yeah, this is also where the "duck and put the textbook over your head" came from as well.
And despite appearances, i'd bet the schools are more likely to survive than houses, and that most kids are safer in the halls than on a slab
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Severe WX March 23-25th, 2023
- Thread starter Lake Martin EF4
- Start date
And despite appearances, i'd bet the schools are more likely to survive than houses, and that most kids are safer in the halls than on a slab
Sawmaster
Member
One of the problems with stronger building codes is that the increased cost of a home then puts more people in trailers, countering your intended results. Many rural areas haven't had building codes in place long enough to affect the survival rate with tornadoes; it's the old homes that fail
I'm glad you're OK and that you have power that means Mom probably has power. From what I can see reviewing the radar footage again it didn't miss my mom's house by too much either. She lives down Seminole Road from the school about 4 or 5 streets down on Cheyenne Avenue. I swear man we got a do something to appease mother nature, because I think she's unhappy about something with the entire county for some reason, especially up towards Smithville. If you add in the F3 that hit Hamilton a few years back to the rest of the storms and I think we've had quite enough in Monroe County.
Gail
Member
tornado examiner
Member
Some of that is easily low end ef4 indicative.
tornado examiner
Member
I wonder what the tree damage is like in this big forested area
Equus
Member
Wow. The debarking was more severe and widespread than I had initially thought. Pretty violent.
TornadoFan
Member
I was really hoping that, after seeing the way things were looking in the afternoon, we were gonna get away without something major happening. Sadly, I was proven wrong and there was that one storm that just managed to find a sweet spot.
jiharris0220
Member
People say it was only that one supercell. But as time goes on and the surveys continue, it’s becoming increasingly apparent that there were plenty of other supercells that produced significant tornadoes.
There are already 3 identified ef2s and the one that occurred in Danville has a fatality.
There are already 3 identified ef2s and the one that occurred in Danville has a fatality.
tornado examiner
Member
Just note. That yes…well bolted structures were either leveled or partially swept away in rolling fork.
Ground scouring mentioned by a met from BMX that was surveying today as a part of the PERiLS project.
You got to remember, this tornado hit one of the poorest part of the state and in the nation.
Shakespeare 2016
Member
That is incredible ground scouring. WOW!!!
Sawmaster
Member
Pix or links? Would like to see any bending or slab breakage to add to my crazy thoughts on the subject.
Equus
Member
Equus
Member
Per the survey DAT, here is where the fatality in Hartselle was; anchored mobile home destroyed. HUN has pretty much all their surveys up on the DAT now
Equus
Member
Time for a post-mortem? Time for a post-mortem! Kind of. Once again, any input/correction is welcomed as I love delving into the science of events and figuring out why things happened (or didn't happen) at least until Convective Chronicles makes a superior version in the next couple days. This is all just speculation plus a bit of what others far smarter than me have brought up so yes please add or debate stuff
The cool thing is Jackson took soundings every three hours the whole event so we have a lot of observed data to work with
Here's what we had at the time of the Rolling Fork tornado on the RAP
Very narrow tongue of mid 60s dews streaming up along central MS based on surface observations; rather dry low level air to the east but the cell was primed to interact with this plume of deeper moisture rather perfectly; instability was pretty decent if nothing spectacular on the arrival of an intense low level jet
This low level jet was no doubt heavily enhanced by a surface low near Memphis, offering low level backing and a dramatic strengthening of the wind profile as the jet max pushed through; a very quick improvement in wind profiles as well as a good aid for rapid advection. However only a couple supercells managed to develop, the Rolling Fork one and the one that moved up to near Tupelo - literally everything else to the south and east struggled and died until the linear conglomeration later. Why is that? Maybe soundings will help
