Moderately Unstable

4 minutes ago, weatherwiz said:

Holy crap...I hope that is just some sort of error. 

I mean, sampling the inbound side's returns, I'm seeing plenty of 180s to 190s with a spot of 210 and 222. So, I don't think it's an error. Mesovorts around an eye like that. Does still seem to be strengthening. Phew.

17 minutes ago, hawkeye_wx said:

Could there be the beginning of an eyewall replacement cycle going on?  Satellite shows what looks like an outer ring popping around the north side of the core.

Edit:  The Cuba radar doesn't really suggest that to me, so maybe not.

Current take: no. Too early. Eye too big, storm itself still finalizing getting its act together and has improved substantially in presentation in the last hour vis a vis clear enhancement of angular momentum and closure of the eyewall. Sat presentation continues to improve, best to look at medium term trends rather than minute to minute on H's. 

1 hour ago, Chreeyiss said:

Obviously you’re the met, so your opinion is much better informed than mine, but it seems to me that if if our intensity scale is to continue relying heavily on damage produced over other indicators, that the scale needs to be updated with more non-urban damage indicators for EF4+ tornadoes, rather than a downward adjustment of winds in the ef5 category. In concept, it doesn’t make a whole lot of sense that a tornado’s intensity is only as strong as the building it hits (or doesn’t hit) but even with improvements in technology, it’s still the best we’ve got. Tornadoes predominantly hit rural or even unpopulated areas, and if tornado intensity is going to continue to be evaluated by this methodology, I would think the next logical step in improving the scale would be to accommodate that fact better.
 

The NIST slideshow about Joplin that was posted above makes note of the large amount of subjectivity that comes into play when evaluating unconventional damage indicators due to construction methods that can’t generate an ef5 rating. I’m sure Tim’s statement was made on the fly, but using two tornadoes that were clearly well above the F5 threshold as the benchmark for 201mph winds doesn’t seem like a fair comparison to me.

 

If I had any say in the matter, I personally would only advocate for lowering the wind threshold if structural engineering studies determined that what is generally considered ef5 damage was produced at lower wind speeds, or if we were to lower the standard for what is considered ef5 damage. 
 

Let me know if my line of thinking here isn’t correct.

Nope, we're on the same page. We need to have a 3rd revision to the EF scale. Specifically we need to be able to come up with valid damage indicators for, as you note, rural areas. One of the main concepts of the EF scale when it was introduced was that it was supposed to retain continuity with the old rating system. E.g. the numerical wind speed estimates were going to change, but, the same type of damage on the F scale was intended to be rated the same on the EF scale...just with more accurate wind estimates and more specific damage indicators. That isn't currently happening imho. An F5 of old does not seem to be an EF5 now. I do think there's some merit to the chatter going around about the rating still being preliminary (other 190 mph tornadoes have indeed been upgraded to 200...it really is a tiny difference). However, if they don't upgrade, I hope they produce a very detailed report (I'm sure they will), that explains all of the factors that got them to their conclusion. And I hope that report doesn't say "we thought there could be EF-5 damage, but, couldn't find damage indicators to support it". Conversely, if they say, "radar estimates along with contemporary research into tornado intensities as related to debris height, vrot, wind tunnel testing and other physical studies, suggest this tornado was demonstrably weaker than EF5s on record because of A, B, C", I would be ok with that. At the moment though, since the damage rating is preliminary, it may yet get upgraded. Either way....we need a better way to rate rural tornadoes. There should also be some type of discussion amongst the research community at this juncture as to whether our radar measurements have grown accurate enough to be allowed to "factor in" to the rating. Take El Reno. We know it was a 5, by 100 mph. Because DOWs measured that. But it's a 3 due to the damage indicator problem. That in my view becomes an actual research problem. If I'm were to do a tornado study, and I am pulling up atmospheric conditions present for "F5" tornadoes, trying to draw conclusions...my conclusions will be flawed if the ratings depend on the type of structures being impacted. Meteorologically, the atmosphere does not care if there's a city or a field below it. But the rating system does, which would lead to biased results (potentially). At the least, it gives researchers an incorrect sample population and incorrectly classifies the rarity or lack thereof of specific tornadic intensities. Our current scale "favors" EF3s and EF4s, when we're talking major damage, and that's solely due to the design of the damage indicator system. I'm not saying every high end EF4 should be a 5, but this is the latest of several tornadoes that really hint at top end damage, and aren't getting that top end rating. 

Hm. Well, it's splitting hairs to some degree I think (10mph from EF-5); very similar overall "thinking" to Bassfield, which as many recall we all were discussing an EF-5 rating as well. 

