NOAA CSI: no attribution of climate change to tornado outbreak

All the bloviation from Think Progress, Climate Progress and the rest of those people that want to turn any disaster into a link to climate change are doing is just that: bloviating.

Told ya so. Here’s the preliminary report from NOAA’s Climate Science Investigation

Climate Change and Tornadoes


Fig. 1. 1979-2010 time series of April total column precipitable water (top and second panel, kgm-2) and CAPE (third panel, Jkg-1), and the magnitude of the vector wind shear in the layer sfc-500mb (bottom, m/s). Precipitable water is shown for two area averages; the Gulf of Mexico (top) and the lower Mississippi Valley (second panel). CAPE and shear time series are for the lower Mississippi Valley. The CAPE and shear are based on the single reanalysis (CFS-R). Also shown for the Gulf of Mexico region is the satellite-based estimate of total column water vapor for the period after 1987 (top, blue curve). Gulf of Mexico is defined as the area 20°N-30°N, 80°W-95°W. Lower Mississippi Valley defined as the area 31°N-40°N, 82°W-95°W.

There is a heightened sense of interest, concern, and urgency to explain extreme events in the context of a changing climate. Preliminary estimates (as of 2 May) are of 226 tornado reports during a 24-hour period on Wednesday 27 April, and 312 tornado reports during 26-28 April. NOAA estimates this to be the largest 1-day outbreak, eclipsing the prior record of 148 twisters estimated to have occurred during 3-4 April 1974. 1

One question on many minds concerns the role of anthropogenic climate change. Two recent national and international assessment reports have summarized the existing state of knowledge on climate change and tornadoes.

According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) :

    “There is insufficient evidence to determine whether trends exist in..#small-scale phenomena such as tornadoes, hail, lightning and dust-storms.”

2

The US Climate Change Synthesis Report SAP 3.3 concludes that:

    “The data used to examine changes in the frequency and severity of tornadoes and severe thunderstorms are inadequate to make definitive statements about actual changes.”

3

The report also concludes that:

    “There were no significant changes in the high-intensity end of these distributions from the 1950s through the 1990s, although the distribution from 2000 and later may differ.”

The difficulties in assessing change directly from the history of tornado data is emphasized in both reports. A simple illustration of the problem is provided by the 1950-2005 time series of the number of tornadoes in Illinois, as constructed by the Illinois State Climatologist Office4; the number of tornado counts has more than doubled since 1990. The post-1990 increase in counts is almost entirely associated with the counts in weak (F-0) tornadoes. Factors that relate to a non-physical trend include changed instrumentation (e.g., the implementation of the WSR-88D Doppler radar after 1990), increases in population, and public awareness via enhanced spotter networks that may have contributed to more reporting.5 It should be further noted that a careful appraisal of historical tornado outbreaks has led scientists to recognize that secular trends in tornado occurrences before 1970 are likely more influenced by non-meteorological factors6, although the quality of time series even after 1970 suffer from inhomogeneities described above. At this time, the historical tornado data are not of a quality to permit a rigorous appraisal of trends, although there is a general belief that the F2+ database of stronger tornadoes is more reliable, especially over the last 30 years.

Are there indirect indications for possible changes in tornadoes that can be inferred from variables other than the tornado counts themselves? A recent special report by the WMO Working Group and Expert Team on Detection and Attribution Related to Anthropogenic Climate Change7 offers guidelines on attribution research. These propose that a first step toward a rigorous assessment is to determine whether a change in an event, or in variables closely related to such events, has been detected. Thus, whereas the tornado data itself is not of a quality for rigorous assessment of physical trends, perhaps trends in the conditions that are believed to be conducive for such storms can be studied.

In this regard, it has long been known that thermodynamic stability, column moisture content, and vertical wind shear are particularly relevant for discriminating non-tornadic from tornadic environments. 8,9 Decreased thermodynamic stability (also consistent with increased convective available potential energy), increased moisture content in the atmosphere, and increased vertical wind shear within the 5km above ground layer characterize an environment more favorable for a tornado outbreak. In particular, tornadoes are much more likely to occur when both high CAPE and high shear are present. Secondarily, the presence of an elevated mixed layer (reflected in moderate values of “convective inhibition” or “CIN”) can delay the onset of convection such that when it occurs it does so more explosively and in the form of more long-lived, isolated supercells. A recent analysis of climate change projections suggests that the number of days during which meteorological conditions are conducive for severe storms may increase during latter decades of the 21st Century as a consequence primarily of increased instability, though projected decreases in vertical wind shear may oppose thermodynamic destabilization.

