April 24-30th Severe Potential

[OUGrad05]

that actually makes sense. and the enhanced risk area, in combination with the model trends the last 3 days, I'm pretty sure the areas affected are pretty much aware the potential is there. waiting one more day before pulling out the moderate or even high risk is not the worst idea in the world in this situation, imho. if they didn't have the "enhanced" option, I'm sure they would have went moderate. but this gave SPC the right leeway to wait for some better focus.

Don't see justification for a high risk at this point...perhaps tomorrow? care to elaborate on what you're seeing in particular?

[PGM]

I'm not sure why everyone is getting concerned about small issues like positioning of VBV in the day 3 range that should sort themselves out. Moderate capping early in the day should prevent morning convection across the risk zone. Bust potential obviously exists as with most threats. However, given the instability and temp profiles in the warm sector, well positioned low pressure and triple point nearest to the high shear/max jet env, and an adjacent strong eastward propagating dryline, I think we're still looking at a high end severe event or tornado outbreak with violent tornadoes possible. SPC probably made the right call with the strong worded enhanced risk because of model variability, but I expect we'll see a day 2 moderate or high risk once everything becomes more clear. This is the best setup I've seen for the cp since I began following the weather closely (2012).

[Indystorm]

Sig Tor 7-10 for central OK Tuesday evening based on 06Z NAM which is probably overdone but still serious.

[MattPetrulli]

Sig Tor 7-10 for central OK Tuesday evening based on 06Z NAM which is probably overdone but still serious.

Yeah 06z NAM is going all out. 

[OUGrad05]

Sig Tor 7-10 for central OK Tuesday evening based on 06Z NAM which is probably overdone but still serious.

I'm looking at the 06Z at hour 66 on Pivotal weather and its only showing 4ish...on the sig tor.  Rolling forward a few hours I see some 6s...what time are you seeing the 7-10s?  

[PGM]

Sig Tor 7-10 for central OK Tuesday evening based on 06Z NAM which is probably overdone but still serious.

I don't think anyone has any doubts about the extremely unstable and moist warm sector. This looks intense!! Only issues some see are regarding VBV and wind profiles making storm mode messy.

[Jim Marusak]

Don't see justification for a high risk at this point...perhaps tomorrow? care to elaborate on what you're seeing in particular?

some of the models, if they hit at the earlier timing, would be leaning towards a high cape good-enough shear environment where anything and everything is likely in OK and KS. but the biggest problems I have with anything more than enhanced is that the models at 00Z still showed a decent spread (4-6 hours) on when the cap is weak enough to use all the potential thermal and mechanical energy. if we had unanimous agreement within 1-2 hours of when that cap breaks, then I would see where everyone would be screaming "where's the high risk?" personally, I was able to see the argument for a d-3 moderate risk being tossed out there if we had the timing all aligned. but right now, moderate risk is the best I see for d-2, then we see  how things align on 13Z and 1630z Tuesday before thinking of going high.

[capbreak]

I'm looking at the 06Z at hour 66 on Pivotal weather and its only showing 4ish...on the sig tor.  Rolling forward a few hours I see some 6s...what time are you seeing the 7-10s?  

There are clearly 6s on the warm front at 00z on Pivotal, are you looking at the dryline? The higher values are only popping up on different sites using different smoothing/contour algorithms like CoD and Earl Barker.

[OUGrad05]

There are clearly 6s on the warm front at 00z on Pivotal, are you looking at the dryline? The higher values are only popping up on different sites using different smoothing/contour algorithms like CoD and Earl Barker.

12Z run has dialed back the sig tor considerably at 00Z wednesday.  Picks it back up again at 03Z, 

12Z slows things down a tad as well pushing the best dynamics just a few miles back to the west at 00 and 03Z

[jojo762]

Who knew everyone could freak out about it being a bust so early, and just live or die after every run. The way I see it is we have extreme instability that will be overspread between 21-00Z by a 50 knot or so mid-level jet. Shortly after 00Z we should see a relatively strong SSW'ly, perhaps even slightly more backed than that, LLJ at 35-45 knots, along with impressively backed surface winds along much of the dryline, and especially near the triple point, which is sufficient for strong tornadoes, let alone just tornadoes. Remember, it only takes one supercell to pop in this type of environment to have chaos and make for a memorable day, especially if it moves over populated areas. Given the potential threats that still exist of very large/giant hail, and numerous tornadoes-- including some strong, possibly long-track-- I don't see any reason to just jump ship yet. If anything, you guys should be happy that we have a good cap in place given how 2015 went down.