I actually have a counter-thought with respect to Tim Marshall. What if he gets called in when the NWS team *doesn't* have the damage indicators it needs to make its own assessment and needs an outside expert to review things that have been destroyed and basically assign a damage indicator rating on the fly? Many have pointed out that the structures on path wouldn't be able to generate an EF-5 rating. My interpretation when they called in the "experts" was that, they had damage that they were struggling to classify. Otherwise, why bring in said experts? Yes high ratings are important publicly speaking--but they're the sole discretion of the office in the affected CWA.

I also wonder, would those 2011 ratings have changed? Or, were there genuinely different building materials or other factors? I feel like, as much as we are kind of trashing tim (et al) right now, he obviously *is* an expert on tornado intensity. I'd be curious to understand the process Tim himself goes through when he does these evals. Does he incorporate Doppler radar data concurrent to the location he's evaluating? How does he and the NWS evaluate something that is "beyond destroyed"? What I mean is, I picture Tim coming in to answer the question, "this well built home was slabbed but xyz was not built correctly so there's XYZ ambiguity, is there anything you can see in the wreckage that looks like it would take a higher wind speed to be able to do THAT destruction?". One thing I've read about EF-5 damage is that the debris is often "pulverized" into a "fine powder" with "little recognizable from the original structure". Of course if that is the bar, there are EF-5s and F5s that would under our current rating scheme get downgraded.

All this said, my gut instinct is, hard as it is to believe, had Tim and co found some type of incredible damage as it were, they could still have issued an EF-5 rating on path. That's why they call in the experts. Arguably, we probably rated tornadoes overly agressive in the past, as opposed to rating them too-low now. Various numerics during the tornado including vrot had many on Twitter and a couple on here calling it EF-4 strength (while noting, if it were a bit closer to higher STPs and more population it'd be a 5). But since it wasn't, technically the radar does kinda track with a very high end 4 ( 30k feet debris loft is significant though--but could also be a function of the strength of the overall supercell's organization, which makes sense for many reasons and is what enabled such a strong tornado in the first place).

My final thought is, based on all the above, this would've been a 5 in 2011, 2007, before the EF scale (etc). The reason it isn't now feels like it is less to do with a change in *damage*, instead, we have a much better understanding of what *wind speed* is required to *produce* given damage (and for what duration and at what angle that wind must impinge on the structure or object in question). We understand now that things like forward speed, and angle of approach, can influence damage to structures. Therefore, I'd argue that the *windspeed* estimate is probably right, and the scale itself might need to be tweaked. We all know, EF5 means "incredible" and "catastrophic" damage. This IS that damage. It is just that. Catastrophic. And not to split hairs but it's more than "Devastating". I'd argue, devastating means everything is destroyed but it doesn't look like entire towns were model cities that had been carelessly thrown off the end of a high table by a child. Particularly what I saw coming out of Bremen. 

I therefore suggest we reconsider our rating criteria, by reducing the wind speed threshold required for EF5 ratings. The point of the rating is to inform the severity. This is top tier severity, it should have a top tier rating. If 190 mph winds do this damage, 190 should be a 5. 

Fair point. Partly because of what I have been reading on twitter. Perhaps I mis-worded what I meant, but that basically was more of this is not conceptually something no one has seen. I didn't mean it was something that had been seen in December, for this path length (etc etc). Those things are all valid. I meant, from a pure damage standpoint, we have seen damage similar to this before. It is very high end, yes. But when I read twitter posts that exclaim (and I'm not talking about the folks that are actually in person taking photos), that this has never been seen, that's what I meant. I've seen this with strong hurricanes and other severe weather a bunch. Every massive high end event is *the* worst event, rather than, a very very bad event amongst other very very bad events. Which is fine if it is the worst event in that context, but that's a high bar to clear, and one that hasn't yet been officially proven (even though yes, the images are bad). 

Right--so my point was not that the event wasn't bad, nor was I even saying it wasn't an EF5. I also wasn't trying to come off as condescending. I'm not sure who exactly I was being condescending towards, particularly on this forum, but I digress. 

I found a couple of useful links, I shared them, and I copied and emphasized some of what was written. I'm not entirely sure how well they are known, that was why I posted them in the first place. Yes, some people do know that, others don't. 

My main "point" in the essay, is to wait for the survey results. Given that Paducah has already been out, and has assigned a range between 158 and 206, they (for whatever reason), are not in the unequivocal camp. That gives a range of 6 mph for EF5, and, 35 for EF4. That's preliminary, but, that's why I wrote the post. 