Here we show a preliminary analysis, covering 1979-2010, to explore only whether changes in such large-scale, time-averaged climate variables for April are detected**. Our diagnosis attempts to reveal whether large-scale conditions may have become more favorable for violent storms to occur over the lower Mississippi Valley, the region of the recent super tornado outbreak. Various data sets are used to estimate the time variability in column precipitable water (Fig. 1, top 2 panels). These are found to be in close agreement with each other with respect to their interannual variability; the water vapor time series are dominated by strong year-to-year variations both over the Gulf of Mexico (top) source region and over the lower Mississippi Valley impact region of possible tornadic activity (second panel). A similar interpretation applies to a time series of thermodynamic stability (based on the index of convective available potential energy, CAPE) which as might be expected, varies coherently with the atmospheric water vapor content (third panel). Finally, the vector wind shear magnitude for the surface-500mb layer is also dominated by interannual variability, with little evidence for a trend during the 30-yr period (lower panel).

Neither the time series of thermodynamic nor dynamic variables suggests the presence of a discernable trend during April; any small trend that may exist would be statistically insignificant relative to the intensity of yearly fluctuations. A change in the mean climate properties that are believed to be particularly relevant to severe storms has thus not been detected for April, at least during the last 30 years. Barring a detection of change, a claim of attribution (to human impacts) is thus problematic, although it does not exclude that a future change in such environmental conditions may occur as anthropogenic greenhouse gas forcing increases.10

The body of knowledge regarding the possible role played by large-scale climate forcings in tornado outbreaks is rapidly evolving, and constitutes a field of study that must integrate existing expertise in meso-scale meteorology with expertise in global-scale climate dynamics. Likewise, the methods for conducting attribution science also continue to evolve, and advances on the tornado-climate linkages will require modeling capabilities beyond current tools. Despite various limitations in data and tools, it should be noted that applying a scientific process is essential if one is to overcome the lack of rigor inherent in attribution claims that are all too often based on mere coincidental associations.

This assessment attempts to summarize a current scientific understanding of the link between climate and tornadoes. The assessment is not in lieu of a more rigorous diagnosis, nor does it preempt the need for better quantification of the physical climate factors associated with tornado outbreaks. This must be the topic of future research.


** An implicit assumption, which should be verified in future research, is that a change in the monthly average conditions would indicate similar changes in the tails of the daily distribution, i.e., a slight increase in the mean monthly CAPE would result in more individual days with CAPE sufficiently high to support tornadic activity. Similarly, a future research, would explore the frequency and change over time of the joint instantaneous occurrence of the high CAPE and high shear, and possibly moderate CIN that are conducive for tornado development.

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source: http://www.esrl.noaa.gov/psd/csi/events/2011/tornadoes/climatechange.html

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28 Responses to NOAA CSI: no attribution of climate change to tornado outbreak

  1. SteveSadlov says:

    I accept the possibility that is may be attributable to climate change. This type of climate change, that is:

    BIG WEATHER STORY WILL THEN BE TO FOCUS ON RAIN CHANCES LATER SATURDAY AFTERNOON WITH LINGERING SHOWER CHANCES INTO SUNDAY PER ALL THE LATEST LONG TERM MODEL SOLUTIONS. 850 MB TEMPS AT OR BELOW ZERO SUGGEST T-STORM POTENTIAL AS WELL BUT WILL FINE TUNE ALL THESE DETAILS AS THE WEEKEND GETS CLOSER.

    ALSO THE GEM AND ECMWF INDICATE POTENTIAL FOR A FAIRLY WET STORM (BY MAY STANDARDS) BY NEXT MONDAY NIGHT OR TUESDAY. SO INDICATIONS ARE THAT PATTERN WILL GET SOMEWHAT ACTIVE YET AGAIN FOR THE SECOND HALF OF MAY.

    ====================

    That was for the SFO CWA.

