Jan 15-16 Winter Storm

[Jonathan]

How much credence do we lend to the FV3? Because that's about the snowiest, less sleety/icy modelk for southern VA into norther NC.

Isn't it a NAM upgrade?

[buckeyefan1]

Just now, olafminesaw said:

True, although I suspect heavier bands of precip will fall as sleet. FRAM for comparison

That's the million dollar question    I've been thinking more ip than zr for mby, but today, I'm not so sure. It reminds me of '14 (being on the zr line), but I'm just not confident enough to discount those totals in half just yet. 

[olafminesaw]

2 minutes ago, Jonathan said:

How much credence do we lend to the FV3? Because that's about the snowiest, less sleety/icy modelk for southern VA into norther NC.

Isn't it a NAM upgrade?

Supposed to be like the hires NAM but run off the GFS. I've found it to be straight trash

[FlatLander48]

Still loading the 12z CMC on my PC. but the LP is further SE than the previous run. (Again, not huge differences at this point but any little change helps/hurts)

[wncsnow]

Canadian is a good hit 

[WeatherExperiment]

22 minutes ago, snowmaker13 said:

That's the model I would rely on at this point. It actually increased totals with the weak low and stronger high. NAM is a meso model and amps things up like crazy all the time. Think it's time for it to go the way of the DGEX at this point. Maybe some machine learning model to replace it. 

 

18 minutes ago, PantherJustin said:

Look at the gradient there around CLT… tell me that’s not classic, Uptown 2-3” but step 30 miles N into Iredell you’ve got 6-8” 

I know we have other maps to consider -- sleet and ice. But, yeah, I'm amazed at that gradient. Just a slight jog of 30 miles by the storm, northwest or southeast, could be the difference between more icing and more snow. The next 48-72 hours will be wicked exciting to watch!

[wake4est]

3 minutes ago, wncsnow said:

Canadian is a good hit 

It moved the heavier ZR east of Charlotte

[CaryWx]

8 minutes ago, NorthHillsWx said:

The low cutting east across South Carolina then due north to DC is a CRAZY storm track and a huge middle finger to many of us especially the triangle 

I kind of glad here for this storm really.  I would not want a drift east that just brings all that heavy accretion of ice to the Triangle.

[WinstonSalemArlington]

9 minutes ago, NorthHillsWx said:

The low cutting east across South Carolina then due north to DC is a CRAZY storm track and a huge middle finger to many of us especially the triangle 

And to Metro DC/Baltimore. Richmond too 

[Lookout]

1 minute ago, buckeyefan1 said:

I'm not sure about how much I'd cut the totals with temps in the 20's for the duration.

This is going to be fascinating to see how we well or bad the gfs does on temps. Its dramatically warmer than Everything else here..by as much as 10 degrees Sunday. Its like being back in the old days of the avn. I would take it as seriously as the avn  if there was more dry air in place which is The only thing that gives me pause for north ga. Instead us in Georgia have to rely on caa after precip starts.  Obviously the Carolinas are a different story but even there it looks about 5 degrees too warm in sc. 

6 minutes ago, Wow said:

The worst is seeing the short range models like the HRRR show an awesome setup then trend to the global models.  The 12z HRRR looks amazing at 48 hrs but it will without a doubt trend toward the rest of the models.

I dont often look at the long range hrrr/rap but it sure makes me wish it was  more reliable at this range.  

[NorthHillsWx]

8 minutes ago, olafminesaw said:

Supposed to be like the hires NAM but run off the GFS. I've found it to be straight trash

Straight trash for sure

[NorthHillsWx]

3 minutes ago, CaryWx said:

I kind of glad here for this storm really.  I would not want a drift east that just brings all that heavy accretion of ice to the Triangle.

I disagree, without that northern push that warm nose would not make it as far north or be as strong for our area and we’d see more snow and then sleet but yea, glad we won’t ice for too long at home 

[buckeyefan1]

2 minutes ago, Lookout said:

This is going to be fascinating to see how we well or bad the gfs does on temps. Its dramatically warmer than Everything else here..by as much as 10 degrees Sunday. Its like being back in the old days of the avn. I would take it as seriously as the avn  if there was more dry air in place which is The only thing that gives me pause for north ga. Instead us in Georgia have to rely on caa after precip starts.  Obviously the Carolinas are a different story but even there it looks about 5 degrees too warm in sc. 