I post this at my own peril (cue the comparisons of images to the scale), but https://www.spc.noaa.gov/efscale/ef-scale.html

There's your degrees of damage scale. Wondering what wind is needed to cause X damage? There's your link. 

For a single family home: https://www.spc.noaa.gov/efscale/2.html

-Slabbed home bounds are expected to require 200 mph winds. BUT, and this is IMPORTANT for everyone on here: the lower bound is *165* mph (that is not an EF5, which begins at 200). 

For a warehouse: https://www.spc.noaa.gov/efscale/23.html

-Complete destruction does NOT require an EF-5. Note: industrial buildings tend to fare WORSE than well built homes in a tornado. They are large, typically presenting a large and flat surface area orthogonal to the wind direction, and have vast, cavernous interiors. Translation: an industrial building being torn apart is actually less indicative of an EF-5 than a masonry structure, well built home, or similar. 

-Structural deformation of a high or mid rise building, generally correlates to a case-closed EF 5 designation. Such as the Mercy medical center in Joplin. 

-Hardwood trees debark at an expected wind speed of 143, (low EF 3). 

-For an institutional building like the Grays county courthouse, https://www.spc.noaa.gov/efscale/20.html I would suggest that the DOD is 10, corresponding to a windspeed of 148 (EF3) ranging from 127 (EF2) to 172 (EF4). Other areas on path have worse damage. But that's high profile. 

Quoting from: https://www.weather.gov/ama/damagesurveys , bolding mine:

Quote

Let’s look at an example to help tie everything together.  For an interactive demonstration, this link will be very helpful: http://www.spc.noaa.gov/efscale/ef-scale.html.  A tornado strikes a house, causing the entire roof to be blown off, but all the walls remain standing.  The survey team will first assign a damage indicator of 2 since this is a one- or two-family residence.  The description of the damage corresponds best to a degree of damage of 6 (http://www.spc.noaa.gov/efscale/2.html).  After careful inspection of the construction quality, it is observed that the ceiling joust was fastened with rafter clips to exterior walls, which meets code.  Therefore, the survey team assigns an expected wind speed of 122 mph.  Based on this wind speed, the team assigns the tornado a rating of EF-2 with winds between 111-135 mph.

To translate, the survey team needs to evaluate (in a lot more detail than we can with photos), HOW the homes were built, and how they were fastened to their foundations. Did they meet code? What did the radar presentation look like at the time the tornado was over the structure? What did people in the building(s) experience as the tornado went through? How were things fastened together? How long were tornadic winds impacting the structure?   They'll also look for office buildings of mid-range height (I doubt there's any high rise buildings on the path of this tornado). The key to those is looking for structural deformation. E.g. well built concrete and steel buildings that have BENT out of shape. Note: the water tower that collapsed DOES NOT qualify for that. It's a freestanding structure, and the deformation seen is almost certainly a result of impact with the ground and being tossed around along the ground, while presumably filled with water versus the wind itself bending the steel. And therein lies the difference.  Ever dropped a full plastic water bottle on the ground (or a metal one) from height? It breaks, right? How about an empty one? Does that break? Nope. If you blow your water bottle with a leaf blower does it deform? Also no, but it probably would blast away into your neighbors yard and make them think you're pretty weird. My point, the bent steel of the water tower is due to the collapse, not the wind. But, if the team finds actual steel in a building bent by the wind, that's different. 

//

For more (albeit old reading): https://training.weather.gov/wdtd/courses/EF-scale/lesson2/FinalNWSF-scaleAssessmentGuide.pdf

This is prior to the switch to the EF scale but the explanations still apply...

From that, bolding mine:

P.30: "Giving a tornado an F5 rating is probably more contentious than it should be; in general, more scrutiny is given to an F5 rating than to an F4 rating. In fact, the reluctance to give tornadoes an F5 rating might well cause some events to be rated F4 that might well have been deserving of the highest rating. In effect, proposing an F5 rating focuses so much attention on the issue that storm survey teams will be hesitant to rate an event at that level unless they find the strongest possible evidence. Most F5-rated tornadoes have hit populated areas; a tornado passing through open country is unlikely to be given the highest rating. In the event a tornado hits a populated area, survey teams can be under some substantial pressure to make an assessment before they have had time to give the issue the careful consideration it deserves. Formally, by the Fujita scale criteria, F5 damage to a frame home not only leaves no interior walls standing, but the debris from the home is swept away, leaving essentially a bare foundation. This sort of “incredible” destruction is as total as it is possible to be; it leaves essentially nothing of the home but a slab or an empty foundation. This criterion would seem to be relatively easy to evaluate but for a number of complicating factors. As always, the structural integrity of the home prior to being hit is a critical element. When distinguishing F5 damage from lesser intensity storms, the attachments along the load path are potential weak points. As already noted, further complicating the issue is the question of the duration of the tornadic winds. The 27 May 1997 tornado that hit Jarrell, Texas, left a number of homes in a particular subdivision with nothing left but empty slabs (Fig. 27).

