Subj : MESO: Mesoscale Discussion 1822
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Mon Jul 28 2025 15:43:15

ACUS11 KWNS 281543
SWOMCD
SPC MCD 281542=20
SDZ000-NDZ000-MTZ000-281745-

Mesoscale Discussion 1822
NWS Storm Prediction Center Norman OK
1042 AM CDT Mon Jul 28 2025

Areas affected...southern North Dakota...adjacent northern South
Dakota...southeastern Montana

Concerning...Severe Thunderstorm Watch 550...

Valid 281542Z - 281745Z

The severe weather threat for Severe Thunderstorm Watch 550
continues.

SUMMARY...Storms now spreading across south central North Dakota
have undergone recent weakening.  It is still possible that this
activity could re-intensify while spreading eastward into early
afternoon, but this remains uncertain.

DISCUSSION...Strongest convection remains confined to a compact
area, near an associated meso-beta scale cyclonic circulation which
has been accompanied by a narrow swath of strong to severe gusts
along its southwestern periphery.  This is now passing near and to
the southwest/through south of Bismarck, though it has undergone
recently weakening based on radar trends.=20=20

It appears that weakening may be in response to updraft inflow of
more stable air.  Objective analysis does indicate some downstream
destabilization is underway, but forcing for convective development
is weak, and there is potentially substantive mid-level inhibition
near the northern periphery of a plume of very warm elevated
mixed-layer air advecting northeast of the Rockies.  This appears
roughly delineated by the +12 to +14 isotherms around 700 mb, which
is forecast to remain quasi-stationary to slowly shift north/east of
the North/South Dakota states border area into this afternoon.

Given these trends, persistence of upstream convection now spreading
near/north of Baker MT into southwestern North Dakota also remains
unclear.  However, this activity appears more likely to remain
rooted in warm advection, above boundary-layer air stabilized by
convective outflow.

...Kerr.. 07/28/2025

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!8I372I4BQ6LtcBYMCpv1o0qRpUY76UQXtuRChWYEcBSWS4U-WQnCQpQ65jYZEP4n4r31Eao7B=
ekdGxjG0kVEcxhmY44$  for graphic product...

ATTN...WFO...ABR...BIS...UNR...BYZ...

LAT...LON   46710051 46589814 45709832 45680050 45530219 45700350
            46030487 46530428 46470262 46710051=20

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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