Prediciting the weather is kinda like reading chicken entrails. If you've looked at a lot of chicken entrails, you can identify certain basic characteristics.
Once upon a time I was in the cattle business. Every day after work I would go to my backporch and take a few basic readings. Things like rainfall, wind direction and speed and barometric pressure. I did this every afternoon at about 5:00 p.m. After awhile I began to see a few basic patterns and got pretty good at predicting short-term. Of course, in the summertime, anyone can predict Louisiana weather: The weather forecast for Bayou Derbonne and the surrounding acreage is as follows: Sunny and partly cloudy with temperatures in the high 90's. Chance of rain twenty percent due to isolated, locally severe thunderstorms in the late afternoon. Lows tonite near 70. This forecast will keep a weatherman in a job in Louisiana 90% of the time.
I was stumbling around the internet today and found this article on Encarta. Turns out the most sophisticated weather model we have now can only forecast out to 72 hours. I guess that the local 15 day forecast is just so much bullshit, unless the weatherman is experienced enough to look at chicken entrails.