Even the debris was blown far away, making the F5 rating an apparently easy decision. However, a post-event survey by structural engineers revealed that there was some variability in the attachments. Some homes were rather strongly attached to their slab foundations, whereas others were not. Beyond that, however, an important question became the duration of the strong winds – this was a large, relatively slow-moving tornado (the damage path was estimated to be roughly 3/4 mile wide, moving at 5-10 mph). At the observed speed, homes would experience damaging winds for 5-10 minutes. Not only would the damaging winds have more time to put structures under stress, but the long duration would be more likely to sweep away the debris than if the tornadic windspeeds been of lesser duration. Moreover, this subdivision was relatively isolated, surrounded by mostly open country. In the case of the tornado that hit the Oklahoma City, Oklahoma, metropolitan area on 3 May 1999, some of the F5-rated damage occurred in the suburb of Moore, Oklahoma. In this case, the tornado moved in from other populated areas, and its debris load was already substantial as it entered Moore. The result (Fig. 28) was large piles of rubble remaining on empty slab foundations. The tornado damage path was about 1/2 mile wide at this point and the tornado was moving around 35 mph. The damaging winds would last only about a minute in such a storm, and if debris from a particular home was swept away, other debris would fall in its place. In fact, that is just what was observed during a post-storm survey – the debris left in a particular location in the F5-rated damage area in Moore did not come from that location, but arrived from areas hit previously by the tornado. Hence, the absence of slabs swept clean of debris could not be taken as evidence of intensity levels below that of F5."

So, the duration of tornadic wind matters too. Here, we have a 1/2-3/4 mile wide tornado. Calculating the amount of time it would be impacting a structure matters when calculating the wind speeds. 

Note, with respect to slabbed homes, an *EF-3* can slab an *un* anchored home. 

Overall, while I continue to believe this is a low end EF-5 tornado based on the totality of images across various communities, radar data, and environmental parameters,  it is NOT as "case closed" as some on here (and on twitter) have made it out to be (and that's why this is a process). Also, with respect to myriad comments of "oh gosh I've never seen this", mostly on twitter--yes you have. And you said the same thing after Moore, Joplin (etc) if you were old enough to be following those events when they occurred. Or Tuscaloosa, Bassfield, Philadelphia (MI) etc. This is not the strongest tornado ever recorded. Period. You've got El Reno (an "EF3" but with measured 300+ mph winds and 2.6 mile width with various sub vortices the size of "regular" tornadoes traveling in trochoidal oscillation), the Moore twisters, obviously Joplin, and many others, that, FWIW, had this degree of damage or WORSE. The length of path, time of year, fatality count, and overall significance of this/these tornado(es) is/are historic, and that will be true regardless of whether it is an EF-4, or EF-5. But, it is not the worst damage most of us have seen. It's BAD--no question. But we don't need to over-dramatize it. We've seen the pictures. What's left is for the experts to physically review the places in those pictures in detail, and determine if those slabbed homes would've blown apart with EF3-EF4 winds, or if that would've required that 200mph wind to do that damage. We can't know that from any picture or video, because that information comes from the blueprints and related original construction documents of the home or structure or at least close physical analysis of the debris to find the relevant joints and fasteners (which, I shouldn't have to specify, we don't have access to). 

On the other hand, there's also a semi, non-scientific empirical relationship between number of fatalities and EF rating. Generally, the "worst" and most fatal tornadoes are EF-5s. That's because despite the best possible warnings, which this storm did have, at the end of the day, EF-5 tornadoes are in some residences or structures not survivable. If you don't have the right underground structure to protect you, you will die, even in a well built house, and with prior knowledge that the tornado is approaching and having taken appropriate actions (covering yourself with pillows or other materials in an interior room on the lowest floor). Stand in front of a jet engine at takeoff thrust with a pile of wood beams, nails, bricks, cars, etc between you and it: you wouldn't fare so well. If your home gets blown away, you're in that environment.

