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Wintry Jan 30-Feb 2 2021 ❄️ Potential
- Thread starter SD
- Start date
Tarheelwx
Member
I'd bet it's colder in those areas because they have had precip and saturated the surface. If you want to know if your trending warmer/colder, you should really be comparing the wetbulb.
TW
TW
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Deleted member 1449
Guest
When that front-end forcing moves over the column becomes nearly saturated from top to bottom (per the soundings). In its wake there is less potential for subfreezing (or well-below-freezing) wet bulbs for the main event. Something to watch, I suppose.
LukeBarrette
im north of 90% of people on here so yeah
Meteorology Student
Member
2024 Supporter
2017-2023 Supporter
Wxrisk says he thinks Nam is too warm aloft, plus not reliable at this range. I agree that it’s not reliable, but it could be right with the temps aloft.
yep the big ice storm in 96 I believe was 1/2 inch and up
L
Logan Is An Idiot 02
Guest
This is the nams best time. I think it will crush the storm TBH. The temperatures are always pretty accurate on the nam. Now precip is another story
smast16
Member
The 2m dew points do something weird in the 12z 3km nam. It's like a burp of warmer moist air gets trapped on the eastern side of the Mtns and gets pushed north. At hour 38 With no precip being depicted Spartenburg, Sc has a dew of 24, Hickory NC. has a dew of 33, and Burlington, Nc 16.
What's going on here?
What's going on here?
Blue_Ridge_Escarpment
Member
Yeah the NAM is usually too dry now Compared to how it use to way overdo precip.
iGRXY
Member
Really depends on your location. Temps around my neck of the woods are very very close to freezing. One thing I am noticing is those DPs are really low prior to the event and that makes me wonder about this. I think this is going to be one of those systems where we honestly aren't going to know much until the day of by looking at DPs and how warm temps get in the day. Is precip moving in faster than modeled (which has been the case so far).
Nomanslandva
Member
Weak precip seems to be a thing with the NAMs even at this range. Soundings look ok on the 3K until noonish here but if the NAM does not trend a little colder, I would bet on mixing earlier than that. And yes, trust the warm nose on the NAM.
Blue_Ridge_Escarpment
Member
RGEM looks colder to me
iGRXY
Member
.This is probably the best guess as of right now where I could see some form of ICE in this scenario. Don't know how much, when and if anybody switches over at any point just. The best bet is likely the NW piedmont and the closer you get to the escarpment. DPs are really low and temps are in the mid 30's for most south of I40 which makes this a very difficult thing to pinpoint on where and how far south the cold air infiltrates.
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Deleted member 1449
Guest
I think it has to do with the temp getting close to wet bulb under the front-end-band.
Blue_Ridge_Escarpment
Member
No in fact it’s usually too warm at the surface.
Last big ice storm I remember was 92/93 in NE NC.
Lets hope the RDPS does not win this model war. It has me at 1.25" of freezing rain; but that's not the worse location. Looks like northern Orange / southern Person counties would "jack pot" (in a bad way) at ~2.25". Terrible outcome for something like that...
I wouldn’t be worried about them totals of ZR. That most likely not happening! RDPS is always way over done with ZR totals, cut them by 1/2-3/4 you might be close. At least we hope it’s like usual
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CAMs coming into range pretty aggressively, lol, they also still show that little front band 
Yeah if your just looking at the map it even shows nearly .45 zr imby, but when I check the soundings, they show a brief window of ip followed by rain and not really a zr sounding there. Makes me suspicious
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Logan Is An Idiot 02
Guest
That model has a cold bias like the icon has a warm bias. Gotta add at least 2 to 3 degrees
how much snow will Columbia sc get
Does it have a cold bias in CAD setups? Or is it more likely to be realistic with its representation here?
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Logan Is An Idiot 02
Guest
Well for example, with that system in December. It was spitting out huge ice totals like it is right now. And most areas just got a cold rain.
Interesting battle set up with Globals and short-range/higher resolution. Allan Huffman alludes to it on his latest tweet. If interested
Wouldn’t want to clear out before stuff moves in, for example, notice where it’s more clear = Radiational cooling and lower temps 
Yeah, this model has shown this types of output in the past (and ended up wrong). The only thing that keeps me thinking things may end up a little more icy than what the other models are showing is the very low dew points that will be initially in place. This type of low level cold tends to over perform (more than modeled) with staying power. Maybe the CAMs look could be close to reality.
Webberweather53
Meteorologist
Global models for the most part can not handle CAD, esp the Euro and GFS because they parameterize a lot of local and mesoscale feedbacks that are necessary for the erosion of CAD. If you’re gonna look at global models with CAD, the CMC is usually the best
Nomanslandva
Member
Our last bad one was 94.
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Logan Is An Idiot 02
Guest
How did the cmc handle the cad event in December?
Webberweather53
Meteorologist
Its depiction of the areal extent of ZR was close to what actually happened. It was a tad on the cold side if anything but wasn’t that far off. Fram model adjusted ice was arguably the best with last December’s event
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Logan Is An Idiot 02
Guest
Yeah I figured it may have been a bit too cold. We do have a much cooler air mass this time so the CMC may be much more accurate this go round.
Understood. It appears that NWS is leaning on Globals more? I know we say "toss" at this range on the globals...
Dec. 2002 is our benchmark ice storm out my way just south of GSO. 0.75”-1.00” ice accrual. Power was out for 2-3 weeks.
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One difference from that storm is this as well
I find it interesting if that front end area of precip endsup overperforming and locking in a CAD dome much quicker (3km does that in the foothills)
Webberweather53
Meteorologist
Yeah that doesn’t make any sense if they are, experienced forecasters in NC really should know better than to take the Euro and GFS over the CAMs when it comes to CAD. For winter storms like Jan 16-18 2018 that are largely driven by CVA, globals are still pretty useful in the short range imo.
iGRXY
Member
The CAMS are what I feared in terms of models not picking up just how dry and cold the surface really is with the DPs being spit out. Just seemed like the temps were not corresponding and falling even with those low DPs like they should on these model runs. Even the NAM and RGEM look like they're not falling enough with the wet bulb. Do I think it will be as south as the CAMS are showing? No but areas along and north of 85 definitely should keep a close eye.
Webberweather53
Meteorologist
Yeah precipitation naturally helps lock in CAD (in-situ) thru condensational deposition in the mid levels coupled to sub cloud layer evaporation and sublimation, creates a low level inversion that increases static stability near the top of the cad dome, thereby reinforcing it.