From Purdue University , a press release related to tornado activity without any mention of a climate change link.
WEST LAFAYETTE, Ind. – Significant tornado outbreaks and especially strong tornadoes are more likely occur within periods of activity lasting three or more days, according to a Purdue University tornado expert.
Jeff Trapp, a professor of earth, atmospheric and planetary sciences, examined 30 years of U.S. weather records and found that an outbreak of 20 or more reported tornadoes had a 74 percent probability of occurring during a period of tornado activity lasting three or more days. During those same periods, a tornado rated 3 or higher on the Enhanced Fujita scale had a 60 percent probability of hitting.
The Enhanced Fujita scale rates tornadoes from EF0 to EF5 with damage rated as “light,” including broken branches and windblown signs, to “incredible,” including leveling of strong-frame houses.
“Two extreme tornado events last year led to 32 deaths, injured more than 377 and cost $2 billion in damage and inspired this study,” Trapp said. “Unfortunately, the devastating tornadoes these past few days, tragically, seem to be bearing out the results.”
Tornadoes swept through Arkansas, Oklahoma, Kansas, Missouri, Nebraska, Iowa and Mississippi on Sunday (April 27); Mississippi, Alabama and Tennessee on Monday (April 28); and North Carolina on Tuesday (April 29). The National Weather Service received 100 preliminary tornado reports for April 27 and 28, and multiple deaths have been attributed to the violent storm system.
Trapp also found the multiple-day periods were more likely to occur during the warm months of April through July.
“The encouraging news is that the larger, more slowly evolving and moving systems that appear to contribute to multiple-day tornado periods may be more predictable,” he said. “The weather system responsible for the tornadoes this week falls in this category and was revealed in the forecast models at least five days in advance with good fidelity.”
Trapp examined tornado activity entered into the National Oceanic and Atmospheric Administration’s historical record of tornadoes in the United States from 1983-2012, which included 3,129 tornado days and 1,406 unique periods of tornado activity. Multiple-day periods made up 24 percent of the unique periods of activity.
A paper detailing his study and the results was published in the April issue of the journal Monthly Weather Review and is available online.
The idea for the research began while Trapp was participating as a lead investigator in the National Science Foundation’s Mesoscale Predictability Experiment (MPEX), a national field project to improve predictions of severe weather.
Writer: Elizabeth K. Gardner, 765-494-2081, ekgardner@purdue.edu
Source: Jeff Trapp, 765-496-6661, jtrapp@purdue.edu
Related websites:
Purdue Severe Weather Research Group: http://web.ics.purdue.edu/~jtrapp/severe/
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Botched the links above. The most recent Cliff Moss post is here.
Grrr, that should read “The most recent Cliff
MossMass post ..”(this was all done pre-coffee).
Breaking news: Global Warming degrades cognitive performance — it’s worse than we thought.
Trapp also found the multiple-day periods were more likely to occur during the warm months of April through July.
I think periods of extra cold spring temperatures are behind the extra tornado activity. Canada is again experiencing a cold spring and spring weather has been getting colder since 1998 for United States especially April and May. When this extra cold sprig air meets the warm moist air from the Gulf the result is usually periods of major tornado activity.I think the authors missed looking at the cold spring air component more closely.. As we enter this 30 year cold cycle, the tornado activity may pick up .
RE: Rasey 4/30 10:36 pm, Joe Born 5/1 2:22 am
If there is any validity to statistical conclusion attributed to Trapp, i.e. “that an outbreak of 20 or more reported tornadoes had a 74 percent probability of occurring during a period of tornado activity lasting three or more days. “
Then it follows that an outbreak of 20 or more reported tornadoes has a 26 percent probability of occurring in a period of only one or two days. This is mildly more interesting to contemplate. Large (20 or more) clusters of tornados are three times more likely to need three or more days to play out than those that need two or fewer. But that statement implies we are talking about equal sized clusters —- and there is no such guarantee. The observation is an artifact of the classification. Bigger clusters need more days. More days allow for bigger clusters.
As for outbreaks of 2 to 19 tornados, we can draw no information.
And is 1 tornado an “outbreak?”
There appears to be a definite correlation between below normal Spring weather in Canada , more specifically the Canadian Prairies region Spring and the number of Spring tornadoes in the United States. The best example is the April 1974 super out break when the spring weather over the Praireies was 3 degrees C below normal. But here are some other years -1982, 1995, 2002, 2008, 2009 ,2011, 2013. These years account for some of the largest spring tornado out breaks . It seems that this cold air continues to sweep south in the Spring where it meets the warm moist air from the Gulf. Lets hope this year does not repeat.
… damage rated as “light,” … to “incredible,”
Really? “Incredible”? Like wow, man, that’s a gnarly adjective, dude. And I thought those scientists were, like, real drips, man.
Intersting….
From the study “weather records and found that an outbreak of 20 or more reported tornadoes had a 74 percent probability of occurring during a period of tornado activity lasting three or more days”.
So let me get this straight: The more days a storm lasts, the more increased chance of more tornadoes. WOW, thats amazing.
I wonder how much money was spent to fund that study?
;>P
Last year saw the fewest US annual tornado count in decades.
Interestingly, this was a non-event for the liberal press, and tornadoes went unreported by the MSM until we had a spat of tornadoes in November – and then this was a sure indicator of “global warming!” Never mind the real story was the record low levels.
Barf.
This was the second-to-last nail in the coffin for ABF news, for me.
The last nail was the typhoon Haiyan MSM news feeding frenzy.
While this tropical cyclone was about as strong as 30 others in the last hundred years, it was a sure sign of “Global Warming” for the profiteers of doom. The liberal press ate it up.
The REAL news – the fact that there were NO Atlantic Hurricanes last year, NONE, went unreported.
This liberal press bias is intolerable.
I have sworn off of Dianne Sawyer and the ABC “World” News, and I now get my news by other less biased means.
ghads. spell checker changed the first ABC to ABF. Why, oh, why, oh why…
…an outbreak of 20 or more reported tornadoes had a 74 percent probability of occurring during a period of tornado activity lasting three or more days.
Yeah! That is sort of like; there is a 74 percent probability of my thirst occurring after a period of three or more hours spent in the hot sun.
It boggles my mind, that grant money is cheerfully given out for foolish stuff like this.
A study a few years ago “discovered” that people living in urban ghettos are exposed more pollution than people in suburbs. Huh.
… exposed to more …
Jeff Trapp. Is that a nom de plume for Captain Obvious?
I’ll refrain from breaking into “Hail Purdue”, but only long enough to point out that it would be nice if all major institutions of higher learning followed the model that John Purdue wrote into the university charter. It’s no coincidence that the output from that institution tends to be ones as straight-forward as this. Isn’t science without a hidden agenda rather refreshing?
I’ll refrain from breaking into “Hail Purdue”, but only long enough that it is quite refreshing to see the straight-forward science that tends to come from this institution. John Purdue was wise to put into the university charter some of unusual mandates that he did, and this is the result.