Moderately Unstable

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  1. Few quick thoughts... 1) Comments about splitting hairs. This is a WEATHER website. To talk about the details. If we were interested in the big picture, that is, large destructive hurricane, and DID NOT care about comparing it to other storms, combing through models, wondering about this or that mesovortex, we could read NOAAs discussion or follow TWC and go on our merry way. This is a weather weenie website primarily, to discuss the details. If not here, there is no place else. That said, there is intelligent banter, and, creative banter. Throwing stuff out because you know some big words but don't know how they fit together, isn't helpful. 2) People DO see what they want to see. Some mets and folks want a weak storm. No one "wants" a strong storm, but, on some visceral level, again, no one would be here if it was a clear sunny day. Rocket scientists like big rockets. Astronomers like big telescopes. Meteorology folks are interested by severe events. The more severe, the more they're interested. That's human psychology. Everyone, deep down, looks at that car crash when they pass, trying to get a view and slowing everyone else down. Same with storms. The sheer power and awe that that causes in humans is why human's always pay attention to "bad" events. News events are the same way. Boring? bleh. Major? Bring on the carnage, where's the popcorn. Humans are a fairly savage species, and beneath all of the pleasant "oh good golly gosh I sure do hope this all goes away", when no one looks, most watch the damage, whatever that damage is. Reality shows are a giant hit for a reason. I'm not saying that to justify the behavior, but when you see people in the forum foaming over these details...that's why. Good or bad. It is human. 3) The eyewall is likely undergoing, or was trying to undergo elements of a replacement cycle. This is easy to spot. There was (until recently) a lot of lightning around the eyewall, which is a hallmark of eyewall replacement cycles. Most hurricanes do not have much lightning surrounding the eye. It is in the outer bands. Lightning around the eye, with deformation of the eye's axis, indicate instability of the eye, and possible initiation of a replacement, which seems to have started around 1.5 hours-2 hours ago. Lightning with no deformation can just indicate an incredibly strong and still strengthening storm. Here we have deformation and lightning...replacement. Almost all major hurricanes of this strength undergo one, particularly when some type of synoptic forcing mechanism is present and even more particularly after a period of rapid intensification. The degree to which Laura strengthened and the rapidity were both off-the-charts high. That means, an eyewall replacement is likely. However, once one starts, they usually take around 12 hours to complete. Within that time, you have concentric eyewalls. Typically this occurs when the storms surrounding the eye tighten and choke the inner circulation. That was the case earlier, but, for somewhat interesting reasons, a portion of the eye weakened to the south, in effect sort of stopping this "choking" process, BUT also, weakening the eye a bit. This leads to two possible future outcomes, either the eyewall replacement cycle will continue and the storm WILL weaken a bit before landfall, likely at a low end cat 4 strength or in a maximum reduction scenario upper 3...which has been noted by almost every single NHC update...or, the opening will slow down the process, the northern eye will continue to keep itself together and reorganize a tight southern eyewall by landfall, keeping the storm at upper 4 strength. Paradoxically, by having this opening, the storm may actually be stronger than it would otherwise be, if a full replacement cycle were able to occur. In either case, upgrading to cat 5 is highly unlikely. The SFMR winds, do not show continued strengthening, and shear is increasing a bit. This is all offset by stupid warm water temps. That's the story of this year, and it means more storms WILL follow Laura, some likely major. A wave just left Africa today. Hurricanes conceptually exist as a transporter of momentum and heat from the equator (where there is more), to the mid-lats (where there is less). The likely scenario is maintenance of category to landfall. That may disappoint all the carnal folks (see #2) that are wishcasting a cat 5 but that isn't the job of meteorologists. The job is, forecast and accurately describe the weather. Views/dreams/hopes are not relevant to forecasting and delineate the difference between the NWS, and this forum. One thing I do, when I realize I'm looking at a situation with bias in any direction, is I try to first imagine the opposite outcome happening. I want something to go one way, I imagine it does the exact opposite-weather or otherwise. That gets me out of wish mode and into objective mode. I've seen the other side of the coin so I can be more objective. So, folks, imagine for a minute before landfall this downgrades to a high end cat 2. Get out your yay's and oh noes or thank goodnesses or whatever is deep inside of you. Once you do that, come back to looking at the data, and you'll be more objective in figuring this all out. Cheers, Moderately Unstable
