The Super Outbreak of April 27, 2011: A Case Study

In-depth case study of the historic super outbreak of tornadoes that occurred on April 27, 2011. This video features a deep dive into the meteorology behind this infamous day, rounded out by a comparison between the April 27 event and the previous standard for tornado outbreaks, the April 3-4, 1974 event.
Thumbnail images via ABC 33/40 and the National Weather Service.
April 27, 2011 journal article (Knupp et al. 2014): journals.ametsoc.org/view/jou...
April 3-4, 1974 journal article (Corfidi et al. 2010): journals.ametsoc.org/view/jou...
Chapters:
0:00 Introduction
3:58 Meteorology behind the April 27 outbreak
44:13 Comparison between April 27, 2011 and April 3-4, 1974

[@evirs]

Watched this countless times, but I'm always fascinated by that massive, punching trough with a jet that overspreads the entire warm sector. Same thing with Apr 3 1974. Discrete supercells spaced perfectly apart to stay alone for hundreds of miles with an incredible environment that didn't change for hours.

[@MeesterJ]

The 2011 Super Outbreak was the pinnacle of tornado outbreaks. Given the EF scale compared to the F scale, it is highly likely that a lot of the EF4s would have been F5s in 1974. With the focus on damage instead of windspeeds, the ebtter construction of homes nowadays, and windspeeds not being directly measured in 1974, it is safe to say this was the most brutal outbreak in history. It also had some of the most intense tornadoes ever recorded, like Smithville and Hackleburg who are right up there with Jarrell and Bridge Creek...

[@JeffreyWilson007]

Live in North AL and lived through this and it was a surreal experience to say the least. We often get tornadic storms, but this was just an entirely different level. I had to drive through the aftermath of the Cullman-Arab F4 to get home from work and it was awful. Most of this video is above my head as I'm no weather expert, but a fascinating perspective of a day I will never forget. Thanks for the video.

[@ConvectiveChronicles]

Thank you for watching! Yeah, that day was a whole other level from a meteorology perspective. Can’t imagine seeing that damage in person.

[@dstre17]

I agree I was living in Mississippi and I remember them talking about the storms possible. One of the scariest times. I was out running smithville in Mississippi.

[@arcticelectric]

i was on active duty with the air force in alaska and had to get updates via facebook. My mom and dad were almost hit by the tornado that crossed the river and took out Dot's Soulfood on 20 in Trinity, and I graduated with Will Stevens and Danielle Downs' sister...

[@BamaRailfan]

I also lived down there at that time. Surreal is putting it mildly. It was the scariest yet most awe inspiring weather event I have ever witnessed. I lived in Albertville. The cell that produced the Philadelphia, MS EF5 and the Cordova EF4 passed directly over my home before spawning the Rainsville EF5 only minutes later. I drove through that damage a couple of days later on my way out of state and it looked like a bomb had gone off. There was absolutely nothing left standing where the tornado had passed.

[@questionitall3053]

The Tornado stat that always gets me is the 7 F5s in 24 hours, during the April 3rd/4th 1974 super outbreak.

[@williamtrakas3142]

Yeah certainly incredible! But I think the standards for EF-5 ratings are higher I think than for F5’s. Likely at least one of the F5’s from that day would have been rated strong EF-4’s in 2011 and probably the Tuscaloosa tornado would have been an F5 in 1974. But I’m no expert and I could certainly be wrong. Anyone have a better educated opinion on this?

[@bigaaron]

​@@williamtrakas3142Also an amateur, and I agree with you for what that's worth.

[@mauriciostorm]

​@@williamtrakas3142you're very likely correct. The EF scale is more strict than the original, so a couple of the EF4 tornadoes on 27 April 2011 would have been rated F5 years earlier I believe. Prime exemple would be the Tuscaloosa tornado.

[@msmith6634]

Yes but they guessed at alot of those ratings. Houses weren't well built with hangers like today. I think it would be fair to say that 74 outbreak may have had one or two f5 not 7.

[@supertornadogun1690]

@@msmith6634 Xenia was definitely one of those, same with Guin, AL tornado.

[@robdoesweather6758]

YESSS! I get so excited every upload I see from this channel. April 27th is an event that made me fall in love with weather. I remember watching it on TV after elementary school. One of the wildest weather events in all of recorded history. I pray we never see an outbreak like this again

[@ConvectiveChronicles]

Thank you!! I, too, remember watching the coverage on the Weather Channel after school and being dumbfounded at what I was seeing. Such an incredible event.

[@briangreen256]

I lived thru it. Excited wasn't how I would describe it!

[@peachxtaehyung]

@@briangreen256 they're saying they're excited for every upload not watching the event lol. But I am sorry you went through it! I hope everyone made it out ok and you're doing well now!!

[@Jjay969]

I survived a tornado that day ripped out roof off and middle of house caved in , I was checked out of middle school due to the weather and we went and hid in the basement with my mom and brother. That Tuscaloosa Al tornado came all the way to Birmingham. I to have since found interest in weather and tornados in my state and Dixie ally . I didn't see that tornado in person but I felt and heard every bit of it . I now would love to see one in person from a good distance but just like ghost kinda fearful but interested at the same time

[@strat5520]

i lived through it! I lived in Danville AL at the time. Phil campbell is a little to the south west. Hilsboro to our north west. The Hackle burg tornado passed a few miles to my northwest, but I was at a walmart trying to get batteries for our radio at the time. So it passed just 2 or so miles north of me ehile I was there. I saw the storm on the horizon as it was passing. Ill never, ever forget that day. I saw impossible things. Huge tractors in pinetrees, etc

[@midsouthexpress]

You know it is going to be a good video when it starts off with a pic of James Spann standing in his suspenders!

[@ConvectiveChronicles]

Hahaha James Spann is the best!

[@WikiDWhack]

Lived through this day in Athens, Al. Still have a picture on my phone of the F5 taken from 2-3 miles away.. it’s fills the entire frame.

