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Heat Wave Across the Central and Southeast US; Flash Flood Threats in the North-Central US, Southeast, and Guam

Dangerous heat is expected across portions of the Central and Southeast U.S. through July. Heavy rains, flash flooding & severe weather are possible across the middle Missouri River Valley and Upper Midwest to the upper Great Lakes. Heavy rains and flash flooding are also possible across portions of the Southeast. A tropical disturbance brings heavy rain to Guam & the Marianas through Saturday. Read More >

Event Overview

Cold core low moved over the area, dragging along a weak and slow moving surface low pressure. While weak, sufficient low level and upper forcing aided in developing strong to severe storms. While instability was more than sufficient, the shear was lacking, but was enough to help develop a few supercell thunderstorms. Due to the weak forcing overall and the slow moving nature of the storms, some storms anchored over locations for an extended period of time, resulting in Flash Flooding. Some repeated storms over the same area also led to similar results. Severe weather reports were mostly in the form of hail, as these storms produced hail very efficiently. Some hail reaching 1.5", with some isolated reports of damaging winds. 

 

This event not only impacted the area on 8/19, but due to little movement of the system as a whole, repeated events were seen the following day, on 8/20. Storm action generally hovered over counties along and east of the Mississippi River on the second day. 8/20 was filled with many mini supercells, where many led to funnel clouds. Along with the funnel clouds, some reports of brief tornadoes were received. 

 

 

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Surface Map on August 20th
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