I dont often look at the long range hrrr/rap but it sure makes me wish it was  more reliable at this range.  

Exactly why I just don't know    We'll find out soon which one did best    

Canada's clowns

 

[olafminesaw]

Our trough that will become the primary low is now over the Northern plains

[Jonathan]

1 minute ago, NorthHillsWx said:

Straight trash for sure

That's a shame. A local met around here said he used the FV3 for the December 2018 storm and it was almost spot-on with snow totals. He called it his "secret weapon" lol.

[NorthHillsWx]

From what I’ve seen I’d say 12z overall trended slightly colder for most areas. CAD is also under modeled most of the time by the globals and I think the NAM is too juiced with precip. I’d undercut temps by a couple degrees based on what you’re seeing in the GFS for many areas especially in the afternoon 

[NorthHillsWx]

4 minutes ago, Jonathan said:

That's a shame. A local met around here said he used the FV3 for the December 2018 storm and it was almost spot-on with snow totals. He called it his "secret weapon" lol.

That was the only coup that model has ever pulled. I remember this board all got excited about it after that, but it has been straight trash since. I am not sure what combination of atmospheric conditions allowed it to nail thar storm, but good lord it locked it in for days before most everything else caught on

[btownheel]

5 minutes ago, NorthHillsWx said:

From what I’ve seen I’d say 12z overall trended slightly colder for most areas. CAD is also under modeled most of the time by the globals and I think the NAM is too juiced with precip. I’d undercut temps by a couple degrees based on what you’re seeing in the GFS for many areas especially in the afternoon 

Another interesting micro feature to me will be what that little finger on Saturday across Northern NC does.  A decent dusting could help hold temps down a hair, which would make a world of difference. 

[Jonathan]

2 minutes ago, NorthHillsWx said:

That was the only coup that model has ever pulled. I remember this board all got excited about it after that, but it has been straight trash since. I am not sure what combination of atmospheric conditions allowed it to nail thar storm, but good lord it locked it in for days before most everything else caught on

Guess the old adage about the blind squirrel.

I am happy to see over the past 24 hours the trend for more sleet and less zr for the foothills. I never got my hands on a generator before last winter's ice storm and I doubt I could get one this weekend either.

[olafminesaw]

It's a bit confusing, but as I understand it, FV3 refers to a trial version of the model. So every time they're working on an upgrade, they'll release both the old and new versions at the same time and eventually make FV3 operational. 

 

What I assume is being discussed is the WRF FV3 that shows on pivotal weather. I believe this is a trial version (hence FV3) of a high resolution GFS model

[SnowGoose69]

12 minutes ago, Lookout said:

This is going to be fascinating to see how we well or bad the gfs does on temps. Its dramatically warmer than Everything else here..by as much as 10 degrees Sunday. Its like being back in the old days of the avn. I would take it as seriously as the avn  if there was more dry air in place which is The only thing that gives me pause for north ga. Instead us in Georgia have to rely on caa after precip starts.  Obviously the Carolinas are a different story but even there it looks about 5 degrees too warm in sc. 

I dont often look at the long range hrrr/rap but it sure makes me wish it was  more reliable at this range.  

The GFS never does well with thermals in a wedge setup or a setup with a 500 low significantly lowering temps and in this instance we have both taking place in a span of 36 hours where you are.  It'll only handle these setups well in a case where the cold is extreme and even then its too warm.  The 2/2013 ice event in the SE the GFS did okay because the wedge was so extreme it could not miss it

[snowmaker13]

1 minute ago, btownheel said:

Another interesting micro feature to me will be what that little finger on Saturday across Northern NC does.  A decent dusting could help hold temps down a hair, which would make a world of difference. 

The surface isn't the real issue, it's the mid levels. The NAM even torches Asheville. Asheville might get rain included with the winter weather if the NAM verfies. 

 

 

[Iceagewhereartthou]

3 hours ago, burrel2 said:

she's a beaut clark!

Indeed. Do you trust the long range HRRR Burrel?

[burrel2]

2 minutes ago, Iceagewhereartthou said:

Indeed. Do you trust the long range HRRR Burrel?

