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Severe January 12/13 severe threat

SD

SD

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To not clutter up the snow thread figured I'd start this up. Best chance of severe looks to be central/south ga, most of SC and parts of NC. Haven't looked at the specifics but seems to be a high shear low cape setup.

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MRX afternoon afd mentions possible thunderstorms but SPC sends sorta 'meh' on it.
"For late Thursday night and Friday, negative tilted upper trough
moves across the region producing strong upper level forcing. Strong
jet dynamics along with strong low-level jet will set the stage for
possibly storms over the southern half of the Tennessee Valley. Have
included chance of thunder. Will need monitor the potential of
strong storms over the southern valley."
 
Ty sir. Ya it looks like a low cape and high shear environment. I will say we have recovered quicky with moisture.
 
Yep, 0-3KM is pretty crazy via 18z NAM for SC.

As of late, SPC is not ready to really jump on yet.
 
GSP's take on Friday.

The upstream trough will sharpen up as it moves east into the MS
River Valley Thursday night, with a southern stream branch likely
breaking off over western Tennessee. A focused period of strong
dynamics will likely lift across the forecast area Friday afternoon
and evening. All models have a robust southerly low level jet with
50+ kt of surface to 3 km bulk shear. If the NAM is correct (with
the much deeper/southern cutoff low solution to the west), then
shear will be much greater across the region with strongly backed
950 to 850 mb flow. The models have also exhibited an uptick in
surface-based instability, with a consensus of about 300+ J/kg
crossing the region Friday afternoon. Chance thunder will be
advertised and high shear/low CAPE severe thunderstorms cannot be
ruled out. An HWO mention could be needed. Despite the abundant
clouds and showers, strong warm advection should push maxes back
into the 60s in many areas. Significant hydro problems are not
expected, with some 2 to 2.5 inch storm totals in southeast upslope
areas mitigated by dry antecedent conditions.
 
Here is what KGSP issued for the KCAE region around 3:30 PM today:

Models continue to depict an amplifying upper pattern through
Friday, in particular a sharp trough and robust cold front moving
across the Deep South. Consensus brings these features through
the forecast area Friday and Friday evening, with peak precip
chances in the afternoon and evening. The primary concern, given
the afternoon timing (especially with temperatures well above
normal on Friday), is for surface based convection developing in
a strongly sheared environment. At least a couple hundred
joules of SBCAPE appear likely in the warm sector. Backed sfc
winds in particular generate somewhat alarming 0-1 km
shear/helicity, along with low LCLs, implying some risk for
tornadoes. This will need to be monitored closely in subsequent
forecast cycles.
 
Do not want! (also don't think it is likely looking at the set up, which most NWS offices apparently think too) Which is worse, severe thunderstorms or ice storms? I go with severe thunderstorms and tornadoes.
 
MichaelJ said:
Do not want! (also don't think it is likely looking at the set up, which most NWS offices apparently think too) Which is worse, severe thunderstorms or ice storms? I go with severe thunderstorms and tornadoes.
Click to expand...
I would say ice storms are worse because they effect more people. Severe thunderstorms tend to be more isolated.
 
I don't expect some big ole outbreak or anything, but I do think some Severe is possible. We tend to do well with low cape and high shear..we will have to see how the trends are the next few days. I will say TD are already near 60 degrees, which is amazing since it was near 0 degrees a few days ago.
 
deltadog03 said:
I don't expect some big ole outbreak or anything, but I do think some Severe is possible. We tend to do well with low cape and high shear..we will have to see how the trends are the next few days. I will say TD are already near 60 degrees, which is amazing since it was near 0 degrees a few days ago.
Click to expand...
Agreed. Need to watch because the chance is there since we have a big winter system with so much warmth out in front. I can't remember exact dates, but there were a couple times in the early 2000's when I was in Atlanta I can remember where it was so warm going to holiday parties we didn't even wear coats, then leaving them late with thunderstorms everywhere and the next morning waking up to a dusting of snow. This seems similar.
 
deltadog03 said:
I don't expect some big ole outbreak or anything, but I do think some Severe is possible. We tend to do well with low cape and high shear..we will have to see how the trends are the next few days. I will say TD are already near 60 degrees, which is amazing since it was near 0 degrees a few days ago.
Click to expand...

Down your way in Macon, with the warmer air and dewpoints, into Upstate SC closer to the low circulation, and down through Columbia and towards the East Midlands, I can definitely see at least a damaging wind threat with locally heavy downpours. Not sure about the coast and the decoupling of the squall line from the parent low.
 
The 00z NAM, via soundings for this area doesn't look nearly as bad vs 18z. I would assume the heavy rainfall is a factor, also. 2-3 inches through here.
 
Shawn said:
The 00z NAM, via soundings for this area doesn't look nearly as bad vs 18z. I would assume the heavy rainfall is a factor, also. 2-3 inches through here.
Click to expand...
I don't know. We have very little cape but this is strong. nam_2018010918_081_34.01--80.85.png
 
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