There was a Marginal Risk of severe thunderstorms earlier today across the south. I did not post about it, and the threat has been reduced.
The conditions today did yield a long squall line.
Looking at the squall line, there are some neat things to notice. Across Mississippi, there are several bowing sections, called “Bow Echoes” where the squall line has pushed forward. The bow comes from the redirection of mid-level flow accelerating in pockets, called Rear Inflow Jets (RIJ). You can identify these by finding areas with lower reflectivities behind the main squall line. I have marked these on the image.
Also, looking at the vertical cross section of these storms, we see a large area of trailing precipitation behind the main core of the storm. Notice that the updraft is tilted forward.
There is a flood watch issued for parts of Mississippi. You can’t see the motion of this storm, but the storm is trailing a little bit east. Therefore, the rain keeps falling in the same areas, leading to the flood threat.
Thank you for reading this post.
All radar images are from GRLevel 2, which I highly recommend.
Just curious about your thoughts on why the updraft would be tilted forward.
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Typically, the updrafts tilt in the due to the speed of the upper level winds. I’ve heard the 500 mb winds referred to as the “steering level” winds, as they drive the cloud tops downwind. This is why shear is such an important thing to track; higher shear means cloud tops are blown downwind, meaning the precipitation region and updraft are separated. This leads to longer-tracked storms.
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