Stormy Weather is Chancy
When the weather becomes humid, it is intuitive that there is an accompanying increase in thunderstorm activity. But trying to forecast the timing and location of storms during humid weather is often very hard. Storms do well in humid environments. In addition to helping it rain, the evaporation and condensation process adds tremendous amounts of energy to the atmosphere, making storms explosive. But storms also need a trigger; something to get them started. Ususally when we get our most humid summer weather, the fronts, lows, and other dynamics are weak. This leads to forecasts of widely scattered storms, possibly severe, and some with very heavy rain. And if people hearing the forecast gloss over the qualifing, "widely scattered," they can get the impression that doom is immenent. When, in reality, these humid weather patterns usually produce lots of fine weather over most of the area.
Later this afternoon and tonight through most of the weekend , there will be widely scattered thunderstorms, some severe, and some with very heavy rain. But this means that most of us most of the time will likely be enjoying some fine summer weather. Meanwhile, some of us some of the time will have storms. A small number of those storms could get rough. Meteorologist John Wheeler