Severe Weather Threat 4/27-4/28, 2024 - (Saturday, Sunday)

[NorthGaWeather]

Not to cherry pick soundings (soundings are just guesses after all), but 18z NAM has the most extreme soundings for tornadoes I have ever seen on that model. Off the charts.

Really more eye candy than anything since I do not expect those will verify.

Most show the 0-1km vorticity layer being highly streamwise as well.

 

[TornadoFan]

Wichita AFD is pretty strongly worded.

 

[warneagle]

Dropping the V-word on day 4 is definitely an eye-opener.

 

[Tempestas Tonitrua]

Wichita AFD is pretty strongly worded.

Just shooting the breeze but it Would be true 2024 fashion to have a synoptic and kinematic setup like this be done in by a massive linear storm mode lmao.

 

[Former Member 1430]

Seriously though, those soundings between 78-84hrs are by far the most favorable I’ve seen this year so far from the Nam.

I don’t doubt the kinematics being that volatile, but CIN is still a big limiting factor.

Buoyant updrafts can overcome moderate levels of CIN

 

[tennessee storm chaser]

Dropping the V-word on day 4 is definitely an eye-opener.

That’s the day that we see high risk …. Things hold

 

[jiharris0220]

It’s quite curious to see the v word being used so far out. Considering how much can change between now and later, they must be very confident models will stay consistent.

 

[Muwx]

Saturday looks highly conditional to me. Way too much uncertainty regarding morning convection to be calling for a high risk at this juncture.

 

[TheSuckZone]

Saturday looks highly conditional to me. Way too much uncertainty regarding morning convection to be calling for a high risk at this juncture.

Yeah, a few days ago I remember the D6,7,8 forecast discussion specifically stating that a lot would depend on what happens the prior day

 

[andyhb]

Lot of takes too far in either direction in this thread.

Saturday could very well be a high end day across OK and part of KS. The synoptics are certainly threatening, especially given the lack of STJ influence. Is it too soon to declare it going high risk? Certainly. However, you start putting a 50 kt LLJ in play by 4 pm in the Plains and bad things tend to start happening.

Saturday has the highest ceiling for a Southern Plains day since 2019 quite easily, and I think its "floor" seems to be elevating in recent guidance too. Early convection might cap the ceiling, but I have suspicion there would be tornadoes with it.

 

[JPWX]

I mean basically

 

[tennessee storm chaser]

Lot of takes too far in either direction in this thread.

Saturday could very well be a high end day across OK and part of KS. The synoptics are certainly threatening, especially given the lack of STJ influence. Is it too soon to declare it going high risk? Certainly. However, you start putting a 50 kt LLJ in play by 4 pm in the Plains and bad things tend to start happening.

Saturday has the highest ceiling for a Southern Plains day since 2019 quite easily, and I think its "floor" seems to be elevating in recent guidance too. Early convection might cap the ceiling, but I have suspicion there would be tornadoes with it.

Well agree

 

[jiharris0220]

Lot of takes too far in either direction in this thread.

Saturday could very well be a high end day across OK and part of KS. The synoptics are certainly threatening, especially given the lack of STJ influence. Is it too soon to declare it going high risk? Certainly. However, you start putting a 50 kt LLJ in play by 4 pm in the Plains and bad things tend to start happening.

Saturday has the highest ceiling for a Southern Plains day since 2019 quite easily, and I think its "floor" seems to be elevating in recent guidance too. Early convection might cap the ceiling, but I have suspicion there would be tornadoes with it.

All of this.
What’s really caught my attention with this upcoming threat is that the global models have yet to actually downtrend, something that has been the norm this year.
Sure cams are more accurate than the global models regarding handling of the environment, but you’re really waving the red flag and increasing confidence tenfold when global models don’t drop the ball and agree with cams this close in time.
I’m not too concerned with crapvection as much as CIN, though it seems like the nam only shows that being a limiting factor.
This may finally be the real deal tornado outbreak I fear.

 

[andyhb]

Just because X, Y, Z event did whatever previously this year, doesn't mean the next one has to.

 

[tennessee storm chaser]

Just because X, Y, Z event did whatever previously this year, doesn't mean the next one has to.

Think for most part , a lot of people starting become complacent …. This one getting in the day 3 range . No backing off with guidance this far like most the setups we have seen this season

 

[KCweatherboy]

All of this.
What’s really caught my attention with this upcoming threat is that the global models have yet to actually downtrend, something that has been the norm this year.
Sure cams are more accurate than the global models regarding handling of the environment, but you’re really waving the red flag and increasing confidence tenfold when global models don’t drop the ball and agree with cams this close in time.
I’m not too concerned with crapvection as much as CIN, though it seems like the nam only shows that being a limiting factor.
This may finally be the real deal tornado outbreak I fear.

I also agree, there seems to be a pretty good model consensus on the shape of the trough and the lack of downtrending too. For example, here's a look comparing models at 18z on Saturday:




*NOT TRYING TO FEARMONGER* but seeing the shape of the trough, a few examples jumped out to me which I will share below.

Similar to what Andyhb said with a 50kt LLJ in play by 4pm in the plains, bad things tend to happen. I'd like to add that troughs with this neutral/negative tilt ejecting into the Plains tend to lead to bad things happening too. Based on the models, this trough seems like it will have a neutral/negative tilt. However, mesoscale details obviously still have to perfectly come together as well for supercells and tornadoes to occur.

An example of this would be 5/24/11, however, the trough was more amplified, with a strongly negative tilt. The mesoscale details also seemed perfect for this event but we won't know those until the day of, of course.


4/14/12 also had a generally similar trough shape, however, it was a lot more monstrous of a trough than this one and generally had a more positive/neutral tilt to it. Of course, the mesoscale details also aided this event in becoming what it did.


And my last example would be the 5/20/19 "bust" which would be an example where the overall trough is very, very impressive, but the mesoscale details did not aid the event in reaching its potential.




As modeled this event certainly has potential and warrants the D4 30%, and I personally always like looking at historical analogs to examine the range of possibilities. As many others have mentioned the mesoscale details are yet to be seen, and will play a big role in the outcome of any storms.

Would love to hear other's insights on this!

 

[jiharris0220]

This setup definitely has the highest shot of breaking the “less than expected” streak. Here are a couple of soundings from the 18z GFS 72-82hrs.

 

[tennessee storm chaser]

Just looking at that shape of the trough with the broadness spell s. Trouble …. Plenty spacing these storms will have to work with

 

[lake.effect]

This setup definitely has the highest shot of breaking the “less than expected” streak. Here are a couple of soundings from the 18z GFS 72-82hrs.

How 'bout these apples?



Posting ridiculous soundings unnecessarily adds to the hype train, but sometimes you just got record these for posterity because even if it doesn't verify, you don't see this very often.

 

[lake.effect]

I know the focus has been on the plains for Saturday but man, the cold core setup in N IL / S Wisconsin looks potent.
The coverage area of Saturday is impressive. On a line from Green Bay to Dallas, significant severe weather seems possible.e