Subj : MESO: Mesoscale Discussion 1969
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Aug 17 2025 01:06:37

ACUS11 KWNS 170106
SWOMCD
SPC MCD 170106=20
ILZ000-WIZ000-IAZ000-170230-

Mesoscale Discussion 1969
NWS Storm Prediction Center Norman OK
0806 PM CDT Sat Aug 16 2025

Areas affected...portions of northeastern Iowa southwest Wisconsin
and northern Illinois

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

Valid 170106Z - 170230Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms forming along a trailing outflow boundary may
remain capable of sporadic hail and occasional strong wind gusts for
a few hours this evening.

DISCUSSION...As of 01 UTC, regional radar imagery showed several
clusters of storms had redeveloped along a trailing outflow boundary
from prior convection across portions of northern IL, eastern IA and
southwestern WI. Several of these storms have shown periods of
higher intensity with reports of hail over the last hour. This
threat should continue with occasional hail or damaging gusts as the
air mass along and south of the outflow remains very unstable with
4000-5000 j/kg of MUCAPE. Vertical shear, while not overly strong
(25-35 kt 0-6km agl), is sufficient for a mixed convective mode of
multicell clusters and transient supercell structures near the
boundary.

The tendency for developing storms to move eastward toward weaker
buoyancy suggests intensification of individual cells should be
relatively brief. Additionally, the strongest vertical shear remains
displaced farther north which should keep overall organization
limited. A WW is unlikely given the lack of a more focused/sustained
severe risk, but occasional hail and a damaging gust are possible.

...Lyons/Smith.. 08/17/2025

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!8KosPvf5q64VM8pWjvlMPPCkwnBQhpuECIzhjoFTLCg7KIBSyd_wc6GGtsS5haKuOniUZzaBu=
8FY3gVXB3APGbFWkZU$  for graphic product...

ATTN...WFO...LOT...MKX...DVN...ARX...

LAT...LON   41308897 41728984 42259068 42849174 43259169 43279015
            42868903 42028796 41488801 41278823 41308897=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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