Severe WX Severe Weather Threat 4/5/17-4/6/17

[CSimonds]

I don't think this system "busted" per se. A few things were "off" in the models to be sure. Just my opinion. I do recall watching the forecasts last night that had this forming right on top of us in N AL and progressing rapidly east. The moderate risk area expanded and contracted based on model data. But the last thing I recall before going to bed was forecasts showing the warm front advecting rapidly to the north and the afternoon system building over the eastern part of Alabama. So, did the warm front move north a good bit slower than projected? Did it take longer for the environment over N AL to destabilize after the morning convection? Did the morning storms set up boundaries? Did the cap hold out longer (bc I don't remember capping as being an impediment in the models) Why did the storms struggle in N AL but intensify over TN and West GA?

When I say I am fascinated by "what happened" after-the-fact is wanting to know the "why's" of what makes some storm systems over perform and some under perform. An example is from about 12 or so years ago. It was a moderate risk day. The morning of the "big event" was beautiful. I took my dog for a walk expecting to hear thunder in the distance. No thunder. As the day wore on nothing was happening. The day ended with absolutely nothing. Not even a thundershower. Afterwards it was told that the strong cap held fast. Another storm system was back in the 90's. Someone will remember this I'm sure. It was either a moderate or high risk day. A tornado watch was issued. The supercells lined up. All healthy on radar. The classic winged V, nice rotation and hook echoes. Warning after warning......wall clouds spotted....but no tornadoes. And so it went....storms rapidly forming and becoming severe - rotating - then...nothing. But one lone storm E of Birmingham spawned one large tornado. After the storms were over, everyone was puzzling. What caused that one storm to put down a tornado and what kept the rest from doing the same? It was later discovered that the surface winds were out of the "wrong" direction and thus there was not enough shear at the lower levels. If the surface winds had been out of the south then it would have been a horrific night. But why the one tornado? A flanking storm had created its own "atmosphere" causing the inflow winds to that one storm to spin all the way to the ground and not just a rotating storm but no tornado. Another fascination is what causes a day that has a slight risk and "not the right ingredients" put down a few tornadoes and surprise everyone? I know my descriptions are not all "scientific" but this part of meteorology fascinates me. Almost a "forensic" meteorology if you will.

I meant West of Birmingham and not East of Birmingham in that instance.

 

[warneagle]

Tornado warning Tallapoosa County

 

[Taylor Campbell]

No severe thunderstorms out for this line, interesting.

 

[Equus]

STP is still at 4 ahead of the line SE of Alexander City. Not impossible to see a few more warnings before it starts dying down. Also the 1z outlook went from High (30% tor) to Enhanced (5% tor)

 

[Kory]

Some absolutely VILE comments towards mets on social media....Spann in particular. He isn't my favorite by a long shot, but it's disgusting.

 

[SilentShadow87]

Some absolutely VILE comments towards mets on social media....Spann in particular. He isn't my favorite by a long shot, but it's disgusting.

That's awful...what are they saying?

 

[warneagle]

Radar confirmed tornado Chambers Co.

 

[MattW]

As someone who influenced others to change their plans, I'll have to take a good deal of criticism tomorrow myself. However, the way I'm avoiding completely beating myself up about it is asking myself one thing: What if I hadn't said something, and the worst HAD happened? It was forecasted to, almost every bit of guidance was saying "big event" and from what I'm gathering, if the winds were just slightly different, it would have been. There was very little reason not to think it was going to be big throughout the region.

 

[Kory]

That's awful...what are they saying?

I would post the screen caption but there are too many expletives. In summary, calling for Spann to be fired and calling him a "murderer" because people died in 4/27. Yeah, the mental gymnastics that requires is exhausting.

 

[Kory]

As someone who influenced others to change their plans, I'll have to take a good deal of criticism tomorrow myself. However, the way I'm avoiding completely beating myself up about it is asking myself one thing: What if I hadn't said something, and the worst HAD happened? It was forecasted to, almost every bit of guidance was saying "big event" and from what I'm gathering, if the winds were just slightly different, it would have been. There was very little reason not to think it was going to be big throughout the region.

We weren't far off from something big. The numerous discrete supercells were rotating aloft. Just couldn't get anything sustained or to the surface. A better sheared environment and longitudinal warm sector and it would've been game on....

 

[Equus]

I have absolutely zero sympathy for anyone who screams at mets for days like this, and though it may be very callous, I wouldn't feel bad in the slightest if their ignorance led to serious repercussions for them in a future outbreak should they choose to ignore warnings. The public could never understand just how many variables and potential caveats that go into a forecast, especially on days like today. No one can predict everything correctly 100% of the time.

 

[jasonechols]

Schools were let out here. They never even went in to school this morning. Not...one...drop!

 

[CoreyandFrosty]

Wow. What a great squall line. One of the best I have seen in years. Amazing light show with some small hail. Lasted a good 15 mins too.

