extreme weather
Photo via NASA Goddard Space Flight Center

I like to be prepared when I leave the house for the day. I have a big breakfast, check the local television channels for traffic and commuter reports, and of course, I always watch the weather forecast to ensure I dress for the weather.

So why was I thrown for a loop recently, when the temperature suddenly had a wind-chill of -17°C (62.6°F)?

We’ve all been in similar situations, wondering: “how come they didn’t forecast this?!?!” as we shiver in colder than forecast temperatures, or get drenched in an unexpected downpour.

Turns out climate change isn’t just changing the seasons, it’s making it harder for professional weather forecasters to predict the weather.

Meteorologists and scientists agree that climate change is creating more extreme weather. We’re seeing increases in the severity of hurricanes, even heat waves.

Severe storm surges such as the recent typhoon in the Philippines and last year’s hurricane Sandy which wiped out much of the American North-Eastern Seaboard are increasing.

As the planet heats up, that heat energy drives storms into monster storms. Warmer weather evaporates more moisture into the air, which is the basis for cloud formations. As the clouds get bigger, they capture more water vapour, and what would have been a simple rain storm, turns into a massive super cell, with high winds, torrential downpours, and the potential for tornadic activity in some areas.

We’ve seen this pattern over what is known as tornado alley in the States every summer, sometimes with devastating results.

However, horrific extreme weather is when it strikes, it’s disappointing and often unfortunate when the daily weather forecast is wrong.

Weather forecasting isn’t an exact science. It’s a series of predictions, based on comparing current trends to past events, to create weather ‘models’ which are most likely going to be accurate.

Most likely going to be accurate doesn’t sound very reliable, however weather forecasting today is far more accurate than about 20 years ago, because of computers.

Thanks to the number crunching power of computers, weather forecasters now use numerical forecasting, which takes weather data from land, sea and air, and creates complex mathematical equations to predict the weather.

However, computer number crunching still can’t be totally accurate, thanks to physics and something called chaos theory.

Our atmosphere is governed by the physics of our planet, in terms of how it moves, cools, and heats the air and water. We see this physics in action when we watch satellite imagery of the Jet Stream, tidal patterns, and other related patterns.

Although predicting the weather has improved significantly over the years, chaos theory from the 1960’s stills makes it a murky science.

The slightest differences in initial conditions can produce very different forecasts – known as the butterfly effect. Imagine a butterfly flapping its wings in one place, and that flapping of wings in principle, can alter the weather pattern someplace else – even if that someplace else is quite far away.

It could be a butterfly, a moth, or even a tree falling in the forest. Chaos theory says that even the smallest changes inject a certain level of randomness into the complexity of predicting the weather.

There are so many elements – large and small in predicting the weather, forecasters may never be 100 percent accurate.

And because our weather is based on a planet-wide scale, that butterfly could cause instability in the atmosphere on the other side of the globe.

Weather services across North America share information, and governments around the world share their weather data, because of the wide spread affects of weather worldwide.

However, it’s still amazing to think, that something as small as a butterfly in one town, can have such an enormous impact on the weather in another town, someplace else on our planet.

Photo via NASA Goddard Space Flight Center

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