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Severe WX April 1-2 (overnight) Severe Weather Event

Kds86z said:
Tomorrow is more conditional for discrete but weds has lot of questions also.. idk
Click to expand...
I think tomorrow is a very large conditional risk; while Wednesday is a quite large general risk. Although there are questions about the storm mode on Wednesday, models are in agreement that a severe event will occur; which is lacking on Tuesday.
 
wx_guy said:
Okay, so finally, I have some data about this event from my model. This is centered at Jonesboro, Arkansas with a 3 km resolution. Let's dig in!
Sadly, my window clips just the far eastern edges of Oklahoma and Kansas, so I may need to do another run centered on tomorrow's threat. Stay tuned.


First off, perhaps the biggest story (beyond the rest of the severe weather even) will be the rainfall amounts. The model projects some areas to get 7-10 inches of rain (the dark orange is 10-15 inches of rain), and this model ends at 96 hours past 06z this morning --> with heavy convective rainfall across this same area present at the model's end. So flooding rains will be a huge problem.
View attachment 38020




Next up is the Vertically Integrated Graupel. Graupel in storms often leads to more intense storm cores with frequent lightning and large hail. You can see a bevy of storms over the forecast period, with numerous large intense storm cores (the white spots).

View attachment 38022


The Hodograph Curvatures (measured by the area formed under the hodographs) is quite high across much of the area as well, indicating their well could be great opportunities for storms to take advantage of that rotation and ventilation.

View attachment 38023


As far as the threats go, the algorithm for Threat Potential Overlay doesn't pick up on anything at all until Wednesday evening (again, KS and OK are mostly chopped off and out of view...). It begins as a Wind threat...


View attachment 38025


By 5 PM, the tornado threat begins in earnest and with a High potential tagged.

View attachment 38026




By 6 PM, I think it's fair to say all hell is breaking lose...

View attachment 38027



7 PM (oz on Thursday):

View attachment 38028



This general pattern continues until about midnight Wednesday night/Thursday morning...


Where it then transition into a high-wind threat in Kentucky and Tennessee. Notice the Flash Flood risk starting over in Arkansas, too.

View attachment 38029




Things are then relatively quiet for a few hours...then...all hell breaks lose again Thursday night:

View attachment 38033


And this saga continues until the model ends a little after midnight on Thursday/Friday morning.








Here's an uninterrupted animation of just the Composite Radar (no threat overlay). Notice the extreme training of cells -- this is going to be a big problem.


View attachment 38034


Overall, this setup is really, really ugly and has a high ceiling. I would say the plethora of storms showing up and all the potential outflow boundaries and convective damping that may occur because of all the training may put the halt on some of this, hopefully? But taken verbatim, this is quite the setup unfolding.
Click to expand...
A walking line of discrete cells on your composite. Wow that’s beautifully horrifying.
 
Just some absolutely horrific rain totals forecast for the Ozarks into the mid/upper MSV and OH River Valley. That the areas suffering a dangerous tornado threat will soon-after be experiencing flooding is just insult to injury.
1743462038026.png
 
Clancy said:
Just some absolutely horrific rain totals forecast for the Ozarks into the mid/upper MSV and OH River Valley. That the areas suffering a dangerous tornado threat will soon-after be experiencing flooding is just insult to injury.
View attachment 38037
Click to expand...
Yes, the setup favors the supercells moving over the same areas repeatedly...I fear somewhere will see multiple tornadoes in the same vicinity, followed by flooding. And the rainfall over several days will undoubtedly hamper cleanups. Not a good setup at all.
 