[@ConvectiveChronicles]

Dang, that’s crazy

[@StayPrimal]

I watched the live coverage like 100 freaking time no jokes. There is something ... I dunno, mystical about it. I often get chills watching it live. Especially at 3am when Jason starts, from minute to minute its getting worst and you can see in his eyes that he understand this is a historic day, just starting off. Anyway, that video was very complementary, that was awesome well done. Discovered your channel yesterday, new sub new fan.

[@ConvectiveChronicles]

Thank you very much! I absolutely love watching the ABC 33/40 coverage of 4-27. It’s the gold standard of how to cover a dangerous tornado outbreak live, and it’s really eerie watching it knowing the outcome.

[@StayPrimal]

@@ConvectiveChronicles Totally agree! Its a textbook coverage.

[@F0urSidedHexag0n]

Seeing the plots of soundings really drives home how the meteorologists seeing these for the first time probably felt: Shock, then maybe fear/panic. 1200 SRH is absolutely insane. What will always get me are these plots and hodos, plus the sheer amount of discrete cells that were in AL at one time.

[@ConvectiveChronicles]

Yeah, this is about as close as it gets to meteorological perfection for a tornado setup. Definitely a confluence of ingredients that doesn’t come around too often.

[@miche1df]

Yeah if you read the SPC outlooks you get the sense of how alarming this was even to the experts. That 1630z outlook felt like their version of the infamous Hurricane Katrina bulletin. I hope they never feel the need to write "this system is very organized and confidence is high regarding the potential for a major tornado outbreak" again. I still get chills when I read it. You could sense it when you went outside too. That was my last day of classes as a senior at Auburn and when people talk about "the feel", that's what they mean. Warm, muggy, overcast with fast-moving clouds, strong swirling winds...ominous in a way I've never felt in any other severe event. You didn't need to know how to read a skew-T or a hodograph to know that something bad was going to happen.

[@Angelica_Tims_Weather]

​@@ConvectiveChronicles I was a forecaster in the Navy during the outbreak and we had chiefs and civilians that had 30+ years experience in meteorology that said they have never seen atmospheric dynamics like that and when I seen the look of concern on their faces you just knew this was going to be devastating for the ones in the path of these tornados. The Philadelphia, Ms EF5 still amazes me with the intensity of the ground scouring.

[@NeonBeeCat]

​@@miche1dfthat feel always gets me, and it makes me unable to sleep since the nashville 2020 tornado hit my neighborhood while i was asleep and somehow didnt wake up despite the damage.

[@jaredpatterson1701]

​@@Angelica_Tims_Weatherand the forward speed!

[@thundersnow93]

The Phil Campbell/Hackleburg EF-5 tracked 1/4 mile north of my house in NW Madison county. It was ~half mile wide and rated high-end EF-3 damage in our neighborhood and sadly killed a person. We were well north of the midday outflow boundary the whole afternoon with temps in the high 50s/low 60s, but that tornado wasn't affected at all by the stable air. In fact, after the tornado tracked through, our temps rose to around 70 and we had training supercells all evening until the dryline finally came through. I measured 6.78" rain that day (~inch and a third each with early morning and midday QLCS, and ~4 inches with evening supercells) on top of the extreme tornado damage to the neighborhood. A day we will never forget!

[@thundersnow93]

On a side note, it bugs me a bit at how often a meteorologist will analyze upper-level charts and allude to diffluence / divergence aloft using a 500-mb map. While 500-mb flow is correlated to the jet stream level ~200-300 mb, the 500-mb level is approximately the level of non-divergence. So to properly analyze areas of divergence/diffluence aloft, one should examine the 200-300-mb maps for the diverging wind vectors that favor areas of upward motion and low-level cyclogenesis.

[@big_yam]

Speaking of 2011 case studies, I think another good outbreak to analyze would be the the April 14-16 tornado outbreak. That's another very significant and widespread outbreak that gets overlooked because of what happened only a couple weeks later.

[@ConvectiveChronicles]

It’s on my list!

[@Cameron_Chase13]

As always, a hell of a breakdown Trey! Always great to go back in time and learn a bit about these setups! Keep it up brotha

[@ConvectiveChronicles]

Thank you!!

[@dillyboyq]

This is now my third time watching this vid, and I have loved it more n more every time ! As I’ve slowly been learning a plethora of things about severe weather from mainly you Trey, it’s been cool to watch back these vids and be able to understand what you’re talking about Compared to when I first started watching and I was so confused hearing all the terminology n such. Makes me appreciate the work you put into this even more! Keep it up!

[@ConvectiveChronicles]

Heck yeah!! Thank you!

[@Rhi_wx]

Absolutely awesome video again Trey, great meteorological breakdown of such an absolutely unfathomable set up!

[@ConvectiveChronicles]

Thank you, Rhi!

[@Tornado376.]

Another amazing video! I stared watching your videos with the Dec. 10 outbreak and have been watching many of your videos since! I've learned so much from these videos, thank you for making them!

[@ConvectiveChronicles]

I really appreciate that! Thanks so much for the kind words!

[@PFA...]

This is my favorite channel right now. Deep analysis. So good, bravo, bravo!

[@ConvectiveChronicles]

Thank you!!

[@dakotastrawn93]

Man thank you so much. I've struggled with determining storm mode for a while. Without the CAMs I would be lost a lot of times. I knew that an EML was needed, but the zonal westerly flow and subtle forcing was something new for me to learn. Great video. Subscribed.

[@ConvectiveChronicles]

Thank you! I also have a recent video on how to forecast storm mode that might help you out, as well: kzbin.info/www/bejne/qWLEZoF9opaDi7c

[@JusTryNc]

It’s amazing that this information is free to watch! Man what a time to be alive! Thank you so much for what you do man!

[@ConvectiveChronicles]

It’s my pleasure; thank you!

