Storm Chasing and Chaos Theory (posted on Stormtrack-website)by Tom Windsor

Does the very act of storm chasing affect potential storms in the future ? According to Chaos Theory the answer is yes. Imagine someone this month (January) down in the Australian outback speeding down a dirt road , moving towards a nice storm off in the distance . In the rear of their van a micro low pressure system is formed in the drag , as the dust swirls into a vortex and vanishes in the mirror . As this parcel of air dissipates and slowly makes it ways around the globe ( let's say 7 times by late spring ) it interacts with the much larger atmosphere . As air masses collide in the great plains this spring , the results will be somewhat different if this chase event had that not happened . ( These are the kind of important thoughts one sometimes wonders during the looong wait till spring convection ) According to some books I've been reading this scenario could hold true.

In the early days of computer forecasting, they would run data results out for weeks and months . One day someone reran some data a second time and got very different results . They couldn't figure out why the same data would yield two different results , until someone realized a very small decimal point in the data had been rounded off . The graph look identical for a weeks but then started to diverge into a completely different path . Extremely small variations in the initial conditions, didn't show up until it played out far in the future ,

On this note , I read that a meteorologist awhile back thought that if you could obtain accurate data from a 100 kilometer cubic grid you could finally , accurately predict the future weather . He couldn't have known that those small differences in between the grids on a smaller scale , would still change the results . We now know why .

This illustrates the problem of complexity in forecasting . There are so many variables which can have a wide range of effects on the outcome , like pressure ,temperature , wind speed, relative humidity , topography, yesterdays storms, El Nino etc . Also, there are factors that can have an infinitely small effect , like heat from cites , solar storms , and now chasers themselves to add to that list .

As an amateur weather enthusiast , I never realized how complex the atmosphere is and also forecasting until I stared researching it in preparation for chase seasons. I now have a much deeper appreciation for those who have it as their profession. . I'm wondering if the atmosphere is the most chaotic system we know of

The more variables the more complex the math ( involving vicious mathematical feedback loops and non-linear equations ) . Also every scale has to be taken into effect as an extremely small scale event can also set off a cascade that effects the larger . One small change earlier in the day in upper level winds , temperature ,or pressure could mean the difference between a town getting rained on or struck by a large tornado or a chaser "caching" a suntan . ( Its like the few snowflakes that triggered the avalanche ) . The term " instability " or "loaded gun " in so appropriate . This all makes for weather living up to its reputation as fickle and unpredictable.

Even 2700 years ago , Solomon wrote a proverb , " you do not know the path of the wind ....". Some centuries later a Man came along who reportedly had authority over the storms spoke that , " The wind blows where it wills , you do not know where it comes from or where it goes"... . These words still ring true today .

As one who has had to plan a storm chase vacation , based on a 3 day forecast and drive out west from the east coast , severe outbreaks are still often a coin toss at this point . However , as computers get more advanced and can crunch calculations involving those staggering number of variables , its getting a lot better since I started chasing around ten years ago ,and that's good news for chasers .

Maybe a very accurate 3-5 day storm forecast is not too far off , but I think its going to be a looooong time before it is accurate to weeks in advance, if ever . So to you chasers down in the outback , the phrase " be careful chasing ", now has another added dimension . Don't spoil things for us mate :) . G'day.

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