 

[bwalk]

I would love to see a "what happened?" paper about this storm system. Meaning - what happened in areas that supposedly had the right parameters but couldn't sustain a single thunderstorm. While areas that were supposedly "worked over" supported training storms. I am fascinated by finding out "what happened" post-events.

I totally agree with the storm system postmortem idea. It could be called a Post-System Analysis & the purpose would be to identify factors/variables that contributed to a given weather system (event) not performing up to its predicted potential (need a better word than 'potential'). Over time multiple analyses could be pooled together to form a predictive dataset of variables associated with system prediction failures. This would serve as a kind of predictive algorithm based on past system failures compared to the variables that were used to justify the underperforming weather system's original forecast predictions of severity.

It would seem this post-mortem process already exists but I have never heard of it. It seems like every time there is a bust people complain about it for a day or two, others rush in to defend the NWS, and then everyone moves on, never giving it another thought. I have never understood this. If you don't learn from your mistakes what keeps you from repeating them - over & over?

Again, maybe the NWS or someone already conducts these analyses & the public is not privy to them.

If not, it just makes no sense, from a common sense perspective, to not learn from one's mistakes.

 

[warneagle]

I don't think this system "busted" per se. A few things were "off" in the models to be sure. Just my opinion. I do recall watching the forecasts last night that had this forming right on top of us in N AL and progressing rapidly east. The moderate risk area expanded and contracted based on model data. But the last thing I recall before going to bed was forecasts showing the warm front advecting rapidly to the north and the afternoon system building over the eastern part of Alabama. So, did the warm front move north a good bit slower than projected? Did it take longer for the environment over N AL to destabilize after the morning convection? Did the morning storms set up boundaries? Did the cap hold out longer (bc I don't remember capping as being an impediment in the models) Why did the storms struggle in N AL but intensify over TN and West GA?

When I say I am fascinated by "what happened" after-the-fact is wanting to know the "why's" of what makes some storm systems over perform and some under perform. An example is from about 12 or so years ago. It was a moderate risk day. The morning of the "big event" was beautiful. I took my dog for a walk expecting to hear thunder in the distance. No thunder. As the day wore on nothing was happening. The day ended with absolutely nothing. Not even a thundershower. Afterwards it was told that the strong cap held fast. Another storm system was back in the 90's. Someone will remember this I'm sure. It was either a moderate or high risk day. A tornado watch was issued. The supercells lined up. All healthy on radar. The classic winged V, nice rotation and hook echoes. Warning after warning......wall clouds spotted....but no tornadoes. And so it went....storms rapidly forming and becoming severe - rotating - then...nothing. But one lone storm E of Birmingham spawned one large tornado. After the storms were over, everyone was puzzling. What caused that one storm to put down a tornado and what kept the rest from doing the same? It was later discovered that the surface winds were out of the "wrong" direction and thus there was not enough shear at the lower levels. If the surface winds had been out of the south then it would have been a horrific night. But why the one tornado? A flanking storm had created its own "atmosphere" causing the inflow winds to that one storm to spin all the way to the ground and not just a rotating storm but no tornado. Another fascination is what causes a day that has a slight risk and "not the right ingredients" put down a few tornadoes and surprise everyone? I know my descriptions are not all "scientific" but this part of meteorology fascinates me. Almost a "forensic" meteorology if you will.

Since I'm a historian in my day job, this kind of thing is really interesting to me as well. Unfortunately, it's only the forecasts that do verify that we get articles and books about.

 

[CheeselandSkies]

Meanwhile, one of the best looking storms of the day radar-wise headed for coastal GA. TORR on it based on earlier TDS. In a bit of a radar hole but had an impressive couplet for 6kft when it went over the Townsend area about 10-15 minutes ago.

Edit: This has the "look" of a storm that is producing at that distance from the radar. Resembles the MS/TN supercell of 12/23/15 when it was producing the first EF3 near Clarksdale, when Memphis radar was hitting it at about 6-7kft.

Over the South Newport area now.

 

[Bamamuscle]

Schools were let out here. They never even went in to school this morning. Not...one...drop!

Yep.. and as a teacher with kids on a bus for up to 90 minutes each way each day it was the right call. The risk was too great not to let kids stay home today.


Sent from my iPhone using TalkWeather mobile app

 

[Jason Ledbetter]

Dang it! I slept through every bit of the storms today! The amazing power of lunesta!

 

[KG4KBU]

We don't have shelters here for storms in my county. Just red cross shelters afterwards if needed so my county ema director told those who called about shelters for storms to go to Lowe's or Walmart and wait it out. If they're in mobile homes

Sent from my Z956 using Tapatalk

 

[volman]

Well, this event finally got me to register on here after lurking for almost nine years. I finally registered so I could see all of the models that were shared. Found this forum after having a near-miss and then an almost direct hit (two trees on my house) in 2008. This forum, and all of the great contributors, have helped me to make sure I am never caught unaware of severe weather...and because of that, my family is safer. So I wanted to take the time to say thank you to all of the site admins and members on this great forum.