  2. DaveS says:

    As a avid fan of the Guardian online comic, VIZ, I now notice that the environmental section is getting a little schizo. One minute on song, the next drifting. I think this site is even changing the Guardian Loonies.

    Now for todays climate change nuttiness. Not Guardian, UK government..

    Global warming threatens wi-fi.

    http://www.guardian.co.uk/environment/2011/may/09/climate-change-wi-fi-connections

  3. pRadio says:

    Similarly, a future research, would explore the frequency and change …………….

    i.e Send more Money

  4. Douglas DC says:

    Cold and wet here and NE Oregon too-Reminds me of the late 60′s early 70′s
    hmm..

  5. Mike Bromley the Kurd says:

    The “Working Group and Expert Team on Detection and Attribution Related to Anthropogenic Climate Change”…

    Uh, yeah. A panel of Oxy-Morons. Uh, I mean REALLY. I’m sorry, I just can’t begin to get my head around what their Year-end Barbecue would be like. Wait…let me read that again. Yup, it says: “Working Group and Expert Team on Detection and Attribution Related to Anthropogenic Climate Change”. How high the moon, how deep the trough.

  6. juanslayton says:

    Hmm. More acronyms. They explain CIN. What is CAPE?

  7. HaroldW says:

    juanslayton -
    CAPE is defined in the report as “index of convective available potential energy”

  8. CRS, Dr.P.H. says:

    …every time I see the word “bloviate,” my mind transposes it to the non-existent term “boviate,” meaning “to vent noxious gas from either end of a bovine.”

    Boviating, indeed!

  9. P.F. says:

    Seems to me the alarmists are looking for a fit. In 2005, it was all about climate change causing more hurricanes. Hurricanes did not increase. Was that because climate change was halted? In 2007-08, it was all about rapidly disappearing Arctic ice. The ice is coming back. Now, in the near absence of severe hurricanes, they want to hang the cause of severe tornadoes on climate change. Next year, when tornado occurrence is more in line with the average, which weather event will be the climate change crisis of the moment?

  10. Dave Wendt says:

    “Disclaimer: This draft is an evolving research assessment and not a final report.”

    I have to wonder, if they had been able to torture the data sufficiently to wring a suggestion of a connection between climate and tornadoes out of it, even if the analysis was no more, or even less, rigorous than their present effort, whether a similar disclaimer would have been attached to this release. I tend to think not. Recent history suggests instead of a disclaimer we’d have seen a hyperventilating broadside press release and a paper that managed to avoid all that equivocal language, reticence about projecting trends, or warnings about how things may turn around in the future.
    The meme is thoroughly ingrained. A decade or three of flat to down is merely a lull, but five years of slightly up indicates an out of control acceleration which will proceed for a century with no suggestion that it will ever brake. If the data doesn’t support the meme it must be questioned. If they can make it support the effort, any problems will be covered in a footnote at the bottom of page 27 of the Supplemental Materials, when they get around to releasing them.

  11. Theo Goodwin says:

    Douglas DC says:
    May 9, 2011 at 10:42 am
    “Cold and wet here and NE Oregon too-Reminds me of the late 60′s early 70′s
    hmm..”

    Yep, get ready for a repeat of the winters of 1976, 77, 78, 79, and 82. In 1979 in Atlanta, the Uhaul Company would pay you to drag an empty trailer anywhere north. No one thirty years old or younger has a clue what it was like to endure those times.

  12. SteveSadlov says:

    Here’s some more climate change … no, not that kind, this kind:

    http://www.squaw.com/uber-cam

    This is today. This degree of coverage would be typical of February.

  13. SteveSadlov says:

    Check out the satellite views on this site’s side bar. Look at the storm taking shape right now over the Great Basin.

    Watch out folks. Here out West, watch out for winter’s revenge (this is but a warning wave of more systems on the way). In the Southern Plains, you are going to be like Job.

  14. Carl Chapman says:

    Global Cooling
    The number of tornadoes and hurricanes was heading down until 2011, when the temperature anomaly fell suddenly. Tornadoes and hurricanes need a temperature difference so energy can move from hot to cold.
    I think the recent uptick in tornadoes and hurricanes is caused by the downward shift in temperature, causing the high latitudes to get colder, causing an increased temperature gradient from tropics to poles.
    Could we be so accustomed to the brainwashing of the CAGW alarmists that we’re not recognising the advent of Global Cooling?

