One More Shot: Feb 20-21 Event

[CentralNC]

2 hours ago, WesternNC_wxm said:

Cullowhee NC ending with a solid 0". Typical around here in our microclimate, snowed all day yesterday but just a little too warm for accum. Last good storm I remember here was something around 8"-10" two years ago!! 

I believe this is the one you reference young Skywalker

https://projects.ncsu.edu/atmos_collaboration/nwsfo/storage/cases/maps/accum.20171209.png

[magpiemaniac]

47 minutes ago, wncsnow said:

Really the whole 74 corridor from Wadesboro to Lumberton up to Fayetteville is probably lowest on the list of NC places to live due to high poverty levels, crime rates, and overall lack of things to do 

Though I will say that we once stopped in a restaurant in Laurinburg (on the way back from vacationing in Oak Island) and the service was exceptionally polite and attentive.  Made a good impression on us to this day.  (Pardon the off-topic comment.)

[wncsnow]

Just now, magpiemaniac said:

Though I will say that we once stopped in a restaurant in Laurinburg (on the way back from vacationing in Oak Island) and the service was exceptionally polite and attentive.  Made a good impression on us to this day.  (Pardon the off-topic comment.)

No doubt. I once had car trouble on the way back from a job interview in Wilmington and was broke down in Lumberton. The people there were nice and helpful albeit a little rough around the edges. There are fine people all across NC.

[Snownado]

16 minutes ago, wncsnow said:

No doubt. I once had car trouble on the way back from a job interview in Wilmington and was broke down in Lumberton. The people there were nice and helpful albeit a little rough around the edges. There are fine people all across NC.

In my experience South Carolinians are nicer than North Carolians in general.

[griteater]

Verification time.  Right as I thought the models would increase the precip amounts, they went the other way.  I also leaned on climo a bit too much (like, it always snows good in Hickory - Greensboro in our storms).  Oh well, live and lean, and move on to the next one.

A = Forecast was generally consistent and verified

F = Forecast wasn't consistent and was way off

[griteater]

So here's what I think went wrong in parts of the western half of North Carolina with the precipitation amounts.  The first map from Thurs at 10AM shows how the core zone of the 850mb warm advection (low level overrunning) stayed to the south from north Bama to SE North Carolina.  This is the region that received the solid precip shield.  NC missed out on that forcing for precipitation.  The second map from Thurs 4PM shows how a large part of NC has flipped over to cold air advection at 850mb.  Warm advection at 850 produces lift (for precip production), cold advection does not.  Along with it being cold advection, there is also a downsloping component there with it coming across the mtns.  The models certainly showed this all along and adjusted downward with QPF late in the game, but were limited all along on the NW side.  With this being a weak wave and not a very dynamic system aloft, it was a must for the western 1/2 of NC to get in on this overrunning precip.  The eastern 1/2 of NC was able to benefit from other processes leading to precip production higher up in the atmosphere - that is, increasing mid-level frontogenesis and upper level divergence as the storm matured and the final trailing upper wave strengthened a little as it moved thru.  The SPC archive maps are really good to view in post analysis - https://www.spc.noaa.gov/exper/ma_archive/

In summary, the text above further supplements the idea that it is much preferred to have cold air in place prior to the storm's arrival.  Not only is it preferred for precip type and pre-storm cold for efficient accumulation when precip arrives, it also helps with lift in the atmosphere as you want warmer air from the south running into colder air to the north to generate overrunning precip - the kind that produces the nice, consistent shield of precip on radar.

[griteater]

In terms of how the models performed, my biggest takeaway was how the NAM had the best handling of the subtropical energy/vorticity coming out of the subtropical jet stream from Baja to Texas.  Without this, there's hardly any storm at all.  There was a point where the typically solid combo of UKMet/Euro was saying no storm or very weak storm, but the NAM and GFS had it more north (especially the NAM).  It was one of the worst performances from the UKMet that I've seen - and it typically does fairly well in our region.

[WinstonSalemArlington]

2 hours ago, wncsnow said:

Really the whole 74 corridor from Wadesboro to Lumberton up to Fayetteville is probably lowest on the list of NC places to live due to high poverty levels, crime rates, and overall lack of things to do 

At least Wadesboro is somewhat close to Charlotte and it’s suburbs 

[griteater]

 

@Isopycnic gets the award for first post on the storm (on the mid to long term discussion thread), where the GFS nailed it from 10 days out  

  

On 2/10/2020 at 6:38 AM, Isopycnic said:

Fantasy snow. 

 

[CentralNC]

Just now, griteater said:

 

@Isopycnic gets the award for first post on the storm (on the mid to long term discussion thread), where the GFS nailed it from 10 days out  

I think EURO had it on the 13th if I recall didn't it?  

 

 

[WinstonSalemArlington]

7 hours ago, Snownado said:

Overall this was just your run of the mill NC snow that you see pretty much every winter. Nothing notable or memorable about this storm. However, I will increase the grade for this winter from an F to a D-.

I concur, although I think an F is still a reasonable grade 

[strongwxnc]

So here's what I think went wrong in parts of the western half of North Carolina with the precipitation amounts.  The first map from Thurs at 10AM shows how the core zone of the 850mb warm advection (low level overrunning) stayed to the south from north Bama to SE North Carolina.  This is the region that received the solid precip shield.  NC missed out on that forcing for precipitation.  The second map from Thurs 4PM shows how a large part of NC has flipped over to cold air advection at 850mb.  Warm advection at 850 produces lift (for precip production), cold advection does not.  Along with it being cold advection, there is also a downsloping component there with it coming across the mtns.  The models certainly showed this all along and adjusted downward with QPF late in the game, but were limited all along on the NW side.  With this being a weak wave and not a very dynamic system aloft, it was a must for the western 1/2 of NC to get in on this overrunning precip.  The eastern 1/2 of NC was able to benefit from other processes leading to precip production higher up in the atmosphere - that is, increasing mid-level frontogenesis and upper level divergence as the storm matured and the final trailing upper wave strengthened a little as it moved thru.  The SPC archive maps are really good to view in post analysis - https://www.spc.noaa.gov/exper/ma_archive/
In summary, the text above further supplements the idea that it is much preferred to have cold air in place prior to the storm's arrival.  Not only is it preferred for precip type and pre-storm cold for efficient accumulation when precip arrives, it also helps with lift in the atmosphere as you want warmer air from the south running into colder air to the north to generate overrunning precip - the kind that produces the nice, consistent shield of precip on radar.

Thanks for the great explanation!


.

[Isopycnic]

2 hours ago, griteater said:

 

@Isopycnic gets the award for first post on the storm (on the mid to long term discussion thread), where the GFS nailed it from 10 days out  

  

 

[magpiemaniac]

23 hours ago, WinstonSalemArlington said:

I concur, although I think an F is still a reasonable grade 

Yeah, I’m sticking with an F.  While I’m thankful to get some snow this week, it’s sort of like a kid turning in a poorly written paper at the last moment to try to pass the class.  Too many zero assignments all season to bring the grade up to a 60.