ACUS11 KWNS 131919
SWOMCD
SPC MCD 131918=20
SDZ000-MTZ000-WYZ000-132045-

Mesoscale Discussion 0398
NWS Storm Prediction Center Norman OK
0218 PM CDT Mon Apr 13 2026

Areas affected...portions of extreme southeast Montana into extreme
northeast Wyoming and far western South Dakota

Concerning...Severe potential...Watch unlikely=20

Valid 131918Z - 132045Z

Probability of Watch Issuance...20 percent

SUMMARY...A localized severe threat may develop through the
afternoon. Severe gusts are the main threat, though a few instances
of hail and perhaps a landspout tornado are also possible.

DISCUSSION...Low-topped storms have recently developed near a
secondary surface low and a low-amplitude mid-level impulse
overspreads the northern High Plains. Ample surface heating has
allowed for deep boundary layer mixing, with surface dewpoints in
the 20s-40s F noted. These storms are likely high-based, and will be
capable of producing a few severe gusts due to evaporative cooling
within the deep/dry boundary layer. 19Z mesoanalysis depicts well
over 100 J/kg 0-3 km CAPE amid very high amounts of low-level
vertically oriented vorticity. Storms will likely be outflow
dominant due to evaporative cooling producing extensive cold pools.
However, any updrafts in this vorticity rich environment that can
avoid undercutting for appreciable periods of time may support a
landspout threat, as well as the potential for some hail. Given the
isolated nature of the severe threat, a WW issuance is not currently anticipated.

..Squitieri/Hart.. 04/13/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_bmS5X0PpHfeED-mCqU0azIIkXJLncu94WbrhuWdb_rs2f2qwwd6BaWQbuFTDXhuAf36XJq5Z= 0OGtaep04OEaKlFJfc$ for graphic product...

ATTN...WFO...UNR...BYZ...

LAT...LON 44710575 45410551 45830459 45940316 45770230 45360190
44950183 44570207 44300281 44160388 44250521 44710575=20

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


=3D =3D =3D
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