counties. I feel like everything north of a line from Cleveland Tn to the Tn/AL/Ga intersection is in warning criteria IMO.


.

Agreed. Everything west of Cleveland on a NE/SW line is probably warning criteria.


.

[ShawnEastTN]

5 minutes ago, Tucker1027 said:

Why would they pull Hamilton County out?


.

I didn't say they would or should, but I bet they have extensively talked about Hamilton county.  The probability outputs they have released a lot of Hamilton County at least southern 2/3 fall below 50% threshold for 3" or more.  However northern Hamilton County has tended to fall about 50% and up for 3".  Safe thing would be to leave Hamilton in the WSW, but an argument based on guidance can be made for either a WInter Weather Advisory, or Winter Storm Warning.  Bradley, Polk and SW NC there is no real argument Advisory based on what MRX is sharing makes sense.