Of course, being a nighttime, December, tornado, didn't help. That is not the fault of the NWS, or TV mets though, as I've seen tossed around a bit (also mainly on Twitter). They did their job. Have you seen the videos of people driving on the highway, in broad daylight, a quarter mile from a giant wedge tornado? I sure have. You think they were expert chasers or mets that knew the direction the tornado was moving and that it definitely wouldn't hit them? I don't. Have you watched your friends and coworkers ignore tornado warnings (and obviously severe thunderstorm warnings) that are ringing their phone? I have. So have you. Even when the warning says a tornado is on the ground? Yep. People continue along as though nothing is happening. At the end of the day, meteorologists can only warn so much. If people choose to ignore every possible warning, including WEAs, not much more can be done after that. People act (not just wrt tornadoes but in general), when they make a personal connection between information and an imaginable threat to themselves. If someone can't imagine themselves actually being hit by a tornado, and, killed, they won't take action to protect themselves. Fear drives safety behaviors in this case. Fear takes understanding of the threat, and recognition that, yes, it can happen to you. 

The link I left for the old training doc contains a plethora of helpful information that can inform you about all that goes into damage assessments, both scientifically and with respect to the psychology of a public wanting answers. Things I didn't copy over but are include good explanations for HOW things are damaged during tornadoes (through both wind action and projectile action), and basically any other question you can think of that you want answered regarding tornadoes and damage assessments (that IS the (old) training doc after all).

57 minutes ago, vman722 said:

 

1 hour ago, BuffaloWeather said:

Estimated wind speed for that Mayfield tornado? 

The "Mayfield" tornado, as it's being referred to, is *not* just the Mayfield tornado. This tornado was on the ground for potentially over 200 miles. Maybe it cycled once; storm survey teams will determine the continuity of the damage track. But based on the images coming in so far, for Mayfield in particular, upper end EF-3 to middle end EF-4 damage is widespread. The image above from Jeff shows **possible** EF-5 damage. That depends on how well anchored that home was and how well it was constructed (materials). In support (or not) of the EF-5 rating, the survey team will look around that area for ground scouring. EF-5s produce extensive scouring. A good "at home" way to demonstrate this is to take a leaf blower, put it on high, and point it at the ground at close range. The extreme concentrated wind jet will actually physically extricate the grass and soil directly below the blower, like it was dug out with a shovel. That's basically the same thing that happens with an extreme end tornado (on a larger scale). Same thing with debarked trees. When we talk EF-5 damage, we are talking very specific markers of extreme damage that are frankly hard to replicate through any other mechanism. EF-4 damage is devastating, but it's just shy of "complete". 

43 minutes ago, Chreeyiss said:

I know you’re stating that as the lower bound, but it’s hard for me to imagine the survey will conclude anywhere near that low, given the insane velocity bins on radar last night. This will be a great case study on how g2g values translate to damage surveys, or don’t.

The damage images coming in, on large scale, I would also go with in the 170ish range, with exception of that Jeff image. If that is not just a one off and that's what the SW side of town looks like, that would change my perspective significantly. At the end of the day, radar is great for in-situ forecasting but it doesn't beat post storm survey and analysis. Unless you're in a DOW a mile from the storm, radar is not perfect. Partly because the radar beam unless in the above scenario, isn't actually viewing the tornado at the ground. And, partly because while radar is excellent, extreme end things (grapefruit hail, 250mph winds, etc), are more likely to cause issues with the radar beam, the returns, and subsequent digital interpretation. The TBSS illustrates that concept. TBSS occurs when objects in the air cause reflection and scattering of the incoming radar beam, such that they then hit the ground, before reflecting back to the hail (in this case, debris), and then to the radar. Radar calculates distance based on amount of time it takes the beam to return. Longer return time + multiple returns equal that long spike of lower reflectivity seeming to emanate from the storm. But that's obviously not actually what's happening! There's no light precip falling under that spike even though according to the radar's algorithm, there is. All of this is to say, we take the combination of data from radar to understand a storm, not just shear. I will also say, for the most part, the WSRs do a great job with parameterization of wind speeds in tornadoes. I'm simply saying, storm damage survey "wins" versus radar estimated shear when they disagree with one another. 

Separately, the action that raises debris up 20, 30, 35k feet into the air is not linearly correlated to tornadic wind speed. That's why the study Sam Emmerson did specifies EF-4+ rather than EF-5. There aren't a lot of EF-5s on which to create a strong data set to make that into its own classification. 

31 minutes ago, DanLarsen34 said:

Looks like we found potential EF-5 damage in Mayfield. 

