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Ground Scouring

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Posts posted by Ground Scouring

  1. I think this event will end up verifying on the “low” side of current expectations. The two most recent GFS runs have shifted toward a higher-amplitude, blockier setup due to their resolving the situation in the North Pacific (Gulf of Alaska) better. This means that the downstream circulation over the Ozark region will have a tendency to become “pinched” due to enhanced shortwave ridging over the Great Lakes. In turn, this implies a surging cold front along with mid-level winds paralleling the surface boundary, especially toward the northern half of the warm sector. I think we may see a few supercells capable of producing a couple of strong tornadoes, but these will likely be localised along boundaries from eastern MS eastward across the southern two-thirds of AL. Most of this event should consist of QLCS and bows, with some isolated, discrete events along boundaries, as mentioned. One thing I have noticed is that “major” events since 2011–13 have ended up underperforming in terms of either severity and/or aerial coverage, perhaps due to the warming Pacific basin, the slowing AMOC, and the +PMM signature; the warmer Pacific basin and emergent -AMO over time have tended to hinder low-amplitude, progressive setups, regardless of temporary shifts toward -ENSO/-PDO.

  2. 51 minutes ago, bluewave said:

    Yeah, a new study indicates that the active phase that began in 1995 may be more of a new normal. With warming Atlantic SSTs, we may not be able to count on a less active phase happening again like the 1970s and 1980s. Another study just out reinforces the idea of the warm pool remaining in place to our east. We saw how the warmer SSTs and higher pressures there last summer lead to an active  close in storm track.

    There does not seem to be sufficient, specific evidence, as opposed to speculative notion(s), as of now to call the independent existence of the AMO cycle into doubt. Spectral AMO peaks clearly exist even in the study by Mann et al. If anything, climate change and the AMO(C) may be inversely correlated, given that a weaker AMOC due to AGW → weaker +AMO signal. The freshening of the North Atlantic will likely lead to an early—that is, premature—onset of the next -AMO period, and some signs, namely temperature and salinity, are that this began in 2013–14, although overall Atlantic TC activity has yet to fully respond accordingly. I think AGW is likely leading to shorter +AMO periods over time and is likely heralding the next -AMO within five to ten years.

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  3. The problem with renewables is that they are highly inefficient in terms of energy output and actually add to the carbon footprint via expensive, environmentally destructive practices, e.g., mining for rare-earth metals. The more one invests in, say, solar panels and wind turbines, the more multinational corporations take over vast swaths of the Third World, while still adding vastly more to the carbon footprint than renewables eliminate, owing to the productive processes involved in manufacturing renewables. Unfortunately, Western discourse on this topic is dominated by a false dichotomy between conventional fossil fuels and a limited, pre-selected array of renewables. Intelligent countries such as China, South Korea, and Pakistan are heavily investing in building new nuclear plants and upgrading their old ones. Nuclear power is both clean and energy efficient. We as a species already have the tools in place to store nuclear waste far more effectively than we did in the recent past. Japan’s disaster in 2011 was due to neglect and negligence, not nuclear power itself. Plus, many governments and semi-private organisations likely have far more efficient, black-budget energy sources than are currently marketable in public. Free energy is not sci-fi, but very viable. This does not even cover the potential for abiotic sources to emerge. Unfortunately, the fossil-fuel monopolies have effectively suppressed information about this and other threats to their power, including nuclear. Pressure from the fossil-fuel lobbies has generated hysteria about the supposed dangers of nuclear energy while performing “bait-and-switch” for the polluters via their pseudo-“‘Green’ New Deal” based on fossil-fuel-consuming renewables.

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  4. Models continue to advertise a potentially significant threat around 30 Jan–1 Feb, with the 12Z deterministic ECMWF and the 12Z EPS showing one of the warmest low-level air masses since 26 Dec 2015 (the date of the Garland, TX, EF4 tornado) over the southern High Plains for multiple days. In fact, even the EPS mean shows 15°C 850-mb temperatures reaching as far north as the TX/OK panhandles on at least two of the days that I mentioned. One important key is the relatively low amplitude of the upcoming pattern, with its lack of significant cold intrusions, which not only may prevent heights from rising too much ahead of any ejecting disturbance, but also allows southwesterly low-level flow to advect richer instability (as well as a noticeable if not strong elevated mixed layer, which is surprising given the subtropical jet) north from the Mexican plateau. The tongue of greatest instability is likely to be at least a bit narrower than projected at this point, but the fact that we are talking about EMLs and a potentially significant southern High Plains threat in a potent El Niño says a lot.

