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I'll allow a waxhaw jackpot with this oneNAM 3km Snow Output
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12/2/2024 - Potential Clipper Action!
- Thread starter packfan98
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I’m all in
I typically follow these types of systems approaching from the NW moreso at the 500mb level as you typically want to be along or north of the track of the 500mb vort max to get in on the precip. For this system, the modeled precip seems to be more closely tied to the behavior at the 700mb level - maybe because it's a compact system??
Anyway, here is the RH rolling thru at 700mb
On the radar simulation, you can see the precip enhance and slow down a touch as it breaks out in the piedmont...this matches well with what typically happens in these scenarios as the upstate mesolow forms and tracks ESE.
Here's the mesolow in the upstate
Anyway, here is the RH rolling thru at 700mb
On the radar simulation, you can see the precip enhance and slow down a touch as it breaks out in the piedmont...this matches well with what typically happens in these scenarios as the upstate mesolow forms and tracks ESE.
Here's the mesolow in the upstate
Webberweather53
Meteorologist
I typically follow these types of systems approaching from the NW moreso at the 500mb level as you typically want to be along or north of the track of the 500mb vort max to get in on the precip. For this system, the modeled precip seems to be more closely tied to the behavior at the 700mb level - maybe because it's a compact system??
Anyway, here is the RH rolling thru at 700mb
On the radar simulation, you can see the precip enhance and slow down a touch as it breaks out in the piedmont...this matches well with what typically happens in these scenarios as the upstate mesolow forms and tracks ESE.
Here's the mesolow in the upstate
Yeah this system is lower down because it’s very cold aloft. A lot of the precip is shallow topped with the DGZ ~750 mb. The 500mb vort max is disconnected with the low level forcing/lift here, mainly coming from 850mb convergence and frontogenesis near the mesolow.
I think the place to be in this event is the southwestern and southern Piedmont (Charlotte to Fayetteville NC or so and maybe a tad north of that). I can see very minor accumulations on elevated surface for a lucky few tonight.
Oth, over places like Raleigh low level forcing/convergence doesn’t look sufficient to overcome the sub-cloud layer drying. Although a few flurries are still possible there
rooting for you guys, nice ball of vort, might be some lee side enhancement as the vort gets stretched as it goes over mountains
Beautiful sight man 
That precipitation shield matches up nicely with in the north side of that meso low 
Canadian RGEM / RDPS is a little farther north (more like the HRRR). The Canadian suite of models has performed pretty well over the years in NW flow events out into the piedmont
This even gets me involved, so we know you can toss this one out lolCanadian RGEM / RDPS is a little farther north (more like the HRRR). The Canadian suite of models has performed pretty well over the years in NW flow events out into the piedmont
Pretty much all of the guidance except this one shows a gap in coverage immediately east of the mountains, which is probably accurate, given downsloping.
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Usually, yes. If you can spin up a mesolow in the upstate though, that can really enhance precip in the lee.
I’m going to go ahead and issue a snow advisory for Iredell and Davie for 1” snow but need to watch radar evolution because I think this will spread into High Point NC. Wilkes and Yadkin would not qualify due to threshold being 2”. Those areas may see very light accumulation. I may setup shop in the Brushy Mountains of south-eastern Wilkes County to see the evolution of system forming overhead. 
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You have no authority to issue a winter weather advisory. I'd think twice about your wording there and consider recanting it before someone reports you to the NWS. I'll confess, your shtick can at times be comical, but impersonating the NWS is a federal offense.
18 U.S. Code § 2074 - False weather reports
I re-worded it to say snow advisory since they do not issue those anymore.You have no authority to issue a winter weather advisory. I'd think twice about your wording there and consider recanting it before someone reports you to the NWS. I'll confess, your shtick can at times be comical, but impersonating the NWS is a federal offense.
18 U.S. Code § 2074 - False weather reports
www.law.cornell.edu
wouldn’t surprise me if there’s some graupel in this setup either, given the really cold air aloft/steep low level lapse rates. Nice omega in the DGZ as well 
I agree with the analysis by you and grit. That said, part of me wonders if the northern edge could be a little more enhanced due to PVA and geopotential height falls. So far today the northern edge of the precip shield over Iowa has been more enhanced than initially predicted. Of course, things look a little different on this side of the apps with the downsloping and other factors I know.