Here's soundings from JAN every three hours from 12z Friday to 06z Saturday, showing a dramatic and fascinating change in the profile; we start with a very significant EML just above the surface, with very dry air and a significant inversion. By 18z, an interesting evolution; widespread sun had allowed surface temps to dramatically rise, steepening lowest level lapse rates tremendously but drying out the surface quite a bit as the dry air from the EML mixed down. Another very important feature here - a very evident warm nose at 3km. This of course is something that tends to cause lapse rates in that layer to suffer, really killing vertical growth had storms been trying to form then; this continues to be evident for hours, only very slowly modifying. Note the surface temperature and dew spreads; we get moistening of the low levels as advection picks up, but the dry air above the surface also quickly vanishes as deep moisture becomes more evident all the way to 3km or so. You really want to see a somewhat drier layer aloft to get steep lapse rates there; a super saturated column tends to have pretty poor lapse rates in southeastern events and there's pretty marginal vertical growth evident in the warm sector here despite slight improvement by 00z. The cell near Jackson really struggled through that environment and was never really able to root and take off. With little forcing and some pretty marginal lase rates, it looks like cells didn't really have enough vertical acceleration to take off and take advantage of this environment. Note also the gradual improvement in wind profiles as the hodograph becomes more impressive, the LLJ and surface low along with the arriving upper air support helping to bring that up. The storm is nearby at 03z and that profile is probably the most representative aside from the ones taken by researchers, but it's important to note that the supercell did not develop anywhere near this environment; it had been growing for quite a while
The cell developed south of Alexandria, LA as a struggling messy shower with lots of mergers along a confluence band and tracked for about four hours across Louisiana before finally taking root crossing into Mississippi, hooking right, and immediately dropping a violent tornado
Here's the Lake Charles profile at 18z, lapse rates are better here but still with a bit of a warm layer between 1-3km that probably held cells back a bit; no shortage of low level moisture however.
A confluence band is an area that can focus convection and act as a lifting mechanism; when these are present, it can negate poor lapse rates somewhat and help cells to grow. The radar evolution combined with the profile seems to tell the story of what happened: the meager vertical acceleration across Mississippi with no real focusing mechanism really made it hard for cells to grow in the open warm sector, leading to not much development there aside from that one cell near Jackson that struggled and eventually died, but the confluence bands across Louisiana managed to get some updrafts going by focusing lift.
These struggled along for a while, but research has shown that multiple cell mergers can help shore up an updraft in a weak lapse rate enviro and eventually build a robust updraft even in the absence of good lapse rates, and it certainly looks like the storm of the day went through several mergers as it tried to take root, helping negate weak vertical acceleration somewhat. Once it neared Mississippi and the edge of the deep moisture streaming in, at about the same time that the LLJ really started screaming in slightly backed surface flow with the low near Memphis and jet support moving in, it was able to really take advantage of the better environment thanks to having an established updraft with multiple mergers before reaching the area where updrafts just couldn't get going. Winds being backed at this point S of the surface low and not veering strongly and supporting a more QLCS setup for a couple more hours when the low was well to the NE made the timing absolutely perfect to maintain discrete structure.
