(GFS Meteogram for MSP; image courtesy of Meteostar.com)
I'm dating myself, but when I went to school to become a meteorologist we used paper maps. Nobody in the late 70s could imagine the wealth of information that would be at our fingertips 20 years later. Today there are an estimated 6,000+ web sites in the U.S. devoted to weather; the National Weather Service has a wealth of information on-line, major universities are another good, trusted source of updated weather information.
Here is the GFS model prediction for the Twin Cities, looking out 7-8 days into the future. This "Meteogram" is fairly self-explanatory, tracking the expected highs, lows, probability of precipitation and cloudcover. The computer models are essential, but research shows that the best accuracy comes from a mix of man & machine, ie. meteorologists knowing when the computers are on-track, or out to lunch and way off the mark. Watch how the forecast for Day 4-8 changes (sometimes dramatically) over time as new data arrives and new models, simulations of how the atmosphere SHOULD flow, display contradictory forecasts. Spend a little time deciphering the models and you too will be pulling what few gray hairs are left on the top of your head. Long-range weather forecasting is definitely not for the timid!