meteorologist Posted December 22, 2011 Share Posted December 22, 2011 http://arstechnica.com/science/news/2011/12/like-factories-tornadoes-wind-down-on-weekends.ars http://www.agu.org/pubs/crossref/2011/2011JD016214.shtml Link to comment Share on other sites More sharing options...
AtticaFanatica Posted December 22, 2011 Share Posted December 22, 2011 I think the weekend idea in general is more controversial than the Ars article lets on. Link to comment Share on other sites More sharing options...
tornadotony Posted December 22, 2011 Share Posted December 22, 2011 Correlation does not imply causation. Though the logic of the explanation does make some sense, I'd like to see it modeled before I consider buying into it. Also, though I'd like to read the actual article to get the full scope of the study, if the first write up (though poorly written) is accurate, then there has to be a major sample size issue, let alone the issue related to the first sentence of my post. Only 14 years of data are examined, and the correlation only exists in the southeastern U.S. during the summer, a time of year where that region is not particularly susceptible to tornadoes outside of tropical systems. That is going to severely limit the sample size of that part of the study. Overall, something just seems fishy about this study. Link to comment Share on other sites More sharing options...
Thunder Road Posted December 22, 2011 Share Posted December 22, 2011 4/27/11 was on a Wednesday. Midweek. That means.... Link to comment Share on other sites More sharing options...
it*has*an*i Posted December 22, 2011 Share Posted December 22, 2011 Depends on which scientist you ask. This one says aerosols and pollutants cause more storms on weekends From the article:An analysis of Eastern Seaboard weather shows it really does rain more frequently on the weekend than during the week. Saturdays receive an average of 22% more precipitation than Mondays, climatologists at Arizona State University report. What’s more, the clouds are, to some extent, the product of the very jobs people are trying to escape. The ASU researchers, who analyzed weather data dating back to 1946, say weekend storms probably are enhanced by air pollution spewed by millions of cars and trucks during weekday commutes. The pollution generates tons of tiny airborne particles, called aerosols, that become the microscopic seeds around which rain drops develop. http://www.damninter...re-on-weekends/ Link to comment Share on other sites More sharing options...
JoMo Posted December 22, 2011 Share Posted December 22, 2011 Joplin tornado was on a Sunday. Clearly it was not taking that weekend off. Weird 'study'. Link to comment Share on other sites More sharing options...
BethesdaWX Posted December 22, 2011 Share Posted December 22, 2011 There has to be an ulterior motive of some sort here. Human aerosol forcing? What is the difference in the forcing between weekdays vs weekends? Limited time + region selection, the locations of various storm systems, or sampling down to a daily basis may find variation in many weekdays, yet the "grouping" the timeframes together may give a deceptive result. More clouds mean more tornadoes or less destabilization? Do we even know the locations or existance of all tornadoes that touched down? Why just the SE US? Why not do the entire US over 20 years? Maybe because the correlation breaks down? Tax money being put to good use! Sometimes I wonder how these type of studies are accepted yet much more viable studies are not. Link to comment Share on other sites More sharing options...
thewxmann Posted December 22, 2011 Share Posted December 22, 2011 Joplin tornado was on a Sunday. Clearly it was not taking that weekend off. Weird 'study'. Thinking of the same thing. Also, May 4, 2003 was on a Sunday. As was March 12, 2006. As was April 2, 2006. As was May 30, 2004. As was November 10, 2002. As was, of course, all the Palm Sunday outbreaks. I call BS. Link to comment Share on other sites More sharing options...
thewxmann Posted December 22, 2011 Share Posted December 22, 2011 Depends on which scientist you ask. This one says aerosols and pollutants cause more storms on weekends http://www.damninter...re-on-weekends/ IF there is any type of correlation (dubious at best but we'll assume one for the sake of this post), it may have something to do with this. It's simple... troughs come ashore in the west and take about 4-8 days to travel across the country, and the same with corresponding ridges. Assuming that wavelengths are, on average, constant over time and space, expect storminess approximately every 4-8 days. And if the trough comes ashore on the west coast in the beginning of the workweek, it will end up in the Plains (where a good amount of severe weather happens) during the middle of the week, and the East Coast during the weekend, and this will, on average, repeat every week or so. And if one does a study on it, they might find some correlation between days of the week and storminess. So it's really not aerosols, but rather the natural periodicity in the perturbations of the jet stream. P.S. I don't actually know off the top of my head how long troughs take to progress through the CONUS, but I hope it doesn't detract from the general principle behind my argument... Link to comment Share on other sites More sharing options...
