Tornadoes occur every month of the year, but we are now going to be coming into what is usually the most active time of the year for tornadic storms – spring.
Generally, the greatest activity advances from south to north as warming expands northward. Last year, after an active February start, was exceptionally quiet most of the year until near the year’s end. This year, there are hints we may see far more outbreaks this spring than last.
Even as I write this, the Storm Prediction Center is concerned with severe storms potential prior to and during midweek:
The sad loss of Bill Paxton is a reminder to the meteorological community of how impactful the exciting movie “Twister” was to budding meteorology undergrads and soon-to-be undergrads.
I was entering middle age when the movie was released, and I couldn’t wait for it to come out after seeing a trailer. After it was released, many of us did – as you might expect – find fault with some of the science in the movie, some of which was seriously flawed. For example, tornado outbreaks don’t typically run from one day into the next with no ebb and flow as the sun’s heating is lost.
Some of its science was stretched, but not that far off the mark. I recall David Letterman’s memorable line about the movie, “I thought the object was to chase tornadoes, not BE chased.”
In fact, the movie’s instrument system named DOROTHY, to hopefully be placed in the path of an approaching a tornado vortex, was a technique already in place when the movie was released. The National Severe Storms Laboratory had developed a system called TOTO (TOtable Tornado Oberservatory), though it was long after the staging time for “Twister,” which was set in 1969. It is far more difficult to safely get such a device out in front of the actual path of a tornado than portrayed in the movie, and the system never experienced a successful encounter.
There were many other elements of science in the movie which were, in fact, well researched and reasonably accurate. It was not junk science, which could have turned out to be the case. The beauty of weather is that there is no need to exaggerate. It can be dynamic enough on its own to make things exciting.
For a quite a number of years there have been other technologies which have greatly advanced the much incomplete understanding of tornadogenesis – the development of a tornado. The heart of the science in chasing emanates from the campus of the University of Oklahoma in Norman, NOAA’s National Severe Storms Laboratory.
In 1993, in a cooperative venture with other universities including OU, NSSL deployed DOW, Doppler on Wheels. DOW is a powerful mobile Doppler radar which can send its beam beneath the altitude of the beams emitted by fixed Dopplers. DOW gives a superior representation of storm structure and dynamics near the ground. Here is an image I took when visiting NSSL and the Storm Prediction Center a few years ago at an American Meteorological Society conference:
There is also a new DOW which uses a different part of the electromagnetic spectrum (called X band) to examine smaller particles and their motions in the lower part of a storm. There are still newer suites of portable instruments which can gather valuable information near storms, though not necessarily in the path of the vortex.
For active researchers and commercial chasers, good Wi-Fi is a must. Given the right computer hardware, software and data connection, we all have access to high resolution National Weather Service and FAA Terminal Doppler radar data.
It has been U.S. policy to allow free access to the vast majority of such data. Skill in interpreting such data is another matter left to the individual – which means if you choose the economic gamble of scheduling a chasing tour in some given week, it had better be with someone who has some academic training and experience. (I should note the odds of having a successful near encounter when you’re booking a tour weeks in advance are not good.
My only chase came in the spur of the moment at the conclusion of a St. Louis AMS conference. A longtime friend and retired brilliant NWS training officer, Mike Mogil, had a rental car and invited me to chase with him on a prime severe weather day. We stopped at the St. Louis NWS Office for a briefing and off we went across Missouri to northeastern Kansas. We missed a tornado touchdown by 10 minutes and drove the hundreds of miles back trapped under a complex of convection with blinding downpours and incredible lightning all the way. Close, but no cigar!
In this next year, it’s remote data from space which may well be the most important new tool for researchers. The GOES-R satellite, still in test mode, has the ability to do rapid scan extremely high resolution images of a focused small area every 30 seconds. Such imagery can’t see everything inside storm cells and supercells, but the change in cloud top configuration, cloud top temperature, visible gust fronts out ahead of the storm, and the satellite’s superior lightning detection will provide far more rapid data on changes in storm development than can be supplied by the network of NWS Dopplers, which take about six minutes to complete a complete set of scans of many different altitudes within a storm to determine a more complete picture of its structure.
As I’ve written, the U.S. still lags in our global weather models in many respects compared to the European Center and the British Met Office. When it comes to the study of severe local convection, though, we are unquestionably the world leader. We have to be. Our tornado frequency, due to our geography, is incomparably higher than that of any other continent.
NOAA’s unique relationship with the University of Oklahoma has created the largest community of meteorologists in the nation. OU also houses, at the National Weather Center, the Storm Prediction Center, the NWS Warning and Decision Training Branch, the NWS Oklahoma City Forecast Office and a host of other facilities. There are even engineering firms surrounding the School of Meteorology which are designing better roofs and structures to withstand extreme wind. The National Weather Center itself has walls lined with Kevlar, and windows which can withstand 250 mph gusts. An EF-4 touched down about 100 yards away the year prior to our conference, which is a reminder of why such protection is needed.
For more information on what your tax-supported, highly productive NSSL does for us, visit nssl.noaa.gov.