[Radtechwxman]

Jojo I couldn't have said it better myself. This cape along supports a sig event and by evening we should have sufficient enough shear to only exacerbate that tornado threat. Obviously timing issues are still apparent but those should be sorted out tomorrow. Our system comes on shore tonight into tomorrow. I have seen time and time again where extreme cape setups can often compensate for lack of better shear.

[rolltide_130]

For today's threat, the GFS seems to have done a good job of handling the quality of moisture return so far. Mesonet data is fairly comparable for what the 06z GFS was expecting at 15z. Also have a couple areas of 60's showing up near the Red River in SE Oklahoma. 

[jojo762]

4K NAM at the very end of the run, 00Z, favors the triple point which it has in SE NE. That is the only place it has DMC as of 00Z, nothing along the dryline further south.

One thing that this setup will likely not have that most big time setups do have is an OFB-- or multiple-- to focus initiation as well as provide a vorticity/SRH rich environment to start with.

[Radtechwxman]

I just don't buy the triple point being that north or east at that time. Even ICT was stating it would be just their west in the evening. With that ridging building ahead of the system, I don't see this being able to surge north esp with how the ridge arcs back to the nw. Also there will likely be a mass of convection north of the warm front so that will hinder its push to the north as outflow pushes south. Gfs has shown more consistency than nam thus far and nam really isn't in its golden range yet

[Chicago Storm]

Who knew everyone could freak out about it being a bust so early, and just live or die after every run. The way I see it is we have extreme instability that will be overspread between 21-00Z by a 50 knot or so mid-level jet. Shortly after 00Z we should see a relatively strong SSW'ly, perhaps even slightly more backed than that, LLJ at 35-45 knots, along with impressively backed surface winds along much of the dryline, and especially near the triple point, which is sufficient for strong tornadoes, let alone just tornadoes. Remember, it only takes one supercell to pop in this type of environment to have chaos and make for a memorable day, especially if it moves over populated areas. Given the potential threats that still exist of very large/giant hail, and numerous tornadoes-- including some strong, possibly long-track-- I don't see any reason to just jump ship yet. If anything, you guys should be happy that we have a good cap in place given how 2015 went down.

I don't think anyone is really freaking out, but instead just giving general commentary.

There are a few issues that are showing up, and they are valid concerns. Being only 2 days out now, potential issues that are popping up have to be taken into serious consideration.

[Chicago Storm]

I just don't buy the triple point being that north or east at that time. Even ICT was stating it would be just their west in the evening. With that ridging building ahead of the system, I don't see this being able to surge north esp with how the ridge arcs back to the nw. Also there will likely be a mass of convection north of the warm front so that will hinder its push to the north as outflow pushes south. Gfs has shown more consistency than nam thus far and nam really isn't in its golden range yet

The 6z GFS was north as well, with a threat well into NE.

[Radtechwxman]

Not that north though. Or east. I mean you have knowledgeable NWS offices even saying otherwise. But I guess only time can tell. Nam to me just seems way east compared to other models. I'm hoping some other hi res models on Mon can give us a better idea of the evolution of this

[Chicago Storm]

Not that north though. Or east. I mean you have knowledgeable NWS offices even saying otherwise. But I guess only time can tell. Nam to me just seems way east compared to other models. I'm hoping some other hi res models on Mon can give us a better idea of the evolution of this

Actually it was, the 6z GFS compared to the 12z NAM.

[Radtechwxman]

I usually don't look into the 06z runs much. Usually 12z and 0z and sometimes 18z. Curious to see 12z gfs

[MattPetrulli]

Dr G upgrading his torcon to 6 and citing explosive t'storm development. Torcon for 6 Central OK, 5 for KS. 

[Chicago Storm]

I usually don't look into the 06z runs much. Usually 12z and 0z and sometimes 18z. Curious to see 12z gfs

12z GFS holds.

[Radtechwxman]

Are you favoring more of a TP play because of better shear?

[Radtechwxman]

12z gfs seems too east with the dryline. And the moisture quality and cape aren't as aggressive as past runs. It def has pushed that surface low more north and therefore low level winds aren't backing as much. Crazy we are 2 days before the event and still have a lot of uncertainty

[Quincy]

For today's threat, the GFS seems to have done a good job of handling the quality of moisture return so far. Mesonet data is fairly comparable for what the 06z GFS was expecting at 15z. Also have a couple areas of 60's showing up near the Red River in SE Oklahoma.

