Weather Forcasts

This is the weather forecast for tomorrow form three different websites, each is slightly different. From  http://www.wunderground.com the high is 27, the low if 14, and it will be partly cloudy, form  http://www.accuweather.com there is a high of 30 and a low of 12, and it will be mostly sunny, and finally, from  http://www.weatheroffice.gc.ca there will be a high of 28 and a low of 13, and it will be completely sunny. Each of these is different because the weather is so enormously complicated that even with computer programs working 24/7 to predict the future, they still get it wrong most of the time. They are each different because each of them has slightly different measurements, and each of them has a slightly different model, and because the weather is so complex, even these slight differences can lead to sometimes radical differences in the overall projection of the weather for the future, and often lead to radical departures from what actually happens, especially for predictions more than 24 hours in advance. Weather prediction has been taking place for many years, probably since humans could communicate with eachother about things as complex as what the weather will be like tomorrow. This history of predictions has lead to a group of surprisingly accurate folk tales and short poems about the weather. Weather forcasting in the modern sense began soon after the invention of the telegraph, when it first became feasable to predict weather based on the current conditions upwind. Soon after that, the barometer was invented, and weather began to be predicted based on air pressure, and soon models and formulas were being created to predict the weather based on current weather conditions much more accurately, but after a certain point the calculations were so complex as to hardly be able to finish them before the weather actually happens. This all changed when computers came around, and soon enough, we had fairly accurate weather predictions for the next week or so.