[@SpacemanSpiff17]

Coming out big with this case study; can't watch all of it now but will when I get out've work. The amount of time and effort you put into these videos is incredible.

[@ConvectiveChronicles]

Thank you! These videos do take quite a bit of time to make, but in the end, it's a great learning process for me, and I really enjoy helping viewers learn about what goes into these complex tornado events from a meteorological perspective. Thanks again; I hope you enjoy this one!

[@64BBernard]

This is a really, really good review and case study of the April 27, 2011 Super Outbreak. I'm very impressed with the work you've done here and also thank you for providing links to the papers that I can read.

[@ConvectiveChronicles]

Thank you so much for the kind words!

[@rpglennj]

So glad I found this channel and absolutely love the analytical method on these events. I remember the 74 outbreak as a kid and taking shelter in our home in East TN at the tail end of that event. Our house and town took some damage that night. It sparked my love for weather. As you laid down the details, it stoked an even more profound appreciation for what it took to trip the atmosphere to the level of chaos that it brought that day. I was at work watching the local media feeds online and just couldn’t believe all the supercells dotting the radar. Would love to see an analysis of the May 2019 Memorial Day outbreak in Indiana/SW Ohio, which for us regionally, was groundbreaking given the storm mode was sustained during the night. I was on the Dayton EF4 that night. Anyway, great work and am subscribed!

[@ConvectiveChronicles]

Thank you so much! The May 28, 2019 event is on my list! I recall watching the Dayton tornado on radar that night; those were some harrowing images.

[@s1kkris40]

Smithville was the most intense tornado ever considering the speed it was moving imo.

[@commiehunter733]

Smithville was an insanely intense tornado 🌪

[@tropicalcyclone2953]

I'm so exited to watch a case study of a historic event from a great meteorologist! I have a suggestion: Do you think you can do a case study on last Wednesday's (10/12/22) tornado event in Wisconsin? I really think its worth talking about given how unexpected it was (and how weird it was, there were tornadoes in a line of showers producing no lightning). I live in Chicago, but I have a lot of friends in Milwaukee, and I was rushing to warn them to take cover. Many of them were really surprised since there was no forecast for severe weather that morning.

[@ConvectiveChronicles]

Thanks so much! I can definitely add that to the list; that was a very interesting event.

[@aaronpeters6209]

There was a fair amount of golf all to baseball. It just gets overlooked because of the tornadoes. Was even a grapefruit Hamilton, Al and later in the evening in Virginia. What matters for hail is large updraft which comes from strong shear allowing for downdraft transport ahead of the LLJ & favorable amount of turning relative to 590m-2km flow. Especially in a deep EIL. Thanks for the overview. Hard to pass up any video of this event. Generally always learn something from you, since focus more on macro/synoptic variables.

[@dravakian]

You did a tremendous job with this video, considering how much was going on with the meterology, the amount of tornadoes on the ground simultaneously, the response after the outbreak had concluded. Just a solid, well put together video.

[@ConvectiveChronicles]

Thank you so much!

[@railfanjackson4531]

Yesterday marked 13 years since that dreadful day. I live in Georgia now but I was in Alabama (Morgan County) when it happened. Scariest day of my life so far, at 21 years old as of typing this. Came within a couple of miles of being hit by the Hackleburg tornado. My grandparents’ farm in Limestone County was just utterly littered with debris. 8 year-old me was just shocked when we drove through the area and saw so much destruction. First time I had ever seen tornado damage. May the 300+ innocent people lost that day rest in peace.

[@Duck_87]

Thank you I've been waiting on your case study from this day

[@ConvectiveChronicles]

You bet; thanks for watching!

[@paradoxicalpoet1525]

This video meet my expectations! I love this channel!

[@ConvectiveChronicles]

Thanks so much! I really appreciate it!

[@VivianLund]

Your channel is fantastic. Just the content to help teach those of use who are hungry to learn! Please consider a video where you explain basic concepts and terms for us uninitiated people!!

[@ConvectiveChronicles]

Thank you so much! I do have my Skew-T/Hodograph series (completed) and Weather Map Analysis series (in progress) that might help for now, but I do plan on many more educational videos in the future.

[@Noahstormvideography]

Great video man. Earned a sub 👍

[@ConvectiveChronicles]

Thank you!

[@josephoppenheimer2196]

This was great! I think another case study idea is 5/20/19 because that event has one of the highest ceilings in meteorological history, a parameter space on its on tier and it ultimately busted.

[@ConvectiveChronicles]

Thank you! 5-20-19 is definitely on my list.

[@noah4463]

Great video, as usual Trey. As a suggestion for a possible case study, I’d love to see your insights on the April 14, 2012 high risk, as I’ve been looking at the archived mesoscale analysis for that day myself, and I’m stuck by just how few tornadoes OK and NE got, despite both being (to my novice eye) in very similar parameter spaces to KS, which got the train of tornadic supercells. To me, figuring out “why not” (for OK and NE) would be just as enlightening as understanding the “why” for central KS that day. Cheers!

[@ConvectiveChronicles]

Thank you! That’s a great point you make about 4-14-12; that case is on my list and I plan on making a video on it soon.

[@railfanmaximstill7279]

Blame me and my dad for the very few tornados in Nebraska They don't strike while we're around. (Keep in I was just 4 years old when my dad left to chase he came back and said "They died as soon as I got to them")

[@lancel71]

Trey I'm brand new to ur channel and I just wanted to say I love these case studies!

[@ConvectiveChronicles]

Thank you so much!!

[@spartansfromhell2201]

I remember when I was 8 years old going to help cleanup in smithville Mississippi how awestruck I was, I am 20 now and I can say I really appreciate how I was able to witness ef5 tornado damage first hand, it was absolutely terrible

[@laureng6412]

I actually use your videos as background noise while I am studying haha! I like your voice and your videos help me to not loose focus or fall asleep while I am studying (I have a sleeping disorder, ur vids are my favorite)

[@ConvectiveChronicles]

Thank you!

