SPC MD 1112

MD 1112 CONCERNING SEVERE THUNDERSTORM WATCH 331... FOR SOUTHERN NORTH DAKOTA AND NORTHEAST SOUTH DAKOTA

Mesoscale Discussion 1112
NWS Storm Prediction Center Norman OK
0629 PM CDT Sun Jul 05 2020

Areas affected...Southern North Dakota and northeast South Dakota

Concerning...Severe Thunderstorm Watch 331...

Valid 052329Z - 060130Z

The severe weather threat for Severe Thunderstorm Watch 331
continues.

SUMMARY...The threat for severe wind and hail continues across WW
331. The greatest near-term threat will be associated with
developing supercells across southern North Dakota and clusters of
storms from northeast to central South Dakota.

DISCUSSION...Satellite and radar trends over the past hour show
intensifying convection along a outflow boundary across southern to
southwest ND and along a diffuse trough axis that is draped from
eastern ND into central SD. The environment remains supportive of
severe convection with 40-50 knots of effective bulk shear and
1500-2500 J/kg MLCAPE (per recent RAP mesoanalysis), and should
remain so in the near-term (roughly the next 1-2 hours). Recent VAD
profiles from KBIS show nearly straight hodographs through a deep
layer, suggesting that discrete to semi-discrete storms may
gradually grow upscale as storm splits and interactions become more
common with time. As this occurs, the primary threat may shift from
severe hail to wind. Despite somewhat weaker shear, clusters of
storms across central to northeast SD should continue to pose a hail
and wind threat as gradual upscale growth continues. 

Additionally, new convective development is possible along an
outflow boundary draped across southeast ND, just north of the ND/SD
border. Recent visible imagery shows some deepening of cumulus along
this line as temperature rebound into the low 80s. This suggests
that boundary layer recovery may be sufficient for convection prior
to sunset.

..Moore.. 07/05/2020

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

ATTN...WFO...FGF...FSD...ABR...BIS...UNR...

LAT...LON   45960306 46660277 46910140 46950026 46839769 46419708
            45669702 44989781 44529857 44079891 43809943 43700019
            44460078 45290140 45960306 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1112.html