     

    For reference:

     

    0KsFC23.gif

  5. Both the EPS and the GEFS are signaling a major long-range pattern shift toward the the end of January and the first week of February (especially around 28 Jan–1 Feb), with a restrengthening of the polar vortex and at least a transient +NAO/–EPO/–PNA period taking hold. Even at this range, models are indicating that the polar jet will take over as the dominant stream with strong hints of multiple shortwave impulses intruding into the Pacific Northwest, likely inducing lee cyclogenesis east of the Rockies. Details regarding ejection and overall evolution are obviously too early to ascertain, but the overall trend toward a more zonal look/longer wavelengths favors a Southeast ridge with likely favorable moisture vectors out of the Caribbean, setting up a potentially decent return flow over the southern High Plains for a few days in advance of any potential ejecting disturbance. There aren't many analogs from strong El Niño events since 1950, but an interesting one is 26 Feb 1958, which was somewhat similar synoptic-wise and featured several significant tornadoes across LA and MS. An interesting difference is that this case may also extend the opportunity for severe weather to the southern High Plains.

     

    NMgEulw.gif

  6. Regarding the subtropical jet and its effect on the EML in recent events, where should I look to find the STJ? Is it at 200 mb, 500 mb, 700 mb? Didn’t major Plains events like 4 May 2003 feature a STJ influence? Also, if the EML is at 700 mb and comes from the Sonoran region of northern Mexico, then why is a STJ coming from N Mexico a problem? Is the STJ within the same level as the EML or not? Can, say, a 500-mb STJ affect the quality of the EML at lower levels? If so, how? Maybe I am totally wrong, but I would like to gain some meteorological understanding.

  7. Might add that another thing that could screw this up is if the ULL closes off significantly before the trough ejects. This would cause problems with backing upper level winds and EML advection (shown by the 18z GFS verbatim and some previous Euro runs).

     

    Also worth mentioning that the 18z run appeared to suffer from some possible convective feedback in the 81-84 hr period.

    Since the ECMWF did not close it off too substantially at 96 hours, does that suggest that it has an edge over the GFS within that range, especially given the ECMWF's usual tendency to cut off lows too much/early? I would add that the GFS seems to be trending toward the ECMWF's evolution by Saturday, is it not?

  8. You're asking for fairness now after your behaviour on Saturday while the event was going on? Sorry to disappoint you, but that's not exactly how things work. Brett and Jim absolutely did not conduct themselves the way you did both before and during this recent event, end of story.

     

    I think Saturday could be a significant day, large upper troughs like that in May will almost always will afford some kind of severe risk. Also, the GFS has been showing a fairly decent looking EML being advected over the Plain states (not extremely strong, but not negligible either). How is a negatively tilted trough bad for severe weather? It may cause problems in the wind profiles in some locations, but it also generally means a stronger surface low, with accordingly stronger low level flow and stronger mid/upper flow overspreading the warm sector. Positively tilted troughs generally cause a lot more problems in the setup in the Plains.

    Regarding the first point, I think my flaw was that I made an outbreak with several tornadoes seem insignificant on the whole, when I was only referring to the original outbreak area in N TX and parts of OK (and even there I was more wrong than right). There turned out to be more visible tornadoes and storm structures than I anticipated, not to mention numerous significant tornadoes (with a count still rising) that definitely caused substantial damage and loss of life. I also should have not overlooked the threat in CO/KS, where there were also significant, long-tracked supercells with strong tornadoes. I really don't know enough to be judging events in progress; even people with more experience and actual background would struggle with a difficult forecasting situation like that which existed on this past Saturday. I can come across as being unwilling to listen, and in fact I am too stubborn and prone to emotional/forecasting swings in many situations. I need to try better/harder to sit back, read, and watch, but sometimes I feel left out when serious questions don't get answered (sometimes understandably, based on my behavior).

