Mesoscale Discussion 1398
NWS Storm Prediction Center Norman OK
0227 AM CDT Sun Jun 22 2025
Areas affected...Across portions of the Dakotas
Concerning...Severe potential...Watch unlikely
Valid 220727Z - 220930Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated to scattered thunderstorms may pose a severe hail
risk through the early morning hours from central South Dakota into
southern/southeast North Dakota. Watch issuance is not anticipated.
DISCUSSION...Convection continues to develop across SD early this
morning ahead of a weak mid-level impulse moving north/northeast
across the Plains. Latest RAP forecast soundings suggests that
near-surface parcels remain capped, and that much of this convection
is rooted between 600-700 mb where CAPE values are roughly around
250 J/kg. However, cloud-top cooling noted over the past 30 minutes
within a more persistent cell near Chamberlain, SD suggests that
this cell is beginning to ingest parcels within the 850-700 mb layer
where richer moisture is contributing to MUCAPE values of around
2000-3000 J/kg. Other storms across the region, such as the ones
developing south of Bismark, ND, are beginning to display similar
progressions. As this intensification occurs, cells may begin to
more fully realize the kinematic environment characterized by 35-45
knots of effective bulk shear and become more organized, possibly
evolving into isolated supercells with an attendant threat of large
hail. In general, this threat is expected to remain sufficiently
sparse/isolated to negate watch issuance, but some severe threat may
linger through the early morning hours.
..Moore/Mosier.. 06/22/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...FSD...ABR...BIS...UNR...
LAT...LON 43359967 43949974 44589980 44879992 45020013 45140046
45270090 45360135 45480167 45950198 46350183 47090135
47570063 47770008 47769939 47689877 47579848 47389819
47159778 46759734 46389710 46019701 45599702 45289706
44979713 44589728 44289759 43989791 43589846 43319893
43209933 43189951 43209963 43359967
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
Category: Watches, Warnings, Advisories, & Hazards