ACUS11 KWNS 112219
SWOMCD
SPC MCD 112218
SDZ000-NDZ000-MTZ000-112345-

Mesoscale Discussion 1935
NWS Storm Prediction Center Norman OK
0518 PM CDT Tue Aug 11 2026

Areas affected...Parts of far southeast MT into southern ND and far
northern SD

Concerning...Severe potential...Severe Thunderstorm Watch likely

Valid 112218Z - 112345Z

Probability of Watch Issuance...80 percent

SUMMARY...Trends are being monitored for watch issuance soon with
widely spaced supercells that have developed this afternoon. Very
large hail and severe gusts may occur with this activity.

DISCUSSION...An intense supercell has developed over far southeast
MT along/near a front extending eastward from a weak surface low
near KBIL, with a separate supercell having also recently developed
over south-central ND near the surface boundary. While surface
temperatures are not overly warm (generally in the 80s), modifying
the 18Z observed BIS sounding for current conditions suggests
minimal MLCIN is present along/south of the boundary in southern ND.
Enhanced mid-level west-northwesterly flow across the northern
Plains is supporting 40-50 kt of deep-layer shear, which will
continue to support supercells in the near term. Mid-level lapse
rates around 7.6 C/km in the 700-500 mb layer observed on the 18Z
BIS sounding and seasonably cool temperatures aloft have fostered
moderate to strong instability across southern ND (MLCAPE around
2000-3000 J/kg). Very large hail potentially up to 2-3 inches in
diameter will be possible with any sustained supercell, and storm
splitting appears probable given the strong westerly deep-layer
shear present/nearly straight mid-level hodographs observed.
Occasional severe gusts may also occur as low-level lapse rates
steepen further. Given ongoing convection, and the potential for
additional activity to develop/move eastward into southwest ND from
southeast MT, watch issuance is being considered soon.

..Gleason/Mosier.. 08/11/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!_hL0ePe13qK-MmJlomN2OxsHrN0Suthmw5rB_DNcndnS_M_FdQpJbjKdLybS-Hf8PQbyQ523swew4YF6OC0OXxv0BtU$ for graphic product...

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

LAT...LON 46000400 46080427 46400425 46630399 46880397 47130154
46589801 46029779 45729796 45629853 45630041 45970189
46000400

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)