  15. LarryT says:

    The panel also recommended ex-communications of global warming deniers and uphelpd the ex-communication of astronomer galileo. The Inquisition of Rome will be reconvened shortly. Long live Nicolaus Copernicus!

  16. Douglas DC says:

    Theo Goodwin says:
    May 9, 2011 at 12:26 pm:

    Yep, get ready for a repeat of the winters of 1976, 77, 78, 79, and 82. In 1979 in Atlanta, the Uhaul Company would pay you to drag an empty trailer anywhere north.

    Just read the local Paper that said April here was the Coldest since 1975. The year
    I fell in to the Baker Valley of NE Oregon in a Cessna 402 shaped ice sculpture
    and I was a Passenger!!

  17. Brian H says:

    This report is trying hard to “stay within the lines” while delivering a massive body blow to the Warmists, I think/hope.

    A change in the mean climate properties that are believed to be particularly relevant to severe storms has thus not been detected for April, at least during the last 30 years. Barring a detection of change, a claim of attribution (to human impacts) is thus problematic*, although it does not exclude that a future change in such environmental conditions may occur as anthropogenic greenhouse gas forcing increases.

    * idiotic

    But there’s a hidden problem here: the rejection of one attribution to human impacts contains the assumption and presumption that ANY such impacts are plausible, as the butt-covering “does not exclude” phrase explicitly states.

    That’s the poison pill.

  18. SteveSadlov says:

    Update:

    MAIN WEATHER FOCUS WILL THEN BE ON RAIN CHANCES THIS WEEKEND. LONG RANGE MODELS REMARKABLY CONSISTENT IN DEVELOPING A TROUGH THAT WILL INTRODUCE SHOWER CHANCES BY SATURDAY AFTERNOON AND EVENING. ECMWF HAS BEEN VERY CONSISTENT NOW FOR A FEW MODEL RUNS IN A ROW WITH LITTLE RUN TO RUN CHANGE WHICH INCREASES CONFIDENCE. SHOWERS CONTINUE INTO SUNDAY AS MAIN UPPER TROUGH AXIS PASSES OVERHEAD. BEST CHANCES LOOK TO BE FROM THE BAY AREA NORTHWARD BUT MONTEREY BAY REGION WILL LIKELY SEE SHOWERS AS WELL. AIRMASS ALOFT WITH THIS SYSTEM LOOKS VERY COLD FOR MID MAY WITH 850 MB TEMPS AT OR BELOW ZERO. T-STORMS WILL LIKELY HAVE TO BE ADDED TO FORECAST AS TIMING DETAILS BECOME MORE CLEAR. NOT EVEN OUT OF THE QUESTION THAT THE HIGHEST PEAKS OF THE BAY AREA AND MONTEREY COUNTY COULD SEE A SNOW FLAKE.

    MORE INTERESTING IS THE 192 HOUR FORECAST FOR NEXT TUESDAY THAT CONTINUES TO SHOW A WINTER LIKE SYSTEM ARRIVING WITH POTENTIAL FOR HEAVY RAIN AND STRONG WINDS. THAT`S STILL BEYOND DAY 7 BU WILL CONTINUE TO MONITOR.

    ========================================

    In a premonition-like nightmare, this is how it begins. The beginning of an age that reminds us how kind the last 10,000 years have been. CO2 don’t matter diddly.

  19. Richard Holle says:
    [posted on WUWT back on]
    October 5, 2010 at 4:26 am

    Got an email yesterday…….Richard, I went to your website for the first time and found it fascinating but some of your forecasts for snow in the NE (I live in North Jersey) in April and May, 2011 and 2012, seem extremely unlikely to verify. Are they real forecasts made using your system, or are they some type of website error? If they were to verify, goodbye interglacial, hello Ice Age!
    Look forward to hearing back from you on this.

    http://research.aerology.com/in-other-online-forums/snow-in-april-may-2011/

    So here is the NWS just now seeing what I was talking about, I am still following this as being valid.

