Thunderstorm “training” results in flash flooding in Allen, Whitley counties

FORT WAYNE, Ind. (WPTA) - Meteorologists talk about it all the time when it comes to inclement weather. When the ingredients come together, the weather can turn nasty, and flooding was the result on Tuesday morning.

The ingredients? Well, it’s all the same ones to produce thunderstorms. Moisture, instability, and lift. However, those weren’t the only ingredients that helped with the flooding.

Extremely dry conditions contributed to water running onto the roadways. We’ve been in a flash drought for about three weeks now and until Tuesday morning, Fort Wayne International Airport had only received 0.23″ of rain since the Derecho on June 13th. The latest drought monitor has most of 21Country in “abnormally dry” conditions. The ground is so dry, that it couldn’t immediately soak up the rain, so some of it flowed into the roads.

The thunderstorms that caused the flooding are called “Training” Thunderstorms. Why training? Think about train cars on train tracks, they keep moving over the same area as the car in front of them. Same thing with training thunderstorms.

It starts with one storm. When it rains, the air cools and that cold air hits the ground, and spreads out, creating what’s called a cold pool. This cold pool keeps spreading, evening after the thunderstorm moves out of the area. However, there was still warm, moist air in its place. So, the cold air lifted those areas of warm, moist air up, creating more thunderstorms in the place of the old one.

This morning, the cold pool of air was spreading so far back so quickly, that storms were primed and ready to keep dumping rain over the same area. Wind was also a key factor in the training thunderstorms this morning. Winds moving from the same direction over a prolonged period of time, as new thunderstorms form behind old ones, ensures that the new storms will move over the exact same area until the air becomes more stable and thunderstorms eventually die out, or until the winds start to shift.

Rain totals as of 11 a.m. were quite impressive, with more than 4 inches of rain reported in parts of Allen and Whitley County.

At the time of this article, the NWS reported flooding in Churubusco with an estimated 6-12 inches of water on the roadways.

Remember, DO NOT ENTER FLOOD WATERS! You never know what debris may be in the water and you don’t know how deep it is. It takes a foot of water to make a car float, and with some area creeks starting to flow over roadways, water could become very deep, very quickly.