[@sadietaylorsversion13]

this is so great! i’m from dekalb county alabama (pretty close to where the tornado that ripped through rainsville initially dropped) this day was traumatizing for me. i was around 7 or 8 and i remember staying in our shelter for hours on end, pretty sure i slept in it. in retrospect though, it’s incredible to see this explained this way! thanks for this!

[@ConvectiveChronicles]

Thank you for watching! I’m glad you made it out unscathed from that day; can’t imagine what that must’ve been like.

[@sadietaylorsversion13]

@@ConvectiveChronicles yes my family and i were so blessed! i still have the worst storm anxiety ever!

[@ConvectiveChronicles]

Totally understandable! As long as you are prepared and have a plan when severe weather approaches, you’ll be okay.

[@dmetriglover3628]

The most epic event I ever witnessed. I remember looking at the weather models 5 days before and what was unusual is that as the days pasted it continued to point to a major event the night before I was in disbelief to how all the significant tornado readings were off the charts. As much as I love weather I hope we never see a outbreak like that again.

[@peachxtaehyung]

I forgot you had uploaded this. I had a loss so I was offline. this video was amazing!

[@ConvectiveChronicles]

Thank you! Sorry for your loss!

[@peachxtaehyung]

@@ConvectiveChronicles thank you!

[@raymondguilbeault4585]

I love this channel and the information you provide. I want to see somebody do a case study or studies on the May 31 1998 and/or June 2 1998 the 2 interesting northeast events that got me interested in weather

[@ConvectiveChronicles]

Thanks so much! I will add them to the list!

[@davidwatson2539]

5/3/99 and 5/24/11 would be another good detailed case study if possible in the future

[@ConvectiveChronicles]

Both are on my list!

[@ponzo1967]

05/22/2011 was the Joplin Missouri tornado. 2011 was a rough tornado season 🌪️

[@ghewins]

Wonderful video. I was in Lexington, KY during the April 3-4 outbreak. Witnessed jaw-dropping lightning displays from two tornadic supercells. I was working at a construction site in Biloxi about a block from the gulf shore on April 27. Very strange wearher. Strong, steady breeze straight off the gulf, maybe 15 mph with gusts to 20. What was so strange was the patchy fog that was riding in on the breeze. (This shows up on the satellite images about 20 min into the video.) I could tell that the air temp was close to 80, so the patches of fog were saying that the dewpoint was extremely high, which in turn was saying that vast amounts of rocket fuel were racing to the north. When I got home after work I immediately went to my computer and brought up the Jackson radar. I couldn’t believe what I was seeing. I never would have thought such a thing possible.

[@ConvectiveChronicles]

Thank you! Wow, that’s awesome you got to experience some of the storms on April 3-4; I’d love to have a time machine to go back and experience that outbreak. And you’re absolutely right about April 27; that southerly wind off the gulf was rapidly transporting juicy air into an environment that was already a powder keg ready to blow.

[@ghewins]

@@ConvectiveChronicles At the time of the April 3-4 outbreak, I had a friend from Louisville. The tornado that struck there came through about rush hour. One of the radio stations (WHAS) had its traffic helicopter in the air at the time. Instead of landing, the pilot followed the storm from behind. From his description, I knew that the neighborhood where my friend was from had been affected. I went over to his apartment, which was where I watched the lightning from the first tornadic supercell. That storm toppled several towers of the main high tension lines into Lexington, causing the entire city to go dark. I’ll never forget the scene that greeted me when I got back home. My mother, who basically ignored the weather and who never moved her carefully placed furniture had, in the darkness, done a 180 with her cherished antique love seat so that it faced a east facing window. It was there that I found her sitting, completely mesmerized by the lightening of the second tornadic cell. I now live in southeastern Kentucky (Knott County). I would be very interested to know your take on the convective set-up that caused the disastrous flash floods during the pre-dawn hours of July 28.

[@ConvectiveChronicles]

@@ghewins Wow, that's awesome; thanks for sharing that. As far as the July 28 floods go, it was just one of those cases where the perfect combination of ingredients for significant flooding came together over a small area. Storms fired along a stationary front draped across Kentucky and just continued to develop and train over the same areas, as the front just sat there for an extended period. Thus, certain areas received storm after storm in a very moist environment, creating high quantities of torrential rain over a several hour period.

[@fitfogey]

I was at work at the Huntsville Airport during the morning round (10AM CST). It is very flat land at the airport obviously. We all piled into the tornado shelter hall when the warnings were issued. Before going in we all were looking at the sky and the convection was just ridiculous. The whole sky was just churning. The sky was green as well. Shortly after that round passed we all went home to take care of our families. After the main afternoon/night round moved through none of us had power for at least 3 days because the TVA transmission towers were taken out. However, the next 3 days were some of the most beautiful days you could ever ask for weather-wise. Mid 60s/70s and bright blue skies. I often say we have some of the best weather here in Alabama, but we do pay for it. Thanks for the great case study video!

[@ConvectiveChronicles]

Thanks for the kind words and for sharing your experience with that day!

[@La_Ru-yg8es]

We only got a banger of a t-storm in Mobile, but, as you describe, the next morning, awoke to that crystalline blue sky, low humidity, rather "chilly", (for Mobile in late April, lol), weather. Family members didn't realize we were quite a ways south of the outbreak, and were calling to check in on us. That aspect has always fascinated me: The video footage of next day recovery efforts, following any given tornado outbreak. The weather is inevitably beautiful, under cloudless blue skies, juxtaposed with the awful wreckage, and human misery, the workers are contending with. Such a study in contrasts.

[@lifeintornadoalley]

I'll never forget the sounds and smells chasing this super outbreak

[@brendan9418]

Yo farm what you stay in

[@jaydancanas5241]

This event was just insane. I remember this day so well.

