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Jan 15-16 Winter Storm


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2 hours 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. 

 

@ilmross - this may be the single best post in all my years reading these forums - well done and a must read.  The phrase "micrometeorology and microphysics wizardry going on there" is wonderfully conceived and written. 

Your latent heat discussion also spot on wherever something is given, something is taken or as is more commonly taught Newton's Third Law" for every action there is an equal and opposite reaction and so it goes when a thumb is pressed against an ice cube = a bad habit....ask me how i know LOL.

@msuwx - hello Matty East - tell Jeff Uncle ANONmet said hello - good times back in his Weather_or_Not chat days!

@everyone - great discussion everybody I'm sure I speak for a lot of lurkers.  Whatever happens, be thankful we had something to chase and if the long range is to be believed, more fun and games around the 27th. 

Some day modeling will constrain all the variables (long after I'm gone) instead of information overload from flawed sources which is unsettling because you never know who, or what, to trust.

In my 63 years living through NC winters harkening back to the 60's/70's in CLT dialing the NWS office to get the hourly time/temp (LOL - still remember the number 704-399-5631), watching WBTV's "Cloudy" Clyde McClean draw with his drippy ink pen all the L's and H's, getting an ideal setup for a pure snow event is like threading a needle, blindfolded, and in a dark room!

For this storm, have not read the usual "ground temps too warm" or "gulf t'storms robbing moisture" posts, the latter of which can be very real and especially since the SPC has hoisted a MRGL risk level for convection from Mobile Bay all the way to south of Tampa Bay. 

I wish for everyone a safe event, no loss of power, and if not this storm, a future winter storm of pure snow from the surface low followed by the encore high altitude beautiful falling flakes from the passing ULL.  

And watch the radar as the coastal/inland primary low moves north for possible backbuilding...not sure there is enough blocking in place but when that happens, it is a thing of joy to watch.

ANONmet_GSO (formerly ANONmet_MGN)

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3 minutes ago, StantonParkHoya said:

I think it's because of the volume of posters does skew toward Raleigh, as it should since more people live in Wake County than just about all the mountain counties combined.

It's beyond me how anyone can be upset with this great pattern after 60's and 70's and dry december. :)

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6 minutes ago, snowmaker13 said:

Is Winter over after Monday? 

I don't know if you know this, but here in CNC, we have a very short window. In the 2020s, winter's door is really shut after Valentine's Day here.

I'll have bradford pears blooming by the first week of March.

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11 minutes ago, StantonParkHoya said:

I think it's because of the volume of posters does skew toward Raleigh, as it should since more people live in Wake County than just about all the mountain counties combined.

Although I bemoan the splitting of this subforum into smaller subregions, I understand why people felt the need to do so. Sometimes, it seems every storm and weather event is dominated by the backyard perspective of people in the Raleigh area.  Even the notion that “central NC” just means Raleigh or the Triangle is rather myopic. I guess those of us in the Triad and western Piedmont need to post more. For us, this storm is looking like a big deal.

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1 hour ago, CentralNC said:

As mentioned my several members, you can cut those totals at least in half due to runoff, etc

Yes, at least in half.  And if we see significant CAD erosion as ILM ROSS suggested could be possible, it won't even be close to half.  You'll see rain washing away all that snow and sleet until it refreezes into Monday morning.  

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4 minutes ago, Wow said:

Uhh the 18z NAM just shifted south a good bit ... c'mon HRRR!

 

I have been watching the nam runs too (both lo and hi res) and was thinking same thing.  They both look very HRRR like.  Not out to 48 yet for full comparison, however.

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1 minute ago, GSO_WX said:

The last 4 runs on NAM appear to show a trend south - but it also looks a bit slower, so maybe it's misleading at this point. 

 

23.gif

The snow line does appear further south though in Upstate SC on the 18z. Lines up pretty close to the Hrrr.

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5 minutes ago, WinstonSalemArlington said:

Although I bemoan the splitting of this subforum into smaller subregions, I understand why people felt the need to do so. Sometimes, it seems every storm and weather event is dominated by the backyard perspective of people in the Raleigh area.  Even the notion that “central NC” just means Raleigh or the Triangle is rather myopic. I guess those of us in the Triad and western Piedmont need to post more. For us, this storm is looking like a big deal.

Imagine the NWS's challenge especially RAL which covers numerous microclimates.   RAL's conservative approach to this storm is IMO well reasoned.

Back in SKYWARN's heyday, as a spotter trainer, I found most Ham operators thought Central/Western NC/SC were served by GSP,  CAE and RAL with surprise to learn that the Blacksburg, VA (ROA) office serves (9) nine NC counties covering half of NC's northern sections to include Rockingham county north of GSO. 

Rare to see ROA's forecast packages quoted here even on the mountain thread which is surprising since ROA is responsible for Watauga County/Boone area.   

Re: SKYWARN, GSP and ROA still have a vibrant group with both CLT and the Triad SKYWARN ceasing operations well over a year ago with barely any inquiry or protest. 

A small splinter SKYWARN group formed in Gaston County to assist GSP for a much smaller footprint (vs. CLT SKYWARN) in the southern NC Piedmont/Foothills but that is a topic better for banter assuming anyone cares - probably not since at least here in the Triad, nobody expect yours truly seems to care!

ANONmet_GSO a.k.a. Marc - Amateur Call W4OVT

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