Forecasters often rely on their understanding of synoptic-scale weather guidance to make a good forecast. At times local effects can have an important impact on the weather, but it is often that "big picture" that will dictate whether or not the sky is clear, cloudy or somewhere in between.
It's at the end of August and Charlotte, North Carolina should be basking in the upper 80s or low 90s. But the afternoon temperatures have been struggling to get out of the 60s making it feel more like an early autumn day. With this kind of anomaly there's no doubt this is related to the what's going on with the big weather picture. To get a view of the synoptic weather starts with a peek at the latest surface analysis chart.
Notice that there's a relative strong (for this time of year) area of high pressure centered over southeast Ontario, Canada. During your primary training you learned that low-level winds flow clockwise around an area of high pressure as depicted by the green arrow. Also unusual for this time of year, there is a frontal system that has managed to make it as far south as central Georgia. For the Mid-Atlantic and northern part of the Southeast that means the winds will be out of the east and northeast north of the analyzed front. This is a moist and generally cooler low-level flow from the Atlantic Ocean. This moist and dense air gets dammed up against the Appalachian Mountains.