Thus, it developed in an area where the confluence bands helped get stuff going and moved into an environment that was super volatile but new cells were unable to develop, just in time for the vicious wind profiles to start peaking and the tongue of deeper moisture aligning perfectly with its path; many factors coming together to put it in the perfect spot, while stifling new convective growth and keeping it all to itself with unimpeded inflow for a long time
The cool thing is Jackson took soundings every three hours the whole event so we have a lot of observed data to work with
Here's what we had at the time of the Rolling Fork tornado on the RAP
Very narrow tongue of mid 60s dews streaming up along central MS based on surface observations; rather dry low level air to the east but the cell was primed to interact with this plume of deeper moisture rather perfectly; instability was pretty decent if nothing spectacular on the arrival of an intense low level jet
This low level jet was no doubt heavily enhanced by a surface low near Memphis, offering low level backing and a dramatic strengthening of the wind profile as the jet max pushed through; a very quick improvement in wind profiles as well as a good aid for rapid advection. However only a couple supercells managed to develop, the Rolling Fork one and the one that moved up to near Tupelo - literally everything else to the south and east struggled and died until the linear conglomeration later. Why is that? Maybe soundings will help
Here's soundings from JAN every three hours from 12z Friday to 06z Saturday, showing a dramatic and fascinating change in the profile; we start with a very significant EML just above the surface, with very dry air and a significant inversion. By 18z, an interesting evolution; widespread sun had allowed surface temps to dramatically rise, steepening lowest level lapse rates tremendously but drying out the surface quite a bit as the dry air from the EML mixed down. Another very important feature here - a very evident warm nose at 3km. This of course is something that tends to cause lapse rates in that layer to suffer, really killing vertical growth had storms been trying to form then; this continues to be evident for hours, only very slowly modifying. Note the surface temperature and dew spreads; we get moistening of the low levels as advection picks up, but the dry air above the surface also quickly vanishes as deep moisture becomes more evident all the way to 3km or so. You really want to see a somewhat drier layer aloft to get steep lapse rates there; a super saturated column tends to have pretty poor lapse rates in southeastern events and there's pretty marginal vertical growth evident in the warm sector here despite slight improvement by 00z. The cell near Jackson really struggled through that environment and was never really able to root and take off. With little forcing and some pretty marginal lase rates, it looks like cells didn't really have enough vertical acceleration to take off and take advantage of this environment. Note also the gradual improvement in wind profiles as the hodograph becomes more impressive, the LLJ and surface low along with the arriving upper air support helping to bring that up. The storm is nearby at 03z and that profile is probably the most representative aside from the ones taken by researchers, but it's important to note that the supercell did not develop anywhere near this environment; it had been growing for quite a while
The cell developed south of Alexandria, LA as a struggling messy shower with lots of mergers along a confluence band and tracked for about four hours across Louisiana before finally taking root crossing into Mississippi, hooking right, and immediately dropping a violent tornado
Here's the Lake Charles profile at 18z, lapse rates are better here but still with a bit of a warm layer between 1-3km that probably held cells back a bit; no shortage of low level moisture however.
A confluence band is an area that can focus convection and act as a lifting mechanism; when these are present, it can negate poor lapse rates somewhat and help cells to grow. The radar evolution combined with the profile seems to tell the story of what happened: the meager vertical acceleration across Mississippi with no real focusing mechanism really made it hard for cells to grow in the open warm sector, leading to not much development there aside from that one cell near Jackson that struggled and eventually died, but the confluence bands across Louisiana managed to get some updrafts going by focusing lift.
These struggled along for a while, but research has shown that multiple cell mergers can help shore up an updraft in a weak lapse rate enviro and eventually build a robust updraft even in the absence of good lapse rates, and it certainly looks like the storm of the day went through several mergers as it tried to take root, helping negate weak vertical acceleration somewhat. Once it neared Mississippi and the edge of the deep moisture streaming in, at about the same time that the LLJ really started screaming in slightly backed surface flow with the low near Memphis and jet support moving in, it was able to really take advantage of the better environment thanks to having an established updraft with multiple mergers before reaching the area where updrafts just couldn't get going. Winds being backed at this point S of the surface low and not veering strongly and supporting a more QLCS setup for a couple more hours when the low was well to the NE made the timing absolutely perfect to maintain discrete structure.
Thus, it developed in an area where the confluence bands helped get stuff going and moved into an environment that was super volatile but new cells were unable to develop, just in time for the vicious wind profiles to start peaking and the tongue of deeper moisture aligning perfectly with its path; many factors coming together to put it in the perfect spot, while stifling new convective growth and keeping it all to itself with unimpeded inflow for a long time
- Confluence bands focusing lift in weak lapse rate environment allowed cell formation
- Multiple cell mergers helped establish an updraft where otherwise would be unable to
- Moved right into rapidly improving dynamics/low level moisture plume along LLJ and S of surface low at the perfect time to take advantage
- Weak lapse rates and no real focusing mechanism just yet prevented other cells from developing/impeding
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