4/1-4/2 severe threat (southern portion of subforum)

[cyclone77]

Broyles did the first day2 outlook early this morning, so wasn't surprised to see a major correction with the midday update.  

Good luck and be safe to all you guys out east tomorrow, looking pretty volatile.  

[OHweather]

16 minutes ago, cyclone77 said:

Broyles did the first day2 outlook early this morning, so wasn't surprised to see a major correction with the midday update.  

Good luck and be safe to all you guys out east tomorrow, looking pretty volatile.  

Broyles has gotten better over the years and usually the SPC is pretty good about not whipping around the outlooks too much, but I don’t think anyone was very happy with the initial Day 2 outlook this morning to say the least 

[zinski1990]

Indy missing out again. I swear all we ever get is rain lol

[TheWeatherPimp]

Not sure I can ever remember in the course of two day 2 outlooks, areas going from 0% tornado risk to hatched 15% tornado risk. Pretty remarkable change. 

[buckeye]

5 minutes ago, TheWeatherPimp said:

Not sure I can ever remember in the course of two day 2 outlooks, areas going from 0% tornado risk to hatched 15% tornado risk. Pretty remarkable change. 

 

 

I was thinking the same thing.   Usually you see adjustments 25 or 50 miles this way or that way....  but that change is like an entirely different forecast.   

So I'll have to see if my anecdotal theory holds.   I've always said the most hyped events around here tend to fall apart while the most significant events, (ie the one a couple weeks back) come out of nowhere.

[Floydbuster]

2 minutes ago, buckeye said:

I was thinking the same thing.   Usually you see adjustments 25 or 50 miles this way or that way....  but that change is like an entirely different forecast.   

So I'll have to see if my anecdotal theory holds.   I've always said the most hyped events around here tend to fall apart while the most significant events, (ie the one a couple weeks back) come out of nowhere.

Twitter world seems to be saying that models are adjusting to a slower moving system with most energy closer to the IN/OH/KY three-corners region. Expect adjustments. 

[Chinook]

this is a confirmed tornado at or near Chesterfield Missouri, near St Louis

[SchaumburgStormer]

Another storm west of STL looking nasty too 

[Crowbar]

28 minutes ago, buckeye said:

I was thinking the same thing.   Usually you see adjustments 25 or 50 miles this way or that way....  but that change is like an entirely different forecast.   

So I'll have to see if my anecdotal theory holds.   I've always said the most hyped events around here tend to fall apart while the most significant events, (ie the one a couple weeks back) come out of nowhere.

Tend to agree.  I recall last year in March, there was similar chatter the day before, and it turned out all we had was a steady rain, or the Jan 2019 "foot of snow" that ended up a few inches. 

[vpbob21]

2 hours ago, OHweather said:

Broyles has gotten better over the years and usually the SPC is pretty good about not whipping around the outlooks too much, but I don’t think anyone was very happy with the initial Day 2 outlook this morning to say the least 

 

Yeah my county went up 3 categories (from general thunder to enhanced) in 1 outlook.  Don't know that I've ever seen that.

[Columbus]

I live north of Columbus in Powell/Lewis Center, pretty much in the bullseye of the Moderate circle. How much of a threat is this really? It seems like a pretty rare forecast for us and some of the forecasts I'm reading almost sound hyperbolic. One case in point from one local tv weatherman out of Lima, OH:

** SEVERE THREAT HAS DRAMATICALLY INCREASED FOR OHIO ON TUESDAY, APRIL 2, 2024- MODERATE RISK (LEVEL 4 OUT OF 5) ISSUED FOR MUCH OF OHIO. A DAY 2 MODERATE RISK IS RARE. ***

*** POTENTIAL EXISTS FOR A SEVERE WEATHER AND TORNADO OUTBREAK IN OHIO- PLEASE REVIEW YOUR SEVERE WEATHER AND TORNADO PLANS TODAY ***

Written: 2:30 PM Monday, April 1, 2024

As I profusely discussed yesterday, models have been trending toward a significantly more amplified storm system for Tuesday, and essentially every model has picked up on this. Therefore, the result is a dramatically higher severe weather threat for Ohio, including Lima, for Tuesday. This outlook is not intended to scare you, but we need to be prepared for a potentially volatile day of severe weather for Ohio.