 

That is much more indicative of the type of devastating damage you talk about with upper end EF-4 or EF-5 storms. If more images like this come out you'll see more mets talking firmly about EF-5 stuff. Central Mayfield is definitely more middle EF-4. This is not. This is more "Joplin". I also think that because the tornado was on ground for so long, there may be other areas where EF-5 intensity is possible. Mayfield is in the spotlight as a fairly big town that got hit near peak strength, but it wouldn't be surprising to learn of ef-5 damage somewhere else on the path, too.

1 minute ago, Disc said:

Could be a fiber cut. If no internet and backups have failed, can't issue products. They will still be able to see the radar locally, but it's not getting out for the world to see.

Very good thought. That would make complete sense. 

5 minutes ago, Disc said:

I think PAH is down hard. Radar image is old. Springfield is doing full service backup.

Yeah. It was my error. Though I remain confused.  (https://www.nws.noaa.gov/directives/sym/pd03041004s042005curr.pdf): For a power failure to take down an office, it would have to take out the generator. Both the office, and the radar, are supposed to have backup power in the event of commercial power failure (https://www.weather.gov/media/bro/pdf/PressReleaseNEXRADGeneratorSLEP_BRO.pdf). So, something isn't adding up for me. Was that offline for them? Was there storm damage to the generators? Etc.

Not sure if others have noticed but because Paducah is so close to Benton, Springfield MO is currently issuing the warnings for Paducah's CWA. (This occurs when the NWS staff need to take cover. There's a built in shelter in every NWS office). Edit: power failure. Hm. My memory is clearly going bad, I thought they had backups for that. 

8 minutes ago, andyhb said:

Debris to 35k feet on that Mayfield storm. Easily an EF4 or EF5.

In light of the debris height, the TBSS, and the fact it basically went through a major town, the odds of finding EF5 damage are actually pretty high. As you know, the surveys done after are looking for degrees of damage. A LOT of the time, there's evidence for a stronger rating, but the tornado didn't hit anything at that time that would be able to score a degree of damage to indicate such wind speed (e.g., the thing would be entirely destroyed, lofted, or otherwise "maximally damaged" at a lower wind speed). Since this hit basically center to a town, many homes were hit. We can reasonably assume this is a multivortex, so, all it takes is 1 subvortex hitting one well built house and sweeping it from the foundation to classify the entire thing as an EF5. The 2020 Bassfield tornado was a potential EF5, couldn't find damage consistent with that intensity. Something tells me this is different. 

9 minutes ago, Calderon said:

This is going to go directly into Mayfield unless something drastic happens. Time is running out very quickly and unfortunately even if it were to occlude, it'll still nail Mayfield.

It's been nailing things for a long time now. This is definitely turning out to be a very bad night based on the reports and photos coming in so far. Far and away capped by this particular cell, which has gone through several towns and left what seems to be chaos in its wake. Remains to be seen if this is a contiguous single long tracker, or 2-3 shorter, still long trackers. A 3 body scatter off debris is pretty telling. When you get a cell that stays discrete like this one has in an environment like this one is in, you get the type of tornado that gets a wikipedia article dedicated to it. It's very rare. There are plenty of "good ingredients" days, but often on such days you end up with a messy storm mode. Everything and anything that goes up turns into a cell, every cell develops some kind of spin, you get upscale growth and collisions and the integrity of the meso gets disrupted. This is what happens when you take the theoretical "lone" supercell and put it into a dynamically intense environment. Until this thing runs into another cell, or a worse environment, this is going to continue. But, honestly, what just happened to Mayfield might end up being the worst. I'm not entirely sure what to even say at this point. 

1 hour ago, Newman said:

I chased Mullica Hill with 4 other friends guys. Un-*******-believable damage. I've never seen anything like this in my life. At least an EF4. Saw the wall cloud and strong rotation, but we were in an open field to the SE of the storm away from it. We then drove on the backside of the storm and caught the damage. House's leveled, trees absolutely sheared apart. My images are too big to post here for some reason

It would be quite surprising, and unprecedented, to see an EF5, given their rarity here--iirc the strongest Philly area tornado was an EF4 that hit the north broad part of town coming down from Norristown over a century ago. But that radar signature was definitely something else. I stopped what I was doing at work and remarked to a coworker, "this is the strongest tornadic signature I may have ever seen around here"--I am not at all shocked by your report. Certainly seemed EF3+ based on the debris sig and definitely based on the videos. Not something you expect to see in the Philly area. Last year we had a couple strong ish ones from Isias EF2 level...but tonight was just shocking. 

