Why we had dirty rain Wednesday

 

If you stepped outside either during the morning or afternoon Wednesday, you may have noticed your car was a little dirtier than what it was before - even after the rain came through. We received many comments and pictures from viewers of their cars wondering where all the dirt and mud came from.

To answer this question, we have to look west and southwest - well west and southwest. A strong trough of low pressure in the jet stream (a dip in the jet stream) developed out west late Tuesday night. Fast moving jet stream winds at the base of the trough, nearly 115 mph, created strong winds near the surface. Those strong surface winds were able to pick up a lot of the dirt across parts of Texas, lofting it into the air several thousand feet above. The dust and dirt then became suspended within the jet stream winds, traveling through Arkansas, Missouri, and Illinois Wednesday morning before moving east late in the afternoon. The dust was so thick it caused significant issues with visibility at times over parts of Arkansas and Missouri.

Parts of Oklahoma and Texas, as well as New Mexico and Arizonia, have been experiencing very dry conditions. The storm system late Friday caused fires to rapidly spread in Oklahoma as major dust storms occurred. A lot of what we experienced Wednesday was left over from what had occurred over the Southern Plains and Southwest from late last week and the weekend.

Once in the air and clouds the dust and dirt particles act as 'collection points' (known as condensation nuclei) for water droplets to form on, helping to create rain drops. As the rain drops fall from the clouds the dust particles travel with it. When the rain hits the surface, we are left with the visible dust and dirt on things like cars, sidewalks, and the grass. This is why your car looked dirty, or why the ground in some locations had more of a tan look to it.