[@nicholasmasse]

Great vid. Would you mind doing a similar video analyzing the august 10, 2020 derecho? Thank you

[@ConvectiveChronicles]

Thank you! I’ll add it to the list.

[@huckstirred7112]

I watched this video more times than I could count . If there was something I didn't understand I researched it until I did . Thank you so much for this video

[@ConvectiveChronicles]

Thank you!!

[@SShrikke]

A lot of these tornadoes far exceeded their rated wind speeds in mph. Probably the most intense in recorded history.

[@iloveonedirection25]

I was about 9 or 10 on april 27th 2011. I didn’t know that I was actually traumatized from that event until recently . It’s a little funny how this event started my obsession with weather. and it’s very bittersweet to finally make sense of what happened that night after all these years. I know this is just a weather breakdown and its probably not that deep, but I am just so happy to be watching this. It’s actually very healing for me. Thank you for making this video. I really needed to see this!

[@ConvectiveChronicles]

That’s awesome; I’m really to happy to hear this has been helpful for you!

[@anthonywhavers8232]

I wish some more focus was put on areas like Cordova (who got hit twice), Smithville, and Rainsville. That Smithville tornado was on a different level. Doing Jarrell type damage in less than a minute.

[@ConvectiveChronicles]

Yeah, those tornadoes were some of the strongest tornadoes of the outbreak, especially Smithville. What a beast.

[@Inurfacewithbass12]

Recently, I came across your channel. It's very interesting, to say the least

[@ConvectiveChronicles]

Thank you!

[@jaredpatterson1701]

The dent in that tower is still there. Actually made me go watch videos where they knock over old water towers and like man those things are very well constructed! That feat was legendary

[@grvolans]

Another great series! When looking at the Doppler radar views at the supercells what view is the radar giving? Is it a top view or side view ? When looking at a supercells with a hook echo it appears that the hook is south of the main storm. Can you explain it? Thank you.

[@ConvectiveChronicles]

Thank you! When you look at a typical reflectivity image of a supercell, you are seeing a top-down view of the distribution and intensity of precipitation in that storm. Generally, the more red/purple/white there is, the greater intensity of precipitation there is in that region. When you see a velocity image, that shows you which way the wind is blowing within a storm (red is going away from the radar, green is going toward the radar). The hook echo is usually on the southern/southwest flank of a storm (given a typical setup of southwesterly/westerly flow aloft). This is due to the wind shear in the atmosphere...the strong upper level winds push the precipitation out ahead/away from the main area of rotation in the storm, which is represented by the hook echo, where precipitation wraps around the rotating updraft in a supercell.

[@grvolans]

@@ConvectiveChronicles ok. So we are looking from above at a cell. And a hook echo is actually south of the main cell usually. Here in Pennsylvania we aren't used to getting many supercells or tornadoes but in recent years things have ramped up. Especially with unusually warm winters and then getting a strong seasonal cold front from Canada that comes crashing down on top of it. We had a tornado one week and a blizzard the next! Thanks again for explaining things to this dummy..lol

[@ConvectiveChronicles]

@@grvolans You bet! Correct, the radar is basically a bird's eye view of the supercell. And the hook echo is usually on the south/southwest side of the main part of the supercell, but you can have cases where it is more on the west/northwest side of the storm; it all has to do with the orientation of the winds aloft. In a typical severe weather setup where the winds in the mid/upper levels are out of the southwest, you will see the hook echo on the southwest side of the storm.

[@xgiftedshotzxandrew7615]

I love your videos man!

[@ConvectiveChronicles]

Thanks so much!

[@xgiftedshotzxandrew7615]

@@ConvectiveChronicles do you think you could make a video on how pre frontal confluence bands form?

[@ConvectiveChronicles]

So that’s a topic I’m not super well-versed in, but in my understanding, there are a number of ways that prefrontal troughs can form. Here’s a really good paper that should help: www.atmos.albany.edu/facstaff/rfovell/NWP/schultz-2005.pdf

[@RenegadeAcre]

So glad I found your channel. Long time weather enthusiast here and perhaps a meteorologist in another life. We farm in this one 😂 and our channel is of a similar size as yours. 🤘 subbed!

[@ConvectiveChronicles]

Thank you very much!

[@kevinjoyce285]

One thing also crazy is the morning QLCS. it produced 76 TORNADOES.

[@FreshEDMMusic]

Thanks for this vide

[@michaelosborne255]

How were the supercells able to be so close together and yet discrete? It’s amazing these didn’t interfere with each other.

[@ConvectiveChronicles]

They were far enough away from each other that each storm didn’t really affect the others around it. Eventually they did congeal into a line, which nixed the discrete nature of the storms.

[@paradoxicalpoet1525]

I feel like at 34:50 the potential hazard type should just read "Death" or "Armageddon".

[@bensingletary4419]

Could we possibly get a case study of the Georgia high risk in 2017? That is something I lived through and there is not much info about it.

[@ConvectiveChronicles]

That’s definitely on my list

[@kazcoyote2402]

34:50, I do see those kind of hodographs with strong tropical systems wow

[@railfanmaximstill7279]

12:04 There also was no cloud cover after that first one meaning the air was becoming more boient and unstable. It was extremely unstable and the sun came out and made it worse

[@jaredpatterson1701]

It was like playing Monopoly and rolling 12, three consecutive times! Understandable how it only can happen every 30 years or so.. think of how many troughs eject over a 30 year time period but only one or two ever do so in this type of way! #legendary

[@peanut4998]

3 of the 4 EF5s occurred on or near the boundary: Smithville, Hackleburg-Phil Campbell, Rainsville

[@garylagstrom3864]

A friend of mine had a dream about two weeks after being in this tornado in 2011. In the dream he asked the Tornado 🌪 which he said had eyes nose and mouth: what’s your name? The tornado 🌪 replied: TUSCALOOSA TAMMY!