Clancy said:
Just some absolutely horrific rain totals forecast for the Ozarks into the mid/upper MSV and OH River Valley. That the areas suffering a dangerous tornado threat will soon-after be experiencing flooding is just insult to injury.
View attachment 38037
Click to expand...
Gunna add to your post here Clancy. Excessive rainfall risks are 3 days straight moderates starting wensday. And it could be 4 but the risks only go out 5 days. Very possible high risk flooding is put up some of these days.

d5wbg.gifd4wbg.gif99ewbg.gif
 
Out of curiosity, assuming storms are indeed able to fire and go severe tomorrow, what's the highest ceiling (or at least an analog of such) that we can expect to see? I'm wondering if the ceiling could get as high as the likes of some of the more (in)famous Great Plains tornado days (e.g. 4/26/1991, 5/3/1999, 5/24/2011, to name a few).
 
Tennie said:
Out of curiosity, assuming storms are indeed able to fire and go severe tomorrow, what's the highest ceiling (or at least an analog of such) that we can expect to see? I'm wondering if the ceiling could get as high as the likes of some of the more (in)famous Great Plains tornado days (e.g. 4/26/1991, 5/3/1999, 5/24/2011, to name a few).
Click to expand...
04/29/22 Andover comes to mind in potential
 
wx_guy said:
Okay, so finally, I have some data about this event from my model. This is centered at Jonesboro, Arkansas with a 3 km resolution. Let's dig in!
Sadly, my window clips just the far eastern edges of Oklahoma and Kansas, so I may need to do another run centered on tomorrow's threat. Stay tuned.


First off, perhaps the biggest story (beyond the rest of the severe weather even) will be the rainfall amounts. The model projects some areas to get 7-10 inches of rain (the dark orange is 10-15 inches of rain), and this model ends at 96 hours past 06z this morning --> with heavy convective rainfall across this same area present at the model's end. So flooding rains will be a huge problem.
View attachment 38020




Next up is the Vertically Integrated Graupel. Graupel in storms often leads to more intense storm cores with frequent lightning and large hail. You can see a bevy of storms over the forecast period, with numerous large intense storm cores (the white spots).

View attachment 38022


The Hodograph Curvatures (measured by the area formed under the hodographs) is quite high across much of the area as well, indicating their well could be great opportunities for storms to take advantage of that rotation and ventilation.

View attachment 38023


As far as the threats go, the algorithm for Threat Potential Overlay doesn't pick up on anything at all until Wednesday evening (again, KS and OK are mostly chopped off and out of view...). It begins as a Wind threat...


View attachment 38025


By 5 PM, the tornado threat begins in earnest and with a High potential tagged.

View attachment 38026




By 6 PM, I think it's fair to say all hell is breaking lose...

View attachment 38027



7 PM (oz on Thursday):

View attachment 38028



This general pattern continues until about midnight Wednesday night/Thursday morning...


Where it then transition into a high-wind threat in Kentucky and Tennessee. Notice the Flash Flood risk starting over in Arkansas, too.

View attachment 38029




Things are then relatively quiet for a few hours...then...all hell breaks lose again Thursday night:

View attachment 38033


And this saga continues until the model ends a little after midnight on Thursday/Friday morning.








Here's an uninterrupted animation of just the Composite Radar (no threat overlay). Notice the extreme training of cells -- this is going to be a big problem.


View attachment 38034


Overall, this setup is really, really ugly and has a high ceiling. I would say the plethora of storms showing up and all the potential outflow boundaries and convective damping that may occur because of all the training may put the halt on some of this, hopefully? But taken verbatim, this is quite the setup unfolding.
Click to expand...
Anyway you could get an imaging for Northern IL/IN? Just composite radar.
 
After looking through the parameters and kinematics for tomorrow, I will say that inversion layer better hold, because if it doesn’t, it’s likely there will be significant tornadoes tomorrow in Oklahoma and southern Kansas. Here’s why.
1743464021704.png1743464165642.png
This longwave trough/jet streak orientation is close to meteorological perfection, the right exit region is positioned directly over the warm sector and is perpendicular to the LLJ.
1743464268732.png
Then you have little to no cyclonic vorticity streamers in the mid levels over the warm sector, which means forcing will be subtle. A discrete mode for southern Kansas and Oklahoma is all but guaranteed with this synoptic set up.
1743464448937.png1743464479369.png
High CAPE and surface moisture will be in place ready to be taken advantage of and emplaced under the strong LLJ.
With all of these factors, it’s likely there will be multiple tornadic supercells capable of producing significant tornadoes.

