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Wintry Machine Learning Mauler 1/30-2/1

Yeah the parallel NBM looks much more realistic with this storm over NC for the moment and is closer to what I’d probably forecast.

General 3-6” or so area wide, with 2 snow maxes. One snow max i am pretty confident in from around Charlotte and just west and south into the upstate of SC and northern midlands. The other one over the coastal plain which has a higher risk, high reward involved and could shift as far west or north as Raleigh or so depending on how this evolves the next day or so

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Webberweather53 said:
Yeah the parallel NBM looks much more realistic with this storm over NC for the moment and is closer to what I’d probably forecast.

General 3-6” or so area wide, with 2 snow maxes. One snow max i am pretty confident in from around Charlotte and just west and south into the upstate of SC and northern midlands. The other one over the coastal plain which has a higher risk, high reward involved and could shift as far west or north as Raleigh or so depending on how this evolves the next day or so

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Is that taken at face or add some for ratios?
 
Webberweather53 said:
Yeah the parallel NBM looks much more realistic with this storm over NC for the moment and is closer to what I’d probably forecast.

General 3-6” or so area wide, with 2 snow maxes. One snow max i am pretty confident in from around Charlotte and just west and south into the upstate of SC and northern midlands. The other one over the coastal plain which has a higher risk, high reward involved and could shift as far west or north as Raleigh or so depending on how this evolves the next day or so

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Hard to pin down for sure. RAH and WTVD both going with twice that amount here right now.
 
Jimmy Hypocracy said:
Dream setup. Peepaw type snowstorm if we can hold onView attachment 191274
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I'm not even getting attached to this look but dang.. that band is right over my backyard in Athens. Kind of lowkey impressed how this has trended today. Still time for it to jog a little east and north though.
 
Mitch West said:
CAE going with 5-8 inches now. That's an upgrade from 2-5!!

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Wow! I know everyone here is super pumped for you guys in the midlands of SC, you have all been so snake bitten. I believe a 5-8” event there in Columbia, SC would be the biggest storm since February 2010?!
 
So I just answered half my questions by putting them into ChatGPT b/c I didn't want to bother the experts on here too much.

  • Question 1. What is the best model for winter weather in the southeast...
    • Globals
      • ECMWF/Euro - Gold Standard (pattern and confidence)
        • Pros - CAD, Southern Stream Systems, Does well handling marginal temps, sniffs out winter wx potential ahead of other models
        • Cons - slow to correct once committed
      • GFS
        • Pros - Faster updates; valuable for trend spotting
        • Cons - more volatile; Too aggressive with QPF early
      • Canadian (GEM)
        • Pros - sneaky good with cold air strength; used as sanity check, not leaders
        • Cons - occassionally wildly wrong;
    • Mesoscale models
      • NAM (12km + 3km) - Temps and Precip Type
        • Pros - thermal profiles; discerning sleet vs. snow vs. frz rn
        • Cons - can overdo QPF; Sometimes hangs onto cold air too long
      • HRRR (0-18hrs) - final details
        • Pros - Nowcasting, Banding, Rapid changes near onset
        • Cons - not reliable beyond 15-18hrs
      • RGEM
        • Pros - underrated for winter setups; sometimes outperforms NAM with CAD
  • Question 2: Why does NWS use the NBM?
    • Think of it as 'what usually works best here, given everything we know now". So NWS forecasters start with NBM and then manually adjust using NAM/HRRR/experience
      • Pros - Consistency, Bias correction, Probablistic output, operational reality
      • Cons - too conservative, CAD erosion errors, smoothing kills extremes
 
Fact is pinpointing a specific location is next to impossible at this point. Where the ULL goes and the strength of it will determine which area wins and which one loses. To expect a Global model to be that precise (20-25 miles here 20-25 miles there) is unrealistic and foolhardy. The CAMS will have a better idea but I wouldn't be on them either with such a dynamic system as we have. After the event we will know for sure but not until then. My guess and everyone else is just that, a guess
 
packfan98 said:
Well, the 12z eps isnt matching up with the op very well. Drier across the board. Lots of nuances with this one.
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Not terrible, at least (widespread 5-10" for most of NC / SC). The ensembles are ran at a lower resolution, right? Wonder if they could be missing some of the mesoscale features as a result? Or perhaps this is wishcasting.
 
xshare said:
Feels like we should be using 2 separate trend gifs for AIFS - one for 00/12 and one for 06/18 as that wobble makes it impossible to actually compare.
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It is SO SO strange how the 18z/6z runs have been so different from the 12z/0z runs. Don't typically see the jumpiness like that.. and it is across the board-- all models that initialize with ECMWF are having this. Even AIFS-ENS and WeatherNext.
 
superjames1992 said:
Not terrible, at least (widespread 5-10" for most of NC / SC). The ensembles are ran at a lower resolution, right? Wonder if they could be missing some of the mesoscale features as a result? Or perhaps this is wishcasting.
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Well, it’s a blessing and a curse. If you’re in a subsidence zone you will be very disappointed
 
packfan98 said:
Well, the 12z eps isnt matching up with the op very well. Drier across the board. Lots of nuances with this one.
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Can definitely see hints of the dry slot there around US-1 and I-95 too. The only area that’s really seeing a lot of run to run consistency is back over Charlotte into the upstate or SC
 
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