Winter 2021/2022 February Thread

[Silas Lang]

Honestly, not too bad for snow next weekend. Not too many total blanks, a lot of lighter events, a few moderate, and one big dog. I don't know about a big dog, but I think odds of seeing some snow on Sunday are pretty good, especially north of 40. Just the fact that for some reason climo likes this time of year (Valentine's day) makes me feel a bit more bullish on the odds. 

[Holston_River_Rambler]

1 hour ago, Carvers Gap said:

The 18z GFS has all kinds of stuff going on including a clean pass of an inland/Apps runner for what was originally a cutter!  LOL.  See hour 228.  This could get kind of crazy.  

Maybe we end up with ye olden suppressed solution from last week (below is la la land GFS run from 12z Feb 1):

I've started saving the nice runs at day 15, after what happened earlier in the month. 

 

Compare the above to what you mentioned, now under 10 days out:

 

And to be fair, this is what this weekend's (now seeming suppressed) storm looked like at in GFS la la land:

:

 

 

 

 

[Silas Lang]

The 18z Euro ensembles are bit more all or nothing. 8 or 9 moderate hits with a lot of blanks and several flizzard and dusting level events. No real big dogs. 

[Carvers Gap]

1 hour ago, Holston_River_Rambler said:

Maybe we end up with ye olden suppressed solution from last week (below is la la land GFS run from 12z Feb 1):

I've started saving the nice runs at day 15, after what happened earlier in the month. 

 

Compare the above to what you mentioned, now under 10 days out:

 

And to be fair, this is what this weekend's (now seeming suppressed) storm looked like at in GFS la la land:

:

 

 

 

 

The ensemble has the overrunning solution.

[John1122]

The GFS keeps trying. 

 

[Holston_River_Rambler]

6z RGEM looked interesting.:

 

 

No clue where that would have gone, but it is quite a bit different from the NAM:

 

 

 

6z GFS that John posted looked more like the RGEM, which seems odd to me since I think the NAMs are closer akin to the GFS wrt their physics. 

 

 

[Carvers Gap]

I know I sound like a broken record but, it is not uncommon for systems to gain strength(on modeling) during February.  Also, I still don't believe modeling has a good handle on this system Sunday, even at this range.  I don't think it will be anything huge, but it is very possible snow will be in the air along(just north and south) of the northern border of TN.  And broken record alert again...low probability(increasing) along with a high upside.

[Silas Lang]

27 minutes ago, Carvers Gap said:

I know I sound like a broken record but, it is not uncommon for systems to gain strength(on modeling) during February.  Also, I still don't believe modeling has a good handle on this system Sunday, even at this range.  I don't think it will be anything huge, but it is very possible snow will be in the air along(just north and south) of the northern border of TN.  And broken record alert again...low probability(increasing) along with a high upside.

Yeah it looks like that snow is mostly coming from the northern energy and the front. The low pressure is still actually pretty far east.

The good news is temps look pretty good and it occurs at night for middle and eastern areas. Even if it stays a lighter event, there shouldn't be a whole lot of wasted precipitation which is always a win. 

[Carvers Gap]

Anyone have the 0z UKMET sequence?  Cosgrove said the system was pretty significant on it, ie big storm.  In the car line, so can’t look...If so, that makes two models that have it this AM.

[Carvers Gap]

It may be that we see a double barrel low with one in the coast and one on the lee of the Apps...reference LC.

[Silas Lang]

13 minutes ago, Carvers Gap said:

It may be that we see a double barrel low with one in the coast and one on the lee of the Apps...reference LC.

Would we see that looking at the surface? At hour 99 on the GFS you can see some lower pressure climbing up into nw south Carolina for a few hours before the low pops out in the Atlantic. That feature was not present on the 0z. 

[Wurbus]

1 hour ago, Carvers Gap said:

Anyone have the 0z UKMET sequence?  Cosgrove said the system was pretty significant on it, ie big storm.  In the car line, so can’t look...If so, that makes two models that have it this AM.

[Carvers Gap]

54 minutes ago, Silas Lang said:

Would we see that looking at the surface? At hour 99 on the GFS you can see some lower pressure climbing up into nw south Carolina for a few hours before the low pops out in the Atlantic. That feature was not present on the 0z. 

That is it I think. I think the UKMET has that setup.  Basically the front pops a lee side low while there is an slp along the Atlantic Coast.

[Carvers Gap]

Take a look at the 500vort maps for the UKMET.  It goes negative tilt.  We either need the northern stream to have some separation with the front runner in the STJ or we need the front runner to slow and get caught.  UKMET is scenario two.  GFS is scenarios one.

[nrgjeff]

Some snow north of I-40 mainly east of Nashville would not surprise me this weekend. Above progged moisture for TRI would get the job done.

Upper Plateau has a good chance of sticking snow IMHO. Mountains will see some good accumulation at higher elevations.

 

[Silas Lang]

12z GFS looks pretty similar to 6z. 

[Carvers Gap]

The 12z GFS is a great run.  9" for JC and half a foot for Sullivan.  The 12z RGEM(at range and noted) looks like it was ready to rock with a vigorous system.  Of note, double barrel systems are tricky as @#$ to forecast.  

[Silas Lang]

Just now, Carvers Gap said:

The 12z GFS is a great run.  9" for JC and half a foot for Sullivan.  The 12z RGEM(at range and noted) looks like it was ready to rock with a vigorous system.  Of note, double barrel systems are trick as @#$ to forecast.  

Yeah the RGEM was looking to form a low in the gulf as well. Curious to see what the Euro does. 

