While the Storm Station forecast anticipated most of the rain to hold off until afternoon, an early onset of showers and thunderstorms occurred on Friday morning. It all happened due to the combination of a weak ripple of energy and the inherent volatility of the Gulf Coast's warm-season atmosphere.

Given the high heat and humidity during the summer, the atmosphere is regularly supportive of showers and thunderstorms. Even small triggers, such as daytime warming and marine breezes, can easily lead to thunderstorm formation. While significant atmospheric disturbances (non-frontal systems that cause unsettled weather in the cool season) are rare in the summer, when they do occur—they can cause storms to blossom. 

Over the last few days, an upper-level trough of lower pressure, cooler air, and therefore more unstable air had settled over the region, hence the daily dose of showers and thunderstorms. Most days, it has taken afternoon warming to spark action. However, on Friday morning, a weak ripple of energy spun into that upper-level trough over Texas and Louisiana, igniting thunderstorms.

In addition to the ripple of energy, near record levels of moisture primed the atmosphere while winds just above the surface were moving in such a fashion that they converged over the region, causing tremendous lifting. These ingredients, triggered by that ripple of energy, caused thunderstorms with persistent, heavy rainfall rates and dumped more than 6 inches of rain near Lafayette.

Once thunderstorms have used up the warmth and moisture, it is often hard to recharge for a second round later in the day. The result on Friday was an active morning and a quieter afternoon in what would be considered by most standards a forecast bust! While this forecast didn’t unfold as expected — the Storm Station is always taking a closer look at what happened, with hopes of identifying patterns that can improve future forecasts.