Forcing looks meager at best with southward extent. I have doubts about any robust updrafts being able to form south of the KS/OK border. I'd favor the area up near Hutchinson to Salina today for a couple of isolated, photogenic supercells. Storm mode may be a bit messy, but north-central to northeast Kansas into southeast Nebraska could be good too.

[brettjrob]

For Tuesday, the concerns are warranted in light of how incredibly hyped this event has been from a week out. It's probably among the most hyped I can ever remember from that early on, and I'm beginning to seriously doubt it will fulfill those lofty expectations.

 

Yes, there's huge CAPE and a big trough coming in, and there will probably be some tornadoes. But it's all relative to expectations, which couldn't be higher, for a lot of the community.

 

A couple days ago, I said the caveats for this setup didn't really look any worse than they did from the same lead time for 4/14/12. That's clearly no longer the case -- there are serious issues showing up on virtually all the current progs. The cyclone is occluding too early, and unless that trend reverses quickly, it will limit the threat of a dryline tornado outbreak considerably. There could still be tornadic supercells on the dryline, but probably not extremely long-track violent tornadoes. Closer to the WF (anywhere from C KS to C NE/W IA, depending on what you believe) still looks pretty ominous, and may end up being the real bullseye if trends hold.

[jojo762]

Dr G upgrading his torcon to 6 and citing explosive t'storm development. Torcon for 6 Central OK, 5 for KS.

hmmm... Dr. Forbes does not seem too concerned with the cap I guess then. On Friday he mentioned that that was the one thing that could really hold this event back, and that's why his number was at a 4 then along with some model discrepancies. Despite that the models do not necessarily show CI at the same time, or even at favorable times, really have to believe that when the mid-level jet overspreads the warm sector in the 21Z to 00Z range if you believe the 12Z GFS, that all hell could break loose. This was a problem with 4/14/12 too, most of the models were not showing very much CI if any due to the cap/EML despite the mid-level jet energy/temps overspreading the warm sector, and we all know how that went. Seems nearly inconceivable to me that the cap wouldn't break with the ejection of the shortwave over the dryline, bringing with it the cold temps aloft and strong mid-level SSW/SW'lys. Main questions to me are: 1. The location of the dryline, which will actually make a difference as to when CI occurs, and 2. How much of a southerly component there actually will be at H5.

 

The GFS and NAM usually are too far east with the DL.

[BuffaloWeather]

hmmm... Dr. Forbes does not seem too concerned with the cap I guess then. On Friday he mentioned that that was the one thing that could really hold this event back, and that's why his number was at a 4 then along with some model discrepancies. Despite that the models do not necessarily show CI at the same time, or even at favorable times, really have to believe that when the mid-level jet overspreads the warm sector in the 21Z to 00Z range if you believe the 12Z GFS, that all hell could break loose. This was a problem with 4/14/12 too, most of the models were not showing very much CI if any due to the cap/EML despite the mid-level jet energy/temps overspreading the warm sector, and we all know how that went. Seems nearly inconceivable to me that the cap wouldn't break with the ejection of the shortwave over the dryline, bringing with it the cold temps aloft and strong mid-level SSW/SW'lys. Main questions to me are: 1. The location of the dryline, which will actually make a difference as to when CI occurs, and 2. How much of a southerly component there actually will be at H5.

 

 

Computer models are showing the presence of a cap (warm layer aloft) which may delay severe storms in some places until evening but then explode. Severe thunderstorm and tornado outbreak likely in northwest to southeast NE, east KS, central and east OK, north-central and northeast TX, northwest AR, west MO, southeast IA

[Smokey_mountain_vols]

Computer models are showing the presence of a cap (warm layer aloft) which may delay severe storms in some places until evening but then explode. Severe thunderstorm and tornado outbreak likely in northwest to southeast NE, east KS, central and east OK, north-central and northeast TX, northwest AR, west MO, southeast IA

Another reason why I really hate living in Tulsa during spring time.

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[ClicheVortex2014]

Quadruple point Tuesday morning

 

[Chicago Storm]

Are you favoring more of a TP play because of better shear?

I'm not fond of crossovers or capping concerns further south.