MD 1916 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHWEST NORTH DAKOTA INTO NORTHERN SOUTH DAKOTA
Mesoscale Discussion 1916
NWS Storm Prediction Center Norman OK
1030 PM CDT Mon Aug 10 2026
Areas affected...Southwest North Dakota into northern South Dakota
Concerning...Severe potential...Watch possible
Valid 110330Z - 110530Z
Probability of Watch Issuance...40 percent
SUMMARY...Elevated convection developing across southwest North
Dakota may continue to intensify and pose a severe threat over the
next few hours, though confidence in exact evolution is uncertain.
DISCUSSION...Convection has been gradually intensifying to the west
of Bismarck, ND over the past 45 minutes, and a few additional
updrafts are noted to the southwest of this cell per GOES IR
imagery. This activity appears to be driven by weak ascent within a
diffuse low-level baroclinic zone draped from southwest ND
southeastward into SD based on recent upper-air analyses. Although
this activity is somewhat displaced to the north of the axis of
greater buoyancy (and is upstream of the cold pool associated with a
leading supercell in SD), the 00 UTC BIS RAOB and recent forecast
soundings suggest buoyancy should be adequate for sustained deep
convection downstream into south-central ND. Additionally, strong
deep-layer shear remains in place across the region and can support
intense supercell development (as evident by the aforementioned
supercell in SD, which matured in a similar kinematic environment).
Despite the favorable convective environment, it remains unclear
whether this emerging cell will remain isolated or if additional
convection will emerge within this zone and foster upscale growth
along the baroclinic zone into SD later tonight. Convective trends
will continue to be monitored, and watch issuance may be needed as
dictated by storm evolution and intensity.
..Moore/Mosier.. 08/11/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...BIS...UNR...
LAT...LON 45570379 46380319 46770250 46329853 46049819 45599830
45289877 45059933 44999957 45570379
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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MD 1915 CONCERNING SEVERE THUNDERSTORM WATCH 560... FOR PARTS OF OH
Mesoscale Discussion 1915
NWS Storm Prediction Center Norman OK
0952 PM CDT Mon Aug 10 2026
Areas affected...Parts of OH
Concerning...Severe Thunderstorm Watch 560...
Valid 110252Z - 110415Z
The severe weather threat for Severe Thunderstorm Watch 560
continues.
SUMMARY...A severe hail/wind threat continues this evening across
parts of Ohio, but the need for a downstream watch remains
uncertain.
DISCUSSION...Two slow-moving clusters have become the primary severe
risk this evening across western OH. While a very unstable airmass
remains in place ahead of this activity (MLCAPE up to 3000-3500+
J/kg per recent mesoanalysis), a lack of recent wind reports
suggests that these thunderstorms may be slightly elevated. Even so,
modest low-level southwesterlies veering to west-northwesterly and
gradually strengthening with height through mid levels will continue
to foster around 30-35 kt of deep-layer shear (reference the 00Z ILN
observed sounding). This should be sufficient for continued updraft
organization, with occasional severe/damaging winds the primary
threat given the ongoing cluster mode. Isolated hail also appears
possible with embedded stronger cores. These clusters will spread
east-southeastward this evening across central OH, and will
eventually encounter a less unstable airmass into far eastern OH and
WV, where prior convective overturning occurred earlier today.
Therefore, the potential for organized severe convection persisting
east of Severe Thunderstorm Watch 560 remains uncertain, as does the
need for a downstream watch.
..Gleason.. 08/11/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PBZ...RLX...CLE...ILN...IWX...
LAT...LON 40578471 41368423 40398171 40078152 39498176 39488224
40038453 40578471
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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MD 1914 CONCERNING SEVERE THUNDERSTORM WATCH 562... FOR WESTERN SOUTH DAKOTA
Mesoscale Discussion 1914
NWS Storm Prediction Center Norman OK
0936 PM CDT Mon Aug 10 2026
Areas affected...Western South Dakota
Concerning...Severe Thunderstorm Watch 562...
Valid 110236Z - 110430Z
The severe weather threat for Severe Thunderstorm Watch 562
continues.
SUMMARY...The threat for very large hail and severe winds will
continue as a robust supercell migrates southeast across western
South Dakota.
DISCUSSION...Over the past hour, a lone, but intense, supercell has
exhibited persistent three-body scatter spikes consistent with very
large hail, and has also produced wind gusts of at least 61 mph per
recent reports. More recently, the reflectivity core has diminished
slightly, and the storm motion has shifted from due south to
southeasterly, suggesting a slight weakening of the storm's internal
pressure perturbations and overall intensity. However, this cell
will continue to reside within an environment very favorable for
intense convection (MLCAPE near 4000 J/kg and nearly 50 knots of
effective bulk shear as sampled by the 00 UTC UNR and ABR
soundings), so some degree of re-intensification appears possible.
Additionally, new updraft development is noted on the western flank
of the cell, which may also intensify and pose a threat for very
large (2 inch) hail and severe gusts. Given the elongated/straight
nature of regional wind profiles, the emergence of this new cell
hints that cell interactions and cold pool amalgamation may increase
over the next couple of hours as the new cell begins to split. This
may result in a very gradual transition from a supercellular to a
clustered/linear storm mode with an attendant increase in severe
wind potential as storms move further south/southeast. A few recent
high-res solutions hint at this transition, but confidence in this
scenario is somewhat limited at this point due to the isolated
nature of the convection.
..Moore.. 08/11/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...UNR...
LAT...LON 45330296 45560261 45620219 44519963 44069982 43780028
43730096 43780180 43870244 45330296
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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MD 1912 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR EASTERN IOWA INTO NORTHERN ILLINOIS
Mesoscale Discussion 1912
NWS Storm Prediction Center Norman OK
0907 PM CDT Mon Aug 10 2026
Areas affected...Eastern Iowa into northern Illinois
Concerning...Severe potential...Watch possible
Valid 110207Z - 110400Z
Probability of Watch Issuance...60 percent
SUMMARY...Convection developing in eastern Iowa will likely
intensify in the coming hours and could pose some severe threat for
portions of eastern Iowa into northern Illinois. Confidence in exact
evolution is limited, but watch issuance may need to be considered.
DISCUSSION...Latest regional reflectivity and GOES IR imagery shows
steady deepening of nascent convection across eastern IA along a
diffuse warm frontal zone. A recent 00 UTC DVN RAOB sampled weak
mixed-layer inhibition that is evidently being overcome by ascent
within the frontal zone as a nocturnal jet slowly strengthens. This
sounding also sampled extreme buoyancy and adequate deep-layer wind
shear for organized convection. Consequently, it seems likely that
further intensification will occur over the next 1-2 hours.
Moderate veering through the lowest 3 km is also noted in the
observed hodograph, which should support the potential for a
supercell or two capable of producing large hail and perhaps brief
tornadoes. The primary uncertainty regarding this potential is the
possibility of destructive storm interactions and clustering given
forecast storm motions largely along the zone of initiation. This
potential is hinted by recent solutions of the HRRR and RRFS, which
show initially semi-discrete cells growing upscale into northern IL
later this evening. Convective trends will continue to be monitored,
and watch issuance may be needed if robust supercells become more
imminent.
..Moore/Mosier.. 08/11/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LOT...MKX...DVN...ARX...DMX...
LAT...LON 41879229 41999275 42309288 42609273 42789230 42508890
42228873 41928879 41718893 41568910 41408941 41879229
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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