Winter 2021/2022 January Thread

[Wurbus]

Lots of big DAWGS (GA fan, couldn't resist) on there for someone. Should be an interesting week ahead of us again!

[Kasper]

5 minutes ago, Wurbus said:

Lots of big DAWGS (GA fan, couldn't resist) on there for someone. Should be an interesting week ahead of us again!

Oh yes, the wife is a huge Dawgs fan, you would have thought it was the second coming of Christ when she knew they were gonna be National Champs!

[Hurricaneguy]

Why do I get the feeling if this snow event does happen East Tennessee will be:

A. Too Dry

B. Too warm/mixing issues

C. All of the above 

lol

[Kasper]

30 minutes ago, Holston_River_Rambler said:

12z EPS low clusters:

I’ll take a developing intensifying low off the Florida panhandle for $1000 Alex. 

[Kasper]

The Jinx is happening, TWC has now placed 1-3 inches for Athens Saturday  

[Matthew70]

I will take my chances with a panhandle FL low here for all of TN.  Most likely more amped it becomes the more NW it trends. Take a blend of gfs & euro & it’s a TN special. 

[Silas Lang]

I like where we are at with the pending NW trend. Is there any reason this would stay suppressed? 

[Kasper]

 

NWS getting onboard:
Wednesday Night through Friday

At the start of the extended period, a mid/upper shortwave will be
diving out of the northern CONUS with surface high pressure receding
to the east. The passage of this shortwave will provide increasing
PoPs into the day on Thursday and Thursday night via increased
vertical motion and a more W/NW flow pattern near the 850mb level.
Recent model runs continue to suggest a more saturated column, even
in the lower elevations with 1,000-500mb thickness values falling
below 5,400 meters area-wide. As such, this will justify a continued
expansion of PoPs into the region with orographic considerations
suggesting increasing potential of accumulations in the higher
terrain. As of yet, low-level WAA during the daytime on Thursday
looks to keep the boundary layer largely too warm in the lower
elevations for much of the region to transition to snow before
moisture exits. Nevertheless, potential does exist for evaporative
cooling to help transition at the surface even in the lower
elevations. With continued N/NW flow and sufficient low-level
moisture into Friday, PoPs will be lingered during this timeframe.
Overall, the pattern does not suggest too ideal of a NW flow setup,
but light accumulations in the higher terrain at a minimum are
increasingly likely. Heading into the weekend, focus turns towards a
shortwave and developing system out of the Great Plains via
cyclogenesis.

Saturday through Tuesday

The aforementioned developing system will be the feature of focus
during the weekend with potential for significant impacts in
portions of the eastern CONUS. Much of the uncertainty lies with the
evolution of the upper pattern as well as the the track of the
surface low. Based on the latest GEFS mean, GFS, and ECMWF
deterministic runs, the upper-level pattern and surface low track do
support potential for widespread accumulating significant snowfall
across the region. It is important to note that, as we have seen
with recent snowfall events, a change in the track or evolution of
the system can make or break potential for snowfall in the area
based on downsloping and other factors. However, with the ensemble
and deterministic consensus with these model runs, confidence has
increased sufficiently for HWO wording to mention this potential. It
is also important to note that, depending on how the pattern evolves
850mb moisture and flow may be more favorable for northwest flow
snowfall in the mountains even beyond the day on Sunday. Beyond the
weekend, the pattern looks to be more settled, but below normal
temperatures could allow for any snowfall that does occur to linger.

[John1122]

3 minutes ago, Silas Lang said:

I like where we are at with the pending NW trend. Is there any reason this would stay suppressed? 

This is going to be an odd one to resolve for a while yet. There's a storm ahead of it that bombs into a 50/50 low with a high over the top. Until that first storm resolves I don't think we know where it's going yet. 

[PowellVolz]

12z EPS low clusters:

That’s pretty tight cluster for this far out. I like that a lot.


.

[John1122]

The NAM is trying to give parts of TN, SE KY and SW Va an inch or two from the dry clipper that turns into the 50/50.

[TellicoWx]

For those south of 40, really need to watch the 850 on the GFS...need it to dig a little more. 12z was tip toeing the line (running it right on the southern border).

[Holston_River_Rambler]

18z GFS is up and running 

[Carvers Gap]

Slightly less digging at 66 and a split hair faster.  Would imply maybe a less amped solution downstream, but not by much.

[Holston_River_Rambler]

So far it looks pretty similar.  A bunch of energy digging towards the western Gulf at hour 75, but the 18z ICON spooked me a bit so I don't want to say how it looks for sure, one way or another, lol. 

[Holston_River_Rambler]

Energy starting to try and wrap up over western Nebraska at hour 81 

[Holston_River_Rambler]

That is a lot of energy aimed at the Gulf. Can it dive, wrap, and make the turn?

[Carvers Gap]

Slowed down a hair at 78 I think.  Might allow for more spacing with the first system.  Might allow it to track a bit further north without the 50/50 to hold it in place.  As Holston notes, looks super similar.

[Carvers Gap]

Track should be about 20-30 miles further north by 84.  That will likely allow a bit more of the warm nose downstream.  Still could change even on this run.

[Holston_River_Rambler]

Two contour closed upper low over OK at hour 99 and still diving. 

[Carvers Gap]

This run is a bit warmer through 90.   Tells me it is digging and is further north.

[Carvers Gap]

Lots of rain on the front end this run.  We really need the north trend to hold up, but I think it is going to continue with this for a few runs.  Likely going to cause a hand-off issue(future runs) if the trend continues.

[Carvers Gap]

Hybrid Miller B incoming.  Low cut into TN and will hand off to the GOM at 111.

[Carvers Gap]

That is a non-starter for our area.  Handoff leaves thermals washed out.  On to the next run.

[Holston_River_Rambler]

Really would sting to get energy diving in from that angle, but still get a nasty Miller B Hybrid. Far NW and far NE section could do ok with that look though. 

[Save the itchy algae!]

Would we need the handoff to happen sooner? Or would that just cause an apps runner?

[Weathertree2]

9 minutes ago, Carvers Gap said:

That is a non-starter for our area.  Handoff leaves thermals washed out.  On to the next run.

Got missed on that run also  

[John1122]

We know there's gonna be a storm. Just no idea where yet. It's been a Miller B from the start just with a weird handoff to the south in a Miller A area instead of to the east like a traditional Miller B. In Miller A set ups we get a lot of our overrunning snow when a storm exits off Texas into the Gulf and sends precip NE. This one has been showing a thump on the northern path and it weakens near or over us on various runs before rolling again over the eastern areas. 

Still a huge hit north of 40. I expect it to waffle back and forth until late in the game and the storm moving over Thursday gets up the coast. 

[Holston_River_Rambler]

2 minutes ago, Save the itchy algae! said:

Would we need the handoff to happen sooner? Or would that just cause an apps runner?

I think in the case of our area (specifically central parts of the eastern great valley), we want a low to pop around New Orleans or Mobile and make a run at Cape Hatteras. TBH we don't want any sort of a hand off, since even if it was cold, that would hurt any TROWL/ deform band as the hand off occurs. 

[John1122]

The 50/50 low moved up the coast a bit faster this run and was a bit more north. The storm came north as a result.