--------------------------------------------------

NEW STORM PREDICTION CENTER OUTLOOK:

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- There is a MODERATE RISK (Level 4 out of 5) for much of Ohio. This includes Lima, Dayton, Cincinnati, Columbus, Springfield, Urbana, Kenton, Delaware, Marysville, Chillicothe, Athens, Newark, Canton, and Zanesville.

- There is an ENHANCED RISK (Level 3 out of 5) extending about 30 miles from the Moderate Risk. This includes Celina, Van Wert, Paulding, Ottawa, Findlay, Sandusky, Cleveland, and Youngstown.

- There is a SLIGHT RISK (Level 2 out of 5) extending about 30 miles from the Enhanced Risk. This includes Defiance, Napoleon, Toledo, and Ashtabula.

--------------------------------------------------

NEW POTENTIAL HAZARDS AND TRENDS:

--------------------------------------------------

With a significantly stronger storm system tracking further north with a much stronger surge of low-level warmth and moisture, the stage is set for a potentially intense severe weather day across Ohio as long as you are in the warm, unstable part of the storm system. There is a potential for several tornadoes including the potential for significant (EF-2 or stronger intensity) and long-tracked (tracking over 20 miles) tornadoes. Parameters are suggesting that a tornado outbreak will be possible. Additionally, large to very large hail (possibly up to the size of tennis balls to baseballs) and destructive damaging winds (potentially 70 to 80 mph). This is a potentially dangerous situation.

The Storm Prediction Center has highlighted a rare 15% significant tornado contour for much of Ohio. This is not issued every year in Ohio and should stress that we should take this threat seriously. Also, large hail and damaging winds contours are at 30% significant, which are both quite high, too.

[Chicago Storm]

2 hours ago, OHweather said:

Broyles has gotten better over the years

[SchaumburgStormer]

Things seem to be “meh” across Illinois so far this evening 

[Floydbuster]

Twitter is discussing how models are trending down for Central OH, and really for the whole event trending less intense. 

 

 

 

[OHweather]

Some random thoughts based off of the 0z NAM and HRRR...how quickly morning convection exits and allows the warm front to start lifting, along with if convection starts getting pretty widespread in the Ohio Valley by mid-afternoon, which would further limit northward/northeastward moisture return and recovery, are both major sources of uncertainty regarding the northeast extent of the tornado threat. Also, models are still trending slower/west with the low and jet streak. 

I think the northern/northeastern portion of the higher tornado probs should be trimmed, perhaps notably, and the overall highest tornado probs shifted a bit farther SW. We'll see what the rest of the 0z models show and what the initial day 1 outlook comes up with. 

[Floydbuster]

Kentucky/Tennessee? Maybe?

 

[largetornado]

Some disagreement between rap, hrrr, nam, and nam3k. It’s a wake up and see kind oF a day which is typical for the OV. 

[OHweather]

6 minutes ago, largetornado said:

Some disagreement between rap, hrrr, nam, and nam3k. It’s a wake up and see kind oF a day which is typical for the OV. 

Considerable uncertainty, largely driven by ongoing/earlier-day convection, is definitely a familiar feeling for the Ohio Valley. There certainly is higher-end tornado potential if a portion of the warm sector is relatively clear and can recover through at least the mid-afternoon, and I feel like that's more likely than not to occur somewhere in the vicinity of central/southern IN, western/southern OH, and perhaps adjacent northern KY. Where exactly that occurs and how large of an area it is are certainly in question. 

From a messaging perspective this is kind of brutal...I'd consider northern and even central (especially east-central) OH to be on the fringe. If ongoing convection and clouds clear quickly enough there's still a viable scenario where those areas recover enough to have a threat, and given the amount of shear in place that needs to be messaged. However, it's also possible that little happens on that northeastern fringe. We've already gone all-in with a tornado-driven moderate risk, so while I'm personally hoping for (and sort of leaning towards) nothing too noteworthy happening in the Cleveland metro and my immediate vicinity just south of Cleveland, a total whiff in the northern/eastern half of Ohio would be a strike against public trust in the severe wx forecasts. 