  2. Well, mesoanalysis shows that the cells are in an environment with STPs estimated to be between 5-6 in about 2 hours, so, theoretically, yes. Overall instability is down from earlier today. As we go along through the evening, low level stabilization should result in storms becoming elevated, which would drop the tor threat. So, as long as they stay surfaced based, sure. But, medium term, they won't stay surface based I don't think. For now, yes. Anything in the area right now is going to spin. And for full disclosure purposes, as I've been writing this and looking at the models to respond, SPC has released a new MDD answering your question, basically saying, yeah, for now. That cell down in the SW is growing pretty fast. But again, as we go through the night, we see an increase in low-level stability. For storms to be tornadic, it isn't enough for there to be decent helicity. Storms have to have a wind field and inflow that actually uses it. Today has basically blown up at anyone trying to make a half decent forecast.
  3. I was about to say, no, but, sure enough, the overshooting top has re-emerged on the cell. This storm should have its own wikipedia entry, all by itself. Just incredible how well organized this thing has been for so long. In any case, supercells can persist for awhile in sub-optimal environments, and actually for a cell this organized it's generating its own lift environment....but they're convective weather phenomena at the end of the day. While the cell won't necessarily die off immediately, it does stand to reason, that having been in such a conducive environment for so long, as it leaves that environment, it will weaken. Maybe slowly, maybe quickly. But, this storm won't maintain itself in stable air at the low levels. The southern of the two northern cells, is still in a favorable thermodynamic environment, AND shear environment, so it bears watching the next 30 mins to an hour. It also has the advantage that the long track cell has had--clear and relatively undisturbed air to the south for inflow.
  4. Oh. Oops. I've got nothing. I feel like this storm is just messing with mets now though. It weakens whenever there's a tor emergency issued. It shoots off some anticyclonics, satellites, and is now threading RIGHT between the warning county line polygons. Good SPC nowcasting: *sees tornado*: conditions are very appropriate for a tornado! However, that's also me, so, retracted. I wonder if moderate risk would have verified today. Starting with the earlier FOUR concurrent tornadic supercells in OK, today has felt more outbreaky than enhanced. I know we won't know until later. Just getting that sense.
  5. This one is actually Jackson's domain. Everyone's s**ting the bed tonight!
  6. Wow, look at that storm near Jonesboro. Echo tops still collapsing on the West Concordia (aka fort polk/jasper/etc) storm. The Jonesboro one is exploding right now, 57k feet, excellent hook. In a better environment, at this point? Edit: Nvm, fort polk is still collapsing, but that's a nasty circulation. Jonesboro circ is intense too, wonder if/when they'll issue for that. In the interim though clearly a near term threat on both.
  7. So, I've been following on a few devices because, if I'm going to nerd out, I'm going to go full tilt. They were delayed in issuing at least one polygon box. There WAS a warning in effect; it didn't cover the area in which the tornado WAS, at least, for a time. It could be that both the NWS site and radar scope were both wrong, but I believe that was the issue. The storm outran their warnings. Yeah, it's definitely been prolific. I'm not sure it's prolific in the sense of, say, a 70 mile long EF5. It's prolific in its longevity, pure overall (not just tornadic) strength, staying discrete through that whole time, the duration of time in which is is potentially tornadic. There are many storms I can think of that are "prolific", it's all relative to your definitions. If prolific means, long lasting, yeah. To all...I've been watching the echo tops sink a bit the last half hour, from around 55-56k down to 50k. That may mean the storm is starting to outrun the area of maximal CAPE. Still a tall, strong, potentially tornadic storm, but bears watching since that will long run portend when this thing dies. Other storms will obviously be pertinent through the evening as they encounter a favorable environment....but, this storm in particular, that'll spell the end of the most serious concerns. Of course, it could do any number of things and re-cycle, it's done that a couple of times already (here, I don't mean recycling of the meso, I mean cycling of the primary updraft's inflow stream).