Here’s the kicker though.
There will be a strong inversion layer in place over the OWS, and almost every CAM fails to produce supercells in the areas of concern due to high CI caused by the inversion layer.

Surface moisture seems locked in loaded, but moisture returns in the low to mid levels is still uncertain. If moisture returns fail to mix out the inversion layer then an utter nonevent for Oklahoma is very much possible. Although for southern Kansas this scenario is looking less likely.

CAMs are notorious for failing to initiate convection in capped dry line OWS, for good reason of course. It’s why the NWS only has a 5% risk for tornadoes in Oklahoma at the moment.

This is a perfect example of a “just in time” moisture return/boom or b$st CAP plains setup. Either nothing is going to happen if the inversion holds, or all hell breaks loose, and nothing in between.
 
jiharris0220 said:
After looking through the parameters and kinematics for tomorrow, I will say that inversion layer better hold, because if it doesn’t, it’s likely there will be significant tornadoes tomorrow in Oklahoma and southern Kansas. Here’s why.
View attachment 38041View attachment 38042
This longwave trough/jet streak orientation is close to meteorological perfection, the right exit region is positioned directly over the warm sector and is perpendicular to the LLJ.
View attachment 38043
Then you have little to no cyclonic vorticity streamers in the mid levels over the warm sector, which means forcing will be subtle. A discrete mode for southern Kansas and Oklahoma is all but guaranteed with this synoptic set up.
View attachment 38044View attachment 38045
High CAPE and surface moisture will be in place ready to be taken advantage of and emplaced under the strong LLJ.
With all of these factors, it’s likely there will be multiple tornadic supercells capable of producing significant tornadoes.

Here’s the kicker though.
There will be a strong inversion layer in place over the OWS, and almost every CAM fails to produce supercells in the areas of concern due to high CI caused by the inversion layer.

Surface moisture seems locked in loaded, but moisture returns in the low to mid levels is still uncertain. If moisture returns fail to mix out the inversion layer then an utter nonevent for Oklahoma is very much possible. Although for southern Kansas this scenario is looking less likely.

CAMs are notorious for failing to initiate convection in capped dry line OWS, for good reason of course. It’s why the NWS only has a 5% risk for tornadoes in Oklahoma at the moment.

This is a perfect example of a “just in time” moisture return/boom or Forecasted Convective Amplification Deficiency CAP plains setup. Either nothing is going to happen if the inversion holds, or all hell breaks loose, and nothing in between.
Click to expand...
Ah good times lol…
 
jiharris0220 said:
After looking through the parameters and kinematics for tomorrow, I will say that inversion layer better hold, because if it doesn’t, it’s likely there will be significant tornadoes tomorrow in Oklahoma and southern Kansas. Here’s why.
View attachment 38041View attachment 38042
This longwave trough/jet streak orientation is close to meteorological perfection, the right exit region is positioned directly over the warm sector and is perpendicular to the LLJ.
View attachment 38043
Then you have little to no cyclonic vorticity streamers in the mid levels over the warm sector, which means forcing will be subtle. A discrete mode for southern Kansas and Oklahoma is all but guaranteed with this synoptic set up.
View attachment 38044View attachment 38045
High CAPE and surface moisture will be in place ready to be taken advantage of and emplaced under the strong LLJ.
With all of these factors, it’s likely there will be multiple tornadic supercells capable of producing significant tornadoes.

Here’s the kicker though.
There will be a strong inversion layer in place over the OWS, and almost every CAM fails to produce supercells in the areas of concern due to high CI caused by the inversion layer.

