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Wintry Machine Learning Mauler 1/30-2/1

January 2003 vibes! Disturbance coming thru the mountains and exploding on the lee side! Think Gaffney to Gastonia got about 8-10”!??
GSP had about 3, but it was dynamic!!
I remember going to bed the evening before with nothing falling yet and getting woken up at 4:00am to a loud crack of thunder that shook the house
 
Would NAM and RAP suffer the same bias? Or RRFS? At least right now all 3 are showing an ATL hit, while the 00z FV3 basically looks like your map or the GFS, with the storm basically dying right along the border of Dekalb County.
Nearly every model overestimates low level winds in the southeast because they handle friction poorly.
 
One potential semi-analog I’m aware of is from 2/7-8/1968: I’m aware of it because it produced a shockingly high for SAV of 3.6”, then the highest there in modern day records.

I consider it an analog based on these maps:

2/7 12Z: 532 dm upper low NW IL and sfc low well offshore NC
IMG_7737.gif

2/8 0Z: upper low moved rapidly SE to Chattanooga (534 dm) and sfc low moved only very slowly NNE to well off VA
IMG_7738.gif

2/8 12Z: upper low had moved ESE to just off CHS/SAV with coastal sfc low moving NNE to well off MidAtlantic:
IMG_7739.gif

Brooklet, GA, got the highest of anyone I could find with 5”! ATL got 1”. Even Sapelo Island got 1”!


This storm was odd in several ways:

-I could find only 7 stations with measurable snow from this: ATL, Covington, Brooklet, SAV, Glennville, Alma, and Sapelo Isl! Hardly any other station even got measurable rainfall!

-snow to rain ratios were unusually high; SAV’s liquid equiv. was a mere 0.21” meaning 17:1! Brooklet got 5” on only 0.29” or again 17:1! Covington got 0.8” on only .04” or 20:1!

-Despite the very high ratios, 2m temps were marginal just before, during, and just after:

Brooklet 2/7 high was 62. 2/8 had a low of 29 and a high of 58! 2/9 was 28 and 52.

So, it appears to me that this GA snow was generated strictly by the strong upper low, similarly to tomorrow’s storm. Despite the marginal 2m temps, evidently the very strong upper low and -5C 850s was enough to result in very high ratios. Based on there be only these 7 getting measurable snow, it appears that these were produced by narrow areas of precip in 2 bands:
1. ATL to Covington to Brooklet to SAV
2. Further SE Alma-Glennville-Sapelo
 
Let’s see who wins…this going to be a big bust by one of them.

I typically like the 3km but I am hoping it’s wrong here.

View attachment 192219
I gotta say and I’m looking at this completely objectively for your area. Something just isn’t adding up with the NAM and it’s something the 3km has been doing at times since yesterday. It just showed RDU getting 8-9 hours of solid light to moderate returns but produced almost no QPF? That just doesn’t make sense.
 
Little concerning that all the CAMS except Nam 12k and FV3 are lessening the coastal and drying faster
Wouldn't pay attention to cams or any models at all at this point. You can already tell they're not handling moisture too well based off obs. Just focus on OBS data and radar, using mesoanylasis, radar and whatever other data you want to find.
 
Snowing pretty here now.


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Lol. I swear I dont know how you do it. Been in the black hole on every model run, but when the starting gun sounds, you are 1st one out of the blocks. I hope you get burried. Pulling for you an everyone on here
 
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