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Wintry January 29th-30th ARCC Slam Dunk Winter Weather Threat

GaWx said:
The timing/duration at ATL (~3-5 hours for ALL of the precip, not just the snow, and starting ~6-9 AM in ATL/ending late AM) and amounts for ATL (near 0.25” is what has fallen?) are about what modeling consensus suggested. But the temps were 8-10+ degrees warmer than what consensus showed!! That’s what got totally missed. Why were the temps so much warmer than modeled??
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The arctic front was slower to move in. Here's an excerpt from recent FFC disco:

Also worth noting that trends over last 6 hours of HRRR runs has shown warmer temps ahead of the front over ATL metro, indicating front may be moving in slower than expected.
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GaWx said:
The timing/duration at ATL (~3-5 hours for ALL of the precip, not just the snow, and starting ~6-9 AM in ATL/ending late AM) and amounts for ATL (near 0.25” is what has fallen?) are about what modeling consensus suggested. But the temps were 8-10+ degrees warmer than what consensus showed!! That’s what got totally missed. Why were the temps so much warmer than modeled??
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While I'm not certain of this particular case, it seems as though temps are always going to be slightly warmer than guidance, regardless of how solid the modeling was. In defense of some of the mets, even the short range models would frequently flip flop on temps for this event.
 
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Showmeyourtds said:
While I'm not certain of this particular case, it seems as though temps are always going to be slightly warmer than guidance, regardless of how solid the modeling was. In defense of some of the mets, even the short range models would frequently flip flop on temps for this event.
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But it wasn't just "slightly" warmer.
 
Using the SPC meso analysis it's pretty easy to see where the colder temperatures supporting snow vs the precip is. It'll be interesting to see how long the mountains hold back the cold for areas in NC too.
SPC 925.jpg
 
Showmeyourtds said:
While I'm not certain of this particular case, it seems as though temps are always going to be slightly warmer than guidance, regardless of how solid the modeling was. In defense of some of the mets, even the short range models would frequently flip flop on temps for this event.
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GaWx said:
But it wasn't just "slightly" warmer.
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I said this yesterday evening (quote below) regarding what would likely happen. It appears all 4 points have proven to be true in this setup as well. The synoptics of this event didn't favor much more than flurries on the backside like the warmer 3km NAM and RGEM runs were showing yesterday.

snowlover91 said:
My experience in these situations (and being burned many years ago when first following weather models) is as follows.
1. The cold air is usually slower to arrive than modeled.
2. The back edge dries up quickly as earnest CAA kicks in.
3. Many times these “cold chasing moisture” scenarios end up with flurries at best on the backside.
4. The 3km NAM and RGEM blended is the best way to go in the short range.

Having said that I sure hope this event turns out differently but trusting the globals over high res models this close usually isn’t a good idea. Good luck everyone, I hope you get a nice snow!
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GaWx said:
But it wasn't just "slightly" warmer.
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Fair point. For me I'd say slightly warmer would be 2-4 degrees? But 5+ degrees, you're correct. I suppose the models then might've underestimated preliminary WWA ahead of the front? I climbed to 58 yesterday which was close to what was forecast.
 
dsaur said:
I figured Rosie might get something, but south of that is a crap shoot with a clipper. They have to dig pretty deep to get down past Marietta. Usually the dusting is north of Gainesville. Anytime a chase is involved it usually ends in tears :)
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Looking at the traffic cam up in Morganton and they have a good coating. I'm guessing Rosie did better than most on this one.
 
snowlover91 said:
I said this yesterday evening (quote below) regarding what would likely happen. It appears all 4 points have proven to be true in this setup as well. The synoptics of this event didn't favor much more than flurries on the backside like the warmer 3km NAM and RGEM runs were showing yesterday.
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And you were exactly right. I've lived down here long enough to know that a clipper/frontal passage alone is often times not enough to get significant snow.

I could come up with a similar list of exceptions and truths for Miller As. (warm nose @ 925, sun angle in Feb, etc)
 
NWS is holding out on that rain/snow for me...... I am doubtful. Rain moving in on radar, maybe it'll start to cool things down
 
Jimmy Hypocracy said:
@Jessy89 any snow up in Maggie valley? cold air has been slow moving
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Nothing on the ground in Maggie Valley. Took my kids up the mountain a little ways and there a good 2-2.5 inches
88706459f94fa832d1764477401f2bdf.jpg



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A friend of mine just posted a picture of his house in the foothills outside of Maryville TN... beautiful snow scene with I'm guessing 2"-3" and snow still coming down
 
Jessy89 said:
Nothing on the ground in Maggie Valley. Took my kids up the mountain a little ways and there a good 2-2.5 inches
88706459f94fa832d1764477401f2bdf.jpg



Sent from my iPhone using Tapatalk
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awesome! That area never fails. If it doesn’t fall in the valley you can always drive 5 minutes up the mountain to see it rip. Radar looks like backend snow in Maggie now
 
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