[@jamespeaden7862]

I still remember how this was like a week after the April 16 outbreak that hit Eastern North Carolina so hard. That everyone freaked out on the 27th and 28th.

[@ConvectiveChronicles]

Yeah, April 2011 was a rough for all of the SE to the eastern seaboard. Very rare to see back to back huge outbreaks like that.

[@wayloncapps9480]

I’m in western North Carolina where tornados doesn’t occur this outbreak had me concerned especially The Tuscaloosa tornado it’s tracked in a beeline towards me. I watched it throughout the day thinking is this thing going to come through these mountains. Luckily my mountains saved the day once again

[@CancerianGamer]

I remember when we got slammed by them in Tennessee Virginia that night. It was so strange , because it was hot outside that night , clear beautiful night... and all of a sudden out of the blue the wind hit hail immediately rocked the house and then after a few mins it disappeared as fast as it came... then few mins later again another super cell and you could see the tornado coming down it looked like a bugle horn coming down lightning youd see it so close as it went over the house... it was horrific.. destroyed glad springs Virginia and other places. I was in it , it completely took the house.. 3 story brick house gone... flipped multiple 18 wheelers destroyed factories ect ect... it was incredibly powerful

[@ConvectiveChronicles]

Dang, that's crazy

[@tatummvp99]

how do you determine HP soundings from LP soundings?

[@ConvectiveChronicles]

The way to differentiate an HP supercell environment from an LP supercell one is going to be through the wind profile, specifically the storm relative winds in the mid and upper levels. The stronger the storm relative wind is (especially above 6 km from the surface), the more the precipitation will be vented away from the updraft base, and the more likely you are to see LP storms. On the other hand, the weaker the mid and upper level storm relative winds are, the less that precipitation is vented away from the updraft base, and the more likely you are to see HP storms. This article might help a bit; scroll down to the "Storm-Relative Wind" section: cameronnixonphotography.wordpress.com/research/the-storm-relative-hodograph/

[@daver00lzd00d]

woooo! can't wait to watch this

[@kainhall]

at the same time..... NE montana was getting HAMMERED with rain (after getting HAMMERED with 164 inches of snow) this melted all the snow.... causing MASSIVE flooding (milk river has NEVER been higher) . it really does seem that if NE MT is getting a nasty storm..... either later that day, or the next day or 2.... the midwest / Tor Alley gets hit its just happened too many times to be a coincidence . however.... NO ONE pays any attention to NE MT..... so i think a lot of these patterns get missed

[@ConvectiveChronicles]

Definitely not a coincidence; often the main trough that provides the forcing for severe weather in the Plains/Midwest helps bring rain to MT the day or two before a severe event...MT just might not have enough moisture/instability for a severe threat, whereas as the trough moves off into the Plains, the instability is there for a severe threat.

[@wolfywise]

What number source are you using? Asking because the SPC basically stopped looking into it very early on, and the final numbers weren't established until very recently. 360 total, 218 on the 27th. Another thing: During the development of Tornado Archive it was found that SPC records have very poor QC overall. Wikipedia is actually a better source in this regard.

[@ConvectiveChronicles]

I used the Knupp et al. 2014 article shown in the video (link in video description).

[@wolfywise]

@@ConvectiveChronicles ah, okay. Just outdated on the numbers. In the future I do recommend going off counts listed by wikipedia, especially from 2010 onwards. The people managing those pages spend months going through the reports to get as accurate a count as possible, whereas the NWS and SPC tend to stop after a week or so.

[@CrazyMF3R]

Ill never forget seeing the Tornado Index at a 15.1, my jaw went slack

[@Duck_87]

Quick question. Why in the high plains you don't need higher dew points as you do in the traditional plains or deep south for severe weather or tornadoes? Is it because of elevation or location?

[@ConvectiveChronicles]

It’s elevation. The air at higher elevations can’t hold as much moisture as at lower elevations, so a dew point of 50 in Denver might actually be equivalent to about 60 in OKC because of the elevation difference.

[@jaredpatterson1701]

Very good question!

[@13_cmi]

On April 25th, 2011, vilonia was hit hard by a tornado. And on April 27th in 2014 it was hit again. If you haven’t done a video on that it would be a good one. I don’t know much about it but I think the timing of that tornado was just crazy. Almost exactly 3 years later.

[@ConvectiveChronicles]

It's on my list.

[@13_cmi]

@@ConvectiveChronicles thanks 👍

[@AndreWehrle]

One of the most impressive examples of applied severe local storms meteorology in a critical warning situation I've ever seen was when Jason Simpson pointed out the outflow boundary on the surface obs on ABC 33/40 while covering the early stages of the Cullman supercell; and all but explicitly stated live on air that given the other conditions already in place he fully expected it to produce a tornado as soon as it interacted with that boundary, and that's exactly what happened.

[@ConvectiveChronicles]

I miss the Spann-Simpson combo. Spann gets the praise, and 100% rightfully so, but Jason knew his geography and meteorology as well as Spann, and they were absolutely on their A+ game during the 2011 coverage. I often go back and watch that coverage because it’s the gold standard in how to cover a prolific tornado outbreak in an efficient, eloquent manner without hyperbole.

[@AndreWehrle]

@@ConvectiveChronicles I do as well. It was one of the reasons I got into local TV news (I'm in behind-the-scenes production for one of the stations here in Madison, WI). Even 12+ years later that coverage hasn't been exceeded in quality (granted, outbreaks of that magnitude are exceedingly rare). I think the only thing that comes close might be WPSD's coverage of the December 2021 western Kentucky EF4. Ever since I started I've been advocating that my station get more skycams, but it hasn't happened yet. 😕

[@ConvectiveChronicles]

@@AndreWehrle Hopefully, they will get some more skycams, as they are such an important tool, as we saw on 4-27-11. As James Spann says, radar imagery looks like spilled paint to most, but if they actually see the tornado on video, they're much more apt to act.

