South Dakota Mesoscale Discussion

Areas affected…Northern High Plains

Concerning…Heavy rainfall…Flash flooding possible

Valid 232334Z – 240534Z

Summary…Thunderstorms developing off a trough in the lee of the
Wyoming Rockies will continue to shift northeast along a trough
toward South Dakota into the evening. Given the warm and humid
airmass flash flooding is possible.

Discussion…A warm and humid airmass along a trough extending
northeast from current activity in eastern WY will draw heavy
thunderstorms toward western SD and southwest ND into the evening.
PWATs are 2 standard deviations above normal and SBCAPE is
sufficient for rapid development at 3000 J/Kg. A strengthening low
level jet up the Plains will continue to provide moisture through
the night. Flash flood guidance is 1 to 2 inches per hour across
the risk area. Rain rates of this magnitude are possible as the
activity continues to develop into the evening hours.

This activity may continue into the overnight and an updated
discussion for further flash flood risk may be needed.


…Please see for graphic product…



LAT…LON 47420293 46680145 44810312 42650291 41190278
41010336 41020439 41050468 42080523 42530612
43020699 44790709 45720679 46370465

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