  8. Wow. I hadn't read that. See, this is why I like coming to the forums. Learn stuff I didn't know. That's shocking, and also strongly proves what happens when you don't warn a tornado.
  9. Maybe they noticed that the circ weakens every time they issue a warning hahahahaha. In all seriousness, this is concerning. Is one of their mets out sick and they are short staffed? I have to say....agree at this point on the Lake Charles office. Not sure what they're thinking. There is a clear CC dropout on massive g2g shear. This is pretty cut and dry.
  10. I've actually done a mini-internship with the NWS, and have a friend that's a lead forecaster at an office so I'll chime in on this. Warning issuance is defined by certain criteria on velocity imagery and a few other factors. Note that, unless you're looking at something like GR2, these are post-processed products. Different WFOs have different training procedures. When you start at an office, they have you do simulator training--seriously, to prepare you for the types of events you'll see in that office, and teach you how to warn effectively. When it comes to severe weather warnings, as I've expressed before, it's about more than just, "does this storm have a hook echo". Because your warnings, are THE *official* source--not just for the public, but for other METs, your warnings are taken very strongly. Places in Dixie Alley, and Tornado alley, often have a higher threshold for warning, than, say, my area (Philly). That's not ALWAYS technically true--but in practice, I see storms in the plains all the time that would definitely be TOR warned in my area, and vice versa. The reasoning is basically limited attention. If my warning goes out to millions of folks' homes, may wake them up if they're asleep, (etc), I'd better be sure it's worth it. You may say, "well, if it's POSSIBLE, you have to warn!". That's not true, and it's bad public policy. If I get too many warnings on my phone, or smart device, or NOAA weather radio, what am I going to do? I'm going to turn it off. I'm not going to seek shelter. I'm not going to take it seriously. I'm going to stand by the window to try and see if *I* can SEE the tornado, or other weather event. Granted---*I* don't do that, but, this is how 95% of people DO think. The goal, in tornado alley, and dixie alley, is to try to warn storms that are likely to produce a tornado, and I don't mean POSSIBLY produce a tornado (that's a specially worded svr tstorm warning), I mean *likely*. You don't want joe the tumbleweed chaser ignoring a tornado emergency because he was incorrectly warned about a weak circulation. One is more deadly. Despite impressive radar returns, this storm, has not produced tornadic damage reports along a lot of its path. At present, the storm is over rural areas, and would be hard to confirm. If the storm shows organization when it approaches a town, they'll probably warn it. But there ARE storms, that LOOK PERFECT, but DO NOT produce a lot of damage, or tornadoes. There may be something to be said for why there is ONLY one supercell in an environment that seems "highly favorable" for tornadoes and severe weather. At present, the velocity imagery coming off of the KPOE radar does not indicate storm relative velocity gate-to-gate sheer, exceeds the threshold for issuing a tor warning. That's what they use, amongst other things, with much better processing than we have on radarscope. Also, look at the storm history. It's had this impressive look, then falls apart. If the ingredients are the same, the storm is the same, and the look is the same, expect similar things to happen. Oldest forecast technique ever, persistence. Bad overall technique, but has merit there. Moral of the story: don't over-warn. People think that you should always warn something if it is POSSIBLE for something to happen. If things ramp up, and there is STRONG gate to gate shear, you'll see warnings, and PDS language etc. With scans every few minutes, and warning issuance possible in about 4 minutes, there is time, when a tornadic storm is over rural areas, to assess the situation, before producing your warning (which then needs to verify for your office to statistically match what has been produced). As a final related note--the tor emergencies issued earlier may not verify, and that's not great. You don't want a high false positive rate on your PDS warnings, and tor emergencies. Hence why, contrary to our thinking, the folks at the NWS think a bit about their choices before issuing. As you can see, now that the circ is re-strengthening, they went right back on that warning.