[Floydbuster]

5 minutes ago, OHweather said:

Considerable uncertainty, largely driven by ongoing/earlier-day convection, is definitely a familiar feeling for the Ohio Valley. There certainly is higher-end tornado potential if a portion of the warm sector is relatively clear and can recover through at least the mid-afternoon, and I feel like that's more likely than not to occur somewhere in the vicinity of central/southern IN, western/southern OH, and perhaps adjacent northern KY. Where exactly that occurs and how large of an area it is are certainly in question. 

From a messaging perspective this is kind of brutal...I'd consider northern and even central (especially east-central) OH to be on the fringe. If ongoing convection and clouds clear quickly enough there's still a viable scenario where those areas recover enough to have a threat, and given the amount of shear in place that needs to be messaged. However, it's also possible that little happens on that northeastern fringe. We've already gone all-in with a tornado-driven moderate risk, so while I'm personally hoping for (and sort of leaning towards) nothing too noteworthy happening in the Cleveland metro and my immediate vicinity just south of Cleveland, a total whiff in the northern/eastern half of Ohio would be a strike against public trust in the severe wx forecasts. 

It doesn't help that there is so much hyperbole (and I never use that word) on social media. I have had a few text messages from Clevelanders thinking F5 twisters are going to level Cleveland, Akron and Youngstown tomorrow. I had to explain to them that the threat was almost all south of the area, and that there was still uncertainty.

Today's (Monday) hype was quite possibly the most I've ever seen for a severe weather event, at least for Ohio.

[largetornado]

3 minutes ago, OHweather said:

Considerable uncertainty, largely driven by ongoing/earlier-day convection, is definitely a familiar feeling for the Ohio Valley. There certainly is higher-end tornado potential if a portion of the warm sector is relatively clear and can recover through at least the mid-afternoon, and I feel like that's more likely than not to occur somewhere in the vicinity of central/southern IN, western/southern OH, and perhaps adjacent northern KY. Where exactly that occurs and how large of an area it is are certainly in question. 

From a messaging perspective this is kind of brutal...I'd consider northern and even central (especially east-central) OH to be on the fringe. If ongoing convection and clouds clear quickly enough there's still a viable scenario where those areas recover enough to have a threat, and given the amount of shear in place that needs to be messaged. However, it's also possible that little happens on that northeastern fringe. We've already gone all-in with a tornado-driven moderate risk, so while I'm personally hoping for (and sort of leaning towards) nothing too noteworthy happening in the Cleveland metro and my immediate vicinity just south of Cleveland, a total whiff in the northern/eastern half of Ohio would be a strike against public trust in the severe wx forecasts. 

Yes from a messaging standpoint, this could be a mess. The miss earlier this month may or may not have played a part with the 15%. I would assume the afternoon outlook was late because there was a significant amount of discussion around the 15%. Realistically I think it’s a good forecast if the area circled in red does not materialize. If it does, the threat for Ohio would likely be significantly degraded. 0z sounding from ILN shows a minor inversion. Might prohibit some early morning convection? 

[OHweather]

14 minutes ago, largetornado said:

Yes from a messaging standpoint, this could be a mess. The miss earlier this month may or may not have played a part with the 15%. I would assume the afternoon outlook was late because there was a significant amount of discussion around the 15%. Realistically I think it’s a good forecast if the area circled in red does not materialize. If it does, the threat for Ohio would likely be significantly degraded. 0z sounding from ILN shows a minor inversion. Might prohibit some early morning convection? 

Yes, my take on the 0z HRRR was that it being more expansive morning MCS in the Ohio Valley, with elevated convection continuing to fire overtop its cold pool through the early afternoon and convection firing in the warm sector and becoming widespread by mid-afternoon, were why it didn't really destabilize north of southern OH. We may have a better lean on how that will play out within the next few hours. 

Yes, I assume there was a ton of internal discussion about the outlook. I was off today so can not confirm or deny. It is a tough spot, and the initial day 2 pulling things farther south really made things worse. I do think that the setup can support one or two long-tracked, violent tornadoes, so based on that I can not fault the day 2 moderate risk. If you expect long tracked, violent tornadoes that's more than an enhanced risk. I could perhaps quibble with it being placed so far northeast, but I do think there is a conditional threat in at least the entire moderate and enhanced risk areas so I can't totally fault it either. Some of the messaging I've seen regarding this threat is some of the strongest I've ever seen around here...there is something to be said about being sure before breaking out the strongest possible messaging. I'm both worried about the higher end of the potential and what that could look like (even if it's just one or two really nasty tornadoes) but am very uncertain on where or if we'll see that pan out. 

