February 17-18th Winter Storm Thread.

[bearman]

MRX is acting like there will be no front end thump of snow for the valley in the morning disco.  They tend to always look the other way when the models say anything about snow chances.  Stick fingers in ears.   Put hands over eyes.    Repeat the mantra, "it never snows in the valley".   The unfortunate reality is, it works most of the time.

[McMinnWx]

Looks like it’s going to be too warm here. Currently showing a low of 33 tomorrow night. 

[Mrwolf1972]

12z hrr good amounts in valley

[Hurricaneguy]

The NE Valley has gotten zero snow love since Christmas Eve. It’s crazy these patterns keep snow away from us each time. 

[dwagner88]

2 minutes ago, Hurricaneguy said:

The NE Valley has gotten zero snow love since Christmas Eve. It’s crazy these patterns keep snow away from us each time. 

It could be worse. Trust me.

[Holston_River_Rambler]

NAM coming in south again (last 4 runs):

[Silas Lang]

21 minutes ago, Mrwolf1972 said:

12z hrr good amounts in valley

My goodness, if that verifies and it then rains a bunch it is gonna be a mess. 

[Holston_River_Rambler]

It does blast the warmth in after that though. 

Yet the sounding over IMBY looks kinda snowy, even though it says sleet. Full saturation in the DGZ, very shallow warm nose that all that forcing and rates might mitigate. At least a sleet/snow mix I would say on this NAM run, anyway:

 

circled area is the sounding:

[Mrwolf1972]

 rdps 12z

[Holston_River_Rambler]

12z para GFS:

 

12z National Blend of Models to offset the above:

[Holston_River_Rambler]

I wish Jack Sillin was doing what he did for that storm a few days ago, where he used RAOB data to analyze model output. That was helpful. Would be nice to see how what's left of the TPV is acting like a pseudo 50/50 low and causing confluence over NE, vs how models are seeing it. NAM seems to be playing catch up with that feature, but being the warmest model, it could still be right with eventual evolution, even if how it sees us getting there is wrong, lol. 

[TellicoWx]

15z RAP with another paste job

[McMinnWx]

8 minutes ago, TellicoWx said:

15z RAP with another paste job

LOCK IT IN!

[dwagner88]

4 minutes ago, McMinnWx said:

LOCK IT IN!

Yeah! What could possibly go wrong with a 12" accumulation gradient cutting the Chattanooga area in half? I bet it's not handling sleet correctly.

[John1122]

The RAP and HRRR have been very good this year within 30 hours. Hopefully they keep this cooking. 

[Holston_River_Rambler]

Here's how the RAP sees the precip types:

 

Here's what it sees as the sounding around Chatt at 2 AM Thursday:

 

It says rain, but shows mix and it is sooooo close with that forcing to being all snow. 

 

[Holston_River_Rambler]

Look how close the above sounding is to an all snow sounding, from over my head:

[Holston_River_Rambler]

12z Ukie:

[John1122]

3 minutes ago, Holston_River_Rambler said:

Here's how the RAP sees the precip types:

 

Here's what it sees as the sounding around Chatt at 2 AM Thursday:

 

It says rain, but shows mix and it is sooooo close with that forcing to being all snow. 

 

I honestly find the soundings way more wrong than the map output from the models. Mainly it works against us. It often shows frozen on the sounding but rain on the model output and its rarely frozen and not rain. 

[Holston_River_Rambler]

1 minute ago, John1122 said:

I honestly find the soundings way more wrong than the map output from the models. Mainly it works against us. It often shows frozen on the sounding but rain on the model output and its rarely frozen and not rain. 

Yeah this is the first time I've had access to soundings from some of these models and the differences between what the precip type says, what the precip type shows on the model output, and what the sounding looks like seem a little wonky. 

[John1122]

1 minute ago, Holston_River_Rambler said:

Yeah this is the first time I've had access to soundings from some of these models and the differences between what the precip type says, what the precip type shows on the model output, and what the sounding looks like seem a little wonky. 

Yesterday the NAM sounding had my dewpoint higher than my temperature. So wonky to say the least. 

[John1122]

12z Icon is 3-5+ inches forum wide almost. Sleet around the edges and zr too that doesn't show up. 

[Holston_River_Rambler]

12z Euro maintains its thumpage:

[Runman292]

51 minutes ago, TellicoWx said:

15z RAP with another paste job

 

[Mrwolf1972]

12z euro has a front end dump then rain.

[Holston_River_Rambler]

 

evolution of the Euro

[Holston_River_Rambler]

Still interested to see what happens with the trailing bits of energy as the system(s) evolve over the next couple of days:

[Carvers Gap]

With the NAM now coming in line, looks like most modeling is now showing a total mess for the NE Valley and potential well SE of that - even southeast of TYS.  Yesterday, I kind of cast a wary eye towards such a quick flip...but it is freakin' cold out there right now.  Wind chills here are in the mid to upper teens.  I know we are supposed to hit the 40s tomorrow...but this is fresh, cold air...not the stagnant stuff that usually sets up most ice storms.  Cold air can definitely get moved around quickly - not saying that.   I have seen very cold air masses evacuated within an hour.  However, as flat as this storm is trending, it may weaken the warm nose or even blunt it.  It would not surprise me to see northern sections of the valley(SW VA) stay frozen most of the way with this.  The flatter it gets, the more it behaves as a slider along the KY/TN/VA borders.  Models since yesterday morning have signaled frozen precip, and increasingly so. Still not a ton of consistency with amounts, and I don't expect that to change.  Right now, looks like sloppiest city!

[Sweetpea Farms]

OK, I just looked at two pages of models (thank you all very much) and they say the same for Lincoln County as the present storm: Maybe, maybe not. Present forecast here is for snow showers with zero accumulation. That'd be fine! 

[Greyhound]

I'll be honest, if it's going to be washed all away by the rain shortly thereafter........I would rather it just be all rain instead.