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
- Start date
Broken024
Member
I’m all in
griteater
Member
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 
griteater
Member
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.
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.
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