Kansas City Weather: Storms spawn bizarre Mammatus clouds

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I wasn’t going to do a weather blog today, but then Mother Nature forced my hand by giving me a topic to write about… so this will be a shorter blog than usual, but answers a question that was on the minds of dozens of you who sent me pictures from the thunderstorms that were going toward the southeast of the Metro Wednesday evening.

The clouds in question were then highlighted by a setting sun that illuminated them in ways that we haven’t seen in many a year in the region, so for those that saw the “weird” looking clouds… keep reading.

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One sentence forecast: Mostly sunny and more comfortable today with highs near 80 with a nice breeze as well.

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Forecast

Today: Much more comfortable with highs approaching 80 with NW winds 15-25 MPH at times

Tonight: Fair and cooler with lows in the mid to upper 50s

Tomorrow: Sunny and mild with highs in the lower 80s

Friday: Partly cloudy and pleasant with highs in the lower 80s. Perhaps an early morning sprinkle.

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Discussion

Let’s answer the question poised at the top of the blog right off the top…

The answer is these types out pouch like clouds are called mammatus clouds.

The set up last evening was a cold front coming into the heat and high dew points (moisture) that was in the region. The front ignited with isolated storms toward the east and southeast side of the Metro which then sort of came together as a line of storms. This happened around 6PM.

As the storms progressed off and away from the Metro, the sun started to set and some of you toward the south and southeast of the area we got to see the backside and underneath part of the departing clouds.

In a diagram it sort of looks like this:

Supercell thunderstorm (in this case there was no tornado!)

Visually it looked like this:

See the mammatus clouds?

The University of Illinois has a great explainer about this.

“Mammatus are pouch-like cloud structures and a rare example of clouds in sinking air.

Sometimes very ominous in appearance, mammatus clouds are harmless and do not mean that a tornado is about to form; a commonly held misconception. In fact, mammatus are usually seen after the worst of a thunderstorm has passed.

As updrafts carry precipitation enriched air to the cloud top, upward momentum is lost and the air begins to spread out horizontally, becoming a part of the anvil cloud. Because of its high concentration of precipitation particles (ice crystals and water droplets), the saturated air is heavier than the surrounding air and sinks back towards the earth.

The temperature of the subsiding air increases as it descends. However, since heat energy is required to melt and evaporate the precipitation particles contained within the sinking air, the warming produced by the sinking motion is quickly used up in the evaporation of precipitation particles. If more energy is required for evaporation than is generated by the subsidence, the sinking air will be cooler than its surroundings and will continue to sink downward.

The subsiding air eventually appears below the cloud base as rounded pouch-like structures called mammatus clouds.

Mammatus are long lived if the sinking air contains large drops and snow crystals since larger particles require greater amounts of energy for evaporation to occur. Over time, the cloud droplets do eventually evaporate and the mammatus dissolve.

Mammatus typically develop on the underside of a thunderstorm’s anvil and can be a remarkable sight, especially when sunlight is reflected off of them.”

So now you know.

What made them so remarkable is the setting sun that illuminated them in different ways like this shot from Alice Aubele