[@AndreWehrle]

@@ConvectiveChronicles Exactly.

[@AndreWehrle]

@@ConvectiveChroniclesComing back to this not much later, ironically. Imagine if we'd had one in Evansville on February 8th.

[@RickyPisano]

After you see your first tornado 🌪 you will definitely pay attention to the weather. I'm paying attention to Thursday 2/16/23 right now.

[@mississippiprincess3421]

I remember working the aftermath of this yazoo storm

[@k5elevencinc0]

Legendary Outbreak. CAPE was crazy.

[@dstre17]

Scariest time. I would rank living through this with the 4 hurricanes I lived through in Florida.. I was 6 months pregnant living in Mississippi.. I was leaving work and trying to ask family for help where the nearest one was. I was out driving the one that hit smithville. I was a school counselor and the teachers at my school lost her family who lived in smithville.. I can’t describe how terrified I was that day.

[@ConvectiveChronicles]

Wow, glad you made it out ok.

[@herestoyoudoc]

so the "possible hazard type" on the soundings--is that something their software models spit out, or is that the published judgment of the meteorologists involved? For example you have "PDS TOR" at 34:59. Is that coming from the model or is that recording that a Particularly Dangerous Situation Tornado Watch was issued by the weather service as a result of this sounding?

[@ConvectiveChronicles]

Those Possible Hazard Types come from an algorithm in the model software. sharppy.github.io/SHARPpy/interpreting_gui.html

[@herestoyoudoc]

@@ConvectiveChronicles nice, thanks for that link, was wondering what product you are looking at in your videos (since I'm just watching random ones and am trying to follow you mostly by osmosis 🤣) good stuff, I enjoy your work

[@ConvectiveChronicles]

@@herestoyoudoc Thank you! Which product are you speaking of specifically? I use a bunch of different products, and they're a bit different between my case study videos and my forecast discussion videos.

[@herestoyoudoc]

@@ConvectiveChronicles sharpppy is what I meant

[@ConvectiveChronicles]

@@herestoyoudoc I have the actual SharpPy program downloaded; you can find it here: github.com/sharppy/SHARPpy/releases/

[@bugdaboss5600]

are you going to do one on november 4th 2022?

[@ConvectiveChronicles]

Uploaded this morning! kzbin.info/www/bejne/eJjOhWyeetNgd5o

[@davidspangler4430]

I believe the march 2 2012 outbreak would be worth breaking down, mainly the central-easterm KY cells. Rare to see tornadic cells that close to the foothills of Appalachia

[@ConvectiveChronicles]

It's on my list!

[@sergeantguile4571]

Rainsville and the smithville tornadoes were digging trenches and foot deep

[@Spade_WX]

Chronochals Can you do the 5-3-99 Outbreak? Not just the tornado that went in history, the full outbreak

[@ConvectiveChronicles]

I do have a case study on the May 3, 1999 event already. It does focus on the Bridge Creek tornado but goes over the background environment that led to the tornadic supercells. kzbin.info/www/bejne/gn68oZ2Mosxrd6c

[@betterthanmost9549]

I've watched that james spann 8 hr news cast quite a few times and watched just about every video on youtube i could find from this day. Doubt we will see anything come close to it for another generation.

[@ICNMatsiko]

Thank you for this very educational video. Just like to ask someone who seems very informed. Has/is there any research into stopping/steering the fuel for these monsters when they first start up? It seems with all the advances in technology from everything to weather control to directed energy could there be a way to implode the vortices monitored by doppler triggering a tool to mitigate their organization? Even if there was unintended side effects might the trade offs be worth it.

[@ConvectiveChronicles]

Thank you! This question comes up often in meteorology circles, and the last time it was really prevalent was after the tornado that impacted the Nashville metro on December 9, 2023. It struck a generating station, causing a big fireball explosion that disrupted the visual characteristics of the funnel briefly before going back into balance. I discuss it toward the end of my breakdown on that event: kzbin.info/www/bejne/qHnUoIZrh8epl9U The answer is that it would have to be something of incredible intensity to fully disrupt a tornado. Tornadoes are modulated by very complex, well-established processes that take an immense amount of energy to break. That's why a brief explosion at the base of the funnel wouldn't do much (and didn't during the Nashville event...all it did was decrease the relative humidity at the base of the funnel so that the tornado de-condensed rather than fully terminate). We'd be talking something like an atomic bomb to fully derail the processes that modulate tornadoes within supercells, which would have much more unintended consequence than letting a given tornado run its course.

[@ICNMatsiko]

@@ConvectiveChronicles thanks so much for your reply. Do you know of any research speaking to electro magnetic properties involved with the formation of these vortices? A disruptive tool for that focused just towards the top of the vortices or even neutron bomb type blast no lethal at that height comes to my thinking. Thanks again.

[@ConvectiveChronicles]

I am not aware of any research in that regard, but I’m not sure that would have any impact, as well.

[@harryparsons2750]

We should not mess with Mother Nature. It could and probably would lead to disaster

[@ICNMatsiko]

@harryparsons2750 we know the parameters of how they start. Triple threat. Warm air rising turns sheer winds vertical. When this doesn't occur, what disaster takes place? It happens constantly with no impacts except for those rare times tornadoes form. All I'm saying is research something to adjust one of the kinematics slightly just as they're forming so they fail - CAP, warm air moisture, dry cold air, directed energy could be ised in mass at a key point.

[@iiDOCKERY]

Was hit by one of the tornadoes from this outbreak in ringgold ga on Cherokee valley road. It was a total loss there’s was nothing left standing

[@ConvectiveChronicles]

Dang, I’m sorry to hear that. Hopefully you were able to recover alright and get back on your feet.