I will add with that line earlier tonight it felt like everything was rotating to some extent at some point. I went outside a couple of times and in addition to the ground scraping LCLs there was just so much non linear motion on everything. It seems rather clear that there must have been some local enhancement of the low level wind field to cause this degree of widespread and significant damage. It will be interesting to read the storm reports when they come out....honestly I just hope no one died. When I saw that sig earlier that was my first thought. Not something something I'd want to be in. 

000
WTNT64 KNHC 300356
TCUAT4

Hurricane Ida Tropical Cyclone Update
NWS National Hurricane Center Miami FL       AL092021
1100 PM CDT Sun Aug 29 2021

...HURRICANE CONDITIONS SPREADING FURTHER INLAND...
...CATASTROPHIC STORM SURGE, HURRICANE-FORCE WINDS, AND FLASH 
FLOODING CONTINUE IN PORTIONS OF SOUTHEASTERN LOUISIANA...

During the past couple of hours, a sustained wind of 66 mph (106 
km/h) gusting to 111 mph (179 km/h) were measured by a 
Weatherflow station in Mandeville, Louisiana.


SUMMARY OF 1100 PM CDT...0400 UTC...INFORMATION
----------------------------------------------
LOCATION...30.4N 90.7W
ABOUT 5 MI...10 KM W OF KILLIAN LOUISIANA
ABOUT 30 MI...50 KM ESE OF BATON ROUGE LOUISIANA
ABOUT 45 MI...70 KM NW OF NEW ORLEANS LOUISIANA
MAXIMUM SUSTAINED WINDS...95 MPH...155 KM/H
PRESENT MOVEMENT...NW OR 340 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...960 MB...28.35 INCHES

$$
Forecaster Stewart/Papin

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The Lafitte situation is gut wrenching. That is the type of report that can indicate a possible mass casualty event--I hope that doesn't occur. And, let's be clear, being trapped in your attic and drowning is not a peaceful way to go. It's one of the most traumatic and painful ways a person can die. When you actually think about what some people are going through *right now* as you read this.. it's tragic. And that situation is occurring in several areas. 

6 minutes ago, jojo762 said:

This guy has to be measuring in km/h... 177km/h (the max he's said he's had comes out to a bit over 100mph) which feels reasonable.

I would frankly be surprised if he's even hit 100. Lots of stuff starts flying once you hit triple digit winds. It's very much "obvious". One easy way to tell--the deciduous trees he's been filming are not toppling over, or even swaying wildly. Those tree types don't handle wind well--palm trees evolved the way they did specifically to handle wind. He's barely seen hurricane strength yet. He will, and he will quickly learn what real strong winds actually look like. His poor estimates are concerning because as a chaser, you need to know what different strength stuff looks like. Also, he should be monitoring the nearby observation sites, have reliable in-situ equipment, and be monitoring radar. If you don't--and I say this having chased before-- you can put yourself into harms way and this isn't a situation where someone can rescue him if he gets into trouble.

4 minutes ago, turtlehurricane said:

One very notable thing is Ida is still at maximum intensity, with zero signs of weakening, it might even be strengthening still! Check out rapid scan IR https://weather.cod.edu/satrad/?parms=meso-meso1-14-96-1-10-1&checked=map&colorbar=undefined

Well, it isn't fully over land yet. It brushed the coastline and is now back over water--albeit shallow. Separately, research has indicated that the low-level mesocale environment near the coast in situations like this can be extremely moist and end up largely mirroring the oceanic environment. Another thing to consider is that the part of the circulation that remains over water (including the replacement eyewall), is still able to tap into the oceanic energy. Once the eye firmly crosses land and begins trekking inland, weakening will begin in earnest. 

That camera is very impressive. Hats off to John and co. Definitely could offer insights for future ways to construct in situ mesonets for strong future landfalling storms were it needed for a research purpose. 

VDM

907 
URNT12 KNHC 291626
VORTEX DATA MESSAGE   AL092021
A. 29/16:01:50Z
B. 28.94 deg N 090.07 deg W
C. 700 mb 2517 m
D. 931 mb
E. 235 deg 10 kt
F. CLOSED
G. C14
H. 101 kt
I. 286 deg 8 nm 15:50:30Z
J. 025 deg 111 kt
K. 286 deg 8 nm 15:50:30Z
L. 114 kt
M. 155 deg 5 nm 16:06:00Z
N. 228 deg 127 kt
O. 146 deg 7 nm 16:06:30Z
P. 16 C / 3041 m
Q. 20 C / 3014 m
R. 3 C / NA
S. 12345 / 07
T. 0.02 / 1.5 nm
U. AF303 1509A IDA    OB 03
MAX FL WIND 127 KT 146 / 7 NM 16:06:30Z
;

11 minutes ago, StormChaser4Life said:

With the high octane fuel of the Loop Current, I'm surprised we aren't seeing a big uptick of eyewall lightning with pressures quickly falling and convection increasing. 

