December 8-10, 2018 Winter Storm

[griteater]

2 minutes ago, burgertime said:

RAP has all of NC snow. 

RAP and HRRR are usually boiling with heat...so, it's good to see though the NAM has a great track record with these winter storms over recent years....I think we all just need to move to the high country and be done with it

[NCSNOW]

850s are -3.1 @ GSO currently

[burgertime]

Just now, griteater said:

RAP and HRRR are usually boiling with heat...so, it's good to see though the NAM has a great track record with these winter storms over recent years....I think we all just need to move to the high country and be done with it

True definition of insanity 

[strongwxnc]

Just now, burgertime said:

True definition of insanity 

Until the wheels fall off! 

[Poimen]

3K and 12K NAM respectively: 

 

[NCSNOW]

Snow is breaking out SW NC. 

[Poimen]

Looks like the RGEM is going to follow suit on previous runs with sleet well into the mountains and Triad. It probably has the same 700mb warm nose as the NAMs and is a huge red flag in my opinion. 

[Poimen]

 

[SnowDeac]

Lubbock now at 9 inches and still snowing. Going to be one of the largest 5-6 storms on record there. 2nd snowiest day ever in December. Vast majority from the ULL. Amarillo getting blanked. I'd say that's a positive for all of us, especially folks on the southern side.

I've also noticed a few local maximums showing, especially on the NAM, south and east of Charlotte. That's quite surprising, especially given where we were last night. I'm guessing it's either a heavier front end thump due to rates, or that ULL low rolling through at the end.

[Buddy1987]

2 minutes ago, Poimen said:

Looks like the RGEM is going to follow suit on previous runs with sleet well into the mountains and Triad. It probably has the same 700mb warm nose as the NAMs and is a huge red flag in my opinion. 

Yea you’re def right Poimen. RGEM is pretty amped up with the moisture influx and the intensity. Looks like sleet to zr with only northernmost zones of NC, mountains and then up into VA would remain snow with that look.

[burgertime]

Just now, SnowDeac said:

Lubbock now at 9 inches and still snowing. Going to be one of the largest 5-6 storms on record there. 2nd snowiest day ever in December. Vast majority from the ULL. Amarillo getting blanked. I'd say that's a positive for all of us, especially folks on the southern side.

I've also noticed a few local maximums showing, especially on the NAM, south and east of Charlotte. That's quite surprising, especially given where we were last night. I'm guessing it's either a heavier front end thump due to rates, or that ULL low rolling through at the end.

Those are good signs in my opinion as well. Shows that there's good cool air coming across the states. 

[GunBlade]

4 minutes ago, burgertime said:

Those are good signs in my opinion as well. Shows that there's good cool air coming across the states. 

Yea we all know what an ULL can do so the fact that the heart of the storm is generating those totals is a good sign 

[wncsnow]

RGEM.. not finished 

[msuwx]

12z NAM in BUFKIT is much less pronounced with the warm nose for KHKY that it was on the 6z run.... FWIW. 

[raysum]

31 minutes ago, fountainguy97 said:

I wouldn’t put much stock in the NAM. 

 

Check this error.

 

Great post. I know a Met on the other board reacted to your post by saying

Great post. IMO if the warm nose is more prominent than expected by NWS, myself, Euro, FV3, GFS, HRRR it's just blind luck. The model has displayed zero skill with this system since it's genesis in TX/OK.

 

 

 

[Jet Stream Rider]

This morning the NWS moved my county (Halifax) into the WSW area. I'm right on the edge of the piedmont, nothing but coastal plain to my east, so of course I expect a mix with sleet and rain. that initial hit though looks substantial. 

We have our slp just west of New Orleans this morning, here we go! Good luck everyone!

[Juliapalooza]

Brad Panovich posted a video about 40 minutes ago.  Still concerned about ice accretion Sun/Mon.

https://www.facebook.com/wxbradCLT/videos/281374155915525/

[Solak]

Forecast amounts have lowered here.

Point forecast was 2-4", now 1-2".

Zone forecast was 1-3", now"'around an inch".

[Poimen]

The upper level low is really a non-factor for our snow chances, in my opinion. It's all coming down to how the models resolve the 700mb low as it approaches and passes through the SE. The NAMs/RGEM have a pronounced warming at this level, whereas the RAP/HRRR are, for the time being, limiting the amount of warming over NC. Who will win? Only time will tell. 

[griteater]

Upper level divergence on the GFS....this is what the big ones look like

[Brick Tamland]

6 minutes ago, msuwx said:

12z NAM in BUFKIT is much less pronounced with the warm nose for KHKY that it was on the 6z run.... FWIW. 

Seems the NAM is going back and forth with the warm nose while the other models have held steady or even improved this morning.

[FallsLake]

7 minutes ago, Solak said:

Forecast amounts have lowered here.

Point forecast was 2-4", now 1-2".

Zone forecast was 1-3", now"'around an inch".

They cut it down across the board. Sunday I was at 5-9" and now its 3-5. Then Sunday night have now have 1-2" of sleet. 

Edit: this might be because of reduced qpf

[PackGrad05]

My official Wake county forecast:  Extreme southern wake near JoCo/Harnett = 0-1" of snow and minor glazing.     Central Wake = 1-2 inches of snow - minor glazing.  Northern Wake = 3-5 inches, minor glazing.

[beanskip]

It seems to me the only way to forecast this storm is to start with QPF and move backward. So, if you are projecting, say, 2 inches is liquid and you are projecting 2 inches of snow, you’ve still got 1.8 of QPF to spend. 

[DopplerWx]

hrrr looking warmer out to hr18 vs the 12z run.

[beanskip]

Just at 6 hours, the 12z GFS 850s improved the entire length of York and Cherokee counties in SC. 

[Poimen]

Actually...looking at the RGEM charts, it is blow torching at 850 by 12Z tomorrow. This is way warmer at this level than any other guidance and makes me a bit suspicious. 

[superjames1992]

I would just say the NAM historically has done a good job with 700-800 mb warm noses and the RAP/HRRR are dangerous to use in their longer ranges.  I would also say that, in my experience at least, we often deal with the ~750 mb warm nose before the 850 mb level warms above freezing.  But, of course, you never know what’s going to happen.  It always seems like warm noses overperform as opposed to underperform, though.

Anyways, I am getting prepapred for the rain storm down here.  Good luck everyone!  Looks like a big winter storm for many, even if a lot of it becomes IP/ZR (more likely IP with a 750 mb warm nose since there’s a lot of air under that to refreeze the droplets before hitting the ground).

[FallsLake]

Just now, CaryWx said:

How does that square with what Jon Wall tweeted about 9" amounts for RDU on next update?

Man I don't know. 

Does anybody know what model the NWS uses for their grid output? You can tell they're using one with the two hour flips between p-types. 

[Lookout]

a note on the 3km and 12km nam, currently it's running on average about 3 degrees too warm right now here in georgia and in a lot of areas seeing rain. If it held this average error into tonight, temps would get to freezing in gainesville/85 corridor between 0z and 03z where it gets these areas down to 34 by 03z.