No but I’m glad it’s on the cold and snowier side of guidance which aligns more with the euro, ukmet, rgem opposed to the gfs/nam which give the upstate very little snow 

[NorthHillsWx]

4 minutes ago, Iceagewhereartthou said:

Indeed. Do you trust the long range HRRR Burrel?

We buy 

[ILMRoss]

Some thoughts... 

- I try to keep a sunny disposition on here because at the end of the day this is a lighthearted forum and not some emergency management network. That colors my thinking and I'd say I have a bias posting about "good things that could happen" and not "failure points". I say this because I've banged the drum about SLP adjustments being too inland for the CAD, models mishandling the transfer that could lead to a more south track, etc and this serves as my "I hope I have not lead anyone astray with false optimism" mea culpa as a rainier picture takes hold. To build on this: 

- I think the models have a great grasp of what's going to happen. There will be ticks and adjustments and some low stakes twists and surprises but the playbook is out. 

- Over the last few days, I thought the CAD strength would redirect our SLP further off the coast. That's happened to a certain degree... (no more runs have this thing visiting South of the Border) but I'm unsure what tangible effects this has on the forecast and I thought that sub-freezing temperatures would hang on a little longer as this modification played out. 

- "The CAD will hang on" is a sound motif in 90% of of situations. I'm beginning to think this is the 10% of cases where that may not hold true. Typically in these scenarios the thing scouring the CAD is screaming 850mb winds. The rate at which the CAD gets eroded is determined by "how well can this model handle the turbulence and eddies between the stable CAD and the screaming 850mb jet". There's micrometeorology and microphysics wizardry going on there and typically the answer to that question is "not very well". However, in this storm we also have crazy lift ahead of a bowling ball upper level low as well as a convection (maybe severe-ish) nudging in from the coast. Our upper air features are typically a lot weaker. This will be a learning experience for everyone, me included, and while I think there's still ample potential for the CAD to hang on, I can easily see why that motif wouldn't hold true with this system and it dissolves much quicker than we're used to.

(For clarification: I am not rooting for a strong CAD. My ideal Sunday is seeing a quick hour burst of snow before settling in at a sports bar and eating 1000 wings and watching the Eagles cover and the 49ers win outright and I can't do that without power)

As far as tangible forecasting goes: 

- Shoutout to the mountains. You should get buried unless there's some Miller B voodoo BS going on and the thermals/moisture transport get screwed up (which can happen). Also shoutout to Nashville who is having a fantastic winter. 

- Sleet/ZR amounts will continue to wobble. Let me bring you through the life of a snowflake through CAD. You fall, melt (cooling the atmosphere) then either refreeze into sleet (releasing latent heat 1000 feet up) or fall as freezing rain (releasing latent heat at the surface. No model is going to be able to nail this down correctly. I also wonder about how latent heating is modeled... Are models assuming everything falling will freeze? In the southern fringes of the ice zone, there are some pretty insane rates being modeled for a winter storm and a lot of that precip will be going down the drain. Are the models assuming that's going to freeze and the latent heat equation is treating it as such? I don't know. 

- I'm not making a snowmap, the market is saturated and I'm no clout chaser. 

 

[NorthHillsWx]

My Snow Call:

Anderson, SC to Raleigh: up to 1” of snow/sleet. 1/4” ice or less. Change to plain rain

Clemson-Greenville-Charlotte-Greensboro: 1-4” of snow/sleet. 1/4-1/2” ice (maybe a small finger of higher totals). Eastern areas may change to rain but may also switch to light backside snow 
 

Clayton, Ga-statesvill/hickory-Winston Salem: this is the biggest battleground with snow and sleet. Also biggest range of possible accumulation. I’m going 4-8” with the potential for less due to sleet compaction. Sensibly I think the lower end of that range is more likely but if that front end is truly a thump I think 8” is possible

Foothills including Asheville: 6-10” with some sleet mixing

Mountains: 10-16” highest on peaks. There could be some mixing issues even here but I think cold air and heavy rates with high ratios at the beginning and end will allow this to be a major snow storm regardless 

My forecast confidence: High- we’ve seen these storms a billion times

Where it could go wrong: foothills to I-85 is my biggest question mark. I really think with the screaming 850 jet out of the east the mixing will occur faster than modeled, so it’s a matter of how much snow comes before the mix. In the Raleigh to Anderson areas, how long does the sub freezing air hang on, and can we approach warning level ice? In the ice storm areas, where does the narrow ribbon of extreme ice (over 1/2”) setup exactly?

