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Severe DEEP SOUTH Severe Weather threat 18-20th

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Told Reed Timmer on Twitter last night to park it at Calhoun CC south of Athens AL north of Decatur AL and wait for the supercells. The strong tornados always take that track .. north of Moulton, NW of Decatur, just South of Tanner and then track NE to Harvest. I've mapped all the strong tornado paths in the last 50 years through North AL using GIS software.
 
Same run, same model, same location, different sites and soundings? Which one is right? Pivotal looks insane for the upper atmosphere having 105% RH and TT looks way too dry. They look bad regardless.
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In most cases the Atlanta metro is spared the very worst from these events thanks to the foot of the Apps just to their north and northwest over NE AL and NW Georgia which can disrupt low-level vorticity and inflow vital to tornadogenesis and intensification, but obviously the metro can still take a huge beating.
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This is just one reason why Dixie Alley is primarily confined to the west and NW of Atlanta, with a historical tornado track density cluster over northern Alabama which is likely to be the primary target for today's tornadoes.

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This doesn't automatically mean people should let their guard down however even w/ poor diurnal timing, potential for upscale growth, etc.
 
Xtreme Weather said:
Oh boy backed winds more pronounced not good... Going to be some violent long trackers I believe... Geez
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Very shallow moisture column though. Very fine line between long trackers or just rapidly rotating supercells with no ground truth.
 
HRRR for KHSV tonight at 0z. Thankfully not showing the 11.3 STP from a run last night, but still significant at 5.4.
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Webberweather53 said:
In most cases the Atlanta metro is spared the very worst from these events thanks to the foot of the Apps just to their north and northwest over NE AL and NW Georgia which can disrupt low-level vorticity and inflow vital to tornadogenesis and intensification, but obviously the metro can still take a huge beating.
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This is just one reason why Dixie Alley is primarily confined to the west and NW of Atlanta, with a historical tornado track density cluster over northern Alabama which is likely to be the primary target for today's tornadoes.

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This doesn't automatically mean people should let their guard down however even w/ poor diurnal timing, potential for upscale growth, etc.
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Thanks for the explanation on that Webb.


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Parker said:
ARCC, what are you thinking about the threat for today?
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I think hail will be the main story for most if us. I'm pretty sure we will see some nice supercells fire with some great radar presentation and they will rotate like crazy. The question in my mind is will the ground truth match the radar. Mixing is the trump card. Create a dewpoint depression at the surface and a long track tornado threat becomes a quick hit threat with weak tornadoes. I've seen this happen many times over the years.

With the sun coming out and low level winds increasing, we should have a good idea whether mixing will be a problem or not by mid afternoon.
 
Long live the wedge. I love a good thunderstorm but I do not like wind and large hail. Hope this thing is a bust but we’re (the south and southeast) due. Be safe
 
Jimmy Hypocracy said:
Long live the wedge. I love a good thunderstorm but I do not like wind and large hail. Hope this thing is a bust but we’re (the south and southeast) due. Be safe
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The area of moderate and slight risk keep creeping in S.C. more and more! It’s about in the low 60s now and breaks in the clouds and getting humid! Forecast high was mid 50s. I think Upstate, especially S and W of 85, will get some pretty nasty storms this evening
 
I know they just upgraded to a MDT risk but there's an appreciable amount of crapvection in NE MS that's fixing to move into northern Alabama and could put a serious dent into instability.
 
Webberweather53 said:
I know they just upgraded to a MDT risk but there's an appreciable amount of crapvection in NE MS that's fixing to move into northern Alabama and could put a serious dent into instability.
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Yeah, if that just lifts north like the HRRR is suggesting, it won't do much. However, it it develops southward as it moves, it may do something. It almost appears to be moving with the dewpoint surge however, so I think it may not last long.
 
Really been locked in with cloud cover and mist today in Etowah County so far. It's limited temps to only 60. I know it's still early, but it doesn't have the usual "feel" of a severe weather day. Maybe the air will remain more stable than expected.
 
ForsythSnow said:
Yeah, if that just lifts north like the HRRR is suggesting, it won't do much. However, it it develops southward as it moves, it may do something. It almost appears to be moving with the dewpoint surge however, so I think it may not last long.
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If the cold pools or just the intensity of this convection in general is stronger than forecast that will result in more east-southeasterly propagation than the HRRR is willing to admit. Right now the cold pools are winning and new, smaller cB are beginning to blossom just ahead of the decaying storm that's crossing into AL. The 1 hour HRRR forecast completely botched the southerly extent and intensity of the convection in NE MS.
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