     

    Regarding this coming Saturday: I must say that the 12Z ECMWF solution, taken ad verbatim, would almost certainly result in a major, quite possibly historic severe outbreak over a wide area, extending from OK/southern KS in the south to NE/SD in the north. What is critically important is that the ECMWF, as early as 96 hours, already begins advection of the first solid EML of the year, with a plume of high-quality inversion spreading northeastward from the Sonoran region over the southern Plains. More than a day and a half before the arrival of the deepening surface low on Saturday, there is already a robust EML in place over the southern Plains, and this EML remains in place through most of early Saturday due to the overall neutral tilt of the 700-mb trough. Moreover, there will be two full days of deep Gulf moisture spreading north, with a fairly strong low-level jet in place by 72 hours. As for the trough itself, the ECMWF has shown a notable shift toward a much broader, consolidated mid-level trough at 96 hours—an important trend as we get within the short range, the ECMWF’s kill zone. If the set-up at 96 hours verifies, then it will automatically have a significant impact by the time the trough ejects on Saturday. Shear is absolutely off the charts for mid May; even considering the ECMWF’s tendency to overdo the strength of the mid-level jet maximum, the pattern depicted would bring H5 winds of at least 55-60 kt into the warm sector Saturday, particularly over OK and southern KS, as a secondary surface low develops over the TX Panhandle. The orientation of the mid-level trough would imply fairly robust to strong backing of the surface winds all along and east of the dry line, extending well north into NE/SD. Such a set-up might also favor dry-line bulges (meaning low-level convergence as the surface low deepens) in OK and southern KS, where the best shear/instability combination seems to be present on the run. There is also no doubt that instability would be strong to very strong if the EML verifies as depicted. The very wide warm sector would also suggest a secondary severe threat along the retreating warm front in NE/SD (although the eventual location/evolution such a threat is more contingent on mesoscale details, such as early convection).

     

    All in all, the pattern on the ECMWF shows mid- to late-April dynamics juxtaposed with mid-May thermodynamics. In fact, it does so to an extent that I can’t recall in any previous Plains outbreak on or after 15 May. The overall pattern reminds me a lot of the late-May 1917 sequence, with a series of southern impulses gradually giving way to multiple large-scale, ejecting disturbances. If trends continue, I think that we may be looking at something very special this coming Saturday (and quite possibly Sunday over the Ozarks/upper MS Valley/upper Midwest, depending on how overnight convection and the upper-air pattern evolve).

  9. So we're already going to start with this? Fantastic.

    For the record, what do you think is likely to happen this coming Saturday? Honestly, I'd be more interested in your meteorological reasoning than another retort. You could also argue with anyone else who has been (justly) noting the lack of an EML, negative tilts/southerly tracks, etc. Argue with Brett or Jim (wxmann), for instance. A little fairness might be appropriate here.

  10. Pretty major league setup on the 00z GFS for next Saturday.

    It might well come to nothing if we don't have a good EML. The trend toward a neutral/negative tilt with a "pinched" trough (i.e., one farther south with time) is not encouraging, as that would discourage a good EML from emanating over the warm sector. Anyway, we don't need more HP cells causing havoc for both communities and chasers.

  11. Coming up on 3 years since the tornado. This PDF ebook with lots of pics and stories has been made available for free. (usually costs $15)

     

    http://www.joplintornadobook.com/

    Even three years later, reading the accounts, and especially this book, never ceases to move me. The entire rebuilding process is like a model and a case study to be compared to those of other cities recovering after disasters. Probably the network of local businesses and the diversity of Joplin's demographics played a significant role in fostering the recovery--better than in, say, other areas that suffered comparable disasters. The bottom-up approach that worked so well in Joplin seems more plausible in a city of its size and composition than in a dense metro area like New York City.