Not a “fun storm” but been fun tracking. Good luck to those in the snow areas and hopefully power stays on for everyone 

 

[RamblinRed]

FWIW, here is WSB (Atlanta) latest estimated snow map for Metro Atlanta and N GA.

I'd actually would be pretty happy with this as I live in the HollySprings/Canton area of Cherokee County and that would put me in the 2-3 inch of snow range. Would be enough that we could take out the new sleds we bought in 2018 and haven't been able to use yet.

Seems like metro Atlanta is largely likely to get out without too many issues, though the area from Lake Lanier and to the NE should hopefully get a nice storm.

[msuwx]

25 minutes ago, ILMRoss said:

Some thoughts... 

- I try to keep a sunny disposition on here because at the end of the day this is a lighthearted forum and not some emergency management network. That colors my thinking and I'd say I have a bias posting about "good things that could happen" and not "failure points". I say this because I've banged the drum about SLP adjustments being too inland for the CAD, models mishandling the transfer that could lead to a more south track, etc and this serves as my "I hope I have not lead anyone astray with false optimism" mea culpa as a rainier picture takes hold. To build on this: 

- I think the models have a great grasp of what's going to happen. There will be ticks and adjustments and some low stakes twists and surprises but the playbook is out. 

- Over the last few days, I thought the CAD strength would redirect our SLP further off the coast. That's happened to a certain degree... (no more runs have this thing visiting South of the Border) but I'm unsure what tangible effects this has on the forecast and I thought that sub-freezing temperatures would hang on a little longer as this modification played out. 

- "The CAD will hang on" is a sound motif in 90% of of situations. I'm beginning to think this is the 10% of cases where that may not hold true. Typically in these scenarios the thing scouring the CAD is screaming 850mb winds. The rate at which the CAD gets eroded is determined by "how well can this model handle the turbulence and eddies between the stable CAD and the screaming 850mb jet". There's micrometeorology and microphysics wizardry going on there and typically the answer to that question is "not very well". However, in this storm we also have crazy lift ahead of a bowling ball upper level low as well as a convection (maybe severe-ish) nudging in from the coast. Our upper air features are typically a lot weaker. This will be a learning experience for everyone, me included, and while I think there's still ample potential for the CAD to hang on, I can easily see why that motif wouldn't hold true with this system and it dissolves much quicker than we're used to.

(For clarification: I am not rooting for a strong CAD. My ideal Sunday is seeing a quick hour burst of snow before settling in at a sports bar and eating 1000 wings and watching the Eagles cover and the 49ers win outright and I can't do that without power)

As far as tangible forecasting goes: 

- Shoutout to the mountains. You should get buried unless there's some Miller B voodoo BS going on and the thermals/moisture transport get screwed up (which can happen). Also shoutout to Nashville who is having a fantastic winter. 

- Sleet/ZR amounts will continue to wobble. Let me bring you through the life of a snowflake through CAD. You fall, melt (cooling the atmosphere) then either refreeze into sleet (releasing latent heat 1000 feet up) or fall as freezing rain (releasing latent heat at the surface. No model is going to be able to nail this down correctly. I also wonder about how latent heating is modeled... Are models assuming everything falling will freeze? In the southern fringes of the ice zone, there are some pretty insane rates being modeled for a winter storm and a lot of that precip will be going down the drain. Are the models assuming that's going to freeze and the latent heat equation is treating it as such? I don't know. 

- I'm not making a snowmap, the market is saturated and I'm no clout chaser. 

 

That is a big reason why you never achieve the maximum freezing rain depictions on modeling in reality. Much is lost to runoff and other factors. Freezing rain just simply cannot physically accrue at 100% of the QPF rate unless it is extremely light in general and temperatures are very cold. 

[BornAgain13]

@Disc @Buddy1987 , I believe yall will get 10"+.... how much do you both think I will get in Dry Fork?