  20. Theo Goodwin says:

    Carl Chapman says:
    May 9, 2011 at 2:28 pm
    Global Cooling

    “Could we be so accustomed to the brainwashing of the CAGW alarmists that we’re not recognising the advent of Global Cooling?”

    I think this is likely. Their brainwashing is ubiquitous, relentless, and dramatic. I doubt that most of us are free from its effects. People who visit this site are good at analyzing the pseudo-arguments put forth by the CAGW Alarmists but I doubt that we are so good at defeating the images of doom that rain upon us daily.

  21. Ed Mertin says:

    There are a few interesting satellite images of the flooding on the Mississippi River here. See in article titles list. http://agfax.com/

  22. SteveSadlov says:

    Update:

    THE WEATHER OF INTEREST IS LOOKING TO OCCUR OVER THE WEEKEND AS AN UNSEASONABLY DEEP UPPER LEVEL LOW DROPS SOUTH FROM THE GULF OF ALASKA TO JUST OFF THE NORTHERN CALIFORNIA COAST. SHOWERS ASSOCIATED WITH THIS COLD LOW ARE PROGGED TO SPREAD ACROSS THE DISTRICT SATURDAY NIGHT AND CONTINUE INTO SUNDAY. SNOW LEVELS COULD ALSO DROP AS LOW AS 3500 FEET IN OUR AREA AND GIVEN THE COLD NATURE OF THE LOW…THUNDERSTORMS ARE A DEFINITELY POSSIBILITY ALONG WITH SMALL HAIL. ANOTHER SHORT WAVE MOVING THROUGH THIS LINGERING UPPER TROUGH COULD KEEP SHOWERS GOING THROUGH MONDAY. MEDIUM RANGE MODELS THEN BRING IN ANOTHER FRONTAL SYSTEM FOR TUESDAY AND WEDNESDAY AS THE WEST COAST REMAINS IN AN UNSETTLED PATTERN.

    ===============================================

    Snow on Diablo and Umunhum, and even, Hamilton and St. Helena, this late in the year, would be unnnnnnnnnnn-precedennnnnnnnnted!

    Actually sort of worried about storm #2. Supposed to go into the high country a week from Thursday and my tires are getting a bit worn. Any real snow on the road and it might be a bit interesting (but not un doable).

  23. Carl Schrum says:

    Republican factory owners killed your family and friends in the catastrophic blizzards, floods, tornadoes, massive wildfires and other climate change that has been wiping out the bible-belt. This is the Climate Change that their factories created. This is the Climate Change that the Republicans lie about not existing. This is the Climate Change that they program their constituents to deny exists. This is the Climate Change that killed people, destroyed homes, further destroyed the economy that the Republican factories emissions caused so they could make profits by killing those people. Republicans deny Climate Change at all costs in order to keep their factories from having to pay to stop it. The Climate Change that is destroying massive pats of our country can no longer be hidden or denied. NOAA is controlled by Republicans

  24. Smokey says:

    Carl Schrum,

    Speaking for myself, I am certainly not a Republican. I assumed you were being sarcastic by commenting like a lunatic. Maybe you were making fun of the wackos who actually think like that, just for the shock value.

    But then the thought struck me that you might actually be serious! If so, you truly need professional help, my friend. Next time someone accuses me of being a conspiracy theorist, I’ll just refer them to your comments about the bible belt being targeted by the climate, etc.

    To the best of my recollection, no one here has ever denied that the climate changes. We know that it changes all the time. Michael Mann tried to claim that the climate was static until the industrial revolution, so maybe that’s who you have us confused with, eh? But of course Mann was debunked by McIntyre & McKittrick. That’s old news.

    Please tell us you were just being sarcastic. Especially about NOAA being controlled by Republicans. That sounds seriously deranged to anyone who follows NOAA. And the rest of it sounds equally crazy.

  25. SteveSadlov says:

    Most of the factory “owners” (more properly managers) I know swing Left. Of course, the real owners are the shareholders, who probably reflect the national mix.

  26. SteveSadlov says:

    OK, a Winter Storm Watch just went up for the high country. The cold pool heading this way is brutal. Talking about snow, graupel and small hail for tomorrow night down to very low elevations. Thunder prog’ed everywhere. For ag, this is going to hurt.

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