[@iiDOCKERY]

@@ConvectiveChronicles yes sir we did amazingly no one was hurt at all only our dog had some injuries and she fully recovered. Just lost everything we had birth certificates, old pictures everything. No one really knows how truly devastating a tornado like that is unless you’ve went through it

[@ConvectiveChronicles]

@@iiDOCKERY That's awesome y'all were able to come out unscathed and that your dog was able to make a full recovery. Thank you so much for sharing your experience. I am always fascinated by the science behind tornadoes but equally as heartbroken when I see the devastation that tornadoes produce. As a storm chaser, I've seen destruction from tornadoes first hand, often right after it happens, but like you said, you can't truly grasp how impactful these tornadoes are unless you've lived through it.

[@iiDOCKERY]

@@ConvectiveChronicles it’s something that sticks with you for the rest of your life for sure but has really made me aware of storms and truly fascinated by storms and how they work. Your channel has taught me a ton and I thank you for that!

[@JanicePhillips]

2011 was quite the year.

[@raymondguilbeault4585]

I just thought of something lol you should do a case study of the forgotten Tuscaloosa tornados of April 14-16 outbreak and December 16th 2000

[@ConvectiveChronicles]

Both are on my list!

[@raymondguilbeault4585]

That's good lol I was watching this video and it clicked that most people talk about this one and not the other ones

[@raymondguilbeault4585]

I'm actually surprised you did not mention Cordova at all they're hit twice on April 27th and nobody really talks about that one EF3 that morning and EF4 at the same time as Tuscaloosa

[@ConvectiveChronicles]

​@@raymondguilbeault4585 Yeah, there were so many notable tornadoes in this outbreak that it would be impossible for me to mention each one without making the video super drawn out/long. I instead tried to focus on the broad-scale science behind the event, which allowed for so many notable tornadoes to occur.

[@raymondguilbeault4585]

@@ConvectiveChronicles will we see another prolific tornado event like April 27th again or not in my lifetime lol also what would the probability of May 31 1985 happening again Im concerned about that area

[@Nerdy_Girl1994]

People keep saying the tornados didn’t start till the afternoon on April 27th but I’m from Hanceville Al outside of Cullman and at 5:48 AM a small EF-2 hit us that morning taking out our house some of the college and my high school gym and a few small businesses. We never got a warning no sirens it took 2 years for our gym to be rebuilt they tried to say it was straight line winds at first but then said it was a tornado later after they came out to observe. I was 16 and when it hit our house I was in my bed it just had reached the peak of a EF-2 they said. My house and my neighbors was hit and all the trees surrounding our homes was under rooted and gone.

[@ConvectiveChronicles]

Yeah, the morning round was rough. The early morning tornadoes were separate from the afternoon outbreak and were spawned by a strong squall line. Created numerous communication challenges for the afternoon event, as power was still out for many areas by the time the afternoon wave started.

[@gloriaevans6359]

Oh goodness. How terrifying. Glad you survived.

[@kenperkins7921]

The beginning was actually in Waterloo Alabama where where Alabama and Mississippi meet up. From that moment on, mother nature's nasty brew was. Boiling eling all around Alabama and Mississippi! And it wouldn't end untill twentty. eith hours later. houre s. . five hours later.

[@Duck_87]

A lot of people were caught off guard when the first line of storms came through it knocked out a lot of power in Alabama and people were thinking the event was over until the second round of storms developed

[@ConvectiveChronicles]

Yeah, that morning round was very intense. Made for some challenges in getting warnings out to people for the afternoon round.

[@jeffzebert4982]

I'm afraid that the April 27, 2011 Super Outbreak demonstrates that a swarm of discrete supercells can potentially remain in that configuration all the way from the western portion of Oklahoma's main body to its eastern portion. I figure that the west-to-east length of the main body of Oklahoma is about the same as the total west-to-east width of Mississippi and Alabama combined.

[@ConvectiveChronicles]

It’s possible

[@basileusgaming7047]

It must have been apocalyptic to those who experienced it.

[@bamaboysmith2723]

It was 214 and the larger was by far the Phil Campbell one. I watched it and it was 1.25 miles wide when I tripped the damage path using my car where it crossed US hwy 243. I escaped thru East Franklin where many many bodies where. I didn’t k is this at the time bc I was shocked and just trying to get home!!!! I looked like a skid Steer pushed everything up into well placed piles if you will!!! It was just just slabs brother!!!! I know this one had winds close or little over 300mph. It was lifting out cars up and bouncing them from the RFD UP TO A MILE TO HALF MILE AWAY!!!! It was so LOUD and I can’t describe it really just the sky touching the ground like a mile wide wall cloud….

[@ConvectiveChronicles]

Dang!

[@missdonna9896]

Can you look at the few times a 60 percent chance of tornados has been released by the SPC?

[@ConvectiveChronicles]

They’re on the list!

[@missdonna9896]

@@ConvectiveChronicles I think if I’m not mistaking. It’s only been posted twice in history

[@ConvectiveChronicles]

@@missdonna9896 I believe there's only been one 60% tornado outlook, which was April 7, 2006.

[@missdonna9896]

@@ConvectiveChronicles I thought there was one in Oklahoma maybe I’m mistaking

[@missdonna9896]

The other one was closer to Tennessee

[@EnderDragonGamerz02]

Looking like round two may happen again….

[@ConvectiveChronicles]

Thankfully we avoided that today

[@bensasser5759]

This was our generational event

[@TheWLady9244]

I know its been 12yrs and going on 13yrs rainsville, Alabama never got a on the news i wanted to point that out i know a family and they have a story to tell😊

[@Duck_87]

Alabama was a powderkeg waiting to go off I've never seen so many loaded gun soundings

[@briantaylor4588]

Great analysis and explanation. A lot of swallowing but otherwise very educational

[@ConvectiveChronicles]

Thanks; I'll be sure to chew some saltines when recording next time

[@peanut4998]

I feel like March 17 2021 could have had a similar outcome had what caused it to underperform didn't happen