Lightning can indicate RI, it is not necessary though conceptually. Also, just to play devils advocate (looking at you Iota and Eta), the plane isn't actually in the eyewall yet (edit: now it is). The forum is convinced due to the sat presentation that it is bombing out--and, yes, anyone looking at that imagery will come to that conclusion. But, the reason we fly into storms is because sometimes the satellite is wrong in either direction--the storm might NOT be bombing as quickly as it looks, or, a seemingly poorly organized storm may in fact have a solid circular closed eye that's just not well discerned on sat imagery. Point is: let's wait for lé plane. That being said if it doesn't find a substantial uptick that accounts both for the current period of intensification and the lack of wind-response to the pressure drops earlier in the day, I would be quite surprised. I was a little surprised that they didn't upgrade to 115 at 10PM frankly but I think the idea was to wait for recon which does seem prudent given earlier sat presentations didn't end up matching the winds that were found. 

It appears that, yeah, it caught up. 

9 minutes ago, David Reimer said:

The plane will be in there within 30-40 minutes. Be happy the 53rd was able to scramble another aircraft so quickly. Otherwise, you'd be waiting another four hours for data.

It's actually the same aircraft, 303. Let's hope they fixed the issue--it helps that the base is not a long flight from the storm. 

4 minutes ago, zinski1990 said:

Whats with these storms past few years just suddenly strengthening right before landfall

A lot of factors. Various teleconnections feed into the Atlantic basin, and thus their phase and orientation can affect the synoptic environment. Hurricanes are heat and momentum transporters. There is more of both at the equator, and less at the poles. Hurricanes do well as I'm sure you know in barotropic environments. Due to (possibly/probably/degrees-of-relativity), climate change, fundamentally two things are happening:

1) There is more heat in the ocean, and that heat penetrates to a greater depth, on average.

2) The temperature gradient between the equator and poles is weakening.

Point 2 has a BUNCH of MAJOR consequences, but, one simple one is, baroclinicity (aka zones of frontal development and the opposite of a barotropic environment), decreases. In simple terms: the temperature difference between the poles, and equator, is decreasing. This reduces frontal strength and makes the environment more homogenous--barotropic--and thus, conducive to hurricane development. 

It goes without saying that there's more to the story than that, but just taking a big step back, you can certainly note a pattern of destructive, high intensity, rapidly strengthening, water-laden hurricanes hitting the gulf....and everywhere else... over the past few decades. That's not in itself atypical in a vacuum, rather, the consistently increased number of strong storms is the red flag...e.g., the frequency. Another thing that happens with reduced latitudinal temperature gradients is that the steering winds are more prone to break down. Wind--> balance of PGF & Coriolis (assuming you also know this). Less temperature contrast--> less pressure contrast--> less PGF--> less wind--> storms tend to slow down and can "linger" over cities which causes the Harvey-type situation where you get 40" of rain in Houston. 

With respect to my original point, beyond the physics fundamentals that are responsible for changes to overall hurricane formation patterns, whose trends are beginning to become more evident now, we are in relatively good phases of several teleconnections at the moment. That helps things along. But at the end of the day, this is quite literally the same thing as boiling a pot of water on the stove. Turn up the energy supplied, you will get more steam. 

1 minute ago, JasonOH said:

Isolated supercell about to cross into AL.

 

Definitely tightening up a bit. 

Unwarned couplet approaching Calhoun on the Huntsville radar. 

So, it's difficult to tell, but what you can see on the radar is the *orientation* of the couplet changes. In a handoff, you see two distinct mesos, one weakens, the other strengthens. Here, we have the same meso which was "oriented" "up down" and after passing the radar is now "left right". That's the same circulation. The doppler effect only shows motion towards and away from the radar. Ergo, as you translate around a radar site, the orientation of the couplet can shift as the storm motion is captured in the non-storm-relative base reflectivity with a different relative motion (given a different angle of incidence to the site). Same tornado folks. In fairness, there was one single scan that looked "confusing", so if you just looked then you could go "hm what's going on", but subsequent scans, and playing them back with the prior ones, tell us the whole story.