SPC MD 1486

MD 1486 CONCERNING SEVERE THUNDERSTORM WATCH 470… FOR SOUTHEAST SOUTH DAKOTA…NORTHEAST NEBRASKA AND NORTHWEST IOWA

Mesoscale Discussion 1486
NWS Storm Prediction Center Norman OK
1147 PM CDT Fri Jun 27 2025

Areas affected...Southeast South Dakota...northeast Nebraska and
northwest Iowa

Concerning...Severe Thunderstorm Watch 470...

Valid 280447Z - 280615Z

The severe weather threat for Severe Thunderstorm Watch 470
continues.

SUMMARY...The threat for damaging winds has likely peaked already
and the storms may begin a slow weakening trend through 06-07z.

DISCUSSION...The bowing cluster with a history of severe outflow
gusts up to 83 mph is now showing the initial signs of weakening. 
An increase in convective inhibition and weakening deep-layer
vertical shear with southeastward extent appear to be contributing
to weakening of the cluster, as evidenced by lowering echo tops and
a fine line/outflow progressing ahead of the main updrafts.  This
weakening trend is likely to continue and the storms should weaken
by 06-07z, though isolated strong-severe outflow gusts may occur in
the interim.

..Thompson.. 06/28/2025

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FSD...OAX...

LAT...LON   42399606 42519722 42769741 43399678 43239582 42729577
            42399606 

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

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2025-06-28 05:05:05