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March 18-19th Possible Severe Wx Outbreak

JHS said:
Timing is not the best on the 6z GFS. Line comes through after midnight here on it. Would still be a small tornado threat though according to soundings.
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Well yeah same here comes through my area after midnight in upstate sc. I will say this I do not want a repeat of Easter Sunday morning those came after 2-3am. Seneca SC had a EF 3 and a EF 0 touched down a couple miles from my house. It was a very terrifying night lost power. I do not want a repeat of that


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That’s a solid looking QLCS, looks highly sheared/Forced with low instability 8F5D9B6A-0542-4C98-BD00-4229DB4F6254.pngECC6C008-E266-4BF1-9B2E-03480288714A.png
 
Looking at models for the Carolinas I notice they bring thru a morning QLCS, but the best cape works in after it moves out when we’re dry slotted
 
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CST Sat Mar 13 2021

Valid 161200Z - 211200Z

...DISCUSSION...
Plenty of spread/differences continue between the GFS and ECMWF for
the medium-range period -- even as early as Days 4-5. While the
broad/overall picture remains fairly clear that a notable increase
in severe threat will occur perhaps as early as late Tuesday
afternoon (Day 4) near a southern Plains dryline, and then
continuing Day 5/Wednesday (lower Mississippi and possibly the lower
Ohio Valleys east across the central Gulf Coast states/Mid South),
and potentially Day 6/Thursday (southern Appalachians/Carolinas).

The differences amongst the models are centered around evolution of
the next upper system moving out of the western U.S. at the start of
the period. The ECMWF depicts a closed low -- strengthening with
time as it ejects, and thus the feature advances more slowly than
the GFS, which depicts a more progressive, open wave. This has
substantial implications for timing/location of surface features
through the first few days of the period -- with these differences
becoming great enough by Day 6 that no meaningful assessment of
areas of possible risk can be confidently highlighted.

With the ECMWF's pattern evolution very similar to the EC's ensemble
mean, and also similar to the UKMET solution, will lean a bit toward
a slower/less progressive evolution and thus a slightly more
westward forecast. Day 4 (Tuesday), some conditional risk for
mainly hail may exist as far west as a northwestern Texas/western
Oklahoma dryline during the early evening, with some hail risk
spreading across parts of Oklahoma and North Texas overnight.
However, with this risk more conditional, will opt not to include a
risk area for Tuesday at this time.

By Day 5/Wednesday, a more substantially unstable environment,
encompassing a large area, is likely, as a moist Gulf airmass
streams northward, beneath rather steep lapse rates advecting
eastward. With an eastward moving surface cyclone and attendant
warm and cold fronts focusing ascent, and the likelihood for broad
warm advection/QG ascent within the expanding warm sector, scattered
severe storms appear likely even given timing/location differences
of surface features amongst the models. While a more concentrated
area or areas of severe weather may evolve Wednesday, those details
-- and any associated outlook highlights -- will require discernment
in subsequent outlooks nearer the event. For now, a large/broad 15%
risk area will be introduced, representing a large envelope of
all-hazards severe potential.

Day 6, model differences become substantial enough that -- while
severe weather risk may continue, no areas will be highlighted due
to the predictability concerns.

..Goss.. 03/13/2021
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Jessy89 said:
Well yeah same here comes through my area after midnight in upstate sc. I will say this I do not want a repeat of Easter Sunday morning those came after 2-3am. Seneca SC had a EF 3 and a EF 0 touched down a couple miles from my house. It was a very terrifying night lost power. I do not want a repeat of that


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Click to expand...
That storm was rough for sure. Seneca had that tornado, the the rest of upstate SC missed out on it, and the the outbreak really got going from the midlands down to the coast. I'm not really sure why more of upstate SC did not have severe weather unless we had a small minimum of cape and instability in the area that morning.
 
Euro still looks like the best setup for sups tbh with a mid level dry slot/EML punching in 95542804-353C-4F0A-88B3-822530ACE415.png734A32F7-AAEC-42CE-9D63-4D0C4BED6485.pngBBAF5C2E-68F9-48E0-9EC1-ADFB58F57571.png125CBFC0-8512-4DF1-BC39-0CE6C7B6F5C4.png
 
SD said:
View attachment 78838

Solid QLCS embedded supercell/tornado setup for Al on the GFS
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Yeah that looks nasty, even the LLVL LRs are high B3F1602C-2E51-4123-B102-142EBCF28E63.png1C16D9E1-D4F1-434F-8150-E73BEA2DFAC3.png5790E9EE-A8EE-4DA7-9EDE-8FEA6BE67BC6.png
for us I wonder how much instability we have for that QLCS looking thing, globals often suck with nighttime instability (NAMS do much better) should be interestingFE91455D-D288-4A4E-ACFF-9A32DB911D89.png
 
Myfrotho704_ said:
Yeah that looks nasty, even the LLVL LRs are high View attachment 78839View attachment 78840View attachment 78842
for us I wonder how much instability we have for that QLCS looking thing, globals often suck with nighttime instability (NAMS do much better) should be interestingView attachment 78841
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It's muddy for us. A lot of divergence out front and plenty of moisture so we should have a good bit of rain and "junk" convection preceding the main line. I'm not sure how much that will allow us to destabilize and if that will help keep an insitu type airmass in play. Another thing is do we see the initial band and pre frontal trough out run the better forcing so we are left with a weakening band and wind shift and overall not a whole lot. Just a few things I'm wondering about right now. If you overlap and time this correctly it's at minimum a strongly forced QLCS with a few embedded tornadoes.

I feel much more confident in the severe threat to our W/SW. It's looking fairly ominous for MS/Al/Ga/Tn
 
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