  11. Mkay. So, Mister, er, Normandy, that "dumbass", is a professional forecaster, who gets paid to predict the weather. And I have a met degree--and I don't work in the field so I don't even claim it on my profile, because *I* don't feel that my posts warrant that level of "respect" per se. Let's not affront the folks who lend this site anything more than weather-foamer status. Because let's be real--without actual forecasters and mets, this site is a bunch of people fascinated by severe weather parroting what the SPC, and NWS say, or someone who knows what they're discussing, AFTER they've discussed it, as though they are somehow themselves competent. As though we cannot all read SPC and NWS posts or already have them open in another tab. Let's avoid prognosticating and correlating a long tracking supercell, to the most deadly, prolific, and dangerous tornado...EVER. This is not that. Period. Trying to compare this storm to doomsday, demeans the caliber of our collective intellect on this forum and site. This is a bad storm, producing damage. It is not the tri-state tornado. Many supercells persist across several states, including cycling tornadic ones. This is a textbook supercell persisting in a good environment and creating its own microscale meteorological climate. This happens several times each year. Tomorrow, or late tonight, we will find out exactly where, and how much, damage has been done. I do NOT agree with the idea that this tornado has been down the entire time, and I will take that bet with a willingness to be wrong. There is not a continuous line of damage reports, or debris signatures, and I've noted several cyclings of the circulation including it being cut off a few times as the strong circulation continues to entrain its own cold outflow. More generally--it would improve the scientific credulity of this discussion, if we can *all* assume that we are all competent enough to watch RadarScope, SPC, and NWS postings (you know, stuff I'd expect of a HS student), and instead, discuss the more specific and esoteric things...like the environment, soundings, hodographs, downstream forecasting, damage reports etc. Not stuff that we can all get elsewhere. It doesn't show knowledge, it does not impress anyone, it wastes space, and doesn't further my, or anyone else's understanding. Rant.end(this). // end rant.
  12. It's a cycling supercell in a good environment. I'm racking my brain thinking about what's causing the cycling instead of a sustained long tracker. The winds are backed, low level SRH is quite high, no other storms to interact with. Odd. Whatever the damage track(s) is/are tomorrow, it will be interesting. There are no spotter reports on this since the Seven Oaks area, yet there have been multiple debris balls, and other signatures, in a good environment. We have learned so much about tornadogenesis and forecasting the last decade, to the point we can use debris heights, to estimate tornadic wind speeds. But I still don't know of any literature that would explain why this supercell is cycling so much and others just "stay down". Not complaining, this would be a heck of a damage path if it was all on the ground. Wonder if the storm base here is higher and it's therefore having more trouble sustaining tornadoes on the ground, even though, say, 1k feet up, we've got a fairly continuous funnel. But earlier videos didn't show a high cloud base so that kinda puts cold water, somewhat literally, on that theory. Edit: spotter report did just come in suggesting a tornado in Jasper, from a 911 call center. 5 E of Jasper. So, that may have been the start of that particular touchdown. There is another uncorroborated report of the tornado OG in Jasper, of unknown magnitude, also 911 call center. That may have been strong RFD that gave off the appearance of a tornado. Won't know until much, much later. Can you imagine what this would have been like were it actually on the ground for the whole distance?
  13. Debris sig. Well, it does look like it hopped up over Jasper. They really lucked out, hopefully. That would have been absolutely horrific. I'm not saying the current situation is good, but, they really dodged a giant bullet. I think what occurred before, and is likely now occurring right after, Jasper, is going to speak to what exactly it was that they avoided tonight.
  14. Yes. Jasper is in serious trouble. That couplet is nasty, and it is getting stronger with each scan, and it's heading right for them. Once someone can confirm this visually, this is one of the times an emergency warning is warranted. People need to get to shelter, now.