SPC MD 1127

MD 1127 CONCERNING SEVERE THUNDERSTORM WATCH 336... FOR SOUTHERN SOUTH DAKOTA...NORTHERN NEBRASKA

Mesoscale Discussion 1127
NWS Storm Prediction Center Norman OK
1244 AM CDT Tue Jul 07 2020

Areas affected...Southern South Dakota...Northern Nebraska

Concerning...Severe Thunderstorm Watch 336...

Valid 070544Z - 070745Z

The severe weather threat for Severe Thunderstorm Watch 336
continues.

SUMMARY...A wind-damage and isolated large hail threat will likely
continue across southern South Dakota for several more hours. The
threat may impact northern Nebraska as the storms move to the
southeast. A new weather watch to the south of WW 336 will be
considered.

DISCUSSION...Latest radar analysis shows a well-developed bowing
line segment across southern South Dakota. A warm-advection wing of
convection extends east-southeastward int southeastern South Dakota.
The developing MCS is located along the northern edge of moderate
instability with the RAP estimating MLCAPE near 1500 J/kg. In
addition, a 30 to 40 kt low-level jet is analyzed across western and
northern Nebraska. This jet along with the instability will help
maintain the storms for several more hours. This line will move
southeastward toward drier air left over from this evening's
convection in northern Nebraska. For this reason, uncertainty exists
concerning how long the severe threat will be maintained. The
current thinking is that the greatest severe threat will be confined
to southern South Dakota where surface dewpoints are greater,
however the isolated severe threat may gradually shift into southern
Nebraska

..Broyles/Edwards.. 07/07/2020

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

ATTN...WFO...FSD...OAX...ABR...GID...LBF...UNR...

LAT...LON   43150130 42830121 42440039 41969908 41669815 41699765
            41909723 42109707 42359703 42579706 43129755 43769844
            43999903 43959996 43510086 43150130 

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