Surface moisture seems locked in loaded, but moisture returns in the low to mid levels is still uncertain. If moisture returns fail to mix out the inversion layer then an utter nonevent for Oklahoma is very much possible. Although for southern Kansas this scenario is looking less likely.

CAMs are notorious for failing to initiate convection in capped dry line OWS, for good reason of course. It’s why the NWS only has a 5% risk for tornadoes in Oklahoma at the moment.

This is a perfect example of a “just in time” moisture return/boom or b$st CAP plains setup. Either nothing is going to happen if the inversion holds, or all hell breaks loose, and nothing in between.
Click to expand...
What's your thinking for the mid south on Wednesday into Thursday?
 
jiharris0220 said:
After looking through the parameters and kinematics for tomorrow, I will say that inversion layer better hold, because if it doesn’t, it’s likely there will be significant tornadoes tomorrow in Oklahoma and southern Kansas. Here’s why.
View attachment 38041View attachment 38042
This longwave trough/jet streak orientation is close to meteorological perfection, the right exit region is positioned directly over the warm sector and is perpendicular to the LLJ.
View attachment 38043
Then you have little to no cyclonic vorticity streamers in the mid levels over the warm sector, which means forcing will be subtle. A discrete mode for southern Kansas and Oklahoma is all but guaranteed with this synoptic set up.
View attachment 38044View attachment 38045
High CAPE and surface moisture will be in place ready to be taken advantage of and emplaced under the strong LLJ.
With all of these factors, it’s likely there will be multiple tornadic supercells capable of producing significant tornadoes.

Here’s the kicker though.
There will be a strong inversion layer in place over the OWS, and almost every CAM fails to produce supercells in the areas of concern due to high CI caused by the inversion layer.

Surface moisture seems locked in loaded, but moisture returns in the low to mid levels is still uncertain. If moisture returns fail to mix out the inversion layer then an utter nonevent for Oklahoma is very much possible. Although for southern Kansas this scenario is looking less likely.

CAMs are notorious for failing to initiate convection in capped dry line OWS, for good reason of course. It’s why the NWS only has a 5% risk for tornadoes in Oklahoma at the moment.

This is a perfect example of a “just in time” moisture return/boom or b$st CAP plains setup. Either nothing is going to happen if the inversion holds, or all hell breaks loose, and nothing in between.
Click to expand...
Needs to be emphasized that some of these models not showing initiation are erroneous in that depiction. They should show initiation, but don't because of issues with their convective/BL schemes. This is particularly relevant regarding the NAM 3 km.
 
andyhb said:
Needs to be emphasized that some of these models not showing initiation are erroneous in that depiction. They should show initiation, but don't because of issues with their convective/BL schemes. This is particularly relevant regarding the NAM 3 km.
Click to expand...
That explains SO MUCH why the NAMNST (3km) more times than up is underwhelming when it comes to convection, even in potential high-end outbreaks.
 
I feel like we've already established that it's a go or no go situation. Now, the only thing remaining is whether it will go; or not go. Models have been giving different scenarios on different runs, so my question is: what factors will ultimately define if it goes or won't go, and what do those parameters look like as of now?
 
Mrgolfman7070 said:
What's your thinking for the mid south on Wednesday into Thursday?
Click to expand...
The kinematics and parameters/synoptic set up also favor multiple tornadic supercells capable of producing multiple significant tornadoes.

However, there are multiple failure modes.
The first is morning convection and widespread overcasting could limit instability.

The second is an over saturation PBL, which could cause a messy storm mode with low topped crapvection disrupting inflow into any supercells trying to put down a tornado.

The third is the OWS inversion layer, which could limit CI strictly close to the cold front, although some CAMs show little to no capping in the OWS. Which would ironically not help with limiting crapvection.

Then you also have meager low level lapse rates, below 6C/km, likely because of the widespread overcasting limiting radiative heating at the surface.

Not surprised at all the NWS is holding of the initiation of a moderate risk, because despite the potent kinematics and parameters, there’s to much uncertainty with the storm mode.
 
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