[andyhb]

A lot of convection over OK and MO that is going to need to be worked out before we figure what tomorrow's ceiling is. I will say that this is on the "more inhibitive" side in terms of convective coverage from what I've seen in past events.

[largetornado]

6 minutes ago, andyhb said:

A lot of convection over OK and MO that is going to need to be worked out before we figure what tomorrow's ceiling is. I will say that this is on the "more inhibitive" side in terms of convective coverage from what I've seen in past events.

At this point, will the EML in Arkansas/Southern MO/TN be eroded by that ongoing convection or will it inhibit it? 

[OHweather]

9 minutes ago, largetornado said:

At this point, will the EML in Arkansas/Southern MO/TN be eroded by that ongoing convection or will it inhibit it? 

I'd lean more towards the convection eroding the EML than the other way around. 

[largetornado]

03z HRRR takes the pressure down to 987. Time for bed and we shall see tomorrow. 

[OHweather]

0z HREF probability for STP >3 and member updraft helicity (supercell) tracks. Mod-high probabilities for STP >3 from central OH-IN through parts of KY & TN surrounded by lower probabilities, with sct'd individual member supercell tracks. The setup has a high ceiling, but:

Neighborhood probabilities for supercell tracks are moderately high in the Ohio Valley (best environment), high in the Tennessee Valley (slightly lower STP >3 probs), and low-moderate north into IN/OH/W PA (lower confidence in STP >3 farther north). There is uncertainty:

For instance, the 0z HRRR has extensive elevated convection in the Ohio Valley that continues through midday, with warm sector convection becoming widespread by 18z. This would be some sort of (potentially more middling, though with conditional risk for strong tornadoes still) OH/TN Valley tornado threat but with more limited northward extent into IN/OH.

On the other hand the NAM clears the morning Ohio Valley convection slightly quicker and also delays warm sector initiation longer into the afternoon. This would lead to a likely more significant tornado threat in the Ohio Valley that extends into much more of Ohio.

The NSSL WRF is a bit in between. It clears the Ohio Valley morning convection a bit quicker but also has a fairly busy warm sector by mid-afternoon. Verbatim it still would be a somewhat messy Ohio/Tennessee Valley evolution but there would be a tornado risk, especially in the Ohio Valley where there could still be a conditional significant tornado risk with this sort of evolution. In terms of northern extent, there'd be at least some threat for most of Ohio along and south of the warm front.

And finally, the ARW with similarities to the NSSL, clearing the morning convection fairly early and developing warm sector convection a bit quickly (tho not as fast as the HRRR), with a middle ground solution in terms of overall tornado risk and northward extent into OH:

Some subtle adjustments can probably already be justified for the initial day 1 outlook at 2 AM eastern...however, I doubt there will be anything wholesale until later in the morning when it's much more obvious how the ongoing convection is behaving. 3z HRRR would probably play out somewhat close to the 0z NSSL WRF if it ran out further... 

[largetornado]

SPC sticking with the moderate with a massive hatched tornado risk

Spc basically said ignore the nam 

Quote

It's not entirely clear if ongoing convection will allow the warm front to lift appreciably north of its current position. However, large-scale pattern is quite dynamic and favors surface low deepening over southern Lake MI during the latter half of the pattern. NAM struggles to reflect this scenario, thus weaker instability is forecast at higher latitudes. Tornadoes, damaging winds, and large hail are expected with supercells that evolve across the warm sector. Some tornadoes may be long-lived and strong

.

[largetornado]

Anyone know if the radars being down affect model inputs? (From my understanding, NWS offices can still see their radars but the feed is down.)

[Spartman]

TWC:

[Floydbuster]

Thankfully the moderate was shifted south slightly more away from Northeast OH where I live. In fact, I'm on the edge of marginal, slight and enhanced now. The local NWS in Akron actually removed the words "severe" from our forecast and replaced with "showers and thunderstorms". Probably not expecting the warm front to drape as far north as some thought 24 hrs ago. Here's hoping that continues and isn't as bad for those higher risk areas down south.