SPC MD 1340

MD 1340 CONCERNING SEVERE THUNDERSTORM WATCH 401... FOR SOUTHEAST NORTH DAKOTA AND FAR NORTHEAST SOUTH DAKOTA

Mesoscale Discussion 1340
NWS Storm Prediction Center Norman OK
0830 PM CDT Sat Jul 25 2020

Areas affected...Southeast North Dakota and far Northeast South
Dakota

Concerning...Severe Thunderstorm Watch 401...

Valid 260130Z - 260300Z

The severe weather threat for Severe Thunderstorm Watch 401
continues.

SUMMARY...Severe threat continues for WW 401. Convective trends
being monitored for possible watch extension.

DISCUSSION...Scattered thunderstorms have developed along and south
of a cold front moving through portions of south-central North
Dakota, with assistance from a mid-level trough providing a focused
area of diffluence and ascent. In addition, low-level convergence is
maximized along/near the baroclinic zone, helping to increase storm
coverage amid a corridor of modest instability (1000-1500 J/kg) and
favorable effective shear (45-55 kt) for storm/updraft organization.
So far only one intense cluster of storms has emerged, traversing
the ND/SD border while producing several damaging wind reports.

Storms that move and/or develop eastward with time will encounter a
more unstable environment, characterized by MLCAPE approaching 2500
J/kg. Given the aforementioned mid-level support and strongly
sheared environment, it seems plausible for the damaging wind threat
to continue into portions of southeast North Dakota and far
northeast South Dakota. This scenario is supported by the latest
convection allowing guidance. Thus, convective trends will continue
to be monitored for the possibility of a watch extension.

..Karstens.. 07/26/2020

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

ATTN...WFO...FGF...ABR...BIS...

LAT...LON   47409879 47289827 46859715 46329672 45969677 45789721
            45669868 45660011 45960084 46580078 47000056 47340018
            47469970 47409879 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1340.html