  12. After observing the circumstances surrounding the most recent tornado outbreaks, particularly since 2007, I would venture that technology has to some degree nullified the sense of danger and uncertainty surrounding tornadoes. During large, intense, urban events up until the mid-2000s, instantaneous communication features such as those equipped with cellular apps were nearly non-existant, so in my view tornadoes were seen less as something accessible, something to be watched for thrill or interest, than as something beyond the limits of observation and knowledge...hence, something to be avoided. Thus death tolls were low, the cut-off being 45 or less, à la Jackson, MS, 03/03/1966; Topeka, KS, 06/08/1966; Lubbock, TX, 05/11/1970; the 1974 Super Outbreak tornadoes at Xenia, OH, and Huntsville, AL (the latter after 9:30 p.m. local time and illuminated only by vivid lightning); Wichita Falls, TX, 05/10/1979; Barneveld, WI, 06/08/1984 (also at night); and the 1990s events at Andover, KS, in 1991, Pleasant Grove, AL, in 1998, and Oklahoma City, OK, in 1999—most of which were well-warned events even back in the late 1960s and particularly during the 04/03/1974 Super Outbreak.

    Certainly, large events like OKC of 05/03/1999 were well-publicized by national media and storm-chaser footage or home video, but such were really not made accessible to a wider audience until about after 2005. To me, the Greensburg, KS, tornado of 05/04/2007 seemed to mark a divergence from the recent past in that footage of actual tornadoes since then has become more widely broadcast, and more frequently, whereas only a relative handful of notable events before 2007 were filmed in such a manner...usually because they hit one of the top major metro areas (OKC 1999), occurred on a day marked by notable severe wx (the Super Outbreak tornadoes like that at Xenia), or caused notable death or destruction and/or did so in an area outside the traditional Plains alley (Worcester, MA, 06/09/1953, as an example of huge death toll [94] / odd location, Udall, KS, 05/25/1955, of death toll, and Topeka 1966 of then-record monetary losses).

    During such a period, myths about tornado morphology...the famous underpass shelter myth as in KS on 04/26/1991, the myth of hypersonic wind speeds, etc....did occur, but such random knowledge tended not to be amplified or spread by Internet chatter or modern communications, which could more easily erode the evolutionary fight-or-flight danger instinct, make tornadoes a source of thrill rather than danger, and also, by breaking down barriers between rural and urban communities, allow common public misperceptions, and the errors of media misinformation, to spread.

    In the past, say, a community’s word-of-mouth belief that tornadoes seem to strike just around, not in, the community based upon historical experience, and that therefore the community is protected...but that belief was never really communicated beyond a small group of people, particularly if they lived in such small places like Hackleburg, AL, or Joplin, MO. And anyway, such beliefs are localisms, unlike misinformation about tornado watches vs. warnings, tornadoes vs. downbursts or microbursts, etc....which may more readily spread among widely different and dispersed communities in an age of boundless communications, iPhones, and chatter.

    My idea is that some major changes have occurred since the late 1990s that have greatly accelerated since 2005, and which were only tested since 2007—when violent tornado activity and bigger/urban outbreaks really picked up—as most of the 2000s were a “low”-activity period in terms of big outbreaks, F4-F5 tornadoes, and big urban tornado activity:

    • Communications industries, due to deregulations in the 1980s and 1990s, began establishing a wider range of network services that increasingly served rural as well as urban areas, thereby breaking down the communications barrier between rural and urban U.S.;
    • The communications revolution, in turn, combined with the rise of urban demographics to allow rural residents to better pursue careers linked to those of their urbanized, service-sector counterparts;
    • The cultural division between urban, media- and service-driven and rural, manufacturing- and communally-based areas weakened, opening the latter up to media and other societal networks;
    • Social mobility and sociability increased exponentially, particularly after 2005 due to innovations in digital communications.

    I noticed that during the 02/05/2008 and 04/27/2011 outbreaks, as well as during the Greensburg and Joplin, MO, 05/22/2011, tornadoes, many people who were interviewed after the tornado indicated they were using digital devices to speak to people...or were using them to check up on their families...as the tornadoes approached. Also, a lot of people seemed to be driving or were out in the streets, either filming the tornado or going to help/warn neighbors...often while relying on mobile communications...even in traditionally insular communities like Joplin or those in rural Alabama, which in the past often sought shelter first and assisted afterward. While warning fatigue, poor construction of shelters, bad visibility, or pure bad luck might have played a role in some of the many 2011 deaths, I would venture that an increasingly publicized, wired, and all-too-complacent, or less cautious, ethos has taken place in much of rural America, which in many ways is now much more urban than it was just ten years ago.

    Any thoughts? It’s great to be posting again.

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