HurricaneJosh Posted December 22, 2011 Share Posted December 22, 2011 In a similar vein, I've heard some chasers say that hurricanes prefer landfalling at night. Link to comment Share on other sites More sharing options...
BethesdaWX Posted December 22, 2011 Share Posted December 22, 2011 Actually more clouds would lead to less net heat intake, meaning, less destabilization. So our activities during the workweek lead to more AERSOSOL production? How so, and how significantly? If we're free on weekends that means more campfires, chimneysmoke, and need for heating and/or cooling of the home. Visa versa at work we're driving to get there, not at home, so on. Seems highly unlikely forcing would very greatly enough to even be detectable in the atmosphere given dispersing of particulates, different patterns indicing various aerosol production conductivity levels..this is a load of s**t. Link to comment Share on other sites More sharing options...
AtticaFanatica Posted December 22, 2011 Share Posted December 22, 2011 There has to be an ulterior motive of some sort here. Human aerosol forcing? What is the difference in the forcing between weekdays vs weekends? Limited time + region selection, the locations of various storm systems, or sampling down to a daily basis may find variation in many weekdays, yet the "grouping" the timeframes together may give a deceptive result. More clouds mean more tornadoes or less destabilization? Do we even know the locations or existance of all tornadoes that touched down? Why just the SE US? Why not do the entire US over 20 years? Maybe because the correlation breaks down? Tax money being put to good use! Sometimes I wonder how these type of studies are accepted yet much more viable studies are not. This general idea has been studied for years, with many arguments published from many different sides, there's not always some ulterior motive or conspiracy in the process. It's a worthy topic to study even if you have problems with this specific argument. To answer one of your questions, we do not know all of the tornadoes that touched down obviously, but the "population bias" seems to be decreasing, so we've probably arrived to a point where we have decent estimates, in terms of number that is, not intensity. Link to comment Share on other sites More sharing options...
andyhb Posted December 22, 2011 Share Posted December 22, 2011 Thinking of the same thing. Also, May 4, 2003 was on a Sunday. As was March 12, 2006. As was April 2, 2006. As was May 30, 2004. As was November 10, 2002. As was, of course, all the Palm Sunday outbreaks. I call BS. I concur Link to comment Share on other sites More sharing options...
Roger Smith Posted December 23, 2011 Share Posted December 23, 2011 I think the reasons are obvious. The people running the HAARP program have weekends off. (sorry, I am kidding. really) Link to comment Share on other sites More sharing options...
BethesdaWX Posted December 24, 2011 Share Posted December 24, 2011 This general idea has been studied for years, with many arguments published from many different sides, there's not always some ulterior motive or conspiracy in the process. It's a worthy topic to study even if you have problems with this specific argument. To answer one of your questions, we do not know all of the tornadoes that touched down obviously, but the "population bias" seems to be decreasing, so we've probably arrived to a point where we have decent estimates, in terms of number that is, not intensity. The word "conspiracy" I do not think even applies to a scientific study, that word suggests some sort of vast widespread intent to decieve which I never go to that extreme, it's more motivation and/or funding related imho. If aerosols are in question, that'd relate to cloud content and moisture availability, but more thunderstorms would result from more convection + moisture content, (aside from large scale dynamics) but there would need to be less cloud cover for an increase in overall convection (instabiltity) which is driven by the presence of thermal energy in the column relative to moisture content in this case? So drawing conclusions on a statistical manner in tornado count on weekends vs weekdays, without knowing the adequate aerosol forcing required to impose change, nor if the change would manifest as such in tornado counts, just seems to be jumping ahead superficially. It seems so pointless to use a small window of data in a focused region of the country to assert human causation to increased tornado outbreaks, on a statistical basis...without a full understanding of the scientific processes first, or even the aerosol count on those days in the first place. Do global aerosol counts fluctuate on the basis of week days to weekends? These gases are "supposed" to be well mixed, at least somewhat, so if there is no measurable change how can one tie a complicated process down in statistical means like that? Link to comment Share on other sites More sharing options...
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