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Ratios should be pretty good here - 13:1 to 16:1 maybe?
Lol this event is overperforming in IL 
NAM 3km suggests around 10-12:1 ratios during the time of precipitation. Surface temps would be the limiting factor to better. It's honestly more rare than most probably realize for us to get true 10:1 though, so this ain't bad (by our standards)!
i've always wondered how much we really can glean from this downstream. the low level dryness that we're fighting in NC is from downsloping, right? something they don't have to worry about. is the fact that its overperforming upstream enough of an indicator of more robust moisture aloft that it can overcome sub-cloud dryness east of the apps?
Last couple HRRR runs have been getting slightly more beefy, esp compared to 12z
Was just seeing that, esp further north on the precip. Pulling for RDU to score too
Feel like its gonna be tough to see more than a passing flurry or two up this way and in north central NC with these soundings. not that this is new information. just quite dry
packfan98
Moderator
UKMET bumped up the footprint of snow and follows the trend of inching north.
weather bubba
Member
The dewpoints do look too low for the precipitation to overcome for points from Fayetteville north except for a snowflake or two. I wish the folks in Charlotte and the southwestern Piedmont the best with this event! An inch of snow is possible in those areas and when you have been in a snow drought as long as most of us have I'm sure there will be some happy campers who will be on the receiving end of this event.
packfan98
Moderator
16z RAP-tastic!
Blue_Ridge_Escarpment
Member
Inching north/west at game time! Imagine that16z RAP-tastic!
Gotta say, the fight and heart being shown for a trace to dusting event warms my heart and gives me hope for the next generation. LOLLOL
The new kid on the block, the Euro AI, has been pretty locked in with precip totals shown here on its last 4 runs.
If you put your cursor on the screen on Pivotal, it shows a 0.04 area roughly from just east of Hickory to Rock Hill to Pinehurst to Chapel Hill to Greensboro. It has a small 0.05 area just N and NE of Charlotte
The new kid on the block, the Euro AI, has been pretty locked in with precip totals shown here on its last 4 runs.
If you put your cursor on the screen on Pivotal, it shows a 0.04 area roughly from just east of Hickory to Rock Hill to Pinehurst to Chapel Hill to Greensboro. It has a small 0.05 area just N and NE of Charlotte
Hrrr looks even wetter this run, and has more activity in northern AL/GA
Those banding features closer to the meso low are interesting as well 
NCSNOW
Member
I've seen that Bermuda Run lollipop like the ukmet packfan posted on a cam this morning, same vicinity maybe 30 miles futher south.
SimeonNC
Member
Now I'm legit scared of this trending too far north and screwing us CLT folk over.
Eh I think CLT is fine here. Closer to the meso low and modest amounts of FGEN/WAA aloft (evident by the slight sly wind barbs above Columbia). Looks like that’s what results in the banding features 
Really cool thing to is you can see the meso low off the 0-3km storm relative helicity
map, imagine this in May
Really cool thing to is you can see the meso low off the 0-3km storm relative helicity
map, imagine this in May
Latest run of the NBM did spread the chances of precip out a bit more across NC.
12z NAM3 doing pretty well upstream right now, precip shield is def a bit wider in reality
meanwhile the hrrrrrrr
meanwhile the hrrrrrrr
NCSNOW
Member
Raleigh NWS has a 30% chance Snow Showers here tonight:
They also have a 30% chance of Rain Sat night with a low of 26 coming off a day time high of 41.
They also have a 30% chance of Rain Sat night with a low of 26 coming off a day time high of 41.
Goodness
Avalanche
Member
Look at those bands coming in from out da lakes.
HRRR seemingly locking on to 2 areas that could perform the best, just west/NW of statesville, and N/NE of CLT. Seems like the first hotspot is driven by lee side enhancement/DCVA, and the second is driven more by weak LLVL FGEN/weak WAA/lift from the mesolow 
Webberweather53
Meteorologist
You could be seeing some release of conditional symmetric instability (CSI).
The bands of snow are oriented parallel to the thermal wind/deep-layer thickness contours & the profile looks moist adiabatic in the DGZ below 600mb. Oth, not a ton of WAA in this sounding (as expected for this system).