[Carvers Gap]

Just now, Silas Lang said:

Yeah the RGEM was looking to form a low in the gulf as well. Curious to see what the Euro does. 

The GFS was flirting (and has been) with an inland runner.  It could still settle on the coastal which is likely just a weak clipper, but if it goes to the inland runner solution...that would be optimal.  The RGEM is likely amped at this range, but that look would be a forum-wide snow if extrapolated...and totals bias corrected to zero for Kingsport and Chattanooga of course.

[Silas Lang]

12z top and 6z bottom

[Carvers Gap]

6 minutes ago, Silas Lang said:

12z top and 6z bottom

Pretty consistent look w/ a slightly eastward jog.

[Silas Lang]

8 minutes ago, Carvers Gap said:

The GFS was flirting (and has been) with an inland runner.  It could still settle on the coastal which is likely just a weak clipper, but if it goes to the inland runner solution...that would be optimal.  The RGEM is likely amped at this range, but that look would be a forum-wide snow if extrapolated...and totals bias corrected to zero for Kingsport and Chattanooga of course.

Just curious, could that other LP you mentioned earlier on the other side of the mountains be a faint signal for an inland runner?  

Don't want to get greedy, but if we are getting close to a big dog event...I would like it. We do have the fact that John is going to be in Chattanooga to increase our luck

[Carvers Gap]

1 hour ago, Silas Lang said:

Just curious, could that other LP you mentioned earlier on the other side of the mountains be a faint signal for an inland runner?  

Don't want to get greedy, but if we are getting close to a big dog event...I would like it. We do have the fact that John is going to be in Chattanooga to increase our luck

Super complex setup which makes me wary.  Basically, the GFS pops a lee side low(western NC) as the front passes.  That happens often(just faint).  The front running energy along the coast interacts, and the lee side energy transfers to the coast.  This is like a Miller B, but east of the mountains.  Those setups do occasionally happen - ceiling is high and bust potential is massive.

[Carvers Gap]

If you live in E TN, you want the flow to back as the front passes.  You combine that backing with orographic lift due to the Plateau and you get a deformation band o sorts in E TN.  Again, I am still wary of this set-up as modeling juggling an enormous amount of plates for this set-up.  This is a timing set-up which is a royal pain to follow.  We need the northern system to catch the southern stream energy which is kind of stalled.  We have to hit the jackpot in terms of confluence.  If the southern stream is too fast, we get a weak frontal passage with light snow.  To slow, and it could legit cut(though highly unlikely)

[Carvers Gap]

The 12z CMC now has a similar set-up with an RGEM-esque look. It has less over E TN, as the inland feature fires a bit late.  That said, pretty much the same synoptic set-up as at the GFS which makes both solutions a bit more believable.  We do have to take into account the GFS amping things a bit too much.

[Carvers Gap]

The 12z ICON has the same set-up but weaker. So, that is the ICON, CMC, and GFS at 12z which have a similar setup and the RGEM looks like it would have gotten there as well.  Time to watch trends at this point.

[Silas Lang]

Good to at least see some snow on the CMC. 

15 minutes ago, Carvers Gap said:

Super complex setup which makes me wary.  Basically, the GFS pops a lee side low(western NC) as the front passes.  That happens often(just fain).  The front running energy along the coast interacts, and the lee side energy transfers to the coast.  This is like a Miller B, but east of the mountains.  Those setups do occasionally happen - ceiling is high and bust potential is massive.

Thanks for the clarification. It almost looks like the CMC wants to make that low the main low and doesn't transfer until well north. I can see how this set up throws off the models. They don't know where to place the low which creates a high bust scenario. Plus you factor in all this energy flying around...yikes. 

I will say, I am feeling more confident we will see snow Sunday. How much remains to be seen. 

[Carvers Gap]

Just now, Silas Lang said:

Good to at least see some snow on the CMC. 

Thanks for the clarification. It almost looks like the CMC wants to make that low the main low and doesn't transfer until well north. I can see how this set up throws off the models. They don't know where to place the low which creates a high bust scenario. Plus you factor in all this energy flying around...yikes. 

I will say, I am feeling more confident we will see snow Sunday. How much remains to be seen. 

Looks like the lee side is a realistic solution.  We need it to fire to our SE vs directly to our east.  

[Carvers Gap]

8 minutes ago, Silas Lang said:

Good to at least see some snow on the CMC. 

Thanks for the clarification. It almost looks like the CMC wants to make that low the main low and doesn't transfer until well north. I can see how this set up throws off the models. They don't know where to place the low which creates a high bust scenario. Plus you factor in all this energy flying around...yikes. 

I will say, I am feeling more confident we will see snow Sunday. How much remains to be seen. 

This is a super similar set-up to how middle and west TN have scored...just displace the primary east of the Apps(instead of the eastern valley and secondary to the coast(instead of western NC).  The really headache is accounting for two mountain ranges(the Plateau and Apps) being under the western precip shield instead of just the Plateau.  The 12z set-up could be a combo of orographic lift and downsloping, one replacing the other depending on location.  Fun times.  LOL.

[Silas Lang]

4 minutes ago, Carvers Gap said:

This is a super similar set-up to how middle and west TN have scored...just displace the primary east of the Apps(instead of the eastern valley and secondary to the coast(instead of western NC).  The really headache is accounting for two mountain ranges(the Plateau and Apps) being under the western precip shield instead of just the Plateau.  The 12z set-up could be a combo of orographic lift and downsloping, one replacing the other depending on location.  Fun times.  LOL.

Ah okay, that makes it easier to visualize as I feel like we have seen that set-up dozens of times the past few years here in the east. lol 

Do you know of any historical events that gave us snow here in the east similar to this storm?