Mesoscale Discussion 1217
NWS Storm Prediction Center Norman OK
0734 PM CDT Mon Jul 13 2020
Areas affected...Southern Minnesota eastern South Dakota and
northwest Iowa
Concerning...Severe potential...Watch possible
Valid 140034Z - 140230Z
Probability of Watch Issuance...40 percent
SUMMARY...Storms capable of damaging winds gusts will be possible
this afternoon and evening. Storm development is uncertain but a
weather watch is possible.
DISCUSSION...Agitated cumulus along a cold front across eastern
South Dakota has shown signs of deepening over the last hour. Lift
from an approaching shortwave trough over the western Dakotas is
forecast to continue to overspread the area eastward this evening.
Height falls and mid-level cooling are contributing to a
moderate/strongly unstable atmosphere with SPC mesoanalysis
indicating 2000-3500 J/kg of MLCAPE. While inhibition is low, storms
have been slow to organize likely due to relatively warm mid-level
temperatures above 10C. Convective initiation is still uncertain
across much of southwestern Minnesota and eastern South Dakota. If
storms are able to develop, effective bulk shear of 35-50 kt would
favor a mixed storm mode of supercells and line segments with a
threat for damaging winds and perhaps a tornado given moderate
veering of low-level wind profiles.
Hi-res guidance shows considerable uncertainty on overall storm
coverage and intensity. Storm development may be delayed until
convection to the west of the area begins to interact with the warm
sector later this evening. Convective trends will be monitored, and
a weather watch is possible.
..Lyons/Hart.. 07/14/2020
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MPX...DMX...FGF...FSD...OAX...ABR...
LAT...LON 42959557 43689456 44509405 45299412 45719427 46059471
46199551 45979619 45299641 44479671 43749708 43199759
42809746 42679690 42599639 42859578 42959557
Read morefrom SPC Forecast Products http://www.spc.noaa.gov/products/md/md1217.html
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